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NDA/RWM/PWIPT/17/001 LLWR/NWP/138

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RWM/LLW Repository Ltd Report

Summary of previous work on problematic waste

Document preparation and approval

Prepared by:

Jenny Kent

Slimane Doudou

Checked by: Mark Cowper

Helen Cassidy

Approved by: Shaun Robarts

Document information

Revision: 5

Date: 27 March 2017

Contract number: RWM008045

Contractor: Galson Sciences Ltd

Publication tracking number: TN18506

Protective marking: No protective marking required

No protective marking required NDA/RWM/PWIPT/17/001 LLWR/NWP/138

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Document history

Status Revision Date Comments

Draft 1 31 October 2016 Draft for review by the IPT core team

Draft 2 7 December 2016

Draft for review by Community of Practice, Shaun Robarts (RWM), Simon Wisbey (RWM)

Draft 3 24 February 2017 Final draft

Final 4 3 March 2017

Final version, addressing minor comments from Mark Cowper

Final 5 27 March 2017 Final version, removing OFFICIAL markings


iii

Executive Summary

All Nuclear Decommissioning Authority (NDA) sites, and many non-NDA sites, have wastes for which no defined waste management route is either available or currently planned in detail, or for which existing solutions are suboptimal. These are wastes from across the radiological spectrum including Lower Activity Waste (LAW) and Higher Activity Waste (HAW). These wastes can be referred to as ‘problematic waste’. They may also be known locally on sites as ‘orphan waste’ or ‘waste requiring additional treatments’ (WRATs). In the context of this report, the term ‘problematic waste’ is used as an umbrella term to include all such wastes. Problematic wastes are identified by waste owners and, because each site has different waste management arrangements, a waste group that is currently problematic at one site may have a defined route at another site. Therefore, the inclusion of a waste group in this report does not mean that all similar wastes are problematic.

There are several reasons why wastes may be problematic, which have been used to inform the development of waste groups within an inventory of problematic waste:

wastes with an unknown provenance/inventory or insufficient characterisation information to enable appropriate waste routing are included in the bulk, mixed and historically conditioned/containerised waste groups, which comprise a significant proportion of the problematic waste inventory by volume; redundant transport containers may also fit within this category

wastes that have a specific additional chemical or physical hazard include mercury, asbestos, oils and oily waste, solvents and sources

wastes that are unsuitable for a standard treatment process include ion exchange resins, reactive metals, chloride and halide-based powders, and pyrochemical waste

wastes that pose issues to the disposability of a waste package include waste containing liquids, filters, bulk fines and particulates, absorbent materials, waste failing the Low Level Waste Repository (LLWR) discrete items limit, LAW graphite, fuel element debris (FED) and FED-contaminated wastes, pressurised waste, putrescible and cellulosic materials, lead and chemotoxic metals, plutonium-contaminated material (PCM) and LAW sources

wastes that pose operational or interim storage issues include miscellaneous activated components (MAC) with high dose rates, physically awkward wastes and metallic items, radium/thorium/americium-contaminated waste, sludges and tritium-contaminated waste

wastes that consist of complex mixtures of hazardous material include batteries, waste electrical and electronic equipment (WEEE), and some streams within the liquid-containing waste and PCM waste groups

The total volume of radioactive waste in the UK currently classified as “problematic” is estimated to be ~40,000 m3, however, waste which is problematic at one site may not be problematic at another site, as capabilities, infrastructure and programmes/strategies to deal with the waste vary. This report focuses on waste identified as being problematic predominantly for technical reasons, as opposed to as a result of uncertainty about their physical, chemical or radiological properties.

An Integrated Project Team (IPT) on problematic radioactive waste, being led on behalf of the NDA by Radioactive Waste Management Ltd (RWM) and LLW Repository Ltd, as defined in the NDA’s Higher Activity Waste Treatment Framework. The objective of the IPT is to develop a co-ordinated and improved approach to the industry-wide management of problematic radioactive waste. The IPT will act a focal point for a co-ordinated industry-


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wide approach and, through ongoing engagement with stakeholders, will establish a community of practice to enable solutions to be developed and delivered.

At the start of the IPT, it was recognised that significant work on problematic waste has previously been completed by individual organisations with responsibility for managing these wastes. However, there has been little integration and sharing of information and there is a clear benefit in collating and publishing this information in an accessible form. Wider communication of the context and current position for problematic wastes is also required to support the development of preferred strategic options.

This report summarises existing work on problematic waste, both in the UK and overseas, and provides sign-posting to where additional information can be found on treatment processes and technologies for specific problematic waste types.

This review has identified gaps in the availability of treatment or disposal routes for the following problematic waste groups1:

high-alpha contaminated oils

higher activity mercury wastes

lower activity waste containing >10% cellulose

higher activity putrescible waste

WEEE

pressurised waste

redundant transport containers

Only a limited range of management routes are currently available for batteries, MAC with high dose rates and physically awkward waste, waste failing the LLWR discrete items limit, containerised waste that may contain liquids (e.g. concrete-lined drums) and PCM that is not compatible with the baseline treatment option of supercompaction.

Barriers remaining to be overcome in implementing treatment or disposal options include:

insufficient characterisation data to support identification of appropriate treatment or disposal routes for some problematic wastes

constraints within the conditions for acceptance (CFA) for treatment and disposal facilities

the availability of treatment technologies for specific problematic wastes (as listed above)

transport (including availability of suitable containers, compliance with safe fissile mass and pressure requirements in the transport regulations)

1 Based on a review of published literature available in December 2016.


v

List of Contents

Executive Summary iii

List of Contents v

List of acronyms vii

1 Introduction 1

1.1 What is a problematic waste? 1

1.2 Strategic context 1

1.3 Objective of this report 2

1.4 Report structure 2

2 Previous work on problematic wastes 3

2.1 Development of a UK problematic waste inventory 3

2.2 Available treatment technologies 5

3 Current understanding for specific problematic waste groups 14

3.1 Overview of the 2016 problematic waste inventory 15

3.2 Oils and oily wastes (groups 10, 20 and 35) 21

3.3 Mercury wastes (group 21) 22

3.4 Solvents (group 33) 23

3.5 Aqueous liquids/liquid-containing waste and chemicals (groups 2 and 7) 24

3.6 Ion exchange material (group 17) 25

3.7 Pyrochemical waste (group 27) 26

3.8 Chloride and halide-based powders (group 8) 26

3.9 Radium/thorium/americium-contaminated waste (group 29) 27

3.10 Tritium-contaminated waste (group 36) 27

3.11 Filters (group 14) 28

3.12 Bulk fines and particulates (group 5) 28

3.13 Sludge (group 32) 29

3.14 Lead and other chemotoxic metals (group 18) 30

3.15 Sources (group 34) 31

3.16 MAC and physically awkward wastes (groups 19 and 25) 32

3.17 Metallic waste (group 22) 33

3.18 Asbestos (group 3) 33

3.19 FED and FED-contaminated wastes and uranics (groups 13 and 37) 34

3.20 Plutonium-contaminated materials (PCM) (group 24) 35

3.21 Waste failing the LLWR discrete items limit (group 11) 35


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3.22 Graphite (group 15) 37

3.23 Absorbent materials (group 1) 38

3.24 Putrescible and cellulosic waste (group 26) 38

3.25 Batteries (group 4) 39

3.26 Electrical and WEEE (group 12) 39

4 International perspective 40

4.1 French programme 40

4.2 US DOE programme 41

4.3 Experience of specific technologies in use worldwide 42

5 Uncertainties in problematic waste management 45

5.1 Inadequate characterisation 45

5.2 Time of arising 46

5.3 Availability of treatment or disposal facilities 46

5.4 Availability of transport containers 46

6 Summary and conclusions 47

7 References 50

Appendix A Bibliography A-1

A1 Generic references A-2

A2 Technology-specific references A-11

A3 Waste group specific references A-24


vii

List of acronyms

ACW active chemical waste

AEA atomic energy act

AGR advanced gas-cooled reactors

ALARA as low as reasonably achievable

ANDRA The National Radioactive Waste Management Agency, France

APS advanced polymer system

AWE Atomic Weapons Establishment

BAT best available technique

BEP box encapsulation plant

BNL Brookhaven National Laboratory, USA

CCIM cold crucible induction melter

CEA The French Alternative Energies and Atomic Energy Commission

CENTRACO nuclear centre for processing and conditioning low-level radioactive waste, France

CFA conditions for acceptance

CFR code of federal regulations

DCP Dounreay cementation plant

DILWEP decommissioning intermediate level waste encapsulation plant

DRP direct research portfolio

DSRL Dounreay Site Restoration Ltd

EARP enhanced actinide removal plant

EDF Électricité de France

EIS environmental impact statement

FED fuel element debris

FSC final site clearance

GDF geological disposal facility

GLEEP graphite low energy experimental pile

GNS Gessellschaft für Nuklear-Service

GRS Gesellschaft für Anlagen-und Reaktorsicherheit

GSL Galson Sciences Ltd

GWPS generic waste package specification

HAW higher activity waste

HE high explosive

HEC head end cells

HEPA high efficiency particulate air

HIP hot isostatic pressing


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IAEA International Atomic Energy Agency

IFR integral fast reactor

IGM impermeable graphite matrix

ILW intermediate level waste

IPT integrated project team

ISIS pulsed neutron and muon source at the Rutherford Appleton Laboratory in Oxfordshire

LAW lower activity waste

LDR land disposal restriction

LLMW low-level mixed waste

LLNL Lawrence Livermore National Laboratory, USA

LLW low-level waste

LLWR low level waste repository

LoC letter of compliance

MAC miscellaneous activated components

MEP Magnox encapsulation plant

MRF materials recycling facility

MW mixed waste

NDA Nuclear Decommissioning Authority

NMED New Mexico Environment Department

NNL National Nuclear Laboratory

NPP nuclear power plant

NWP national waste programme

OPC ordinary portland cement

ORNL Oak Ridge National Laboratory

OWL oil waste leaching

PCB polychlorinated biphenyls

PCM plutonium-contaminated material

PFA pulverised fuel ash

PNCC passive neutron coincidence counting

PNGMDR the national radioactive materials and waste management plan, France

POCO post-operational clean out

R&D research and development

RAL Rutherford Appleton Laboratory, UK

RCRA resource conservation and recovery act

RHILW remote handled intermediate level waste

RSRL Research Sites Restoration Ltd


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RWM Radioactive Waste Management Ltd

RWMD Radioactive Waste Management Directorate

SAMMS Self-Assembled Monolayers on Mesoporous Supports

SCF sulfhydryl cotton fiber

SIAL silicoaluminate geopolymer

SILWE solid intermediate level waste encapsulation

SLCs site license companies

SNL Sandia National Laboratories, USA

SNM special nuclear material

TBP tributyl phosphate

TEC ternary eutectic chloride

THOR thermal organic reduction

TILWSP transportable intermediate level waste solidification plant

TRU transuranic

UKAEA UK Atomic Energy Authority

UKRWI UK radioactive waste inventory

US DOE United States Department of Energy

US EPA United States Environmental Protection Agency

UVF Ulchin vitrification facility, Korea

VES vinyl ester styrene

VLLW very low-level waste

WAC waste acceptance criteria

WAGR Windscale advance gas-cooled reactor

WEEE waste electrical and electronic equipment

WEP waste encapsulation plant

WAMAC waste monitoring and compaction plant

WILREP wet intermediate level waste retrieval and encapsulation plant

WIMS waste information management system

WIPP waste isolation pilot plant, USA

WPEP waste packaging and encapsulation plant

WPS waste package specification

WRACS waste receipt assay characterisation and supercompaction

WRATs waste requiring additional treatments

WTC waste treatment complex, Sellafield


1

1 Introduction

1.1 What is a problematic waste?

All Nuclear Decommissioning Authority (NDA) sites, and many non-NDA sites, have wastes for which no defined waste management route is either available or currently planned in detail, or for which existing solutions are suboptimal. These are wastes from across the radiological spectrum including Lower Activity Waste (LAW) and Higher Activity Waste (HAW). These wastes can be referred to as ‘problematic waste’. They may also be known as ‘orphan waste’ or ‘waste requiring additional treatments’ (WRATs). In the context of this report, the term ‘problematic waste’ is used as an umbrella term to include all such wastes.

There are several reasons that wastes may be problematic, for example the waste may:

have an unknown provenance or inventory (e.g. concrete lined drums originally destined for sea disposal) or insufficient characterisation information to enable appropriate waste routing

have a specific additional chemical or physical hazard (e.g. pyrophoric material)

be unsuitable for a standard treatment process (e.g. reactive metals which are unsuitable for encapsulation by standard cementitious grout)

pose issues to the disposability of a waste package (e.g. particulates)

pose operational or interim storage issues (e.g. radon emanating waste)

consist of complex mixtures of hazardous material or waste with unknown provenance

Problematic wastes are identified by waste owners and, because each site has different waste management arrangements, a waste group that is currently problematic at one site may have a defined route at another site. Therefore, the inclusion of a waste group in this report does not mean that all similar wastes are problematic.

1.2 Strategic context

The need to improve the management of problematic wastes in the UK is set out in strategies for the management of lower and higher activity wastes, developed for the UK and NDA estate respectively [1, 2]. The total volume of problematic radioactive waste in the UK is estimated2 to be ~40,000m3, however, waste which is problematic at one site may not be problematic at another site, as capabilities, infrastructure and programmes/strategies vary. The absence of an industry-wide approach to the overall management and delivery of solutions has led to inconsistent approaches across the SLCs and potential opportunities for optimised shared solutions have not been realised.

Some Site Licence Companies (SLCs) have made significant steps in treating problematic wastes, and many technical solutions have been found. Through work conducted by Radioactive Waste Management Ltd (RWM), the Low Level Waste (LLW) Repository Ltd National Waste Programme (NWP) and the NDA’s Direct Research Portfolio, further technical solutions have been found and a number of research needs have been identified. However, the absence of an industry-wide approach to the overall management and

2 This volume estimate (rounded to the nearest 1,000 m3) is based on inventory analyses

undertaken in 2015 by two separate studies, which identified approximately 13,700 m3 of LLW [7]

and 26,800 m3 of HAW [8]. It is noted that the waste is often not well characterised, many entries

do not have volumes specified and there is potential for uncertainty on categorisation to lead to duplication between the two inventories.


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delivery of solutions has led to inconsistent approaches across the SLCs and potential opportunities for optimised shared solutions have not been realised.

The management of most problematic radioactive waste is not currently planned in detail. However, for some sites this activity is on the critical path for site decommissioning or preparations for entry into Care and Maintenance. Delays to decommissioning programmes may result in extended operational periods before reaching interim or final end states, with potentially significant impacts on SLC costs. If a co-ordinated approach to the management of problematic radioactive waste is developed in the short term, there is potential to remove these activities from the critical path, to save time and money on the treatment of these wastes, and to reduce risks and uncertainties. This case for change is set out in the NDA Gate A paper on problematic waste management [3].

An Integrated Project Team (IPT) on problematic radioactive waste, being led on behalf of the NDA by RWM and LLW Repository Ltd, as defined in the NDA’s Higher Activity Waste Treatment Framework [4]. The objective of the IPT is to develop a co-ordinated and improved approach to the industry-wide management of problematic radioactive waste.

Waste owners outside the NDA estate also hold problematic radioactive waste. If the NDA strategic approach regarding problematic waste includes collaboration with these non-NDA organisations, there is a potential to maximise overall benefit and minimise total cost and NDA cost. Therefore, the IPT will act as a focal point for a co-ordinated industry-wide approach and, through ongoing communication with stakeholders, will establish a community of practice to enable solutions to be developed and delivered.

At the start of the IPT, it is recognised that significant work on problematic waste has previously been completed by individual organisations with responsibility for managing these wastes. However, there has been little integration and sharing of information and there is a clear benefit to collating and publishing this information in an accessible form. Wider communication of the context and current position for problematic wastes is also required to support the development of preferred strategic options.

1.3 Objective of this report

The objective of this report is to summarise existing work on problematic waste and provide sign-posting to where additional information can be found on specific problematic waste groups. This included work done in the UK and overseas. Data sources were limited to those in the published literature, as available in December 2016.

An integrated problematic waste management approach has been adopted. This is in line with the approach laid out in NDA’s Strategy (Section 3.8.4 of [1]) and recognises that similar activities are likely to be required to deliver solutions to enable optimised management of both problematic LAW and HAW.

1.4 Report structure

This report is structured as follows:

Section 2 provides a chronological description of development of problematic waste inventories, analysis of opportunities and waste type-specific studies by RWM, LLW Repository Ltd, NDA and waste owners

Section 3 summarises the UK’s problematic waste inventory and identifies work done and treatment routes identified previously for specific problematic waste groups

Section 4 briefly summarises international programmes of work on problematic waste management in France and the USA (focusing on programme priorities and



strategies as examples of work overseas relevant to specific problematic waste groups have been included in Section 3)

Section 5 highlights uncertainties relating to problematic waste management identified within previous work

Section 6 presents the conclusions of this review and outlines the work planned within the problematic waste IPT

Appendix 1 provides a detailed bibliography of previous work, including a short summary of each report identified in this review

2 Previous work on problematic wastes

2.1 Development of a UK problematic waste inventory

Work completed by RWM’s HAW programme (previously the Upstream Optioneering project), the LLW Repository Ltd NWP and through the NDA’s Direct Research Portfolio (DRP) has developed an inventory for problematic wastes, including both HAW and LLW.

In 2011, the Upstream Optioneering project identified an opportunity to improve the management of “orphan” wastes [5]. In 2012/13, this work was completed by the ASSIST consortium, liaising with waste owners to obtain information on volumes, physical, chemical and radiological properties, dates of arising and any relevant historical information or R&D work undertaken to support plans for treatment. Following compilation of an inventory database for problematic HAW, the report developed 35 categories of “orphan” waste and identified potential treatment technologies for each one [6].

An initial version of the LAW Problematic Waste inventory was developed in 2013/14 by the NWP as a response to the similar work undertaken for the HAW inventory. To support this task, Amec undertook a review of the United Kingdom Radioactive Waste Inventory (UKRWI) to identify potential problematic waste streams and in parallel known points-of-contact at each of the LLW Repository Ltd customer organisations were contacted to request information on their inventories. These information sets were then summarised into the database developed by RWM for HAW. The initial inventory was not published but NWP has since undertaken annual updates of the problematic LAW inventory (e.g. [7]). The 2015/16 LAW inventory contained approximately 13,700 m3 of waste, with significant proportions of undefined waste (~54% by volume), asbestos (~21%) and bulk waste (~16%, e.g. contaminated soils, concrete, rubble) [7].

In 2014/15, the NDA DRP funded an update of the problematic HAW inventory by Galson Sciences Ltd (GSL) and National Nuclear Laboratory (NNL) [8]. The information sought from the waste owners included (in addition to updating the 2012 data), the likely retrieval time of the wastes, the commencement date of preparatory work (i.e. when necessary research and development (R&D), design or detailed planning activities for waste treatment must begin), and the latest dates for treatment that would be necessary in order to achieve key dates in the waste owners’ work programmes and strategies. The 2015 HAW inventory contained approximately 26,800 m3 of waste, with significant proportions of sludge (~43% by volume), containerised waste (~17%) and high fissile content wastes (~13%) [8].

In 2016, the LAW and HAW inventories were both updated as one of the initial activities conducted by the problematic waste IPT; these data were analysed to identify priority waste types and inform the development of the IPT work programme; this work has not been published.



Problematic HAW was categorised by Galson Sciences Ltd and NNL into 34 different generic groups, each having characteristic properties and common issues associated with treatment, processing and packaging that contribute to it being considered problematic [8]. These were further grouped according to their characteristics, as follows:

high-hazard (potentially mobile) waste: bulk fines and particulates, oils and solvents

high-volume, high-hazard waste: sludges

multi-site wastes: tritium-contaminated wastes; high fissile content wastes, ventilation filters and ion exchange materials

opportunities to apply the waste hierarchy: materials for which decontamination and recycling would address disposability issues, including lead and mercury

opportunities for rapid progress (quick wins): radium/thorium wastes and sealed sources

wastes benefiting from unpacking, sorting and segregation: containerised waste; concrete-lined drums; undefined waste; miscellaneous activated components (MAC) and physically awkward items.

Similar groups were identified for problematic LAW by LLW Repository Ltd, noting that some HAW groups are not applicable and that additional categories are identified, such as batteries and waste exceeding the discrete items limit in the Low Level Waste Repository (LLWR) Waste Acceptance Criteria (WAC) [7]. The top problematic LLW groups by volume can be seen in Figure 1. This should be used for guidance as it only considers wastes with specified volumes and therefore carries a high degree of uncertainty. Waste that has not yet been characterised is largely included in the “other” and “undefined” groups. Some streams are also included in both the LAW and HAW inventories as their radiological classification is not yet known.



Figure 1 Indicative volumes of problematic LLW in the FY2015/16 inventory [7]3

2.2 Available treatment technologies

In 2014/15, NNL, as part of a work programme funded through the NDA DRP, also considered treatment technologies that were available and their potential suitability for the problematic HAW groups identified above [9]. This report examines the basis for the WAC at existing or planned UK treatment plants, and considers whether there may be opportunities to route problematic radioactive wastes from all UK sites through existing treatment facilities and processes, or to modify existing treatment processes and WAC to widen the range of wastes that can be accepted. In addition, the planned operational timescales for treatment facilities, their extent of utilisation, and the scope for lifetime extension are important factors that may constrain when additional waste streams could be received and processed.

The following facilities relevant to the management of problematic waste are included in [9]:

At Sellafield:

o Operational plants: Magnox Encapsulation Plant (MEP), Wastes Encapsulation Plant (WEP), Waste Packaging and Encapsulation Plant (WPEP), Waste Treatment Complex (WTC), Waste Monitoring and Compaction Plant (WAMAC), Decontamination Centre

o Plants in development: Box Encapsulation Plant (BEP), NNL Windscale Laboratory and Central Laboratory including Hot Isostatic Pressing (HIP) and Geomelt® demonstration facilities

3 In the FY2015/16 problematic waste inventory, “other” was defined as waste chemicals and/or materials that did not fit in another category, while “undefined waste” often had many unknowns, and was poorly characterised.



o Conceptual plants: Bulk Uranic Fuel Treatment plant, Decommissioning intermediate level waste Encapsulation Plant (DILWEP), future plutonium-contaminated materials (PCM) Treatment and Processing Plants

LLWR (disposal facility and grouting plant)

Springfields: Westinghouse and NNL waste and residue processing and treatment facilities

Dounreay: Dounreay Cementation Plant (DCP), Waste Receipt Assay Characterisation and Supercompaction (WRACS) facility

Harwell: Waste Encapsulation Plant (WEP)

Magnox Ltd reactor sites:

o Bradwell: fuel element debris (FED) dissolution

o Trawsfyndd: Transportable Intermediate Level Waste Solidification Plant (TILWSP)

o Hunterston A: Solid Intermediate Level Waste Encapsulation (SILWE) plant, Wet Intermediate Level Waste Retrieval and Encapsulation Plant (WILREP)

Treatment facilities operated by a limited number of UK-based commercial organisations, including Tradebe Inutec at Winfrith (e.g. mercury treatment and detritiation of wastes), Cyclife UK Ltd metal recycling facility at Lillyhall, Cumbria (previously owned by Studsvik) and hazardous waste landfill sites, e.g. Sita Ltd’s Clifton Marsh site near Preston, Lancashire

Figure 2 presents a matrix comparing the WAC for these facilities against HAW problematic waste groups. This can be used to identify the potential for each of these waste groups to be treated in existing facilities (Table 2 of [9]). For HAW, the review identified that the following problematic radioactive waste types appear to have few options for treatment, and therefore a more detailed viability assessment may need to be conducted for the options that have been identified and/or R&D to develop additional treatment options may need to be prioritised [9]:

mercury waste

zinc bromide4

contaminated bulk oil

tritiated oil

solvents

undefined wastes5

A similar study to identify treatment technologies for problematic LAW was undertaken in 2014/15 [10]. This work identified that the highest priority waste groups for stakeholders are:

1. contaminated oil and oil-contaminated materials

2. inorganic and organic ion exchange resins

3. radium-bearing wastes

4 Zinc bromide no longer appears in the 2016 problematic waste inventory.

5 Noting that the reason that undefined wastes are problematic is a lack of understanding of the chemical, physical and radiological properties of the waste and therefore routes for its management cannot be identified until further characterisation is completed.



4. surface-contaminated items

5. waste failing the discrete item limit (as specified within the WAC for the LLWR)

6. asbestos

For the first four key waste groups, the technology mapping study identified [10]:

optimum technologies for managing the key waste streams, based on an assessment of attributes relevant to the development, implementation and application of the technologies

technology gaps and recommendations on progressing and implementing technologies in order to facilitate earlier management of the waste

that better characterisation is needed for a significant number of the waste streams, and with improved characterisation, a proportion may be able to be managed through existing waste routes

that wastes from different owners could be collated and processed together; either when waste technologies are applicable to several waste types or where wastes of similar characteristics are present at different facilities, which has the potential to open new routes higher up the waste hierarchy (e.g. disposal to hazardous waste landfill rather than to the LLWR)

Table 3 of [10] provides a summary of the relevant treatment technologies for a range of LLW problematic groups, shown in Figure 3. While Figures 3 and 4 both use a red, amber, green (RAG) scale, the definitions that apply to each of the colours differ between the two studies.

Appendix 1 of reference [10] includes “wiring diagrams” for each of the key waste groups to illustrate the technologies available for the management of these wastes and the gaps and risks to deployment of those technologies (an example is included in Figure 4).


8

Figure 2 Summary table for problematic HAW study illustrating potential compatibility for generic problematic waste groups at specific treatment facilities using a RAG scale [9]. Acronyms are defined in the list on p. vii.

Sellafield Ltd

LL

WR

Sp

rin

gfi

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s

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Harw

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WE

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Tra

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ny

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WIL

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1 Bulk Fines or Particulates

2 Reactive Metals

3 Pyrophoric Material

4 Organic Ion Exchange Materials

5 Inorganic Ion Exchange Material

6 Radium/Thorium/Americium Contaminated Waste

7 ILW Fuel

8 Tritium Contaminated Waste

9 Pyrochemical Wastes

10 Halide-Based Fire Suppressant Powders

11 Mercury Wastes

12 Contaminated Bulk Oil

13 Material Contaminated with Oil

14 Tritiated Oil

15 Ventilation Filters

16 Solvents

17 Zinc Bromide

18 Sludge

19 Putrescible and Cellulose Waste

20 Batteries

21 Lead

22 Isotope Cartridges

23 MAC

24 Sealed Sources

25 Graphite

26 Asbestos

27 Concrete Lined Drums

28 Containerised Waste



Sellafield Ltd

LL

WR

Sp

rin

gfi

eld

s

DSRL

Harw

ell

WE

P

Hunterston

Tra

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ny

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WS

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Lilly

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Win

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SIL

WE

WIL

WR

EP

29 High Fissile/Moderator/Heat Waste

30 Pressurised Waste

31 Aqueous Liquids Including Bottles of Liquid

32 Physically Awkward Waste

33 Undefined Waste

34 Absorbent Material

Key

Problematic radioactive waste type is likely to be compatible with the treatment facility and it is worth investigating the feasibility of using the plant for treatment of specific wastes within that group in more detail.

Problematic radioactive waste type could be made to be compatible with the treatment facility but the plant is not ideal for this type of problematic radioactive waste, e.g. particulate waste could be dispersed on solid wastes allowing vibrogrouting or waste can be annulus grouted. Worth consideration if better routes are not available.

Problematic radioactive waste type is incompatible with the existing process.

† These plants are currently licensed to treat solid LLW only, through characterisation and supercompaction.

‡ These are commercial organisations that have multiple treatment facilities. They are currently licensed to treat LLW and potentially certain types of high activity waste (HAW).



Figure 3 Summary table for problematic LLW, demonstrating how potential compatibility is illustrated using a RAG scale (from [10] with minor edits). A red, amber and green colour coding has been applied to visually present the technologies that are deemed more appropriate, with green being most relevant, red being least relevant but feasible. Unscored (white) options are deemed not to

be relevant or suitable for management of that specific waste group. Acronyms are defined in the list on p. vii.

Waste

Gro

up

Oil

Para

ffin

Oily

slu

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Oily

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r

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ent slu

dge

Sea d

isposal packages

Mild

ste

el

Me

tals

Cd s

heetin

g

Cd lin

ed p

oly

thene b

ox

Me

tal gauge f

ilters

Fin

e f

ilters

PW

TP

fin

e filt

ers

Filt

er

resid

ues

Encapsula

ted r

esin

s

Resin

im

mers

ed in

w

ate

r

Dovex r

esin

U A

ctive R

esin

Ze

olit

e r

esin

Mis

c. re

sin

Chro

ma

togra

phy r

esin

s

Resin

beads

Clin

optilo

lite

Pyro

chem

ical S

lag

Calc

ium

flu

orid

e

Ra c

onta

min

ate

d w

aste

Encapsula

ted liq

uor

Surf

ace c

onta

min

ate

d

tanks

Whessoe t

ank b

ases

Vessels

conta

min

ate

d

with e

xplo

siv

es

Na/K

Pum

ps/V

alv

es

Gra

nite b

lock

Sulp

huric a

cid

Nitric a

cid

Rust

rem

over

Flo

or

coatin

g

Spra

yable

coatin

g

Rusto

leum

TE

CH

NO

LO

GIE

S

CH

EM

ICA

L

Acid digestion

Acid washing

Alcohol washing

Alkaline hydrolysis

Amalgamation with Zn or Cu

Arvia

Calcination and sintering

Carbonation

Caustic process

Modulox

Chemical decontamination sol.

Chemisorbing surface wipes

Detergent solutions

Dissolution

Distillation

Electro-chemical treatment

Filtration

Metal hydrides

Oxidation

Pinhole filtration



Waste

Gro

up

Oil

Para

ffin

Oily

slu

dge

Oily

wate

r

Oil,

absorb

ent, g

rease

and o

ily w

ate

r

Oil/

wate

r/gly

col m

ix

Hazard

ous

oils

/chem

icals

Oil

soaked w

aste

Cem

ente

d w

ate

r

treatm

ent slu

dge

Sea d

isposal packages

Mild

ste

el

Me

tals

Cd s

heetin

g

Cd lin

ed p

oly

thene b

ox

Me

tal gauge f

ilters

Fin

e f

ilters

PW

TP

fin

e filt

ers

Filt

er

resid

ues

Encapsula

ted r

esin

s

Resin

im

mers

ed in

w

ate

r

Dovex r

esin

U A

ctive R

esin

Ze

olit

e r

esin

Mis

c. re

sin

Chro

ma

togra

phy r

esin

s

Resin

beads

Clin

optilo

lite

Pyro

chem

ical S

lag

Calc

ium

flu

orid

e

Ra c

onta

min

ate

d w

aste

Encapsula

ted liq

uor

Surf

ace c

onta

min

ate

d

tanks

Whessoe t

ank b

ases

Vessels

conta

min

ate

d

with e

xplo

siv

es

Na/K

Pum

ps/V

alv

es

Gra

nite b

lock

Sulp

huric a

cid

Nitric a

cid

Rust

rem

over

Flo

or

coatin

g

Spra

yable

coatin

g

Rusto

leum

Salt extraction

SAMMS

Solidification

Solvent extraction process

Stabilisation using sulphur

Supercritical water oxidation

Thermochemical treatment

Water vapour –nitrogen

Wet oxidation

HIG

H T

EM

PE

RA

TU

RE

Incineration

Melting

Molten salt oxidation

Plasma treatment

Pyrolysis

Spray burning

Steam reforming

Vitrification

IMM

OB

ILS

AT

ION

Cementation

Compaction in clay

Drying agents

Geopolymerisation

Macroencapsulation

Microencapsulation

Nochar polymers

TECHNOLO

GIES

CH

EM

ICA

L



Waste

Gro

up

Oil

Para

ffin

Oily

slu

dge

Oily

wate

r

Oil,

absorb

ent, g

rease

and o

ily w

ate

r

Oil/

wate

r/gly

col m

ix

Hazard

ous

oils

/chem

icals

Oil

soaked w

aste

Cem

ente

d w

ate

r

treatm

ent slu

dge

Sea d

isposal packages

Mild

ste

el

Me

tals

Cd s

heetin

g

Cd lin

ed p

oly

thene b

ox

Me

tal gauge f

ilters

Fin

e f

ilters

PW

TP

fin

e filt

ers

Filt

er

resid

ues

Encapsula

ted r

esin

s

Resin

im

mers

ed in

w

ate

r

Dovex r

esin

U A

ctive R

esin

Ze

olit

e r

esin

Mis

c. re

sin

Chro

ma

togra

phy r

esin

s

Resin

beads

Clin

optilo

lite

Pyro

chem

ical S

lag

Calc

ium

flu

orid

e

Ra c

onta

min

ate

d w

aste

Encapsula

ted liq

uor

Surf

ace c

onta

min

ate

d

tanks

Whessoe t

ank b

ases

Vessels

conta

min

ate

d

with e

xplo

siv

es

Na/K

Pum

ps/V

alv

es

Gra

nite b

lock

Sulp

huric a

cid

Nitric a

cid

Rust

rem

over

Flo

or

coatin

g

Spra

yable

coatin

g

Rusto

leum

Organic polymers

PH

YS

ICA

L

Blasting

Compaction / supercompaction

Drying

Electrothermal cutting

Freezing

Hot isostatic pressing

Laser ablation

Mechanical cutting

Mechanical separation

Reactive strippable coating

Seal in polyethylene container

Segregation

Shredding

OT

HE

R

Freon cleaning

Limit of content

Microwave treatment

OWL process

Dew drops

Plasma vitrification

TECHNOLO

GIES



Figure 4 Example process wiring diagram for pyrolysis of oils [10].


14

3 Current understanding for specific problematic waste groups

This section first summarises the 2016 problematic waste inventory for both HAW and LAW to provide an overview and context for the subsequent discussions. In particular, this includes indicative volumes for each waste group (noting that many streams in the inventory do not include volume data).

Previous work and approaches that have been adopted for the management of waste groups identified as being problematic predominantly for technical reasons, as opposed to as a result of uncertainty about their physical, chemical or radiological properties, are discussed in this section, with an emphasis on potential treatment routes. It should be noted that the following problematic wastes are not included in this report:

those that are not included in the 2016 problematic waste inventory as a result of successful treatment, noting that there is relevant experience within the nuclear industry – this includes alkali metals (e.g. NaK coolant), isotope cartridges and zinc bromide, used as shielding in cell windows

bulk, mixed and historically conditioned/containerised waste groups, which comprise a significant proportion of the problematic waste inventory by volume – these waste groups are problematic predominantly due to the lack of characterisation data that would enable an appropriate management route to be selected (uncertainties are discussed further in Section 0)

pressurised waste or redundant transport containers, as no treatment technologies or management routes have been identified

The information in this section has been collated from the following sources:

work on specific problematic waste groups commissioned by RWM, LLW Repository Ltd and NDA, through the DRP

studies undertaken by waste owners, some of which have resulted in specific groups of problematic waste now having a treatment or disposal route and so no longer being classed as problematic waste

work on problematic wastes collated by IAEA and conducted by other international waste management organisations, including Areva, the French Alternative Energies and Atomic Energy Commission (CEA), Gessellschaft für Nuklear-Service (GNS), Gesellschaft für Anlagen-und Reaktorsicherheit (GRS) and the US Department of Energy (US DOE).

Treatment facilities that may be suitable for the management of each waste group are shown in Figure 2 for HAW and Figure 3 for LAW and are not repeated in this section, noting that waste group titles differ slightly between those developed for the previous studies and the consolidated set developed by the IPT and shown in Table 1. Detailed descriptions of the WAC for these facilities are provided in reference [9] for HAW. For LAW, reference [10] is a summary of a more detailed unpublished report.

More detailed information is included in Appendix A, together with sign-posting towards any work done to date regarding any of the problematic waste groups shown in Table 1. Remaining gaps in the information presented are highlighted within this section and listed in Section 6. Information is also needed on potential management options for pressurised waste.



3.1 Overview of the 2016 problematic waste inventory

A summary of the data provided by waste owners in response to the 2016 data call for the LAW and HAW problematic waste inventory is provided in Table 1. This inventory is produced independently of the UKRWI and is not related to the 2016 UKRWI update. The problematic waste inventory will not be published in full.

In Table 1, waste groups are listed alphabetically; however, in the rest of this section they are presented as addressed in previous work (i.e. with similar groups discussed together) and with the highest priority and most well understood groups first.


16

Table 1 Summary of 2016 problematic waste inventory data by group. For many waste streams, information on volumes was not provided and so the volume figures do not represent the total volumes, only those entries where the volume is quantified.

ID Problematic waste group

Description Reason waste is problematic Total

reported volume (m

3)

No. of streams

1 Absorbent material

Cloths, pads, swabs and desiccants.

Particulate material may not become fully immobilised using standard large scale encapsulation processes. Absorbed liquids could be expressed under pressure if not suitably treated

No data 4

2 Aqueous liquids and liquid containing waste

Aqueous liquids; bottles of liquid found in otherwise solid, dry waste.

Liquids are often not compatible with existing solid waste processes. They are also not disposed of in a liquid state

No data 12

3 Asbestos Contaminated or activated asbestos wastes.

Asbestos is a hazardous material that needs to be managed during the packaging/treatment process. Restrictions on disposal of some types of asbestos at LLWR.

No data 18

4 Batteries All types of batteries including batteries used in monitoring equipment and plutonium batteries.

Batteries contain heavy metals (e.g. cadmium, mercury, silver and lead) which are hazardous materials. This hazard may need to be managed during the packaging/treatment process. Restrictions on disposal of some heavy metals at LLWR and a GDF.

1 7

5 Bulk fines or particulates

Fines, particulate, vacuum cleaner bag contents, filings, sawdust, sand.

Particulate material may not become fully immobilised using standard large scale encapsulation processes.

32 14

6 Bulk waste Excavation, construction and demolition waste, usually present in large volumes.

Uncertainty regarding ability to demonstrate compliance with the WAC for LLWR for some components of these large volume waste streams. Further characterisation is likely to be needed.

No data 23

7 Chemicals

Chemicals that do not fit in another category e.g. waste chemicals from analysis and research, decontamination reagents, calcium fluoride.

Often small volumes of many different chemicals that need further characterisation and identification of appropriate disposal routes. Low priority waste streams.

18 25

8 Chloride and halide-based powders

NaCl based fire extinguishant for metal fires; Ternary Eutectic Chloride (TEC) powder for extinguishing glove box fires.

Particulate material may not become fully immobilised using standard large scale encapsulation processes.

No data 1





reported volume (m

3)

No. of streams

9 Containerised waste

Waste already in drums, cans, or paint tins, that was not packaged in accordance with a LoC. Often very little inventory data, as waste was packaged many years ago.

Further characterisation is needed. For historically containerised waste, uncertainty regarding the package inventory may mean that waste requires intrusive characterisation or has to be unpacked.

118 5

10 Contaminated oil Oil contaminated with radioactive material (excludes tritiated oil). For LAW, classed as oil unsuitable for incineration.

Further characterisation may be needed to identify whether oils meet the WAC for incineration. If dose rates are too high, there may not be treatment routes available and oils may not be compatible with standard large scale encapsulation processes.

127 35

11 Waste failing the LLWR discrete item limit

Wastes (such as large metallic items, historically conditioned waste etc.) which do not meet the discrete item limit criteria in the LLWR WAC.

Waste does not meet WAC for disposal at LLWR and is generally higher-activity LLW which may preclude alternative treatment.

39 9

12 Electrical and WEEE

Contaminated electrical items, including fluorescent tubes, x-ray tubes, battery chargers and printers/laptops.

Waste may be contaminated, often has a complex geometry that is difficult to swab effectively and contains a mixture of different materials.

3 7

13 FED and FED-contaminated waste

Fuel element debris and secondary waste from treatment of FED, contaminated gravel.

Waste contains reactive metals and potentially fuel particles, which may not be compatible with standard encapsulation processes.

618 24

14 Filters High Efficiency Particulate Air (HEPA) and charcoal filters, also cartridge filters from active effluent processing.

Filters may be loaded with significant quantities of fine particulate that may not be immobilised for packaging using standard encapsulation processes.

84 24

15 Graphite Waste of which the majority is graphite.

Graphite has high C-14 and Cl-36 inventories, which are volatile radionuclides. Much of the problematic waste graphite exceeds the LLWR WAC limits for these nuclides.

No data 12

16

Historically conditioned (containerised and encapsulated) waste

These are wastes which have been historically encapsulated and / or stored in concrete lined drums (e.g. "sea disposal drums" that were created before 1983 and were originally destined to be disposed of at sea).

Original disposal route unavailable. Characterisation often needs improvement, but is challenging due to the concrete shielding. May contain mobile waste requiring encapsulation.

485 9





reported volume (m

3)

No. of streams

17 Ion exchange material

Includes inorganic (e.g. zeolites, Ionsiv® and clays) and organic (resins composed of high-molecular-weight polyelectrolytes such as DeAcidite FF, A400) ion exchange materials.

Fines and particulate material may not become fully immobilised using standard large scale encapsulation processes. Some organic ion exchange resins contain detectable concentrations of complexing agents, which do not meet the WAC for the LLWR.

48 25

18 Lead and other chemotoxic metals

Lead shot, sheets and bricks. Cadmium.

Lead and cadmium are hazardous materials. This hazard may need to be managed during the packaging/treatment process. Restrictions on disposal of some heavy metals at LLWR and a GDF, such that disposal is often not the best management option, but reuse or recycling may not be simple.

1 1

19

Miscellaneous activated components (MAC)

MAC is irradiated metal components removed during maintenance of a reactor or remaining in-situ for decay storage until final site clearance.

Difficult to manage due to very high dose rates and some are large and may be physically awkward to handle and size reduce for packaging.

471 21

20 Material contaminated with oil

Radioactive material contaminated with oil. Oil contamination may result in the waste not being compatible with standard large scale encapsulation processes.

17 10

21 Mercury waste Mercury contaminated with radioactivity, or other radioactive waste contaminated with mercury.

Mercury is highly toxic and this influences its handling, processing and final disposal. Segregation of mercury from other waste can often be difficult due to dispersion as fine droplets. Its volatility also limits treatment options and available facilities for the treatment of LLW mercury may not be able to accommodate HAW mercury wastes.

1 16

22 Metallic waste Metals from decommissioning reactors, tritium facilities and research laboratories.

Uncertainty remains regarding the type of metals, whether there is residual internal contamination and whether the waste meets the WAC of available treatment or disposal facilities.

7754 24

23 Mixed waste Waste streams containing a wide range of waste types from post-operational clean out (POCO) and decommissioning activities.

These wastes are by definition not yet characterised and so packaging and disposal routes are yet to be determined.

2625 15





reported volume (m

3)

No. of streams

24 Plutonium contaminated material

Legacy drums and items contaminated with plutonium.

Waste exceeds fissile mass limits for preferred management or disposal routes (e.g. supercompaction via WTC or above the previous limits for Pu at the LLWR).

500 14

25 Physically awkward waste

Material with enclosed voidage, large objects. Also includes large plastic sheets which could contain trapped particulate.

May need size reduction and characterisation. Operational difficulties due to the size or shape of the waste items, requiring extra equipment or facilities.

9 10

26 Pressurised waste

Aerosols, fire extinguishers, gas cylinders and contaminated x-ray or fluorescent tubes.

Pressurised waste may not meet transport regulations and may need to be made passively safe before it is packaged.

1 2

27 Putrescible and cellulosic waste

Putrescible materials are liable to be readily decomposed by micro-organisms that may give rise to a health hazard and include animal carcasses and sewage sludge).

Cellulosic waste includes paper, cardboard, cotton and vegetative plant materials.

Putrescible waste is unstable, generates gas and could result in waste packages containing voidage or liquids following decomposition.

Cellulosic waste will, over time, generate biodegradation voidage, which needs to be limited at the LLWR to prevent issues with cap performance. Cellulosic waste is acceptable for disposal to the GDF.

No data 2

28 Pyrochemical waste

Waste salts and slags from pyrochemical processes. These are typically contaminated fluorides and chloride salts.

The resulting material is difficult to characterise because neutrons produced by (alpha-n) reactions make accurate quantification of fissile material difficult.

No data 4

29

Radium/thorium/ americium contaminated waste and active particle bearing waste

Radium/thorium-contaminated wastes that emanate radioactive gases (radon and thoron). For LLW, the problematic waste inventory also contains americium-contaminated waste.

Gaseous discharges of radon and thoron can cause problems during operations and storage including unacceptable inhalation doses to workers and the spread of alpha contamination following decay of gaseous to solid radionuclides.

2 13

30 Reactive metals

Highly reactive metals which can react with water e.g., lithium, sodium, potassium, NaK (sodium and potassium alloy), and metals that can react with cementitious grout to form hydrogen (e.g. aluminium, Magnox).

Reactive metals may not be compatible with standard grout encapsulation processes, due to the potential for hydrogen generation and the potential for development of expansive corrosion products that may reduce wasteform integrity.

1 6





reported volume (m

3)

No. of streams

31 Redundant transport containers

Transport containers, including those for liquid waste, that are no longer required.

The internal surfaces of these containers may be contaminated. Packaging and disposal options may not have been developed to date.

1 3

32 Sludge Bulk sludge, residuals and heels. Once dewatered, particulate material may not become fully immobilised using standard large scale immobilisation processes.

170 37

33 Solvents Contaminated solvents, non- halogenated or halogenated.

Solvents require specialised treatment processes to separate radionuclides from organic liquids.

4 9

34 Sources

Includes neutron sources such as Cf-252, Am/Be, Am/Li and Ra/Be. National Disposal Service sources, other sealed/closed sources. Leaking sources that were previously sealed.

Often very high dose rates (gamma or neutron), may be physically awkward, or may contain gas

1 27

35 Tritiated oil Oil contaminated with tritium, where tritium has replaced hydrogen within the hydrocarbon chain of the oil.

May not meet WAC for incineration. Not compliant with standard conditioning and packaging approach.

6 9

36 Tritium-contaminated waste

Tritium-contaminated solid or liquid waste. Excludes tritiated oil.

The discharge of tritium during processing or storage must be minimised. Cross contamination and gaseous discharges during processing means standard operations may not be suitable. Various alternative management routes possible (decay store, near-surface, geological disposal).

46 16

37 Uranics Includes uranium, contaminated uranium residues and decommissioned uranium processing facility equipment and detectors.

Packaging and transport are the main issues identified for these wastes. A component of the problematic uranium is in metallic form, which may not be compatible with standard grout encapsulation processes, as for other reactive metals. Link to the NDA's uranics strategy [11].

No data 29



3.2 Oils and oily wastes (groups 10, 20 and 35)

There are effectively four main forms of oils and oily waste [8]:

contaminated bulk oil: oil contaminated with radioactive material, normally present as very fine particles or as material dissolved in the oil

oil/water emulsions: emulsions that also contain radioactive material present as very fine particles or as material dissolved in the emulsion

materials contaminated with oil (including oily sludges): radioactive materials that also contain significant amounts of oil

tritiated oil: oil that contains tritium that is chemically bonded to the hydrocarbon chain

The main obstacles to a treatment solution are incompatibility with disposal to near-surface or a geological facility because they are in a liquid form and standard conditioning and packaging approaches such as cementation are often unsuitable. Oils are also classified as hazardous substances by the environmental regulators. Oils and oily wastes may also not meet the WAC for incineration due to radiological or non-radiological contaminants.

Treatment technologies already implemented in the UK include (Table 4 of [6], Section 4.2.1 of [8] and Table 3 of [10]):

incineration [12, 13] for lower activity oils

acid washing (e.g. Oil Waste Leaching (OWL) process for the treatment of contaminated organic wastes: oils and solvents) [14] and oil washing process at Springfields (for higher activity oils containing uranium)

chemical oxidation (e.g. ModulOxTM, Dewdrops process) [15, 16]

electrochemical treatment (e.g. ArviaTM process) [17, 18] for oil/water emulsions

Potential technologies, which are yet to be implemented in the UK, include (Table 4 of [6] and Table 3 of [10]):

thermal treatment in overseas processing facilities (e.g. at Belgoprocess [19]), accessed via the LLWR framework contracts for treatment

thermal treatment in UK-based facilities (Section 4.3.2)

immobilisation on solid matrices, e.g. through use of Nochar PetroBond® absorbent polymer technology [20, 21, 22]

detergent washing

pyrolysis and steam reforming (e.g. THermal Organic Reduction (THOR) process) [23]

use of sodium to remove polychlorinated biphenyls (PCBs) and non-tritium β/γ

radioactive contamination [24]

For problematic LLW, thermal treatment of oil, in particular incineration scored highest in the optioneering exercise [10]. Barriers to the application of incineration relate to alpha content and limits associated with existing disposal routes available through the LLW Repository Ltd Waste Services Contract and other potential existing facilities at waste owners’ sites. Another consideration is ensuring that the residue generated can be disposed of and does not form a secondary problematic waste stream.

In 2015, to address this gap in capability, the NWP undertook a feasibility study to identify treatment technologies suitable for oily wastes not suitable for incineration [25]. This study


22

concluded that there were a range of technologies that may be suitable for different types of oily waste, as summarised in Table 2.

Table 2 Credible treatment technologies for non-incinerable oils and their feasibility by waste group [23]

Technology

Tritiated

oils

(organically

bound 3H)

Tritiated

water

(3HOH) in

oil

Oils with

active

solids

Oily

water

(<50%

H2O)

Oil

contaminated

solids

Th

Pyrolysis Yes Yes Possible Yes No

Plasma treatment Yes Yes Yes Yes Yes

Ph

Absorption Yes Yes Yes Yes Possible

Centrifugation No Possible Yes Yes No

Filtration No No Yes No Possible

Decontamination No Yes Yes Yes Yes

Ch

Electrochemical treatment

Yes Yes Possible Yes No

Wet oxidation Possible Possible No Possible No

Th = Thermal, Ph = Physical, Ch = Chemical

3.3 Mercury wastes (group 21)

Mercury wastes arise in two forms, mercury contaminated with radionuclides and other radioactive waste contaminated with mercury. Mercury wastes are problematic because they pose the following specific challenges [8]:

assay is complicated by the density, which prevents the use of most remote monitoring techniques; characterisation is often based on sampling and chemical analysis

mercury is highly toxic and this influences its handling, processing and final disposal

special packaging arrangements are required for the transportation of liquid mercury to minimise the impacts from potential spills in accident situations

Fifteen potential treatment processes for mercury wastes are identified in Appendix E of [6], of which six have previously been used in the nuclear industry:

acid washing to remove soluble contaminants [13, 26]

distillation [27]

filtration

pinhole filtration [27]

cementation (no longer likely to be acceptable without any pretreatment [28])

the segregation of mercury from other wastes

A combination of pinhole filtration, acid washing and distillation is used in the Tradebe Inutec process at Winfrith to decontaminate mercury [29]. Pinhole filtration followed by triple-distillation was also used successfully at Harwell to treat mercury contaminated with uranium oxide particles to allow its re-use in non-dental applications [6].


23

Dounreay Site Restoration Ltd (DSRL) previously operated a distillation rig for decontamination of elemental (liquid) mercury, but this has now been decommissioned. DSRL has been considering the use of technology owned by Perma-fix Environmental Services UK Ltd to convert mercury to its sulphide form and identified that filtration to remove activated swarf could significantly reduce entrained activity. One of the main uncertainties remaining is the disposability of the HgS product to the LLWR. As this is limiting the applicability of the technology for the wider nuclear industry, the NWP has arranged leaching trials for the HgS product encapsulated in either grout or SIAL, a silicoaluminate geopolymer. These ongoing trials, which will be completed in March 2017, are being funded by NDA’s DRP [30] and aim to collect data to demonstrate that the product meets the WAC for the LLWR.

A range of other techniques for the stabilisation of mercury and mercury-containing wastes are described in a review by Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) [31]. These can be grouped into three categories:

stabilisation as mercury sulphide or mercury selenide

stabilisation as amalgam (alloy with other metals like lead, copper, zinc, nickel or cobalt)

stabilisation with the components of an insoluble matrix (cement, phosphate ceramic, magnesia binder)

The US Department of Energy (DOE) has been directed to designate a facility or facilities for the long-term management and storage of elemental mercury generated within the United States (up to 10,000 metric tons). Work completed includes an Environmental Impact Statement in 2011 [32] and a supplementary statement in 2013 [33], based on which the US DOE will decide (1) where to locate the elemental mercury storage facility/ies, and (2) whether to use existing buildings, new buildings, or a combination of existing and new buildings.

R&D completed on behalf of the US DOE has shown that decontamination of other materials contaminated with mercury may be achieved by [34]:

Chemical cleaning with iodine/iodide lixiviant for mercury contaminated metals and porous surfaces. Since this is a chemical cleaning technique, the target treatment surfaces should not be reactive to the iodine/iodide lixiviant

Decontamination with strippable coating (e.g. ALARA™ 1146) is a potential technique, although further work is needed

Direct use of sulfhydryl cotton fiber (SCF) adsorbent for removal of mercury from the metal surfaces shows low removal effectiveness. Pre-treatment may be necessary to convert “non-reactive” mercury species, such as elemental mercury and HgO, to mercury ionic compounds, which form complexes with sulfhydryl functional group in the SCF adsorbent

3.4 Solvents (group 33)

Solvents are organic liquids. In the problematic waste inventory, these include degreasers that have been used on contaminated components, scintillants from laboratory analysis and drums of redundant solvents that have not been used. These may be problematic to characterise, and no appropriate treatment facilities exist at some sites.

The following potential treatment processes for solvents are identified in Table 4 of [6] and in the references included below:

alkaline washing (i.e. the Solvent Treatment Plant (STP) at Sellafield)

NNL OWL process [14]


24

high-temperature incineration [35]

pyrolysis [12]

Arvia process [17, 18]

The STP has treated all stocks of legacy effluent, which comprises a mixture of tributyl phosphate (TBP) in diluent odourless kerosene (OK), produced as part of Sellafield’s reprocessing cycle [36]. It removes the radioactivity from the solvent and treats it so that the OK can be combusted and the TBP converted into an aqueous form, suitable for discharge to sea (via the Segregated Effluent Treatment Plant) within the agreed limits set by UK regulators. Alternatively, if the material requires further treatment it is sent to the Enhanced Actinide Removal Plant (EARP) where the bulk of the activity is then sent for cement encapsulation in the Waste Packaging and Encapsulation Plant. The plant continues to process solvents from on-going reprocessing operations on site.

The NNL OWL process has been used for treatment of uranium-contaminated TBP/OK solvents [14].

Lower-activity solvents (e.g. organic scintillants) may be suitable for treatment via high-temperature incineration at facilities for the treatment of hazardous waste. These facilities can be accessed via the LLW Repository Ltd treatment framework if waste meets the WAC for combustible waste [35]

In France, the French Alternative Energies and Atomic Energy Commission (CEA) is developing a process (named DELOS) for washing and evaporation treatment of uniform batches of non-halogenated solvents, allowing mineralisation of the non-incinerable residues by means of a hydrothermal oxidation treatment process [37]. CEA is also developing a second process (named IDHOL) specifically for halogenated solvents, based on treatment to destroy organic compounds in an oxygen plasma to produce an effluent that can then be sent to effluent treatment plants [37].

3.5 Aqueous liquids/liquid-containing waste and chemicals (groups 2

and 7)

Aqueous liquids are often routinely managed as effluents, but may become problematic if effluent treatment facilities are not available at a particular site. This category may also include chemicals in laboratory bottles and small quantities of liquid inside historically-conditioned waste containers (e.g. a bottle in a drum of soft laboratory waste). Suitable characterisation and treatment techniques will be different for each of these scenarios.

Miscellaneous chemicals can be characterised using gamma spectrometry or passive neutron coincidence counting (PNCC). Several waste owners have contracts in place with supply chain companies for disposal of uncontaminated chemicals (e.g. [38]) and others have identified routes through existing effluent treatment plants.

Treatment of waste containing liquids, such as large PCM items and concrete-lined drums containing bottles or vials, are another challenge for which few suitable technologies have been identified. Potential treatment processes that may be suitable for liquid-containing waste include:

sorting and segregation, as was undertaken at Harwell for the legacy remote-handled ILW drums [39]

thermal treatment (see Section 4.3.2)


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3.6 Ion exchange material (group 17)

Both organic and inorganic ion exchange materials are present at a number of sites. Organic ion exchange resins are composed of high-molecular-weight polyelectrolytes such as DeAcidite FF (A400), while inorganic materials include zeolites, Ionsiv® and clays [6].

Ion exchange materials are problematic because they are particulates that may not become fully immobilised using standard encapsulation approaches. Some organic ion exchange resins may also contain complexing agents that do not meet the WAC for disposal at the LLWR.

Treatment technologies already implemented in the UK include (Table 3 of [6] and Table 3 of [10]):

cement or polymer encapsulation ([40], Section 8.3 of [41])

incineration of (lower activity) organic ion exchange resins

steam reforming using the THOR process [42]

decay storage of resins from Rosyth (MOD) until activity levels are suitable for consignment to the LLWR [8]

resins from Devonport (MOD) are currently dispatched to the Tradebe Inutec LLW cement plant at Winfrith for encapsulation prior to disposal at the LLWR and therefore would only become problematic if this route became unavailable

drying and packaging in robust containers, noting that EDF Energy used mobile GNS FAFNIR and NEWA plants to fill and dewater 55 MOSAIK® containers, emptying the ILW resin tanks at Sizewell B [43, 44]

at Trawsfynydd, Magnox has used polymer encapsulants (based on Vinyl Ester Styrene, VES) to condition ILW ion exchange resins for disposal to a GDF [45]

at DSRL, small scale trials have been completed on immobilisation of ion exchange resins [46], including vacuum infiltration with an epoxy polymer (Advanced Polymer System, APS) and also in drum mixing with a 1:1 ratio mix of Ordinary Portland Cement (OPC) and Pulverised Fuel Ash (PFA) grout

RWM issued thematic guidance in 2015 on the use of organic polymer encapsulants, which summarises lessons learnt from disposability assessments for packaging of ion exchange resins at Trawsfynydd [47].

For organic resins, pre-treatment such as heating to remove trimethylamine [48] addition of high-alumina cements and NaOH to manage high borate concentrations [49], or selection of a suitable cement formulation may be required prior to cement encapsulation for disposal at a GDF [50]. Some organic ion exchange resins may also contain complexing agents, which would require either a variation (following assessment at a waste-stream-specific level) or treatment prior to disposal at the LLWR [6, 10].

Potential solutions that have yet to be implemented include pyrolysis and Hot Isostatic Pressing (HIP) (Table 3 of [10]). A wide range of different treatment technologies were reviewed on behalf of US DOE in [51], which noted that acid digestion was only applicable to organic resins and that joule-heated vitrification would be applicable to a wide range of resin types.

At Fukushima, zeolites have been used to decontaminate large volumes of water, they now have high Cs-134/137 loadings and contain NaCl and other salts found in seawater. An impermeable graphite matrix has been developed, which is mixed with up to 60% zeolite and placed into containers, using HIP to immobilise these secondary wastes [52].


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3.7 Pyrochemical waste (group 27)

These wastes result from pyrochemical processes undertaken in the production of metallic plutonium and enriched uranium, using molten salts (e.g. calcium fluoride) at high temperatures to reduce plutonium and uranium salts to the metal form. The resulting wastes are composed of the solvent salt, residual metals and often fragments of ceramic crucibles from the processing equipment. Pyrochemical wastes pose the following specific challenges [8]:

they contain fissile material, potentially in quantities greater than those associated with typical contact-handled PCM wastes, and so handling and processing requires an accurate assay methodology

the waste management process needs to be robust in preventing criticality accidents (i.e., small batch processing)

the accurate assay of the wastes is complicated by the presence of plutonium in intimate contact with fluorine of the calcium fluoride

the potential for bulk fragments and finely divided reactive metals to exist within the salt matrix may prevent the waste being converted to a form suitable for disposal

many of the salts such as CaF2 are insoluble in water; however, the plutonium and uranium may be more soluble and therefore could be leached from the waste

Treatment technologies identified in [8] as being suitable for application to pyrochemical wastes include calcination and sintering [53,54], salt extraction process [55], salt scrub, cementation [56], encapsulation in organic polymers (Section 6.4.1 of [47]) and HIP [57,58].

The pyrochemical wastes at AWE are planned to be immobilised within epoxy resin within 5 litre cans, which would then be cemented into 500 litre stainless steel drums [59]. For residues with higher levels of actinide contamination, immobilisation in calcium phosphate cements has been considered by AWE and considered by RWM to be potentially appropriate at the conceptual stage [60].

3.8 Chloride and halide-based powders (group 8)

A range of materials have been used as a powder fire extinguisher, including Ternary Eutectic Chloride (TEC) powder and NaCl powders. These have been used in glove boxes or controlled areas and are therefore contaminated or potentially contaminated with a range of radionuclides. Chloride-bearing wastes are incompatible with Portland cement-based encapsulants and have potential significant deleterious effects on the performance of the waste containers [61].

RWM guidance on the production of encapsulated wasteforms proposes that organic polymer encapsulants can be used to produce acceptable wasteforms for ILW streams containing “high concentrations of chemical species such as sulphate or chloride ions” [61].

Polyethylene encapsulation and modified sulphur concrete encapsulation are both mentioned in [62] as potential thermoplastic methods that can be used to stabilise chloride salts. Brookhaven National Laboratory has investigated the efficacy of a modified sulphur cement as an encapsulant for Idaho National Engineering Laboratory mixed-waste-contaminated incinerator ash that contained metal chloride salts, primarily zinc chloride [63]. Laboratory-based studies sponsored by the US DOE also showed that polyethylene encapsulation can accommodate up to 70 wt% nitrate salt waste [63].

An impermeable graphite matrix, which is compatible with chloride-containing zeolites, has been developed to embed inorganic ion exchange resins and this may also be compatible with TEC powder (see Section 3.6 and reference [52]).


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3.9 Radium/thorium/americium6-contaminated waste (group 29)

Radium/thorium-contaminated wastes originate from facilities that have processed radium or thorium. These elements have previously been used to produce containment sources and instrument dials [6]. Unirradiated thorium metal bars are also included within the 2016 problematic waste inventory.

The decay products of radium and thorium are the gaseous radionuclides radon (Rn-222) and thoron (Rn-220) which are alpha emitters that pass through particulate filters in normal ILW stainless steel waste packages [6]. The operational issues associated with gaseous radon and thoron discharges leading to inhalation doses and the spread of alpha contamination cause these wastes to be problematic. Therefore, these gases must be held up within the wasteform so that they decay within the container rather than being released to the environment. This can be achieved by encapsulation with a polymer or cementitious grout [6]. Transport is usually minimised before the waste is encapsulated to prevent transport packages becoming contaminated with alpha-emitting radionuclides [6].

For lower activity thorium/americium contaminated waste, an additional issue is that the LLWR WAC requires that waste containing, or that may contain, active particles, or materials that may break down into active particles, requires additional assessment before the waste can be accepted for disposal at the LLWR (Section L3.2.5 of [64]).

At Harwell, radium wastes were successfully treated as follows [45]:

small scale (up to 5 litre) encapsulation with VES

then encapsulated in grout in 500l drums with other solid waste

This process led to better encapsulation and reduced radon emissions [45]. A final stage Letter of Compliance (LoC) has been obtained from RWM for the radium waste packages [6]. The wasteform evolution of VES and epoxy resins in a GDF is summarised in Section 7.3 of [41].

In France, thorium is currently considered to be an asset, but if in future it were declared as a waste it is likely to be disposed of in a sub-surface disposal facility [37].

3.10 Tritium-contaminated waste (group 36)

Tritium-contaminated waste includes soft waste, desiccants, concrete and metals, dust (including carbon and beryllium dusts), catalysts and uranium. The reason that these solid wastes are problematic is that tritium is mobile, can pass through multiple layers of containment and is not captured by High Efficiency Particulate in Air (HEPA) filters. As tritium has a half-life of 12.32 years, the rate of escape during transport and operations needs to be limited so that the radioactivity decays, either in situ or within the waste package.

Treatment processes used within the UK include [6]:

decay storage

managed discharge to air/water

incineration

6 No specific techniques have been identified for treatment of americium-bearing wastes (the LLW problematic group includes thorium and americium, whereas the HAW problematic group includes radium and thorium).


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RWM has issued guidance on the packaging of tritium-bearing wastes [65], which discusses the following potential treatment technologies:

encapsulation in organic polymers

encapsulation in grout, either blended Portland or calcium aluminate cements

use of alternative methods for immobilisation, such as molecular sieve for tritiated water and metal hydrides for tritium gas

In France, three potential management routes are available for tritiated wastes [37]:

thermal treatment when tritium waste presents an excessive activity or an excessive tritium degassing rate that makes safe storage impossible. This treatment is carried out at the defence facilities at Valduc and comprises a fusion process for the metallic waste and a subsequent drying process for the organic waste to reduce the activity and/or the tritium degassing rate

incineration for liquid waste at the CENTRACO treatment plant

decay storage for the tritium waste which are not acceptable at the CENTRACO plant or existing ANDRA disposal centres (different facilities are used or planned to be constructed to store tritium waste with high and low degassing rates7)

3.11 Filters (group 14)

Filters include HEPA and charcoal filters [8] and also cartridge filters used to remove radionuclides and particulates from active effluent. Filters are problematic because they are loaded with significant quantities of fine particulate that may not be immobilised for packaging using standard encapsulation processes.

HEPA filters usually comprise the filter medium (such as glass fibre) held within a metallic frame. Filters are designed to remove particles from gas streams, and these particles are sometimes only loosely held on the filter medium. The air-flow channels within many of the filters used prior to the early 1990s were maintained by corrugated aluminium spacers; this introduces a material that reacts with cement based grouts, liberating significant volumes of hydrogen, and results in high-volume, low-density waste. In addition, many older filters are of an awkward geometry that does not facilitate packaging within standard disposal containers such as 500 litre drums. Filters therefore present a number of challenges to processing for disposal [8].

RWM has developed revised guidance on the packaging of filters that identifies a number of potential treatment methods, including experimental evidence from Sellafield Ltd that demonstrates successful grout encapsulation of filters [66].

In AGR reactors, coolant blow-down filters comprise sintered stainless steel units, followed by passing the CO2 gas through charcoal filter beds prior to release to atmosphere (Section 5.11.2 of [67]). While no specific technologies have been identified for treatment of charcoal beds (which are often ILW), it is possible that these could be immobilised prior to disposal using similar technologies to other bulk fines and particulates, as described below.

3.12 Bulk fines and particulates (group 5)

Bulk fines and particulates arise in a number of forms, including the contents of vacuum cleaner bags, filings, sawdust and sand, and are often present in small quantities. Some fines include boron, activated metal, beryllium flakes or a mixture of materials. They are

7 Tritiated waste is considered to have a low degassing rate if the tritium gas release from each package is less than 1 GBq/year/package.


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often not suitable for treatment using large-scale encapsulation processes because the fine particulate may not be immobilised. This is required for the resulting waste packages to be suitable for disposal at the LLWR or a GDF.

Possible treatment processes include [6]:

melting [20,26]

limiting the content per package to 10 litres/500 litre drum [39]

encapsulation in polymer or cement [68]

compaction [12, 20, 66]

Fines were treated by Research Sites Restoration Ltd (RSRL), now Magnox Ltd, at Harwell (as endorsed by a final LoC (fLoC)), where they are intimately mixed with beads of bentonite clay and compacted in a steel can to form a homogenous, immobilised waste [39]. This can then be packaged with other waste, for final encapsulation. The Harwell process operates on a relatively small scale, with a maximum of 2.4 litres of fines processed at a time.

3.13 Sludge (group 32)

Sludges arise in tanks, sumps and ponds and comprise a mixture of materials in particulate form. Some are contaminated with oil. These tend to be high priority problematic wastes because they are hazardous, mobile wastes and large volumes are present at some sites. Sludges pose the following challenges [8]:

significant technical challenges in the characterisation of sludge (due to heterogeneity in the settled material)

the need to remove relatively small amounts of materials that are difficult to treat, or place limitations on the disposal of the final wasteform, can add to the complexity of the treatment and disposal processes

the remobilisation/recovery of sludges for processing can be technically challenging and often requires the development of bespoke equipment

both on-site transfer and transport of the raw waste to other sites for treatment can result in both technical challenges and stakeholder issues

It is likely that the difficulties in addressing these issues, rather than the lack of available proven treatment technologies, prevent the processing of sludge wastes for disposal and render them problematic at some sites. One approach for dealing with the large quantities of sludge could be to treat the volume that can easily be removed separately from any residual sludge, so that different techniques could be applied.

Possible treatment processes include those identified in Table 4 of [6]:

cementation [41]

encapsulation using polymers or geopolymers

dissolution [69, 70]

ArviaTM process [17, 18]

vitrification

molten salt oxidation

pyrolysis

steam reforming


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Technologies such as cementation and dissolution [68] have been used successfully to treat sludges in the UK. This experience is discussed from a wasteform evolution perspective in Section 8.4 of [41]. Drying of sludges to remove water and reduce volume have been demonstrated by Magnox Ltd (discussed further in Section 0).

Geopolymers have been used to immobilise dewatered hydroxide sludges from a Mine Water Treatment Facility at Schlema-Alberoda in Germany [71]. A specific type of geopolymer, SIAL, was used to immobilise higher-activity sludges and resins from the Jaslovske Bohunice nuclear power plant in Slovakia [72].

Treatment routes are planned for sludges from a range of plants at Sellafield. About 90% of the sludge volume at Sellafield derives from the filter beds (predominantly alumino-ferric floc, contaminated sand, gravel and clinker). Most of this material is now considered to be non-problematic, the proposed management route is for these wastes to be retrieved and packaged in 4 m boxes [8].

In France, sludges have historically been immobilised using bitumen, but alternative processes are currently being developed [37]. The legacy waste project at La Hague (STE3) is developing a technique for drying-compacting of sludge resulting from the chemical precipitation of low and intermediate-level effluents [37].

In the US, large quantities of sludge classified as low-level mixed waste has been retrieved from tanks at the US DOE Rocky Flats site and blended with either polymers or lime and soda ash to ensure compliance with the waste disposal site (Envirocare, Utah) criterion of no free liquids in the final waste product [73].

3.14 Lead and other chemotoxic metals (group 18)

Lead is often used for radiation shielding due to its density, and can become contaminated as a result. Lead is problematic for the following reasons [8]:

it is chemotoxic and classified as a non-hazardous pollutant, such that lead inputs to groundwater should be limited

it does not fit within the WAC of existing facilities because of its shielding properties and consequent impact on accurate assay of wastes

its density and weight restrict the quantity of waste that can be placed into waste packages and therefore the efficient use of storage space

Due to its chemotoxic properties, there are also restrictions on the quantity of lead that can be disposed of to the LLWR [64] and, potentially, to a GDF [74]. Experience of the cement encapsulation of lead is described in Section 8.2.3 of [41].

Potential treatment technologies identified in [6] include:

chemical/physical decontamination [75, 76]

acid washing [13, 26,]

co-package with other waste [8]

laser ablation [77]

metal melting [78]

Significant quantities of contaminated lead blocks were successfully decontaminated at the Harwell site using a dry cutting technique with a handheld rotary industrial planer that removed 0.5-2mm from the surface of the blocks (Appendix A.3 of [26]).

There is a lead melting furnace on the Sellafield site [78]. This has not been in operation since it was discovered that the ventilation failed to meet modern standards. The capacity


31

when operating was 3 tonnes/day. A 2009 report noted that it was proposed to refurbish the facility, which if completed would have a capacity of 4 tonnes/day [78].

NWP guidance on the management of cross-boundary pond furniture is relevant because, although this is predominantly steel it does also comprise ~9% lead [76].

In France, a lead recycling route, using a melting process, was put in place in 2003 at Marcoule to decontaminate LLW lead [37]. This route became unavailable in 2013 due to the dismantling of the facility and so the lead was then recycled in conventional foundries. However, the level of lead decontamination required prior to acceptance by the conventional foundries (to an activity below 0.5Bq/g) has turned out to be expensive, making the business strategy unsustainable [37]. A new technology, using fusion process principles, has been developed by AREVA, CEA and EDF, who state that around 12,000 t of lead (low-level and intermediate level) could be treated, but this has yet to be demonstrated [37].

In Belgium, clean lead was separated from a contaminated casing by melting to extract the lead before dismantling the BR3 reactor (Appendix A.4 of [26]).

For other chemotoxic materials, such as cadmium and chromium, information on potential treatment solutions is scarce. For cadmium (in the form of metal sheets), the following treatment processes were identified in Table 3 of [10] for cadmium sheeting:

acid washing

chemical decontamination solutions

blasting

Chromium in US DOE orphan transuranic (TRU) waste is treated using an in-drum pyrolysis and steam reforming (THOR process), which also converts reactive metals to stable compounds [79].

3.15 Sources (group 34)

Sources, including sealed, leaking and/or closed radiation sources, contain a wide range of different radionuclides. While many are fairly straightforward to manage, others pose specific problems regarding dose, heat or A2 limits for standard waste packages [8]. Some sources also contain gases or generate gaseous radionuclides via radioactive decay such as Ra/Be, Kr-85 and tritium, which could lead to pressurisation and/or localised high concentration gas releases if the sealed sources are breached.

The following treatment technologies have been implemented in the UK [6]:

package within localised shielding (e.g. polyethylene shielding for neutron sources) [39]

decay storage

limit contents of package [39]

co-package with other waste so as not to breach limits [39]

A LoC has been issued for sealed sources in the remote-handled ILW stream at Harwell, for packaging in 500 litre drums. Specific limits are given for certain radionuclides in the Waste Product Specification [39]. RWM has also developed a generic conceptual design of a novel packaging concept for sources, requiring no pre-treatment, no encapsulation and minimal grouting at the packaging site [80].

Lower activity sources are disposable at LLWR subject to approval of a specific waste characterisation form and the sources a number of conditions regarding their activity, physical form and configuration within the waste package (Section L3.2.4 of [64]).


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In France, the strategy for management of sealed sources includes six potential management routes [37]:

tritium sources managed through the current disposal routes, either disposal in near-surface disposal facilities run by ANDRA or decay storage depending on the activity level

liquid sources managed through existing liquid disposal routes

incinerable sources treated through the CENTRACO incineration route

processing of sources used for reactors through routes used for management of irradiated internal structures

sources without a physical containment barrier through any suitable solid disposal route

other sources through a source-specific packaging approach, without ruling out that a controlled mix of sources and other wastes may be acceptable in some containers

It is noted in [8] that reuse of sources may be possible for certain applications.

The IAEA has tested a prototype canister for disposal into narrow boreholes, a few hundred metres deep. The concept was developed originally by the South African Nuclear Energy Corporation and was adapted for the containment and disposal of sealed sources with higher levels of activity. Inactive trials carried out in Croatia in 2015 showed the concept to be technically feasible and the IAEA plans to roll out the technology to countries with stockpiles of disused sources and no available disposal route or waste management plans to deal with them [81].

3.16 MAC and physically awkward wastes (groups 19 and 25)

Miscellaneous activated components (MAC) are irradiated metal components removed during maintenance of a reactor or remaining in-situ for decay storage until final site clearance. These represent approximately one-fifth of the HAW inventory by volume but most do not arise until final site clearance (except at RAL). Some MAC is difficult to manage due to very high dose rates. Some waste items are also large and may be physically awkward.

Other physically awkward waste (e.g. reactor pressure vessels or components from the ISIS experiment) can be large items or items with a complicated geometry that are difficult to decontaminate and/or contain significant voidage. These features result in difficulties in characterising, handling and size-reducing the items for packaging.

Potential treatment technologies for physically awkward wastes identified in [6] include:

placing in a 3m3 box and entombing in grout

sorting and segregating

shredding

compaction (yet to be demonstrated)

Some larger items cannot be packaged in a 3 m3 box without significant size reduction and the feasibility of direct disposal into a larger waste container is currently being considered by RWM [82]. The LLWR has historically accepted items larger than an ISO container for disposal, but this is considered to be challenging due to mass limits for the waste receipt and handling infrastructure at the LLWR and the poor suitability of both rail and road infrastructure in UK [83].


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3.17 Metallic waste (group 22)

Metallic wastes may be problematic because they are large and physically awkward items (e.g. tanks, pipework, equipment) or because they have not yet been characterised. The items may also have internal contamination and voidage that is difficult to access for characterisation or encapsulation.

The following treatment technologies were identified in the national strategic BAT study for LLW metallic wastes [84]:

surface-decontamination, including for example:

o wiping and other simple approaches

o water or other fluid jetting

o surface-abrasion (e.g. shot and grit-blasting)

o chemical decontamination

melting, involving:

o recovery of contaminated slag and filters and release or declassification of

bulk metal

o for a subset of specific matrix radionuclide contaminants, potentially a more

limited inventory reduction, combined with volume reduction due to

elimination of voidage

compaction or supercompaction (e.g. of thin malleable metal sheets in mixed waste

streams)

disposal with no prior treatment, or disposal of residues, including secondary wastes and discharge of effluents

Metal melting is a mature technology that has been available for over 20 years and LLW Repository Ltd offers a range of service providers and facilities for the treatment of metallic waste in Germany, Sweden and the United States [85].

The use of ice pigs to decontaminate the internal surfaces of metal pipes is common practice in the drinking water and food industries and there is potential for technology transfer to clean out of enclosed systems during POCO and decommissioning [86].

The behaviour of metals in cement-encapsulated wasteforms is described in Section 8.2 of [41].

3.18 Asbestos (group 3)

Asbestos is a hazardous material that has been used extensively in reactor buildings (e.g. cladding for boilers and heat exchangers) and may therefore be contaminated or activated. It arises during decommissioning of the reactor sites and this hazard needs to be managed during the packaging/treatment process. In the problematic waste inventory, the majority of asbestos arising in the near-term is LAW, most HAW asbestos is expected to be generated during final site clearance of the Magnox sites and so will not arise until after 2080.

Development of treatment options for LAW asbestos was the focus of significant recent work, as restrictions on disposal of asbestos were included in the LLWR WAC. Once the asbestos is treated or conditioned, it is no longer an issue for disposal at a GDF and is therefore not included in the WPS for low heat-generating waste [87]. The following treatment technologies were identified in the NWP Gate B paper for LAW asbestos (Table 3).


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Table 3: Long list of options for management of LAW asbestos [88]

Technique type Option

Enabler Shredding

Physical Encapsulation in cement material

Encapsulation in polymer / resin / alumina-silicate material

Super, high and low force compaction

Chemical Use of dampening agents / sealants

Acid digestion

Thermal Thermochemical Conversion Technology

Thermal Organic Reduction (THOR)

Microwave Thermal Treatment

Vitrification – Joule Heating

Vitrification – Plasma Arc

Ceramic Encapsulation

Incineration

Disposal (as raw

waste)

Interim storage and disposal as VLLW or out of scope

Disposal to appropriately permitted landfill sites

In-situ disposal of asbestos and ACW

Disposal to LLWR

Interim storage and disposal as HAW

Disposal to near / on site facility

The Gate B paper identified three LAW asbestos populations [88]:

non-friable and low friability asbestos containing manufactured products

moderately friable asbestos containing manufactured products

highly friable and loose asbestos forms

Further details of the treatment options for LAW asbestos listed in Table 3 are given in Appendix 2 of [88].

Asbestos-concrete clad buildings at Hanford’s K East Basin have been demolished using fixatives to prevent spread of asbestos and radiological contamination and disposed of together with other demolition waste, including steel columns/beams and concrete [89].

3.19 FED and FED-contaminated wastes and uranics (groups 13 and 37)

FED is the splitters and lugs removed from Magnox spent fuel to increase the packaging efficiency prior to sending the fuel to Sellafield for reprocessing. It is largely magnesium, with small amounts of other metals [90]. FED-contaminated waste includes secondary waste from the treatment of FED and FED-contaminated gravel from storage vaults. Magnesium and other reactive metals may not be compatible with standard encapsulation processes. Some FED streams may also potentially contain fuel particles (uranium metal).

Treatment options for FED considered during the recent Magnox Ltd strategic review included [91]:

treatment by dissolution

segregate high activity components and package for LLW disposal where appropriate

package for ILW disposal

decay storage for LLW disposal


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Experience of cement encapsulation of Magnox swarf and uranium metal is discussed in Sections 8.2.4 and 8.2.6 of [41]. Polymer encapsulation of Windscale Piles fuel and isotope cartridges in liners that would then be grouted into 500 litre drums has received a Conceptual LoC from RWM (Section 6.2.1 of [47]).

The final preferred option for the management of FED is segregation of high activity components (e.g. nimonic springs) followed by direct disposal of the separated LLW FED Magnox [91]. Trials being conducted by Magnox Ltd at Hinkley Point A and Oldbury showed that removal of the ILW springs, together with broken spring fragments, via an X-ray sorting process (using airport X-ray scanners that check luggage) together with the magnet-based technology of Eddy Current Separation, enabled a significant volume of the bulk waste FED, which is lightly contaminated, to be treated as LLW [92].

Treatment options for problematic uranic waste include:

cement encapsulation

polymer encapsulation [47]

processing in NNL’s Preston laboratories [93]

Encapsulation of Graphite Low Energy Experimental Pile (GLEEP) fuel (uranium metal bars clad in aluminium) [94] within storage cans using an epoxy resin has been endorsed by RWM by way of the issue of a Final stage LoC (Section 6.3.2 of [47]).

3.20 Plutonium-contaminated materials (PCM) (group 24)

PCM waste streams include legacy drums or items used in operations or retrieved during decommissioning that are contaminated with plutonium. Other items include chromatography resins and residues that may not be suitable for reprocessing. The baseline for PCM management at most sites is supercompaction of 200 litre drums into pucks, which are then grout-encapsulated into stainless steel 500 litre drums for management as ILW (e.g. [95]). PCM that is not compatible with this baseline, or for which disposal at LLWR is a potential disposal route if barriers can be overcome, is considered by waste owners to be problematic and are recorded in the problematic waste inventory.

Thermal technologies are under development for the treatment of PCM (e.g. plasma vitrification, pyrolysis, HIP) within the UK nuclear industry (as discussed in Section 4.3.2).

3.21 Waste failing the LLWR discrete items limit (group 11)

LLW Repository Ltd define a discrete item as “a distinct item of waste that, by its characteristics, is recognisable as unusual or not of natural origin and could be a focus of interest, out of curiosity or potential for recovery and recycling/re-use of materials should the waste item be exposed after repository closure” [96].

Items failing the discrete item limit [96] specified in the WAC for the LLWR can no longer be disposed of in the LLWR and therefore need to be managed as ILW unless an alternative option is identified. Therefore, a credible options study was completed to identify technologies that might be used for the effective management of these items [97]. For this study a discrete items inventory was produced and four waste groups identified that cover all types of materials in the inventory:

1. metals with simple geometries and predominantly accessible surfaces (e.g. framework, bars, plates, containers, skips, trolleys, rams and bogies, and magazine bodies)

2. metals with complex geometries and inaccessible surfaces (e.g. pipework, pumps, flowmakers, crane parts, filters, and heat exchangers)


36

3. cemented drums (metallic (mild steel) drums that either contain cement-encapsulated waste, such as water treatment sludges, or cement-encapsulated items of waste, such as metallic filters)

4. sources (not considered further within the study but these are a separate problematic waste group, discussed in Section 3.15 of this report)

Discrete items that fail to conform to the WAC may be managed either by modifying the physical form (e.g. shape) of the object so that it no longer qualifies as a discrete item of waste, or reducing the total activity of the item so that it is within the relevant discrete item activity limits8. A summary of the results of the assessment of credible options for discrete items [97] is presented in Table 4.

Table 4: Summary of the credible options for discrete items [97]

Technology

Waste group

Metals: simple geometries

Metals: complex geometries

Cemented drums

Shredding ✔ ✔ ✔

Jaw crusher ✖ ✖ ✔

Supercompaction ✖ ✖ ✖

Circular saw ✖ ✖ ✖

Wire saw ✔ ✔ ✔

Reciprocating saw ✔ ✔ ✖

Torch cutting ✔ ✔ ✖

Plasma cutting ✔ ✔ ✖

Laser cutting ✔ ✔ ✖

Chemical ✔ ✔ ✖

Physical ✔ ✖ ✖

Metal melting ✔ ✔ ✖

Incineration ✖ ✖ ✖

Plasma arc processing

✔ ✔ ✔

Vitrification ✔ ✔ ✔

Disposal elsewhere ✔ ✔ ✔

Decay storage ✔ ✔ ✔

✔ technology credibly applicable to a specific waste group

✖ technology not credibly applicable to a specific waste group

Evaluation of the inventory data, specifically generated for the credible options study, has shown that there is a lack of characterisation for many of the items in the inventory that have been defined as discrete items. It is likely that when these items are more adequately characterised, a significant proportion may be found to be outside the definition of wastes failing the discrete item limits and therefore to be suitable for disposal without further

8 The cutting or dismantling of a waste item with the sole intention of reducing its weight or specific activity to meet the discrete item limits in the WAC is prohibited by the LLWR WAC. Physical modification in this context is that which makes the item no longer unusual or a focus of interest, rather than changing its radioactive properties


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treatment. Conversely, it is possible that ongoing characterisation of wastes will identify other waste items, and populations of different waste types, that do not comply with the discrete item limit.

3.22 Graphite (group 15)

Graphite is chemically unreactive in conditions relevant to storage and disposal in a GDF, although a fraction of its C-14 and Cl-36 inventory, characterised by a relatively high solubility, low reactivity and low sorption, are considered to be mobile and will leach over long periods once in contact with groundwater (Section 7.5.2 of [41]).

Any graphite that has been irradiated in a nuclear reactor by fast neutrons will contain Wigner (stored) energy, arising from the residual displacement of carbon atoms in the graphite crystal lattice. The quantity and characteristics of this energy depend on the irradiation history of the graphite. As a general rule, Wigner energy is only released at a temperature some 50°C above the irradiation temperature in the reactor. Therefore, for Magnox and AGR core graphite there is little likelihood of self-heating under normal storage and disposal conditions. Graphite irradiated at lower temperatures (such as the Windscale Pile reactors) may experience temperatures comparable with or higher than those experienced previously and so stored energy could be released during normal transport or disposal conditions [98].

The problematic waste inventory contains graphite from operations (e.g. AGR fuel sleeves) and graphite core blocks arising at final site clearance of the reactor sites. Much of the LAW problematic waste graphite exceeds the LLWR WAC limits for these nuclides. Most of the HAW problematic graphite inventory does not arise until final site clearance from the 2180’s onwards.

In the UK, options for the management of operational graphite (e.g. Magnox and AGR fuel sleeves) and reactor cores (from Magnox, AGR and research reactors) have been developed by NDA in [99] and [100], respectively. The preferred options for the near-term management of operational graphite have been identified as follows [99]:

Berkeley site – to manage all the graphite waste as ILW for interim storage (in resilient, self-shielding containers) and assume unencapsulated final disposal in the GDF

Hunterston A site – to manage all the graphite waste as ILW for interim storage (unencapsulated in stainless steel containers) with encapsulation at Final Site Clearance (FSC) prior to management in accordance with Scottish Policy

Sellafield site – to manage the graphite waste within the scope of this study as ILW for interim storage (in mild or stainless steel drums) with encapsulation prior to final disposal in the GDF

The credible options for the long term management of reactor core graphite include both direct disposal and pre-disposal treatment options. It is not currently considered credible to directly dispose of reactor graphite to either the LLWR or to other radioactive waste permitted landfill sites. Opportunities are highlighted for the use of near-term waste arisings (for example RSRL and DSRL research reactor graphite) as pathfinder material for core dismantling or treatment trials to inform decisions on the management of larger volume, later arising Magnox Ltd, Sellafield Ltd and EDF Energy reactor graphite.

In 2006, the IAEA published guidance on treatment options for graphite wastes producing during the decommissioning of nuclear reactors [101]. This report included the following treatment processes:

encapsulation, e.g. cement, polymer-modified cement and polymers


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impregnation and/or surface coating (to prevent migration of volatile radionuclides)

thermal oxidation processes, e.g. furnace incineration, fluidised-bed incineration, laser incineration or steam pyrolysis, which results in release of tritium, C-14, Cl-36 and other volatile radionuclides. The resulting graphite may be treated as LLW or is converted wholly to secondary ash.

The development of best practises for the retrieval, treatment and disposal of irradiated graphite was the aim of the 7th EURATOM Framework Programme CARBOWASTE (Treatment and disposal of Irradiated Graphite and other Carbonaceous Waste)9 that finished in 2014. Potential treatment processes investigated included [102]:

thermal processes (as above)

chemical processes, e.g. the steam-reforming THOR process, or the Russian Self-propagating High Temperature Synthesis methodology (in which the graphite is mixed with aluminium metal and titanium dioxide, forming an insoluble, unreactive mix of alumia/titanium carbide which incorporates a number of volatile radionuclides)

options for recycle/re-use

3.23 Absorbent materials (group 1)

Absorbent materials include desiccants and materials used to absorb water or other chemicals. In the Magnox reactors, a drier system was employed to remove excess water moisture from the carbon dioxide reactor coolant gas, to reduce the corrosion rates of metal and graphite components in the reactor primary gas circuit [103]. Magnox desiccants were either activated alumina or molecular sieve materials [103], whereas the AGR reactors used silica gel-based desiccants [104]. These wastes are problematic because they contain particulate material that may not become fully immobilised using standard large scale encapsulation processes and because the absorbed liquids could be expressed under pressure if not suitably treated.

Opportunities have been identified to decontaminate absorbent and desiccant materials from reactor sites so that the waste can be dispositioned promptly, rather than being placed into interim storage as ILW. Review of characterisation information for ILW desiccants from Berkeley, Trawsfynydd and Wylfa enabled Magnox Ltd to use the supply chain for washing (decontamination) and incineration of desiccant [105]. Prior to this, a conceptual LoC was granted for packaging of desiccant from the Magnox Trawsfynydd site as ILW, using inner mild steel 200 litre drums grout-encapsulated into a 3 cubic metre box for interim storage and subsequent disposal at the GDF [103].

3.24 Putrescible and cellulosic waste (group 26)

Putrescible10 waste includes organic matter such as vegetation (e.g. moss and algae) or animal carcasses. This is problematic because it can be decomposed by microorganisms, resulting in gas generation and potentially creating voidage within a waste package.

Cellulosic wastes include paper, wood, pallets and cardboard. Alkaline chemical degradation of cellulose results in the generation of a range of soluble products, some of which are able to complex radionuclides and potentially enhance their mobility (e.g. isosaccharinic acid) [106]. Cellulose can also degrade by alkaline hydrolysis to form acidic species and the degradation of materials such as polyvinylchloride by radiolysis can

9 www.carbowaste.eu

10 Materials liable to be readily decomposed by micro-organisms, excluding wood and paper


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produce hydrochloric acid. These acids could react with the backfill and reduce its pH buffering capacity [61].

Lower activity putrescible and cellulosic wastes can be incinerated if they meet the WAC for such facilities (e.g. [107]). If disposed of at the LLWR, such materials will degrade over time, resulting in the generation of voidage that might be expected to have a significant effect on the performance of the cap above the wastes. The total potential voidage, also including inaccessible and compression voidage, is not to exceed 20% of the internal volume of the waste container [64]. For disposal at the LLWR, the LLWR WAC also requires that reasonably practicable means shall be taken to “limit the quantity of Putrescible Materials within a Waste Consignment and if present Putrescible Materials must not exceed 1% of the Internal Volume of the Disposal Container” [64].

For higher activity putrescible and cellulosic wastes that would potentially cause gas generation and wasteform integrity issues for disposal in the GDF, there are no currently available routes.

3.25 Batteries (group 4)

Batteries that are contaminated or potentially contaminated are problematic because they contain heavy metals (lead, cadmium or mercury, depending on the battery type), which are hazardous substances. There are restrictions on disposal of hazardous substances at the LLWR and the GDF. Other hazards relating to the storage and disposal of batteries include short-circuiting, which could lead to a battery fire [108]. Due to the variety of battery types and designs (e.g. lithium-ion, alkaline, lead-acid and sealed gel fork-lift truck batteries), it can be difficult to demonstrate that these items are not internally contaminated, particularly with alpha-emitting radionuclides such as plutonium.

No relevant experience has been identified in this review for the treatment and packaging of contaminated batteries in the UK.

In the United States, the Environmental Protection Agency (US EPA) published guidance in 2002 on a variance to the Land Disposal Restrictions Treatment Standards for radioactively-contaminated cadmium-, mercury- and silver-batteries, which recommended that “macroencapsulation” is used for the treatment of these wastes. This is the same standard technology as required for other waste in the “radioactive lead solids” subcategory wastes including lead acid batteries, lead shielding and other forms of elemental lead and hazardous debris [109]. The macroencapsulation process involves either application of a surface coating of organic polymers or placing the batteries inside a sleeve or jacket of inert inorganic materials that are inert to the batteries themselves and any contaminants arising from them (as defined in standard 40 CFR 268.45). These encapsulants act as a barrier to any external environmental stressors (temperature, groundwaters, microbes, other wastes) following disposal in landfill or other near-surface facilities [110].

3.26 Electrical and WEEE (group 12)

Electrical and WEEE items include contaminated or potentially-contaminated fluorescent tubes, x-ray tubes, battery chargers and printers/laptops. These wastes are problematic because they often have a complex geometry that is difficult to swab effectively and contain a mixture of different materials.

Lower activity electrical items have previously been incinerated, as the component materials (e.g. non-halogenated and halogenated plastics, rubber, cables) are included within the list of acceptable or provisionally acceptable materials in the LLWR WAC for combustible wastes [107].

No relevant UK experience for higher-activity WEEE has been identified in this review.


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4 International perspective

Many of the problematic wastes that are included in the UK’s inventory are also defined as problematic in other countries. In this section, a brief introduction is provided to work programmes on problematic waste in France and the USA, together with references to more detailed reports. These are of particular interest because both countries have wastes from a range of nuclear activities including defence, R&D, a range of reactor types, and fuel reprocessing and manufacturing activities. The strategies and programmes developed to manage problematic waste in other countries are not included here.

4.1 French programme

Since 2007, France has been implementing a national plan to address the key challenges for radioactive waste management, in particular problematic waste management [37]. This plan11 summarises the existing management methods for radioactive materials and waste. For problematic wastes with no final management solution, the PNGMDR sets deadlines for the definition of new management methods and organises research and studies to support the creation of new facilities or the improvement of existing facilities as needed.

The PNGMDR develops the strategy for managing problematic wastes in France. The purpose of the strategy is to target efforts more efficiently as the PNGMDR does not address every problematic waste that can be found in France but the most significant ones. The first PNGMDR was issued in 2007 and it is updated every three years to reflect the progress achieved and identify future objectives.

In the 2010-2012 PNGMDR, an inventory of problematic wastes was collated and analysed. Five waste categories considered to be “priorities” were identified by the working group as effectively corresponding to the definition of waste with no disposal solution [112]:

certain asbestos waste liable to release fibres (loose asbestos)

waste containing potentially hydrosoluble mercury compounds

non-incinerable organic oils and liquids, owing to their physico-chemical specifications and their activity

activated accelerator parts

batteries

The work programme has progressed solutions for asbestos (cement encapsulation, thermal destruction or vitrification) and batteries (defined disposal routes) to the point that these are no longer considered problematic. Once a solution has been found for a problematic waste group, it is removed from the plan.

The approach under development for mercury is a sulphur stabilisation process, similar to that being considered in the UK (Section 3.3). Incineration of organic wastes, sludges and solvents as well as metal melting technologies have been applied for waste treatment in France [111]. Oils and solvents that are unsuitable for incineration may be washed/evaporated or pre-treated using an oxygen plasma process prior to management via existing effluent treatment plants; however, these processes are not yet available on an industrial scale [112].

11 The national plan on management of radioactive materials and waste, which in French is the “Plan national de gestion des matieres et dechets radioactifs” or PNGMDR.


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4.2 US DOE programme

The US DOE also has a programme of work to consider problematic waste streams [113]. The work programme was discussed at the Waste Management conference in 2014 [114],

which highlighted issues such as the availability of appropriate treatment technologies to meet land disposal restriction (LDR) requirements

12 and of permitted disposal facilities

able to accept higher activity mixed waste along with the necessary funding to identify, characterise, treat and dispose of the DOE mixed waste inventory.

Waste and material data is collated within the Waste Information Management System (WIMS) [115], which provides DOE Headquarters and site waste managers with the tools necessary to visualize, understand, and manage the vast volumes, categories, and problems of forecasted waste streams.

Treatment of the following range of particularly challenging mixed waste streams from Sandia National Laboratories (SNL) is described in [116]:

septic tank residues with biological activity and gas generation issues

absorbed oil containing high tritium activity

mock high explosive (HE) materials, containing high barium nitrate concentrations

sealed sources

explosives (thermal batteries, timer-drivers)

oil with high mercury

spark gap tubes

manufactured items <60 mm

Experience gained from the accelerated closure of the US DOE site at Rocky Flats is captured in a detailed report that discusses both technical/scientific and policy/programmatic issues addressed during the project [117]. Early in the project, orphan wastes were overlooked as a result of more pressing special nuclear material (SNM) packaging and disposition issues. As these SNM issues were resolved, orphan waste treatment and disposal gained visibility as a critical issue.

Orphan wastes, including organic and mercury contaminated radioactive wastes were some of the most complex from a closure project perspective, because facilities permitted to treat the hazardous component were not licensed to handle radioactive waste. One particular issue that caused ongoing problems was the identification, collection, and disposal of excess chemicals. There were numerous instances of legacy chemicals, many with hazardous, oxidizing or explosive characteristics that continued to be discovered as site demolition proceeded. Chemicals that were radioactive or retrieved from radiologically controlled areas, while small in volume, were extremely expensive to dispose of, one of the most extreme examples being one truckload costing over one million dollars. Two final types of material, laboratory returns and sources became a problem in 2005, not because they were inherently difficult to dispose of, but because the waste management infrastructure was being reduced and disposal of these materials had not been properly anticipated and planned [117].

At Rocky Flats, all orphan wastes were placed on a tracking system, regardless of the volume or number of containers. The status of treatment and disposal options was

12 Noting that in the US, several problematic waste groups including contaminated mercury and organic wastes are described as mixed waste, because they contain both radioactive waste subject to Atomic Energy Act (AEA) and a hazardous waste component regulated under the Resource Conservation and Recovery Act (RCRA).


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reported routinely at the US DOE headquarters level to provide visibility. Because of the myriad factors affecting the disposition of orphan wastes, it was considered essential that actions and responsible parties be clearly identified [117].

4.3 Experience of specific technologies in use worldwide

This section includes signposting to sources of information about specific technologies that are applicable to more than one of the waste groups discussed in Section 3. It focuses on the following topics of broad applicability to problematic waste where there is significant international experience:

polymer encapsulation

thermal treatment

drying of mobile wastes

Techniques such as cementation and compaction that comprise the baseline option for many radioactive wastes are not included here but significant information about these options and their applicability to different wastes is available elsewhere (including from RWM [41, 61], and LLW Repository Ltd) [64, 118].

4.3.1 Polymer encapsulation

Polymer encapsulation has previously been used in France, Germany, USA, Canada and Japan [45]. The range of polymers considered for use includes bitumen, polyethylene, epoxy resins, polyester resins and urea formaldehyde (Section 3.1.2 of [41]).

RWM has compiled guidance on the use of organic polymers for encapsulation of ILW [47], which includes examples of previous experience of polymer encapsulation for ion exchange resins, Magnox FED, aluminium-clad uranium fuel and isotope cartridges, reactive metals, radium-contaminated waste and pyrochemical residues.

4.3.2 Thermal treatment

Thermal treatment is commonly used for LLW (e.g. incineration, metal melting [78]) and is under development for ILW and PCM (e.g. plasma vitrification, pyrolysis, HIP) within the UK nuclear industry, with demonstration facilities available and being developed by the NDA, Sellafield Ltd and NNL through the thermal IPT and significant overseas experience (listed in Table 5). A review of the wasteform evolution of thermally-treated ILW and PCM, to support their suitability for disposal in a GDF, is presented in Section 7.4 of [41].

Table 5: Compilation of UK and international experience in high-temperature waste treatment technology

Location High temperature technology

Level of development (including whether facilities for treatment of radioactive waste, “active” systems are available)

Australia HIP Full-scale inactive systems, active systems being developed

Belgium Hydrocarbon-fed torch Industrial facility: solids, liquids and ion exchange resins [119]

Bulgaria Plasma vitrification Full-scale plant under construction at Kozloduy NPP, Bulgaria (Belgian technology)


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France

Cold Crucible Induction Melting

Fully operational facility at La Hague, experimental facility at Marcoule

Supercritical water oxidation (SCWO)

Low temperature incinerator for liquid wastes processing

Germany Plasma vitrification In development but operational plant available only for hazardous waste, not for nuclear waste

Japan Plasma vitrification Active system for ILW

Russia

Plasma vitrification Full-scale active system

Cold crucible induction melters

Full-scale active system

South Korea

Cold crucible induction melter

Operating facility for ILW [120]

Plasma arc, plasma torch vitrification

Inactive, pilot scale systems

Sweden Plasma vitrification Inactive pilot plant

Switzerland Plasma vitrification Full-scale active operation with LLW (US technology)

UK

Geomelt®, Joule heated in-situ or in-container vitrification

Demonstration facility

Plasma vitrification Inactive, pilot scale cold crucible and refractory lined melters

HIP Active systems (for PCM and ILW) in development

USA

Joule Heated Ceramic Melter

Full-scale active melter systems

Pyrolysis of organic resins

Full-scale active systems

Slurry-fed cyclone combustion melter

Trial scale with LLW simulant

Carbon electrode melter Trial scale with LLW simulant

Plasma torch-fired cupola furnace

Trial scale with LLW simulant


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Geomelt®, Joule heated in-situ or in-container vitrification

Demonstrated at large-scale at Los Alamos National Laboratory

4.3.3 Drying of mobile wastes

In-drum thermal drying is used for drying contaminated wet solids (e.g. sludges, resins and filter elements), liquid concentrates and decontamination solutions to a solid cake [121, see Section 4.2.7 for illustration].

Similar systems were proposed by GNS for treatment of sludges and ion exchange resins in MOSAIK casks. Vacuum drying trials were conducted by Magnox Ltd at Bradwell in 2013, where two tanks were emptied using the GNS FAVORIT® plant. Sludge and ion exchange material have been dried and the moisture content of the final waste product shown to be less than 1 % [43]. An alternative plant, the Advanced Vacuum Drying System (AVDS) developed by MechaTech Systems has been used by Magnox Ltd at Berkeley to dry sludge and resin, reducing moisture content by as much as 99% and the volume by approximately half [122] (Figure 5).

Figure 5: MechaTech Systems Advanced Vacuum Drying System (AVDS) and simulant product obtained following trials [121]


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5 Uncertainties in problematic waste management

A range of technical uncertainties are associated with the management of UK problematic wastes. Those identified by previous work, in particular the Gate A paper for the management of problematic waste [3] and initial work on problematic wastes conducted on behalf of RWM [6], LLWR [7, 10] and NDA [8, 9], include:

inadequate characterisation, resulting in poor quality inventory data

timing of waste arisings and site lifetime plans

availability (including capability and capacity) of treatment facilities

availability of transport containers, particularly for unpackaged waste

Other uncertainties include potential stakeholder concerns if problematic waste management leads to changes to existing plans, such as if sites start to receive and treat or store waste from other sites [3]. Opportunities for improved problematic waste management are identified in the NDA’s Gate B paper [123].

5.1 Inadequate characterisation

It has been recognised that the quality of data for streams included in the problematic waste inventory is variable, with particularly limited data for volumetric and non-radiological properties [6]. Data for some waste streams that are expected to arise during future decommissioning or final site clearance is limited to the waste type and location of origin (e.g. area of site or building number). Many entries within the inventory do not have volumes specified. There is also potential for uncertainty on radiological categorisation to lead to duplication between the two inventories.

In 2015/16 about 54% of the LAW by volume was made up of undefined waste; i.e. waste for which insufficient characterisation has been undertaken or for which there is insufficient information available to formally include them in another group [7]. Work has been undertaken in 2016 to assign “other” and “undefined” waste to specific waste groups, in conjunction with the Community of Practice, and so these groups are no longer included in Table 1.

Many uncertainties around the properties of the waste are only likely to become clearer at the time of retrieval and subsequent characterisation. This leads to risks with currently projected costs and timescales for treatment of problematic radioactive wastes as they are based on assumptions [3]. Doing further work to more accurately determine volumes and identify the root causes of the problematic status of the different entries could lead to more efficient use of the problematic waste inventory to target specific waste groups and reduce the overall volume of problematic waste [7]. Work is ongoing within the nuclear industry on characterisation of radioactive wastes, including R&D co-ordinated by the NWDRF working group on characterisation [124]. There are two aspects to this problem:

a lack of characterisation capability for the specific waste types identified, either across the industry or at particular site

prioritisation relative to other wastes, because often problematic waste does not pose a significant or immediate risk/hazard

Conducting fit-for-purpose characterisation activities would provide more information about the physical, chemical and radiological form of the waste, which in turn would enable opportunities to process specific streams within existing treatment facilities or with similar problematic waste arising on the same timescales across the industry to be identified and implemented as appropriate.


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5.2 Time of arising

The time of arising of problematic waste streams is not available for the majority of waste streams in the inventory. There are many assumptions in the current plans for the treatment of problematic radioactive waste at each site, including unknowns regarding which treatment techniques may be employed in the future and large uncertainties relating to the inventories of problematic wastes, as discussed above [3]. This results in further uncertainties relating to the availability of treatment facilities at a suitable time.

Even where these data are included, this is liable to change for wastes arising in future as a result of changes to site lifetime plans. Lifetime plans are reviewed on a regular basis for NDA sites. In particular, the EDF sites may receive life extensions to the AGR reactors, which would extend the duration of operations and delay decommissioning activities.

5.3 Availability of treatment or disposal facilities

Uncertainties are associated with the operating dates for planned treatment or disposal facilities, depending on the stage of planning, construction or commissioning. For existing facilities there are further uncertainties regarding the potential for extending the operational life beyond that currently planned.

There is potential for some problematic wastes to be treated in existing treatment plants, either on other sites or within the supply chain. Existing treatment plants are generally designed to treat specific waste streams such that, although potentially capable of treating a wider range of materials, there is uncertainty regarding their capability and capacity (both volumetric and radiological) to accept additional problematic wastes [9]. Potential constraints, including existing WAC, and opportunities to use existing facilities for HAW were examined in [9], which identified the following specific uncertainties:

opportunities to extend the life/modify existing plants to accept a wider range of waste types may not be possible until they complete their current mission

site-wide schedule constraints (e.g. the start of Care and Maintenance) may also prevent plant lifetimes being extended at some sites

Other uncertainties exist where problematic waste has a proposed route but this has not been confirmed by completing the disposability assessment process, for either the LLWR or a GDF as applicable. For some sites, the use of treatment or disposal facilities on other sites may not be compatible with national policies or strategies, or with site end states, particularly for those sites with accelerated programmes [7].

For some problematic wastes, specialist treatment facilities will be required (e.g. mercury, oils). Due to the small volumes and challenging physical/chemical properties of many problematic wastes, it can be relatively time-consuming and expensive (on a price per cubic metre basis) to develop new treatment technologies or management routes. This increases the uncertainty within the site or SLC costs and schedules, as identified in relation to inadequate characterisation [3].

In the case where similar problematic wastes occur on several sites, efficiencies could be gained by sharing technology/experimental trials/disposability assessments/safety cases between sites, developing a centralised treatment capability and transporting waste from other sites or developing mobile treatment facilities [1].

5.4 Availability of transport containers

The Gate A paper for problematic waste management [3] identified the risk that transport containers will be needed to transport raw waste off sites. This leads to uncertainty regarding the use of treatment facilities at other sites for the management of problematic wastes, which are particularly significant for mobile wastes, such as liquids [3].


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6 Summary and conclusions

This paper summarises work that has been completed in the UK and overseas to identify and develop waste management solutions for problematic wastes.

Development of the problematic waste inventory

The development of the problematic waste inventory is described in Section 2.1. Problematic wastes are identified by waste owners and, because each site has different waste management arrangements, a waste group that is currently problematic at one site may have a defined route at another site. Therefore, the inclusion of a waste group in this report does not mean that all similar wastes are problematic.

Wastes may be problematic for a range of reasons, which have been used to inform the development of the problematic waste inventory as follows:

wastes with an unknown provenance/inventory or insufficient characterisation information to enable appropriate waste routing are included in the bulk, mixed and historically conditioned/containerised waste groups, which comprise a significant proportion of the problematic waste inventory by volume; redundant transport containers may also fit within this category

wastes that have a specific additional chemical or physical hazard include mercury, asbestos, oils and oily waste, solvents and sources

wastes that are unsuitable for a standard treatment process include ion exchange resins, reactive metals, pyrochemical waste and chloride and halide-based powders

wastes that pose issues to the disposability of a waste package include waste containing liquids, filters, bulk fines and particulates, absorbent materials, waste failing the LLWR discrete items limit, LAW graphite, FED and FED-contaminated wastes, pressurised waste, putrescible and cellulosic materials, lead and chemotoxic metals, PCM (exceeding fissile limits) and LAW sources

wastes that pose operational or interim storage issues include MAC with high dose rates, physically awkward wastes and metallic items, sludges and tritium-contaminated waste and radium/thorium/americium-contaminated waste

wastes that consist of complex mixtures of hazardous material include batteries, electrical and WEEE items, and some streams within the liquid-containing waste and PCM waste groups

This report focuses on waste identified as being problematic predominantly for technical reasons, as opposed to as a result of uncertainty about their physical, chemical or radiological properties. Uncertainties are discussed further in Section 0.

Existing treatment and disposal routes for problematic wastes

Treatment technologies available for problematic LAW and HAW were reviewed in 2014/15 [9, 10] and the scope and results of these reviews are summarised in Section 2.2. For each problematic waste group, this report identifies what waste is included, why it is problematic and, based on a review of published literature, identifies any treatment processes and technologies that have previously been implemented in the UK and overseas.

A wide range of existing treatment and disposal routes have been identified for some problematic waste groups, together with relevant experience from facilities that are no longer operational. The review points to further information on potential management routes for both LAW and HAW problematic wastes, including on-site plants, supply chain capability and overseas facilities where experience within the UK is limited.


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Waste groups that are not included in the 2016 problematic waste inventory as a result of successful treatment are omitted from this report; however, it is noted that there is relevant experience within the nuclear industry for alkali metals (e.g. NaK coolant), isotope cartridges and zinc bromide (used as shielding in cell windows), should such items be identified in future.

The topic of problematic waste with unknown provenance/inventory or insufficient characterisation is not specifically considered in this report, because the lack of data prevents identification of relevant previous work.

Gap analysis

This review has identified gaps in the availability of treatment or disposal routes for the following waste groups and sub-groups:

high-alpha contaminated oils

higher-activity mercury

higher-activity putrescible/cellulosic waste

a small volume of operational higher-activity asbestos-contaminated wastes (noting that a larger volume may arise during final site clearance)

higher-activity electrical and WEEE waste

pressurised waste

redundant transport containers

There are also a limited range of management routes currently available for the following sub-groups:

a treatment technology for alkali, lead-acid or lithium-ion batteries is available in the US, but has not yet been implemented in the UK

MAC and physically awkward waste

waste failing the LLWR discrete items limit

containerised waste that may contain liquids (e.g. concrete-lined drums)

PCM that is not compatible with the supercompaction baseline

Identification of barriers to the management of problematic waste

Insufficient characterisation data to support identification of appropriate treatment or disposal routes is one of the most significant barriers to the management of problematic waste. With improved characterisation, a proportion of these wastes may be able to be managed through existing routes [10].

Other barriers include the CFA for treatment and disposal facilities, the availability of treatment technologies for specific problematic wastes, as identified in the gap analysis above, and compliance with transport requirements. These are discussed in turn below.

The existing WAC for treatment facilities is a barrier to the treatment of a proportion of the HAW problematic waste. Reference [9] identified the potential to extend the WAC of some HAW facilities to include a wider range of waste types and a range of constraints. Further work is needed to explore these opportunities and to consider whether there is potential to extend the WAC of LAW treatment facilities to accommodate some lower-end HAW.

The WAC for the LLWR [64] contains limits on hazardous materials (e.g. asbestos, mercury, lead), free liquids, unimmobilised particulate and discrete items that are barriers for disposal of some problematic waste. Work is currently ongoing to address some of these topics, including leach testing of immobilised mercury and developing options for


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discrete items. The range of applicable WPS for disposal to a GDF also includes constraints relating to hazardous materials, free liquids and unimmobilised particulate that may result in waste being identified as problematic.

For waste that is not compatible with standard cement-encapsulation processes, work is currently underway to overcome barriers to the implementation of thermal treatment technologies for HAW (as discussed in Section 4.3.2). Other specialist treatment technologies may be required to address the gaps identified above if HAW problematic waste cannot be managed via existing processes and facilities.

Transport is a potential barrier for the movement of raw waste to off-site treatment facilities and, for some problematic wastes, compliance with regulatory requirements for pressurisation and safe fissile mass may be barriers to packaging these wastes for transport and subsequent disposal. Another barrier is the availability of larger containers for packaging and transport of the waste, and work is ongoing to develop concept designs and implementation plans for a larger waste container and associated larger transport container.



7 References

1 NDA, Integrated Waste Management: NDA Higher Activity Waste Strategy, May 2016. https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/522435/NDA_Higher_Activity_Waste_Strategy_2016.pdf

2 DECC, The Scottish Government, Welsh Government and Northern Ireland DOE, UK Strategy for the Management of Solid Low Level Waste from the Nuclear Industry, February 2016. https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/497114/NI_LLW_Strategy_Final.pdf

3 NDA, Improved Management of Problematic Radioactive Waste: Credible Options (Gate A), Report no. 25604203, September 2016. 4 NDA, Higher Activity Waste Treatment Framework, NDA Report 23792960, October 2015. 5 NDA, Geological Disposal: Upstream Optioneering Phase 2 Overview, Technical Note no. 16734027, June 2012.

https://rwm.nda.gov.uk/publication/geological-disposal-upstream-optioneering-phase-2-overview-june-2012/ 6 C. Hamblin, R. Thied, T. Turner, S. Wickham, S. Doudou, J. McTeer, B. Porritt and R. Woodcock, Upstream Optioneering: Optimised Management of

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55

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93 http://www.nnl.co.uk/media/1902/nnl-tech-conference-15-poster-wmd-a709-pilot-plant-ops-howard-greenwood.pdf 94 NDA, Encapsulation of GLEEP Fuel at Harwell (Final Stage – Close Out of Action Points), Summary of Assessment Report, February 2011. 95 M. Ashton, Sellafield Plutonium Contaminated Material Strategy, Sellafield Ltd report no. PCMSSG(1)P01, November 2011. 96 LLW Repository Ltd, The LLWR Environmental Safety Case: Assessment of Discrete Items and Basis for WAC, LLWR/ESC/R(13)10055, August 2013. 97 LLW Repository Ltd, National Waste Programme: Management of Waste Failing the Discrete Item Limit, Feasibility Study, NWP-REP-139, Issue 1,

December 2016. 98 NDA, Geological Disposal: Review of Baseline Assumptions Regarding Disposal of Core Graphite in a Geological Disposal Facility, NDA Technical

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99 NDA, Higher Activity Waste - Operational Graphite Management Strategy (Gate A&B) – v2.0, Report no. SMS/TS/D1-HAW-10/001/B Doc ID: 21083563, August 2013. https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/457086/Operational_graphite_management_strategy_credible_and_preferred_options__Gates_A_and_B_.pdf

100 NDA, Higher Activity Waste: The Long-term Management of Reactor Core Graphite Waste Credible Options (Gate A), September 2013. https://tools.nda.gov.uk/publication/the-long-term-management-of-reactor-core-graphite-credible-options-gate-a/

101 International Atomic Energy Agency, Characterization, Treatment and Conditioning of Radioactive Graphite from Decommissioning of Nuclear Reactors, IAEA-TECDOC-1521, September 2006.

102 A. Wareing, L. Abrahamsen, A. Banford, M. Metcalfe, W. von Lensa, CARBOWASTE: Treatment and Disposal of Irradiated Graphite and Other Carbonaceous Waste, Deliverable D-0.3.12, Final Publishable CARBOWASTE Report

103 NDA RWMD, Packaging of Trawsfynydd Desiccant Waste (Conceptual stage) Summary of Assessment Report, Issue date of Assessment Report: 26 April 2007.

104 P. Winkle, Letter to SEPA: Radioactive Substances Act 1993 EDF Energy Nuclear Generation Ltd, Torness Power Station , Certificate of Authorisation – RSA/A/0070116, Application for Variation to the Certificate of Authorisation, November 2013. https://www.sepa.org.uk/media/113165/app-1-torness-application.pdf

105 Magnox and LLW Repository Ltd, Joint Waste Management Plan 2015/16 to 2019/20, Issue 3, January 2015. http://llwrsite.com/wp-content/uploads/2015/04/Magnox-JWMP-September-2015.pdf

106 P.N. Humphreys, A. Laws and J. Dawson, A Review of Cellulose Degradation and the Fate of Degradation Products Under Repository Conditions, Report no. SERCO/TAS/002274/001 Issue 2, September 2010.

107 LLW Repository Ltd, Waste Acceptance Criteria – Combustible Waste Treatment, Report no. WSC-WAC-COM, Version 3.0, April 2012. http://llwrsite.com/customer-portal/resource/waste-acceptance-criteria-combustible-wsc-wac-com-version3-0/

108 G&P Batteries, Storage of Waste Batteries Risk Assessment, http://www.recycle-more.co.uk/files/risk_assessment.pdf 109 US EPA, Part IV Environmental Protection Agency 43 CFR parts 268 and 271, Land Disposal Restrictions: National treatment variance to designate

new treatment subcategories for radioactively-contaminated cadmium-, mercury- and silver-containing batteries; Final rule and proposed rule, Federal Register, Vol. 67, No 194, Monday, October 7, 2002 / Rules and Regulations

http://www.nnl.co.uk/media/1902/nnl-tech-conference-15-poster-wmd-a709-pilot-plant-ops-howard-greenwood.pdf

https://rwm.nda.gov.uk/publication/review-of-baseline-assumptions-regarding-disposal-of-core-graphite-in-a-geological-disposal-facility-nuclear-decommissioning-authority-16495644-16495644-2012/

https://rwm.nda.gov.uk/publication/review-of-baseline-assumptions-regarding-disposal-of-core-graphite-in-a-geological-disposal-facility-nuclear-decommissioning-authority-16495644-16495644-2012/

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/457086/Operational_graphite_management_strategy_credible_and_preferred_options__Gates_A_and_B_.pdf

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/457086/Operational_graphite_management_strategy_credible_and_preferred_options__Gates_A_and_B_.pdf

https://tools.nda.gov.uk/publication/the-long-term-management-of-reactor-core-graphite-credible-options-gate-a/

https://www.sepa.org.uk/media/113165/app-1-torness-application.pdf

https://www.sepa.org.uk/media/113165/app-1-torness-application.pdf

http://llwrsite.com/wp-content/uploads/2015/04/Magnox-JWMP-September-2015.pdf

http://llwrsite.com/wp-content/uploads/2015/04/Magnox-JWMP-September-2015.pdf

http://llwrsite.com/customer-portal/resource/waste-acceptance-criteria-combustible-wsc-wac-com-version3-0/

http://www.recycle-more.co.uk/files/risk_assessment.pdf


56

110 W. Fortune and N. Ranek, Land Disposal Restrictions Treatment Standards: Compliance Strategies for Four Types of Mixed Wastes, WM’06 Conference, Tuscon, Arizona, February 26 – March 2, 2006

111 M. Dutton, CoWRM Options, November 2004. http://webarchive.nationalarchives.gov.uk/20130503173700/http://corwm.decc.gov.uk/assets/corwm/pre-nov%202007%20doc%20archive/plenary%20papers/2004/november%20meeting%2004/791-%20cowrm%20options.pdf

112 F. Kaloustian (2016), Overview of the Problematic Waste Management Strategy in France, ONR: TRIM Folder 1.18.1208. File ref. 2016/361131. 113 http://energy.gov/em/office-environmental-management 114 D. Blauvelt, WM2014 Conference Panel Report, PANEL SESSION 73: US DOE Mixed Waste: Addressing Proposals for Dealing with Problematic

Waste Streams and Policy Changes Affecting Waste Disposition, 2014. http://www.wmsym.org/archives/2014/panelreports/PanelReportSession073.pdf.

115 Applied Research Center, Florida International University, Waste Information Management System, 2014. http://www.emwims.org/ 116 S. D. Carson, P. K. Peterson, E. M. Dinsmore, D. Meyer, M. T. Spoerner, Treating Small-Volume Waste Streams: The Devil is in the Details, WM-4474,

WM ’04 Conference, February 29-March 4, 2004, Tucson, AZ. 117 F.R. Lockhart, Rocky Flats Closure Legacy Report, August 2006. http://www.lm.doe.gov/Rocky_Flats_Closure.pdf#Apx2 118 LLW Repository Ltd, Waste Acceptance Criteria – Supercompactable Waste Treatment, Report no. WSC-WAC-SUP, Version 3.0, April 2012. 119 J. Deckers, The innovative plasma tilting furnace for treatment of radioactive and problematic chemical waste, Presentation given in London, November

2015. http://www.igdtp.eu/index.php/key-documents/doc_download/483-5-twg1-jan-decker-belgoprocess 120 K-H. Yang, S-W. Shin and C-K. Moon, Commissioning Tests of the Ulchin LLW Vitrification Facility In Korea, WM2009 Conference, March 1-5, 2009,

Phoenix, AZ. 121 International Atomic Energy Agency, Mobile Processing Systems for Radioactive Waste Management, ISBN 978–92–0–141010–8, IAEA, Vienna

http://www-pub.iaea.org/MTCD/Publications/PDF/Pub1621_web.pdf. 122 NDA, Insight into Nuclear Decommissioning, Issue 14, June 2014, p.6.

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/461258/Insight_into_nuclear_decommissioning_-_June_2014_Newsletter.pdf

123 LLWR and RWM, Improved Management of Problematic Radioactive Wastes Short, Medium and Long Term Preferred Options (Gate B), LLWR Report no. NWP/REP/141, RWM Technical Note TN18505, April 2017.

124 D. Wickenden, Webinar slides from NWDRF Characterisation Working Group meeting, September 2015. www.nnl.co.uk/media/2012/webinar-slides-charac-dw.pptx

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http://www.nnl.co.uk/media/2012/webinar-slides-charac-dw.pptx


A-1

Appendix A Bibliography

This Appendix provides further details of the references used to compile the summary of previous work presented in the main report. Generic references that cover a wide range of problematic waste types (either a group or component of a group discussed in the main report) are described in Appendix A1. References that focus on a specific treatment technology that can be applied to one or more problematic waste types are described in Appendix A2. In Appendix A3, references that focus on a specific problematic waste type, as well as potential applicable treatment techniques, are detailed. The focus of Appendices A2 and A3 is slightly different, and no references are duplicated between the two tables. Therefore, it is intended that both tables should be consulted, if the reader is interested in a particular waste type, to ensure that information on both applicable techniques and the waste stream is covered.


A-2

A1 Generic references

This table lists the references used in the main report that cover a wide range of problematic waste types and treatment technologies.

Reference Title of study Summary of key points Author Year Applicable waste types

3

Improved Management of Problematic Radioactive Waste: Credible Options (Gate A)

This is a Gate A paper which uses the findings from previous studies on problematic wastes in the UK to identify potential strategic options to be taken forward for the management of these wastes. 17 potential options for the improved management of problematic radioactive waste were identified, and 12 of these were identified as being credible. Some credible options are very similar from a strategic point of view, but the commercial case, financial case and management case are likely to be very different, so they have been described separately. However, for convenience, the similar credible options have then been combined, in this Gate A paper, to form five consolidated strategic options that will be taken forward for analysis in a Gate B paper. The five options are:

no change to current strategy

promoting timely characterisation of waste

improve knowledge transfer regarding problematic radioactive waste

share treatment facilities

make better use of the supply chain to treat problematic radioactive waste

NDA 2016 All problematic LAW and HAW at a high level


A-3


6

Upstream Optioneering: Optimised Management of Orphan Wastes

Information on the orphan wastes present at all major UK nuclear licensed sites and belonging to all major UK waste owners was compiled, and used to define generic orphan waste groups. All information was consolidated in a Microsoft Access database for ease of retrieval and analysis. The database allows high-level exploration of the UK orphan waste inventory by waste type, by waste owner and nuclear site, by potential treatment technology and, for many wastes, by raw volume.

A key conclusion was that there are technologies available for the treatment of the 35 generic HAW orphan types identified within this study. A treatment matrix (Appendix D) that maps the applicability of treatment technologies to the generic orphan waste groups was developed. This matrix shows that a minimum of one potential treatment technology is applicable to each generic orphan group. A technology table (Appendix E) was also produced. This table lists all of the treatment technologies applicable to the treatment of problematic wastes and summaries their advantages and disadvantages, as well as their use in the UK or overseas.

Wiring diagrams (Appendix H) were also prepared for each generic orphan waste group that show the technical needs, risks and opportunities associated with the implementation of waste management routes and treatment technologies for each generic orphan group.

C. Hamblin, R. Thied, T. Turner, S. Wickham, S. Doudou, J. McTeer, B. Porritt and R. Woodcock

2013 All HAW problematic waste groups


A-4


7 LLW Problematic Waste Summary FY 2015/16

This paper provides a high-level summary of the findings from the FY2015/16 update of the LAW problematic waste inventory and, in particular, focuses on describing the proportions of waste in the inventory in terms of:

radiological classification

the physical/chemical types of problematic waste

the reason for the waste to be classified as problematic

The LAW inventory contained approximately 13,700 m3 of waste,

with significant proportions of undefined waste (~54% by volume), asbestos (~21%) and bulk waste (~16%, e.g. contaminated soils, concrete, rubble). The remaining 9% of waste by volume is made up of different waste streams including: sludge, lead, graphite, oils and solvents.

LLW Repository Ltd

2016

LLWR LAW groups, including: oils, solvents, graphite, lead, sludge, bulk waste, asbestos, undefined waste.

8

A UK Inventory of Problematic and Orphan Wastes – Management Options and Timing of Treatment

This study follows on from the previous exercise on problematic HAW (see entry above on ref. 6), with the aim of better defining the existing inventory of problematic wastes and enhance the database developed in ref. 6 to record data, information and assumptions about the nature of the waste and the expected timescales for its management, including the time of waste arising and the latest possible treatment dates.

The study included compilation of the treatment timing opportunities against key problematic waste groups across all UK sites (Table 2).

S. Doudou, S.M. Wickham and S.J. Palethorpe

2015 All HAW problematic waste groups


A-5


9 Report on the Assessment of WAC

This report identifies the potential to expand the WAC of existing UK treatment plants for HAW, with specific application to categories of problematic radioactive wastes, and records the timings of potential opportunities. For each treatment plant the following information is reported:

a description of the waste treatment process in the plant and the waste stream(s) planned for processing in the plant

a summary of the WAC, including specific exclusions, and drivers (e.g. store WAC, safety case, LoC constraints)

a summary of the constraints that may not allow the current WAC to be widened (e.g. safety case, planning permission, environmental permits, regulatory conditions)

a summary of how the WAC could be widened (with appropriate agreement) and a brief assessment of what would need to be done to widen the WAC

any physical constraints on receiving waste into the facility (e.g. container type, mass limit) and on sentencing waste into the associated store after treatment

the planned operating period for the treatment plant, and reasons for the timescales, to understand if they could be changed to accommodate the treatment of other wastes

Table 2 summarises the compatibility of problematic radioactive waste groups with treatment plants.

K. Carruthers, H. Godfrey, S. Doudou and S.M. Wickham

2015

All HAW problematic waste groups are considered for compatibility with existing treatment facility WAC


A-6


10

LLW problematic waste technology optioneering summary report

For priority problematic waste groups, this study identified optimum technologies for managing the key waste streams and made recommendations for progressing and implementing technologies in order to facilitate earlier management of the waste

Table 3 provides a summary of the relevant treatment technologies for a range of problematic groups.

Appendix 1 includes “wiring diagrams” for each of the key waste groups to illustrate the technologies available for the management of these wastes and the gaps and risks to deployment of those technologies.

The study highlighted the need for better characterisation for a significant number of the waste streams and, with improved characterisation, a proportion may be able to be managed through existing waste routes. Wastes from different owners could be collated and processed together; either when waste technologies are applicable to several waste types or where wastes of similar characteristics are present at different facilities, which has the potential to open new routes higher up the waste hierarchy.

LLW Repository Ltd NWP

B. Cummings

2016

Contaminated oil and oil-contaminated material, organic and inorganic ion exchange resins, radium-contaminated waste and surface-contaminated waste

12

Predisposal management of organic radioactive waste

This report identifies techniques for the treatment and conditioning of organic wastes, including non-destructive and destructive techniques (processes that chemically alter or destructively modify the organic nature of the waste). Treatment techniques against the identified organic waste groups are summarised in Table 3.

Examples also are given of successful applications of treatment techniques, including alkaline hydrolysis, drying/evaporation, distillation, direct immobilisation, compaction, incineration, pyrolysis, vitrification, plasma treatment and a range of oxidation processes. These are summarised in Table 6.

IAEA 2004

Rubber/plastic, cellulose, ion exchange resins, biological material, mixed solids, lubricants, organic solvents, other liquids


A-7


20

Magnox WRATs and Orphan Wastes Disposition Project (Project 01-2008/09N) Final Report

This study aimed at identifying proven or potential disposal routes for identified WRATs and orphan wastes for inclusion in Magnox Ltd waste management strategies, and identifying those wastes for which there are no appropriate disposal routes and thus inform future R&D projects.

The majority of wastes were identified as “potential” rather than “genuine” WRATs and Orphan wastes, many of which are anticipated future arisings. Information was also collated on a total of 39 potential treatment and/or disposal techniques. Table 4 provides the list of the orphan waste types and Tables 11 to 14 provide lists of identified treatment techniques.

A. Arden and D. Varley

2009

A large number of waste types similar to those included in the 35 HAW groups

26

Management of problematic waste and material generated during the decommissioning of nuclear facilities

This report identifies the form of problematic waste, typical hazards, possibilities for recovery and reuse and potential methods for processing and treatment, including examples of international experience where available.

IAEA 2006

Beryllium, sodium, cadmium, mercury, lead, cyanide, decontamination chemicals, asbestos, polychlorinated biphenyls

39

Waste Product Specification for Packing RHILW Drums in B462.27

This report gives the specification for the repackaging of Remote Handled Intermediate Level Waste (RHILW) in the B462.27 Head End Cells (HEC) on the Harwell site. The packed wasted is stored in the B462.27 Vault Store in 500-litre drums until the Harwell WEP is operational. The report includes a table of problematic wastes that require pre-treatment before storage in 500 litre drums and grouting (see Table 7).

T. Turner 2010

Liquids, bulk particulate, NaK residues, fire suppressant powders, reactive metals , salts


A-8


37

French National Plan for the Management of Radioactive Materials and Waste (PNGMDR)

This document is the French national plan and it addresses the key challenges for radioactive waste management, including problematic waste management. This plan summarises the existing management methods for radioactive materials and waste. For problematic wastes with no final management solution, the PNGMDR sets deadlines for the definition of new management methods and organises research and studies to support the creation of new facilities or the improvement of existing facilities as needed.

ASN 2012

Spent oils and solvents, asbestos-bearing waste, incinerable tritium-bearing waste, irradiated beryllium reflectors, absorbent reactor BF3 detectors, irradiated lead, irradiated aluminium, irradiated cadmium, uranyl nitrate, waste with boric acid, silica (ISOTOPCHIM) C-14, clean-up sludge of effluents, special ash, contaminated mercury, lead tower, cobalt waste, hafnium waste, bulb containing UF6, tritium-bearing distillates, and NaK coolant

112

Overview of the Problematic Waste Management Strategy in France

This is a note provided by an ONR secondée from ASN to the Problematic Waste IPT. It provides an overview of the problematic waste management strategy in France. This note includes a cross-comparison between the UK and French types of problematic wastes, which identifies a number of areas of synergy where bilateral exchange may accelerate progress in the treatment of these wastes.

F. Kaloustian 2016

Asbestos, mercury, oils and solvents, activated accelerator parts, batteries, tritium wastes, sealed sources, graphite, thorium, sludges, lead, reactive metals


A-9


114

Panel Session 73: US DOE Mixed Waste: Addressing Proposals for Dealing with Problematic Waste Streams and Policy Changes Affecting Waste Disposition

This is a record of a Panel Discussion at the Waste Management conference of 2014. The discussion focused on progress made to resolve remaining issues surrounding primarily the disposition of US DOE high activity mixed waste and to examine any remaining challenges in this problematic waste category.

D. Blauvelt 2014 Mixed waste

116

Treating Small-Volume Waste Streams: The Devil is in the Details

This paper discusses several mixed waste (MW) types that have been particularly challenging at the Sandia National Laboratories (SNL) in Albuquerque, New Mexico. These wastes must be treated to meet the requirements agreed to by SNL, the US DOE and the New Mexico Environment Department (NMED) and formalised in SNL’s Site Treatment Plan.

Treatment issues for these wastes included potential biological activity and gas generation in the septage, high tritium activity in the absorbed oil, high barium nitrate concentration in the mock high explosive, determining if the sealed sources were in fact mixed waste, ensuring the thermal batteries and timer drivers had been fired, the mercury concentration in the waste oil, high radioactivity in the spark gap tubes, and the fact that macroencapsulation was the only viable treatment for certain manufactured items that were not covered by the debris rule.

The septage, explosives, high mercury oil, and spark gap tubes have been successfully treated. Treatment plans have been developed for the remaining wastes listed above and are being implemented. Details concerning issues resolution, waste treatment, and lessons learned are presented in the paper.

S.D. Carson, P.K. Peterson, E.M. Dinsmore, D. Meyer, and M.T. Spoerner

2004

Mixed waste including: septage, absorbed oil, mock high explosive, sealed sources, explosives (thermal batteries, timer-drivers), oil with high mercury, spark gap tubes, manufactured items <60 mm


A-10


117 Rocky Flats Closure Legacy report

This report was created to capture and preserve ground breaking analyses, strategies and decisions carried out at Rocky Flats in support of the accelerated closure effort. It presents the lessons learned during the course of accelerated closure.

At Rocky Flats, all orphan wastes were placed on a tracking system, regardless of the volume or number of containers.

Early in the project, orphan wastes existed in the shadow of more pressing special nuclear material (SNM) packaging and disposition issues. As these SNM issues were resolved, orphan waste treatment and disposal gained visibility as a critical issue.

Orphan wastes, including organic and mercury contaminated radioactive wastes and legacy chemicals, many with hazardous, oxidizing or explosive characteristics were the focus of this work programme, with laboratory returns and sources becoming problematic towards the end of the project.

F.R. Lockhart 2006 Mixed waste

121

Mobile processing systems for radioactive waste management

Examples of mobile processing systems for pre-treatment, treatment, conditioning, combined treatment and conditioning, and waste characterisation. Case studies on processing solid, liquid, gaseous and multiphase waste streams have been provided.

Techniques detailed include filtration, membrane and ion exchange resins to treat liquid ILW.

IAEA 2014 Oils, chemicals, cables, soils


A-11

A2 Technology-specific references

This table describes the references in the main report that focus on a particular treatment technique that can be applied to one or more types of problematic waste streams (either a group or component of a group discussed in the main report).


14

Processing Liquid Organic Wastes at The NNL Preston Laboratory

This paper describes the Oil Waste Leaching process, which is an industrialised process used for the treatment of contaminated oils and solvents. It was developed by the National Nuclear Laboratory (NNL). The process was originally developed for the treatment of a residue comprising sawdust which contained uranium-contaminated tributyl phosphate and odourless kerosene). This residue was successfully treated by stirring with weak aqueous sulphuric acid to displace the solvent from the sawdust and extract uranium from the organic phase to the aqueous phase. The solvent was easily separated from the bulk aqueous and solid and was suitable for disposal via non-radioactive waste routes. Over the years, the OWL process has been refined for a range of oils including “water emulsifiable” cutting oils, lubricating oils, hydraulic oils/fluids and “Fomblin” (fully fluorinated) oils.

The paper also describes additional treatment processes that are available for oily solids/sludges and solvents.

D. Coppersthwaite, H. Greenwood, T. Docrat, S. Allinson, R. Sultan and S. May

2013

Oils and solvents, including water emulsifiable oils, hydraulic oils/fluids and fluorinated oils

15

Development and Deployment of the ModulOX

TM Process

for the Destruction of Organically Contaminated Wastes

This paper describes a technology developed for the treatment of certain types of organic materials such as organically-contaminated tank waste (at the Savannah River Site and the Idaho National Engineering and Environmental Laboratory), organically-contaminated liquid effluents, chemical weapon agents, ion exchange resins and wastes containing organic chelating agents. The technique, developed by AEA Technology, is known as the ModulOX

TM process. It is a low-

temperature, low-pressure technology and uses catalysed hydrogen peroxide to oxidise organic material, with the main products being carbon dioxide, water and inorganic salts.

T.J. Abraham, M. Williams and J. Wilks

2004

Organically-contaminated liquid effluents, Organically-contaminated tank waste, chemical weapon agents, ion exchange resins and wastes containing organic chelating agents


A-12


16

A truly Industrial Solution for the Elimination of Radioactive Oils or Solvents

This paper describes a process developed by DewdropsTM

for the treatment of toxic waste oils and solvents. The process is based on the mineralisation of a wide range of radioactive organic wastes using chemical and biological oxidation mechanisms. The oxidised organic materials form predominately carbon dioxide, water and inorganic salts. The major benefit of the process lies in its room temperature and atmospheric pressure working conditions.

First the organic waste is oxidised using hydrogen peroxide with a catalyst in order to enhance biodegradability of the organic waste. Carefully selected microorganisms use the organic waste as an energy source for their metabolism. The aqueous phase is continuously separated from the biomass using cross flow filters. The output aqueous phase is treated with ozone to eliminate the remaining organic compounds. The radioactive elements and heavy metals usually found in lubricating oils are trapped by biomass which is recovered by centrifugation and mineralised either by methanisation or by ozonation technology. The mineral residue obtained is suitable for long range storage.

This paper details the procedure and the results obtained for a particular case at the Tricastin nuclear site of Areva NC (South France). The result of the tests was a radioactive waste reduction factor of 20.

A. Jacobs and W, Everett

2010

Oily and organic wastes including: several non-water soluble lubricating oils, alcohols, trichloroethylene (TCE) and tetrachlorethylene (PCE), and oils mixed with TCE and PCE


A-13


17 and 18 The Arvia

TM Process

for Oil Waste Destruction

This presentation outlines the different possible treatment

options for oily wastes and the challenges. The ArviaTM

process was presented as an alternative process for high-alpha oils that cannot be incinerated because they exceed the UK incinerator limits for alpha-emitting nuclides.

The adsorption, separation and destruction of the organics takes place in a single cell, using a fluidised bed of Nyex

TM (a

graphite flake which adsorbs organics), followed by settling. A current is then applied across the cells, which results in electrochemical oxidation of the organics, producing H2/CO2/CO/Cl2 gases and regenerating the adsorption media.

D. Wickenden and M. Lodge

2012 Oily and organic wastes

19

The innovative plasma tilting furnace for treatment of radioactive and problematic chemical waste

This presentation introduces a plasma technology that was developed in the 1960’s to treat problematic chemical wastes and was applied in 2004 to problematic radioactive wastes. With this plasma method, the organic material is vaporised in volatile hydrocarbons, carbon monoxide, etc. while non-combustible and other inorganic constituents are melted and transformed into glassy slag.

J. Deckers 2015

Organic wastes including oils and spent resins, mixtures of organic and inorganic wastes

21 Oil immobilization program at Sellafield: an innovative approach

This paper describes a test program at Sellafield in 2006 to apply the Nochar PetroBond® polymer treatment technique to immobilise oil wastes. It was shown that Nochar PetroBond® polymer systems were effective in the immobilisation of liquid hydrocarbon waste streams into a solid polymeric matrix, with no leaching of liquid.

H. Cassidy and D. Kelley

2007 Oil wastes


A-14


22

Nochar Petrobond® Absorbent Polymer Tritiated Oil Solidification

This report provides an analysis of the cost and performance of the Nochar PetroBond® absorbent polymer technology. The Nochar PetroBond® technology was demonstrated at Mound Large-Scale Demonstration and Deployment Project, in Miamisburg, Ohio to test its suitability for use as an absorbent and solidification agent for high-activity tritium vacuum pump oils. The Nochar PetroBond® absorbent is a polymer solidifying agent offered by the Nochar, Incorporated.

The purpose of this absorbing agent is to perform safe, efficient solidification of radioactive or mixed-waste oils and provide an acceptable means of transportation and disposal. Nochar PetroBond® polymer crystals have been found to be nontoxic, nonbiodegradable, and incinerable to less than 0.02% ash with an absorbent capacity of up to 15:1 (oil–to– solidification agent ratio by weight).

US DOE 2001 Tritiated oils

23

Pyrolysis/Steam Reforming Technology for Treatment of TRU Orphan Wastes

This paper describes the pyrolysis/steam reforming process developed by THOR Technologies to treat orphan wastes. The technique consists of two treatment stages: an in-drum pyrolysis process followed by a steam reforming process. In the first stage, TRU waste is heated in an inert environment to temperatures between 650°C and 750°C. Drums of waste were placed in an electrically heated pyrolysis chamber where water was evaporated, organics volatised and pyrolysed, and corrosives and reactive materials converted into non-hazardous oxides or carbonate compounds. The pyrolysed residue in the drums was an inert, inorganic, carbon char containing radioactive metals. In the second stage, the off-gases from the pyrolysis process were treated by a steam reformer and a downstream scrubber for neutralisation of acid gases. The off-gas produced by pyrolysis consists of water vapour, volatised organics, and acid gases from the decomposition of cellulosic materials (i.e., paper, wipes, anti-contamination clothing, etc.), plastics and other organics in the drums.

J.B. Mason, J. McKibbin, D. Schmoker and P. Bacala

2003

Liquids, volatile organic compounds (VOCs), hydrogen gas, corrosive acids or bases, reactive metals, or high concentrations of polychlorinated biphenyl (PCB)


A-15


27 Metallic Mercury Recycling – Final Report

This 1994 report outlines progress towards a process by which metallic mercury may be recycled and discusses the applicability of this method to the Hanford Site in the US. The treatment process consisted of an initial pinhole filtration step followed by additional pinhole filtrations if required, and an optional distillation step. The finished product is then analysed by liquid scintillation counting.

M.A. Beck 1994 Mercury wastes

42

THOR® Steam Reforming Technology for the Treatment of Ion Exchange Resins and More Complex Wastes Such as Fuel Reprocessing Wastes

This paper introduces the THOR® Steam reforming technique for treatment of radioactive waste and provides an overview of current THOR® projects and summarises the processes and outcomes of the regulatory and safety reviews that have been necessary for the THOR® process to gain acceptance in the US. The THOR® fluidized bed steam reforming process has been successfully operated for many years in the United States for the treatment of low- and intermediate-level radioactive wastes generated by commercial nuclear power plants. The principle waste stream that has been treated is ion exchange resins and dry active waste, but various liquids, sludges, and solid organic wastes have also been treated. The principle advantages of the THOR® process include: (a) high volume reduction on the order of 5:1 to 10:1 for ion exchange resins and up to 50:1 for high plastic content dry active waste streams depending on the waste type and waste characteristics, (b) environmentally compliant off-gas emissions, (c) reliable conversion of wastes into mineralized products that are durable and leach-resistant, and (d) no liquid effluents for treatment of most radioactive wastes.

J.B. Mason and C.A. Myers

2010

Ion exchange resins, liquids, sludges, solid organic wastes


A-16


44 The drip-dry waste job

This note describes two techniques used by the German radioactive waste management specialist, GNS, to dry out liquid waste at the Sizewell B and Bradwell sites in the UK. At Sizewell, the technique used consists of draining the spent ion exchange resins, packaging them into high-integrity MOSAIK type containers and removing their free water content. At Bradwell, a different technique (vacuum drying) was used to treat sludge and ion exchange resins.

J. Viermann 2014 Ion exchange resins and sludge

45 Polymer encapsulation of nuclear waste: alternatives to grout

This presentation introduces polymer encapsulation techniques as an alternative to grout encapsulation in the UK. Several examples of their use to treat ion exchange resins, metallic uranium, etc.

A. Green 2009

Ion exchange resins, graphite dust, GLEEP fuel, Oils in Imbiber Beads

46 Small scale ion exchange resin immobilisation trials

This report describes small scale trials undertaken by UKAEA on behalf of DSRL to test ion exchange resin immobilisation techniques. This included vacuum infiltration of the ion exchange resins with an epoxy polymer and also in drum mixing of the ion exchange resins with grout. The results showed that both methods can produce acceptably immobilised products. The vacuum infiltration method was proposed to be tested at a larger scale as it was less intrusive and minimises the potential for worker dose and release of contamination.

S. Farris 2009 Ion exchange resins


A-17


47

Geological Disposal: guidance on the use of organic polymers for the packaging of low heat generating wastes

This is an RWM-issued guidance note on the use of organic polymers to encapsulate low-heat generating waste. The guidance summarises lessons learnt from disposability assessments for packaging of ion exchange resins at Trawsfynydd and for other problematic waste types submitted by Magnox Ltd (including Harwell), DSRL, Sellafield Ltd and AWE. This guidance has identified three polymeric materials (i.e. polyethylene, epoxy resin and polyester resin) which are deemed by RWM to be suitable for the conditioning of ILW. Two others (i.e. bitumen and urea-formaldehyde resin), have a number of potentially significant drawbacks, which could preclude the endorsement of packaging proposals involving their use (although they may be suitable for small-scale use with particular waste types).

RWM 2015

Ion exchange resins, fuel elements debris, isotope cartridges, GLEEP fuel elements, pyrochemical residues

49

Formulation development for the encapsulation of borated resins

This report describes a formulation that was developed for the encapsulation of borated mixed bed ion exchange resins in cement. Borated ion exchange resin arose from treatment of pond water at AGR power stations. The spent ion exchange resins are transferred to resin storage tanks where they are stored in settled form, under water. The main requirements of cement systems intended for encapsulation of borated mixed bed ion exchange resin are the ability to withstand the following:

effect of borates on cement hydration

extremes of waste composition

effect of submersion in water

effect of γ-radiation

M. Constable, C.G. Howard, M.A. Johnson,

C.B. Jolliffe and D.V.C Jones

1994 Borated ion exchange resins


A-18


50 Immobilization of ion-exchange resins in cement

This report describes a formulation that was developed for the immobilisation of organic ion exchange resins of the polystyrene type in cement.

The formulation which was produced from a 9 to 1 blend of ground granulated Blast Furnace Slag (BFS) and Ordinary Portland Cement (OPC) containing 28% ion exchange resin in the water saturated form. If 6% microsilica is added to the blended cement, the waste loading can be increased to 36% (equivalent to 21.6% oven-dried resin by weight).

Results obtained from testing small scale samples show that acceptable products can be produced. The formulation was scaled up to produce 200 litre monoliths of cemented ion exchange resin (mixed anion and cation). These samples exhibited acceptable compressive strengths and dimensional stabilities.

C.G. Howard, C.B. Jolliffe and D.J. Lee

1991 Organic ion exchange resins


A-19


52

Impermeable Graphite Matrix (IGM) for the conditioning of spent Absorbers at Fukushima

This paper describes a new technique for conditioning of spent ion exchange resins used during the purification of large amounts of contaminated water at Fukushima. The resins are highly loaded with radioisotopes, like Cs-134/7, with significant dose rates and heat generation, and they also contain sodium chloride and other salts. Traditional treatment processes like cementation, melting, vitrification etc. face problems with respect to radiolysis, corrosion, non-compatibility with Chlorides, volatilization of Cs, etc.

The newly developed Impermeable Graphite Matrix (IGM) process has been investigated concerning its applicability on such spent inorganic absorbers. The IGM process mixes graphite with some percent of borosilicate glass, and compacts the mixture under pressure and temperature of 1,000 bar and 1,000 °C respectively. The resulting matrix is virtually free of pores, and the well-known characteristics of graphite and glass, concerning chemical and mechanical stability, leaching resistance, heat conductivity make it the ideal matrix to embed radioactive waste. The technical application would make use of the HIP process, with HIP containers (e.g. 400 L) being filled with premixed IGM/waste, evacuated, and processed through HIP autoclaves. The ion exchanger embedded IGM will be a long term stable waste package suitable for interim storage and final disposal.

J. Fachinger, W. Müller, G. Brähler, E. Marsat and K-H Grosse

2014

Inorganic ion exchange resins (including zeolites containing NaCl)

54 High-temperature calcination test

This reports presents the results of a pilot plant calcination test for treatment of acidic, hazardous, and radioactive sodium-bearing waste which is stored in stainless steel tanks at the Idaho Nuclear Technology and Engineering Center. Results of the testing indicate that sodium-bearing waste could be successfully calcined at 600°C.

R.D. Boardman, B.H. O’Brien, N.R. Soelberg, S.O. Bates, C.P. St Michel, R.A. Wood and B.J. Ward

2004 Sodium-bearing wastes


A-20


68

Review of stability of cemented grouted ion-exchange materials, sludges and flocs

A variety of waste sludges, ion exchange materials and flocs either currently or proposed for encapsulation in composite cements have been identified, and the performance of these wasteforms considered. No significant degradation of these waste forms is expected during long-term storage with possible exception of the following issues: gas evolution; release of liquid organics; carbonation; and radiation stability.

C. Utton and I.H. Godfrey

2010 Ion exchange materials, sludges, flocs

69 Dissolution treatment of depleted uranium waste

This report presents the results of experimental studies to test a technique that was developed at Lawrence Livermore National Laboratory (LLNL) to convert pyrophoric depleted uranium metal turnings to a solidified final product that can be transported to and buried at a permitted land disposal site. The technique consists of a 3-stage process, as follows: 1) pre-treatment 2) dissolution and 3) solidification. Each stage was developed following extensive experimentation.

D.D. Gates-Anderson, C.A. Laue and T.E. Fitch

2004 Pyrophoric material

69 Novel applications for Magnox dissolution

This report looks at possible opportunities to use a dissolution technology that is already being successfully applied in the UK for the dissolution of FED, for other wastes or materials of interest. The use of Magnox dissolution technology, or adaptations of it, could potentially yield significant benefits such as accelerating decommissioning, improving waste stability and reducing radioactive waste inventories. Potential applications of the technology that were identified in this study include: treating isotope cartridges irradiated in the Windscale piles and later in Calder Hall and Chapelcross, wastes arising from post operational clean-out of vaults and silos, decontamination of plant and items, and wastes from pond sludge volume reduction and stabilisation.

P. Sibley 2009 Magnox, isotope cartridges, sludges


A-21


71

Solidification of various radioactive residues by Géopolymère® with special emphasis on long-term stability

This paper presents a solidification technique called Geopolytec® that uses Géopolymère® binder to solidify sludge wastes. The product from this technique was considered to have excellent long-term structural, chemical and microbial stability, as well as satisfying high standards of contaminant retention. This technology gives a monolithic product which can be easily handled, stored and monitored. The technique has been tested in laboratory studies and in pilot-scale experiments.

E. Hermann, C. Kunze, R. Gatzweiler, G.Kießig and J. Davidovits

1999 Sludge

72

Behaviour of aluminosilicate inorganic matrix SIAL® during and after solidification of radioactive sludge and radioactive spent resins and their mixtures

This paper describes a type of geopolymer called SIAL® used for the immobilisation and solidification of sludges and ion exchange resins. Infrared spectroscopy measurements and X-ray analysis confirmed that the SIAL® matrix is mostly formed in an amorphous phase. Various remotely-operated devices have been designed, manufactured and successfully used for the radioactive sludge and sludge/resins mixture solidification at the Nuclear power plant (NPP) A-1, V-2 in Jaslovske Bohunice, at Mochovce NPP (Slovak Republic), at Dukovany NPP and at Temelin NPP (Czech Republic). The SIAL® matrix has been approved for radioactive waste immobilisation and solidification and for disposal by the Slovak and Czech Nuclear Regulatory Authorities.

P. Lichvar, M. Rozloznik and S. Sekely

2013 Sludge, ion exchange resins


A-22


86

The development and initial testing of the ice pig cleaning method for nuclear reprocessing plants

This paper describes initial testing and demonstration of the application of ice pigging technology to clean and displace radioactive materials from complex topology ducts and pipes, without the risk of having conventional pigs becoming lodged in a plant, coupled with the need to minimise effluent volumes.

Experimental data and operational experience from other industries demonstrates that whilst there is high shear, the ‘Ice Pig’ does not damage the surface of the pipe wall. A further attractive characteristic of the ’Ice Pig’ is that it eventually melts rendering it a simple effluent for processing by downstream processes.

The underpinning experimental work undertaken by Sellafield Limited enabled them to include the ice pigging process in baseline plans for Post Operations Clean Out and decommissioning activities.

A. Jenkins, J. Quarini and D. McBryde

2015 Metals, pipework, decommissioning waste


A-23


120

Commissioning tests of the Ulchin LLW vitrification facility In Korea

This paper describes the design and commissioning tests performed at Ulchin Vitrification Facility (UVF) in Korea. The UVF employs a vitrification process using a Cold Crucible Induction Melter (CCIM) to treat low-and intermediate-level radioactive waste. The UVF treats combustible dry active waste and low-level ion exchange resin. The UVF has a waste feeding capacity of 20 kg/h and consists of waste pre-treatment and feeding systems, a CCIM system, an off-gas treatment system, a dust recycling system, as well as other systems. Equipment tests, system functional tests and inactive performance tests were conducted. Furthermore, a long-term inactive test was carried out for 202 hours to evaluate the overall performance and stability of the facility. During the test, about 1,700 kg of surrogate waste was vitrified and 302 kg of waste glass was poured into a glass mould. As the gaseous emission from the UVF was one of the key issues for the operational license and public acceptance, 25 hazardous gases and dusts were analysed. The compressive strength of the waste glasses was also measured. Results showed that effluent concentrations of the off-gases and the quality of the waste glass met the regulatory limits with sufficient margins. Operation procedures of the UVF were revised based on experiences gained from the tests.

K-H. Yang, S-W. Shin and C-K. Moon

2009

Combustible dry active waste and low-level ion exchange resin


A-24

A3 Waste group specific references

This table describes the references in the main report that focus on a particular type of problematic waste (either a group or component of a group discussed in the main report). The references may also describe the applicable treatment techniques for that particular waste type.

Waste group or sub-group

Title of study Summary of key points Author Year Reference

Asbestos

LAW asbestos and asbestos containing waste Gate B (preferred options) study

Based on the UKRWI, asbestos and ACW was divided into three populations:

Non friable and low friability asbestos containing manufactured products

moderately friable asbestos containing manufactured products

highly friable and loose asbestos forms

The preferred option for group 1 is disposal to the LLWR and for group 3 is decay storage or on/near site disposal. If waste is classified as very low-level waste (VLLW) or lower-activity low-level waste (LA-LLW), disposal to an appropriately permitted landfill is the preferred option. Population 2 needs to be dealt with on a case-by-case basis as it falls under either group 1 or 3.

Ed Ghosn

LLWR 2016 88

Discrete items Management of Waste Failing the Discrete Item Limit, Feasibility Study

A credible options study was completed to identify technologies that might be used for the effective management of discrete items. A discrete items inventory was produced and four waste groups identified that cover all types of materials in the inventory:

metals with simple geometries and predominantly accessible surfaces

metals with complex geometries and inaccessible surfaces

cemented drums

sources

Matthew French and Irena Tanase

LLWR

2016 97


A-25



Filters

WPS/905: Thematic Guidance on the Packaging of Ventilation Filters

This document provides guidance regarding the challenges that arise from the treatment of air filters and presents the options for treatment and packaging which will ensure that waste packages containing air filters meet the requirements for transport and disposal, as defined by the Generic Specification for waste packages containing LHGW. It includes experimental evidence from Sellafield Ltd that demonstrates successful grout encapsulation of filters.

RWM 2017 66

Graphite

Operational Graphite Management Strategy Credible and Preferred Options (Gate A and B)

This paper defines the credible and preferred management options for graphite waste in the UK in the near-term. The preferred options for the management of graphite have been identified as follows:

Berkeley site – to manage all the graphite waste as ILW for interim storage (in resilient, self-shielding containers) and assume unencapsulated final disposal in the GDF

Hunterston A site – to manage all the graphite waste as ILW for interim storage (unencapsulated in stainless steel containers) with encapsulation at Final Site Clearance (FSC) prior to management in accordance with Scottish Policy

Sellafield site – to manage the graphite waste within the scope of this study as ILW for interim storage (in mild or stainless steel drums) with encapsulation prior to final disposal in the GDF

NDA 2013 99


A-26



The Long-term Management of Reactor Core Graphite Waste Credible Options (Gate A)

This paper establishes the credible options for the long-term management of graphite wastes arising from the final decommissioning of reactors. The credible options identified include both direct disposal and pre-disposal treatment options. These options are screened against four criteria for each of the SLCs within scope. The conclusion of this screening exercise is that it is not currently considered credible to directly dispose of reactor graphite to either the LLWR or to other radioactive waste permitted landfill sites. Opportunities are highlighted for the use of near-term waste arisings (for example RSRL and DSRL research reactor graphite) as pathfinder material for core dismantling or treatment trials to inform decisions on the management of larger volume, later arising Magnox Ltd, Sellafield Ltd and EDF Energy reactor graphite.

NDA 2013 100

Graphite

Characterization, treatment and conditioning of radioactive graphite from decommissioning of nuclear reactors

In 2006, the IAEA published guidance on treatment options for graphite wastes producing during the decommissioning of nuclear reactors. This report included the following treatment options:

encapsulation, e.g. cement, polymer-modified cement and polymers

impregnation and/or surface coating (to prevent migration of volatile radionuclides)

thermal oxidation processes, e.g. furnace incineration, fluidised-bed incineration, laser incineration or steam pyrolysis, which results in release of tritium, C-14, Cl-36 and other volatile radionuclides. The resulting graphite may be treated as LLW or is converted wholly to secondary ash

IAEA 2006 101


A-27



CARBOWASTE: Treatment and disposal of irradiated graphite and other carbonaceous waste

The development of best practises for the retrieval, treatment and disposal of irradiated graphite was the basis of the 7th EURATOM Framework Programme CARBOWASTE (Treatment and disposal of Irradiated Graphite and other Carbonaceous Waste) that finished in 2014. Potential treatment processes investigated included:

thermal processes (as above)

chemical processes, e.g. the steam-reforming THOR process, or the Russian Self-propagating High Temperature Synthesis methodology (in which the graphite is mixed with aluminium metal and titanium dioxide, forming an insoluble, unreactive mix of alumina/titanium carbide which incorporates a number of volatile radionuclides)

options for recycle/re-use

European Commission

2013 102

Ion exchange materials

Ion exchange compatibility with cement and polymer desktop study

This reports studies the compatibility of different polymer encapsulation methods and grouting of six different ion exchange resins at Dounreay. The report recommends undertaking small scale immobilisation trials primarily using an epoxy polymer. The trials will be based on direct infiltration of the polymer through the ion exchange resins and achieving suitable immobilisation.

S. Farris 2009 40


A-28



Application of Ion Exchange Processes for the Treatment of Radioactive Waste and Management of Spent Ion Exchangers

This report presents the current status of the applications of ion exchange processes for the treatment of particular liquid radioactive waste streams, and discusses the different approaches for the treatment and conditioning of spent ion exchange media.

A variety of pre-treatment, treatment and immobilization options exist for spent ion exchange materials. Two main methods for the treatment of spent organic ion exchange materials are discussed: (1) the destruction of the organic compounds to produce an inorganic intermediate product that may or may not be further conditioned for storage and/or disposal and (2) direct immobilisation, producing a stable end product. Inorganic ion exchange materials are generally treated by the use of direct immobilisation or by high temperature processes such as vitrification or plasma incineration.

IAEA 2002 48

Engineering study for the treatment of spent ion exchange resins resulting from nuclear process applications

Review of existing and planned ion exchange resin treatment and disposal plans at US DOE sites and assessment using criteria including lifecycle and capital cost, volume reduction, operability, environmental permitting etc.

B.G. Place

Westinghouse Hanford Company

1990 51


A-29



Lead

INTEK Decon Solutions: An Aqueous Based Chemical Decontamination Process

US DOE project to achieve decontamination of significant volumes of lead sheet, shot, brick, and wool. In this instance lead was identified as a material excluded from regulation as a solid waste and could be decontaminated and recycled provided it met free release criteria.

INTEK DECOM ND-207 is formulated specifically for use with radioactive contaminated lead. It is a nontoxic, biodegradable, nearly neutral pH, aqueous-based proprietary chemical. It decontaminates lead by neutralising ionized particles on the surface and removing oxides from the lead without attacking the base material. The chemistry disassociates the inorganic metal compounds entrapping radio nuclides and forms metal complexes with the radioactive ions, thus releasing them.

R.W. Durante

INTEK Technology

2006

75 (and reference therein:

Decontamination of Radioactive

Lead for Recycling, Roger

Moore, S. Overdale and R.

Amar, Energy Technology Engineering

Center, Rockwell Aerospace,

Canoga Park, CA)

Strategic Guidance on the Management of LLW and ILW/LLW Cross Boundary Pond Furniture

This report provides a cross-NDA estate compilation of inventory data and waste management approaches specifically for pond furniture, with the intent of providing an effective vehicle for the transfer of knowledge – particularly good practice, lessons learned and innovation – across the NDA estate. The pond furniture waste is predominantly stainless steel material, however, small amounts of lead are also present in some pond furniture at Harwell. The report included a listing of a wide range of treatment techniques and waste management approaches that are in routine use for pond furniture.

H. Cassidy 2013 76


A-30



BNL Building 650 lead decontamination and treatment feasibility study: final report

A large inventory of excess lead (estimated at 410,000 kg) in many shapes and sizes was being stored at Brookhaven National Laboratory (BNL). This study included investigating potential treatment methods by (i) conducting a review of the literature, (ii) developing a means of screening lead waste to determine the radioactive characteristics, (iii) examining the feasibility of chemical and physical decontamination technologies, and (iv) demonstrating BNL polyethylene macro-encapsulation as a means of treating hazardous or mixed waste lead for disposal as an alternative to decontamination, or for cases where decontamination is either not technically or economically feasible.

P.D. Kalb, M.G. Cowgill, L.W. Milian, and E.C. Selcow

1995 77

Mercury

Final Long-Term Management and Storage of Elemental Mercury: Environmental Impact Statement

This is a summary and guide for stakeholders presenting an overview of the major issues addressed in the Final Long-Term Management and Storage of Elemental Mercury Environmental Impact Statement (EIS). The EIS considers a range of reasonable alternatives (storage facilities) for the long-term, safe, secure storage of elemental mercury generated in the United States. The EIS analysed the potential environmental, human health, and socioeconomic impacts of elemental mercury storage at seven candidate locations: Grand Junction Disposal Site near Grand Junction, Colorado; Hanford Site near Richland, Washington; Hawthorne Army Depot near Hawthorne, Nevada; Idaho National Laboratory near Idaho Falls, Idaho; Kansas City Plant in Kansas City, Missouri; Savannah River Site near Aiken, South Carolina; and Waste Control Specialists LLC site near Andrews, Texas. The overall conclusion was that there would be no major differences in impacts on resource areas among the mercury storage site alternatives.

US DOE 2011 32


A-31



Final Long-Term Management and Storage of Elemental Mercury: Supplemental Environmental Impact Statement

This is a supplement to the EIS presented in ref. 32 above. The US DOE prepared this Mercury Storage Supplemental EIS (SEIS) to evaluate three additional locations for a long-term elemental mercury storage facility, all three of which are in the vicinity of the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico. Similar to the 2011 EIS, the overall conclusion was that there would be no major differences in impacts on resource areas among the mercury storage site alternatives. This conclusion is based upon the evaluation of the candidate sites analysed in the January 2011 EIS and the three additional WIPP vicinity reference location sites analysed in the SEIS.

US DOE 2013 33

Mercury Contaminated Material Decontamination Methods: Investigation and Assessment

This report lists several decontamination techniques for cleaning mercury from mercury-contaminated surfaces of metals and porous materials found in many US DOE facilities. These include mechanical and chemical techniques. The technologies used for decontamination of water and mixed wastes (solid) are specifically discussed (reactive strippable coatings, chemical decontamination with iodine/iodine lixiviant, chemisorbing surface wipes, surface/pore fixation through amalgamation or stabilisation). Two processes, strippable coatings and chemical cleaning with iodine/iodide lixiviant, were experimentally investigated in this study.

M.A. Ebadian 2001 34


A-32



Metals and MAC

National Strategic BAT for Metallic Lower Activity Radioactive Wastes

This report identified a generic national ‘baseline’ BAT option to underpin strategy for the future management of the UK’s metallic LAW.

There was no single option, or combination of options, that will be BAT for all metallic wastes. The characteristics of individual waste streams need to be reviewed within the context of individual waste owner or treatment provider strategies in order to identify BAT. For example, while a strong justification would be required, for some specific problematic LAW wastes, no treatment prior to disposal might be the BAT main treatment option. More broadly, cost disproportionality arguments may be important in evaluating BAT for lower hazard wastes.

It was possible to establish a hierarchy of preferred treatment options at the ‘generic’ national strategic level. The hierarchy indicates which are most likely to be associated with desirable end-points. Example options include:

surface decontamination, including for example:

o wiping and other simple approaches

o water or other fluid jetting

o surface-abrasion (e.g. shot and grit-blasting)

o chemical decontamination

melting, involving:

o recovery of contaminated slag and filters and release or declassification of bulk metal

o for a subset of specific matrix radionuclide contaminants, potentially a more limited inventory reduction, combined with volume reduction due to elimination of voidage

compaction or supercompaction (e.g. of thin malleable metal sheets in mixed waste streams)

disposal with no prior treatment, or disposal of residues, including secondary wastes and discharge of effluents

A. Paulley and G. Towler

2015 84


A-33



UK Management of Solid Low Level Radioactive Waste from the Nuclear Industry: Metal Decontamination Study

This study aimed to determine and improve the use of existing metal decontamination facilities within the UK for LLW (examples include metal recycling and metal melting facilities). Possible spare capacity within existing NDA and supply chain decontamination facilities was highlighted, and recommendations were made to optimise the use of these existing systems. The study also included technical guidance on the most effective use for decontamination systems.

M. Lindberg 2009 78

Oils and oily wastes

Radioactive oil decontamination development: An Overview

Insulating, hydraulic and vacuum pump oils are used extensively in Canada deuterium uranium (CANDU) plants. This paper provides an overview of waste oil streams that have been problematic in the CANDU nuclear industry and the decontamination processes that were developed for each to effectively remove a variety of radioactive species including tritium as well as conventional hazardous materials such as PCB, lead and cadmium.

The decontamination process for βγ-contaminated oils uses catalytic thermal oxidation to decompose these additives and causes them to become particulates in the oil, which can be removed by mechanical means. For tritium-contaminated oil, a simpler process can be followed and only the vacuum degassing unit is required.

J.P. Krasznai 2009 24 (also described in Section 4.2.1 of

IAEA ref. [121])


A-34



Management of Contaminated Oils Feasibility Study

This first feasibility study was commissioned by the NWP following the FY14/15 inventory update exercise to address non-incinerable oils, one of the waste streams identified by the stakeholder community as high-priority.

Based on LAW inventory information, 68 non-incinerable oil waste streams were categorised based on their composition, into five distinct groups where different treatment approaches might be necessary or desirable: oils with organically bound tritium, oils with tritiated water, oils with active solids, oily water and oil-contaminated solids. The study identified 8 credible treatment options, which were taken forward for full assessment.

This assessment showed that there was at least one credible technology that could be applied for each waste group identified in the inventory. However, none of the technologies identified are likely to provide a complete solution, although thermal techniques and absorption could be used to manage most of the waste groups, and all will generate products or secondary wastes that will require conditioning before disposal. The study also made a number of recommendations for further work.

M. French and I. Tanase

2015 25


A-35



Pyrochemical waste

Sodium Waste Technology – A Summary Report

This is a report summarising the Sodium Waste Technology (SWT) Program at Argonne National Laboratory (ANL) in the US. The SWT Program was established to resolve long-standing issues regarding disposal of sodium-bearing waste and equipment. Comprehensive SWT research programs investigated a variety of approaches for either removing sodium from sodium-bearing items, or disposal of items containing sodium residues.

The most successful of these programs was the implementation of the Sodium Process Demonstration Facility at ANL. The technology used was a series of melt-drain-evaporator operations to remove non-radioactive sodium from sodium-bearing items and then converting the sodium to storable materials.

C.S. Abrams and L.C. Witbeck

1987 53

Molten salt/metal extractions for recovery of transuranic elements

This paper describes a pyrochemical method that is being developed at ANL to recover transuranic elements from the integral fast reactor (IFR) electrorefiner process salt. The method uses multi-stage extractions between molten chloride salts and cadmium metal at high temperatures. With this method, the rare earth fission products can be taken out of the salt to a transuranic free waste form, and return the transuranic elements to the IFR as fuel.

L. S Chow, J. K. Basco, J. P. Ackennan and T. R. Johnson

1992 55


A-36



Immobilisation of chloride-rich radioactive wastes produced by pyrochemical operations

This report presents the results of a review of three immobilization technologies to determine if mature technologies exist that would be suitable to immobilize pyrochemical salts resulting from processing to separate plutonium at the Rocky Flats Environmental Technology Site in Colorado. These immobilisation techniques are: cement-based stabilisation, low-temperature vitrification, and polymer encapsulation.

On a laboratory scale, it is possible to immobilise >30wt% sodium chloride in a cement-based matrix. Work at Oak Ridge National Laboratory (ORNL) and in the UK has shown that intense radiation fields decompose free water contained in the cement-based matrix into hydrogen and oxygen, thus creating a safety problem. Bench-scale tests on concrete formed under elevated temperature and pressure have shown that the potential for gas generation was reduced to near-zero when free water was removed from the final waste form.

Immobilisation of pyrochemical salts in low-temperature glass may be possible. The probability of gas generation from vitrified salts is near zero because of the elevated temperatures required to produce the glass and the absence of water and organic compounds in the melt formulation. The low solubility of chloride anions and plutonium cations in glass would require both glass formulation and melter development.

Polymer encapsulation by either polyethylene or sulfur-polymer cement was determined to be infeasible.

E.W. McDaniel and J.W. Terry

1997 56

Packaging of pyrochemical waste by AWE: Conceptual Stage

Summary of disposability assessment of a proportion of the pyrochemical salt residues based on encapsulation in polymer in 500 litre drums. This process was reserved for packaging pyrochemical salt residues with low levels of actinide contamination.

NDA RWMD 2011 59


A-37



Pyrochemical waste

Packaging of AWE pyrochemical salts in calcium phosphate ceramics

For more highly contaminated pyrochemical residues, AWE has developed a conditioning process based on incorporation of the salt into a ceramic product. The pyrochemical salts were calcined in the presence of calcium phosphate to incorporate the actinides into a number of mineral phases. The resulting granular mineral product was then bound together by sintering in the presence of a phosphate binder to generate a solid ceramic product. The solid pieces of ceramic material were sealed within steel cans for interim storage.

The conclusions of the assessment were that conditioning of the pyrochemical residues using a ceramic wasteform was expected to generate a high quality wasteform for disposal, because both the actinides and chlorides within the residues should be well immobilised within the mineral phases. The heat output of the waste was considered to be the most restrictive parameter.

The proposals were not endorsed at the conceptual stage, but it was concluded that it should be feasible to make a disposability case covering transport, handling and disposal of the proposed packages, subject to suitable development work, coupled with the potential to restrict the content of each package to demonstrate compliance with heat and safe fissile limits.

NDA RWMD 2012 60

Sources Optimised management of radioactive sources declared as waste

This documents presents a generic conceptual design of a novel packaging concept for sources declared as waste based on a robust container which places no performance requirement on the wasteform, requires no pre-treatment of the waste, requires no encapsulation of the waste, has negligible release of activity in impact and fire accident scenarios, and complies with the requirements of waste package specification (WPS) 315 for the corner lifting 3 cubic metre box has been developed.

RWM 2014 80


A-38



Sludge

New treatment rids Rocky Flats Environmental Technology Site of largest low-level mixed waste stream

This note describes treatment recipes for three types of pond sludge (A, B and C-pond sludges) that have been developed and successfully implemented in the US. Sludge waste from tanks at the US DOE Rocky Flats site was characterised as low-level mixed waste (LLMW). The sludge met the radiological criteria for disposal at Envirocare, Utah but there were two obstacles that needed to be overcome: (1) the sludge could not be disposed of in its current form due to the presence of free liquids, and (2) the sludge from C-pond did not meet land disposal restrictions (LDR) because of its chromium and cadmium contents.

Treatability studies demonstrated that when Pond-A/B sludge was mixed with the correct amount of polymer, the pond sludge solidified enough to absorb the free liquids. Pond sludge from the C-pond presented additional challenges. It was found from the treatability studies, that the addition of lime and soda ash would bind the metals to make the treated sludge LDR compliant. Additional treatability tests were done to determine the optimal quantity of absorbent polymer needed to be added to the sludge in order to comply with the waste disposal site criterion of no free liquids in the final waste product.

Harrison K-H Communications

2003 73

Tritium contaminated wastes

WPS/907: Guidance on the packaging of tritium bearing wastes

The chemical form of tritium in wastes varies, and influences the behaviour of tritium after wastes have been packaged. This guidance provides advice on packaging of tritium-bearing waste with respect to disposal in a GDF, including consideration of pre-treatment, packaging, conditioning and storage conditions. A bibliography of references relating to tritium behaviour is included.

RWMD 2007 65