radioactive waste management and decommissioning …decom... · 27.09.2012 1 iaea international...
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IAEAInternational Atomic Energy Agency
Radioactive Waste Managementand Decommissioning
- Ernst Warnecke -
Nuclear Law Institute27 September 2012
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Contents
• Introduction• Topics not addressed• Basic information• Radioactive waste management• Predisposal management of radioactive waste• Disposal of radioactive waste• Final remarks
• Attachments• Illustrations
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Introduction
• Purpose of the presentation: To introduce essential elements to be considered when a national legal and regulatory framework for RWM is drafted
• Huge amount of material is available• Selection of topics based on personal judgement• Basis for the presentation and material for further
reading: IAEA provides international recommenda-tions in Safety Standards; download is free of chargehttp://www-ns.iaea.org/standards/documents/default.asp?s=11&l=90&sub=40&vw=9#sf
http://www-ns.iaea.org/downloads/standards/superseded-safety-standards.pdf
• The presentation is on safety and not on technology
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Topics not addressed
1. Joint Convention …2. Legal and regulatory infrastructure3. Transport4. Radiation protection, including dosimetry, monitoring etc.5. Emergency preparedness6. Physical protection7. Safeguards (if applicable)8. Environmental monitoring9. Education and training10. Documentation and records11. Quality assurance12. Non nuclear hazards (outside the IAEA mandate; Statute)
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Basic information (1)
• Radioactive Waste (RW)1. Contains or is contaminated with radionuclides2. Concentrations / activities above trivial levels (‘clearance
levels’)3. Needing control (by regulatory body)4. No further use is foreseen
• Radioactive Waste Management (RWM)1. Predisposal:
processing (pre-treatment, treatment, conditioning)decommissioningstorage and transport
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Basic information (2)
2. Release from nuclear regulatory control, e.g. by discharge / ‘clearance’
3. Disposal• Types of radioactive Waste1. Solid (burnable, metallic, non-metallic, …)2. Liquid (aqueous, organic, …)3. Gaseous
For disposal: waste in solid form• Origin of Radioactive Waste1. Medical waste2. Research waste
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Basic information (3)
3. NPP waste (operational, decommissioning, spent fuel)4. Fuel cycle waste (front end, back end)5. Mining and milling waste6. Naturally Occurring Radioactive Material (NORM); e.g. oil,
phosphate … industry7. Legacy situations needing remediation
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Basic information (4)
• Half lives and disposal options1. Long lived waste (Half lives above about 30 years)
� Disposal in geological formations2. Short lived waste (Half lives of up to about 30 years)
� Near surface disposal (or geological disposal)3. Decay waste (Half lives of days or maybe up to a year)
� Decay and then release from nuclear regulatory controlNote: Take ‘conventional’ hazards and non-radioactive toxic
substances also into account!
• Activity levelsHigh level / heat generating; Low level / intermediate level; Very
low level (disposal similar to industrial waste)
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RW management (1)
1. A policy should be in place, e.g. on the use of nuclear power plants for energy generation, on the application of clearance, on the classification of radioactive waste, on waste disposal, on the role of the State (e.g. in disposal) and on import and export of radioactive materials
2. An independent regulatory body and a funding system for RWM should be in place
3. A RWM strategy should be available which outlines how to deal with all types of radioactive waste
4. Radioactive materials should not be imported if the resulting waste cannot be managed
5. Interdependencies among all RWM steps need to be taken into account, i.e. decisions at one step should not foreclose options or have undesirable impacts on subsequent steps
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RW management (2)
6. An uninterrupted transfer of responsibility from one operator to another needs to be ensured, even for time frames beyond closure of a repository
7. RW should be segregated in accordance with clearance / processing / disposal needs
8. The necessary waste processing / storage / disposal facilities have to be available
9. A destination for the RW generated has to be available10. RW has to be managed safely
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Predisposal management of RW (1)
• RW processing1. Try to avoid the generation of RW2. Minimise the amount of RW (segregation / release; reuse /
recycle; volume reduction …)3. Select the RW processing technology in accordance with
the types and quantities of RW4. Produce a solid RW form in an appropriate packaging5. Process RW in such a way as to comply with handling,
transport, storage and disposal requirements6. Characterise waste and control waste processing to ensure
that the knowledge of waste package properties for demonstration of compliance with relevant requirements
7. Ensure radiological protection through the implementation of the safety assessment
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Predisposal management of RW (2)
8. Take industrial safety and non-radiological hazards into account
• RW Storage1. Storage may be needed between and after predisposal
steps2. Storage may be used for decay prior to discharge, re-use /
recycle, clearance3. The intended storage period should be known4. After storage the RW properties should allow retrieval,
handling, transport and disposal, as necessary (degradation, corrosion, …)
5. Passive safety is preferable for storage
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Predisposal management of RW (3)
6. Regular monitoring, inspection and maintenance is needed7. Take RW properties into account, e.g. heat generation,
criticality safety, gas generation, precipitation / settling of solids in liquid waste
• Decommissioning of nuclear facilities1. A nuclear facility that is of no use any more is a RW has to
be managed as a RW2. The end point of decommissioning needs to be defined3. The facility will be dismantled by a gradual removal of the
radioactive inventory until the defined end point is reached4. A decommissioning plan (DP) is necessary and needs
regular update
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Predisposal management of RW (4)
5. A nuclear facility should already be designed in such a way as to ease decommissioning
6. A DP should already be available when a nuclear facility is being planned (initial plan)
7. The DP should be improved during operation when more detailed information is available and amended in the case of changes in the facility (ongoing plan)
8. A DP approved by the regulatory body should be available when the facility is shutting down (final plan)
9. A DP should be prepared immediately if it is not yet available for a facility
10. A decommissioning strategy should be selected by the operator and approved by the regulatory body
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Predisposal management of RW (5)
11. Three basic strategies are available: (a) immediate dismantling (preferred option); (b) deferred dismantling = safe enclosure; and (c) entombment = near surface disposal
12. In the case of deferral it has to be ensured that (a) the deferral is as maintenance free as possible and (b) after deferral all prerequisites for dismantling will be available (e.g. operator and funds)
13. It should be ensured that funds will be available when needed
14. Characterisation of the facility is important for all purposes, in particular for providing safety and for waste management
15. Decommissioning may be a large source of waste16. Decontamination and clearance may reduce the RW
amounts to <5%
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Safety Requirements WS-R-5
http://www-pub.iaea.org/MTCD/publications/PDF/Pub1274_web.pdf
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Safety Guides on Decommissioning (1)
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Safety Guides on Decommissioning (2)
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Safety Standards on Decommissioning
WS-G-2.1 (NPPs and RRs)http://www-pub.iaea.org/MTCD/publications/PDF/P079_scr.pdf
WS-G-2.2 (Med., industr. + research facilities)http://www-pub.iaea.org/MTCD/publications/PDF/P078_scr.pdf
WS-G-2.4 (Fuel cycle facilities)http://www-pub.iaea.org/MTCD/publications/PDF/Pub1110_web.pdf
WS-G-5.2 (Safety assessment)http://www-pub.iaea.org/MTCD/publications/PDF/Pub1372_web.pdf
Revision of Guides + WS-G-2.1 / WS-G-2.4 combinedFor review by MS: Decommiss. Safety Requirementshttp://www-ns.iaea.org/downloads/standards/drafts/ds450.pdf
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Predisposal management of RW (6)
• Small scale users of radionuclides1. All the prerequisites for safe RWM are fully applicable to
small users2. Small users have to overcome a number of obstacles: e.g.
limited number of qualified staff; very diverse waste types; very small amounts of waste which make proper RW management a challenge; disused or orphan sealed sources (SS)
3. Staffing: There may not be sufficient qualified staff available in a country as to have independent expertise available for operators and regulators � look for expertise from abroad or ask IAEA for help
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Predisposal management of RW (7)
4. Sealed sources (SS): (a) SS should only be imported if they can be returned to the country of origin; (b) SS should be controlled very tightly because otherwise they may be very dangerous (registry, safe and secure storage); (c) Orphan SS have to be brought back under control
5. Import of radionuclides: (a) Import of radionuclides needs a strict control; (b) If possible, only short lived radionuclides should be imported (release from nuclear regulatory control after decay storage); (c) Imported long lived radionuclides should be returned to the country of origin, if possible
6. Import of reactor fuel: With a return to country of origin7. Try to avoid the need for a disposal facility; if not: Borehole
disposal may be an option (see next slide)8. Several countries with small RW amounts may decide to
co-operate in RWM, incl. RW disposal
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Safety Guide SSG-1 (Borehole disposal)
SSG-1: http://www-pub.iaea.org/MTCD/publications/PDF/Pub1418_web.pdfSSG-17: http://www-pub.iaea.org/MTCD/publications/PDF/Pub1509_web.pdf
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Predisposal management of RW (8)
• Mining and milling waste / NORM1. Originating e.g. from Uranium / Thorium mining and milling,
oil / gas industry, phosphate fertiliser, geothermal plants2. Issues: (a) Very large waste volumes with long-lived radio-
nuclides from Uranium or Thorium decay chains, including Radium; (b) Airborne emissions (Radon, dust etc.); (c) Chemical hazards (toxic elements in the waste rock; acids, organics and other chemicals from ore processing or in situ leaching); (d) Many legacy sites with unsafe conditions exist which need remediation; (e) Providing long-term safety for the very long term nuclear and chemical hazards after closure of a disposal facility (institutional control)
3. Needs: (a) Very early planning not only for the operational safety, but also for the safety of the very long time frames;
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Predisposal management of RW (9)
(b) Develop a safe and robust technical concept for the operation and the management of the waste, (c) Establish radiation protection requirements (d) Calculate the costs and set up a funding system to cover all costs, including those originating after operation, (e) Ensure the operator cannot walk away and leave a legacy behind that would need remediation by public funds (very expensive)
4. Example of a remediation project (Wismut, Germany)(a) rehabilitation is intended to be completed in a time period of about 30 years (i.e. 1990 - 2020), (b) the total rehabilitation costs are estimated to be about 7,1 x 109
Euros (about 9,2 x 109 USD / present exchange rate), (c) Many countries will not be able to afford paying such an amount of money for a remediation project!
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Safety Guides WS-G-1.2 and RS-G-1.6
WS: http://www-pub.iaea.org/MTCD/publications/PDF/Pub1134_scr.pdfRS. http://www-pub.iaea.org/MTCD/publications/PDF/Pub1183_web.pdf
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Requirements WS-R-3, Guide WS-G-3.1
WS-R-3: http://www-pub.iaea.org/MTCD/publications/PDF/Pub1176_web.pdfWS-G-3.1: http://www-pub.iaea.org/MTCD/publications/PDF/Pub1282_web.pdf
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Disposal of RW: General (1)
• Disposal is the final step in RWM• Aim: To isolate the waste and keep the radionuclides out of
the biosphere as long as necessary (i.e. until after decay)• Classification of RW leads to the disposal options• Disposal may be carried out in a ‘maintenance-free’ or
‘passive’ manner (geological disposal) or it may involve ‘institutional control’ for a few hundred years as a safety factor for a limited period of time (near surface disposal)
• Radiological protection during the operational period is in accordance with normal RP standards (BSS)
• Radiological protection after closure of a repository should be such that predicted impacts to future generations will not be greater than impacts that are acceptable today
• Radiation safety has to be demonstrated with an operational and a long term safety assessment
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Disposal of RW: General (2)
• If necessary, safeguards measures should be planned from the beginning and in such a way as not to jeopardise safety
• Non-radiological hazards have also to be assessed• Relevant scenarios for possible releases of radionuclides
from a closed repository into the biosphere (primarily by migration of radionuclides on a water pathway) have to be assessed to demonstrate long term safety
• Scenarios involving (human) intrusion will in particular be relevant for a closed near surface disposal
• Uncertainties will increase with time and will have to be assessed very carefully
• Safety of RW disposal is provided by a combination of the overall geological and hydro(geo)logical situation at a site, the engineering of the disposal facility (including its closure) and the radioactive waste to be disposed of
• Heat generation is special and needs extra consideration
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Disposal of RW: General (3)
• A very careful site investigation and a prediction of the future site development is necessary
• Such site data and the prediction of types and amounts of RW are necessary to develop an engineering concept and to carry out the safety assessment, including long term safety
• The acceptance requirements for RW disposal are derived from safety assessments
• The early knowledge of such requirements is vital for a proper conditioning of RW at operating nuclear facilities and for the demonstration of compliance with such requirements
• Some countries consider retrievability of RW which may have an effect on safety(!)
• Most countries operate repositories only for national RW and do not allow an import of radioactive waste for disposal
• International repositories are very controversial although they may be appropriate for countries with small amounts of RW
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Disposal of RW: Planning / siting
• RW disposal is often controversial in the public• A good communication with the public and its involvement in
a stepwise process helps in the acceptance of a repository• In a first step a country is typically assessed for potentially
acceptable geological formations and locations (desk studies)• Typically, a number of sites is selected for further, more
detailed investigations based on (inter)national criteria• Detailed investigations may be carried out on one or two sites• In geological disposal detailed site investigations must be
carried out in such a way as to prevent the destruction of the potential disposal area (underground site investigation!)
• A final site selection is carried out after a full investigation of the site and the surrounding area based on a detailed safety assessment which includes closure and post closure safety
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Disposal of RW: Licensing / Operation
• The RB can license a disposal facility when it is satisfied with the review of the application with independent means
• A license should specifically include detailed (executable) waste acceptance requirements
• A decision on post closure issues should also be part of the license (institutional control, responsibilities, documentation)
• The repository can then be operated and finally closed in accordance with the license conditions
• Compliance with waste acceptance requirements has to be demonstrated in a sophisticated and intelligent approach
• The RB will supervise the operation in accordance with a plan• The license may be modified if necessary, e.g. when new
information becomes available• An amendment needs application and regulatory review
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Disposal of RW: Post-closure period
• When is the responsibility of the operator coming to an end and who is taking over?
• Maintenance of information on the repository• Implementation of active institutional control (near surface
disposal), including surveillance, water management, repairs, security, fencing, limiting access
• Setting of markers to indicate the location of a repository
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Safety Requirements SSR-5
http://www-pub.iaea.org/MTCD/publications/PDF/P1449_S_web.pdf
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Safety Guides GSG-1 and SSG-14
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Safety Guides: 111-G-3.1, WS-G-1.1
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IAEA Safety Standards on disposal
• SR: Disposal of RWhttp://www-pub.iaea.org/MTCD/publications/PDF/P1449_S_web.pdf
• SG: Geological disposal facilities for RWhttp://www-pub.iaea.org/MTCD/publications/PDF/Pub1483_web.pdf
• SG: Siting of near surface disposal facilitiesTo be superseded by DS 356
http://www-pub.iaea.org/MTCD/publications/PDF/Pub965e_web.pdf
• SG: Safety Ass. for near surface disposal of RWhttp://www-pub.iaea.org/MTCD/publications/PDF/Pub1075_web.pdf
• SG: The managem. system for the disposal of RWhttp://www-pub.iaea.org/MTCD/publications/PDF/Pub1330_web.pdf
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Final remarks
• It is very difficult to address a presentation to an audience with a varying level of experience and I hope I was able to:- give a presentation not too challenging for newcomers- and not too boring for more experienced participants
• The topic of the presentation was extremely broad• This did not allow to go into the very details• References to IAEA Safety Standards should give access to
more detailed information, as necessary• It should be taken into consideration to request help from the
IAEA or to access expertise from other countries• Obligations after the end of operations should be taken into
account as they may seriously impact on the national budget
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Attachments onFunding
Release from nuclear regulatory control
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Funding (1)
1. RWM expenses may occur far behind operations of nuclear facilities at times when no revenues can be expected
2. This may apply to decommissioning and waste disposal3. Reserves must be accumulated during operations for later
expenses4. A good cost calculation with regular updates is necessary
to forecast the necessary amount of money well (see slide)5. The time frame for the collection of the money must be
defined6. The availability of funds has to be ensured during the
collection period7. Funds must be appropriately managed to be available
when needed
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Funding (2)
8. Funds may be managed by operator, government or in a segregated account
9. Each option has its risks. Finally, the government is responsible!
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Decommissioning costing: OECD/NEA; IAEA; EC
http://www.oecd-nea.org/rwm/reports/2012/ISDC-nuclear-installations.pdf
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Release from nuclear regulatory control: Materials (1)
1. The release of materials with trivial radionuclide contents from nuclear regulatory control is termed ‘Clearance’
2. IAEA recommends to base ‘clearance’ on the ‘trivial’ dose of 10 µSv / a above natural background
3. IAEA derived a full suite of generic radionuclide concentrations through safety assessments from this dose level (‘unconditional clearance’)
4. Materials with radionuclides below the derived values may be cleared
5. In most cases more than one radionuclide is involved and then the ‘summation rule’ is to be applied, i.e. the sum over the fractions of the actual radionuclide concentrations divided by the derived values must be below one
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Release from nuclear regulatory control: Materials (2)
6. IAEA recommends ‘unconditional clearance levels’ in a Safety Guide and gives recommendations on the ‘derivation of activity levels’ in a Safety Report (see next slide)
7. Countries applying ‘clearance’ developed specialised clearance levels, e.g. for ‘conventional disposal, for scrap metal for melting, …
8. ‘Clearance’ is an irreversible process and needs strict measurement / control
9. All ‘clearance’ activities have to be well documented
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SG No. RS-G-1.7 / SR No. 44
SG: http://www-pub.iaea.org/MTCD/publications/PDF/Pub1202_web.pdfSR: http://www-pub.iaea.org/MTCD/publications/PDF/Pub1213_web.pdf
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Release from nuclear regulatory control: sites (1)
1. IAEA recommends to base the release of sites on the ‘normal’ radiation protection criteria of justification, dose limitation (above pre practice background) and optimisation of protection and not on the ‘trivial’ dose of 10 µSv / a as land remains in place and the certainty of land use is higher
2. Some countries implemented the 10 µSv / a criterion also for the release of sites
3. The IAEA recommends criteria for the release of sites for unrestricted and restricted use
4. Radiological contamination on the site and below ground (leaking pipes, groundwater contamination) needs to be assessed and removed
5. A final radiological survey is necessary before a site can be released
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Release of sites: Dose criteria (WS-G-5.1)
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Safety Guide WS-G-5.1
http://www-pub.iaea.org/MTCD/Publications/PDF/Pub1244_web.pdf
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Illustrations
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Wismut: Ronneburg remediation site (1991)
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Wismut: Ronneburg remediation site (2007)
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VLLW repository (Morvilliers)(and Centre de l’Aube in the back)
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Morvilliers: Construction and loading
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Morvilliers: Closing of a disposal cell
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Centre de l’Aube: Short lived (SL) waste
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Centre de l’Aube: Loading and grouting
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Closed SL waste repository (La Manche)
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SL waste disposal (< 100m deep): Forsmark
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SL waste disposal (<100 m deep) : Finland