norm final disposal options (risk & cost considerations) gert jonkers engineering &...

NORM Final Disposal Options(risk & cost considerations)

Gert JonkersEngineering & Analytical - GSEA/4 “Problem Solving”(Shell E&P Ionising Radiation/NORM HSE Expert CHP)

location

Shell Research & Technology Centre, AmsterdamP.O. 38000

NL-1030 BN Amsterdamthe Netherlands

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E&P NORM WorkshopMuscat, February 21-24, 2005

tel. +31 20 630 [email protected]

G. Jonkers, GSEA/4 at SRTCAP.O. Box 38000, 1030 BN Amsterdam

NORM after abandonment - Internal & External Radiation Hazard

TARGET Reducing both External and Internal Dose by Naturally Occurring Radionuclides in Deposits (NORM ) from former Gas/Oil Production Activities to a Negligible Level for Future Inhabitants

Ingestion Determine amount of radioactivity in the food chain.

Inhalation Potential (topsoil) dust activity levels extremely low.

External (Sub)soil activity levels sufficient low.

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NORM (PRE)TREATMENT OPTIONS(pre-disposal)

Target Method NOR’s [left] in Vol. Reduct.

Produced Water Filtration plant (Matrix [re]injection) TDS/TSS > 99%

Filtering/Gravity separation TDS/TSS > 99%

Sludge Thermal (physical) “Solids” > 99%

De-oil/de-scale (mechan-/chem-ical) Solids/TDS > 95%

Bio/chemical/physical ? “Solids” > 95%

Vitrification “glased solids > 95% ?

Incineration ? slag/fly-ash > 95%

Contamination Scale-water/grit/CO2-pellets Jetting Liquid/Solid > 95%

De-scaling (chelating agents) TDS > 99%

Scrap melting slag/fly-ash > 90%

Soil Wash (mechanical/chemical) TDS/TSS > 95%

Waste Immobilisation (bitumen/polymers) drums ~ 0%

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NORM FINAL DISPOSAL OPTIONS

Immobilisation & Sealed Subsurface Storage

Injection in Sealed Reservoir

Dilution into the Environment

Controlled Surface Storage

Iso

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gas/oil industry-specific exposure scenario’s encompassing dedicated radiation protection controlled work with “NORM”& potential future public use NOR-contaminated items

set of NOR-specific Conditional Release Limits (CRL’s; only to be applied within the constraints of the gas/oil industry specific exposure scenario’s)

to be issued and endorsed by the competent authority for radiation

workers, workforce/public at largesource constraint for dose control

radiation workers 20,000 Sv/aworkers (2,000 h/a) 1,000 Sv/apublic 1,000 Sv/aNORM- source constraint 300 Sv/a

DOSEannual limits

Effective Dose in Sievert

Generic EP or Group operating unit specific scenario’s competent authority enveloping scenario's Generic CRL’s for EP NORM disposal URL’s

set of enveloping exposure scenario’s encompassing all industrial uncontrolled

work with “NORM” leading to workforce/public exposure

set of NOR-specific Unconditional Release Limits

(URL’s; may be applied under all circumstances)

CONCENTRATION(limits for air, water, soil)

Becquerel per m3, L or g

EXPOSUREscenarios

External & Internal

Conditional Release Limits (CRL)

CRL (Bq[…]/g) 226Ra 210Pb 228Ra 228ThCondition Spreading Sludge farming Shallow disposal Deep hole disposal

226Ra 210Pb 228Ra 228ThEU BSS 0.5 5 1 0.5ICRP 2005 1 1 1 1

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Dose Assessment Study Conditional Release Limit (referenced against the NORM Source Constraint defined the Competent Authority)

Collection/compilation of site specific data characterising the (geo)hydrological setting, climate conditions, background radiation levels and radioactivity concentration in various environmental media including soil, subsoil, surface water, ground water, airborne dusts, fauna and flora.

Identification and quantification of the source terms (input of NORM for intended final disposal option), the chemical and physical form of the radionuclides the points of release, and the time distribution of release.

Identification of the potential environmental pathways.

Identification of the critical population, defining (conditional) scenarios

Assessment of the individual dose using a computer modelling.

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Assume Worst Case Scenario, but don’t loose reality

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NORM FINAL DISPOSAL.

Environmental exposure acceptability

Public acceptability

Economic acceptability

Universal acceptability

Time to make the option viable

Time for industry use once the option is viable

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DOSE ASSESSMENT REQUIRES MODELLING

Versatile RESidual RADioactivity code (all pathways) applicable to

• Soil Contamination (Landspreading, Cleanup);

• Shallow Burial (Landfill, special fills)• Deep Burial

Have developed dose assessment, incl. site/target specific parameters

Specific & In-house (Shell)• flat source (external radiation,

microshield), • sludge farming (external & dust)

Deep downhole disposal (matrix or fracture injection) other in-house disciplines

In-house (Shell)• Mores,• FORDAM

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Sludge farming (Landspreading) with dilution includes mixing of the applied wastes thoroughly within the topsoil. The area covered may be arbitrarily large. Analyses of landspreading with dilution also are based on incremental increase of NOR concentrations above background levels, and thus are also restricted to one-time disposal in a given area (record-keeping!).

0.2 <> 5 Bq[226Raeq]/g

Grinding (de-oiled) scales to a prescribed particle size distribution and subsequent overboard disposal dilutes these materials into the marine environment. Disposal is based on incremental increase of NOR- concentrations above natural marine background levels. Record-keeping and possible radiation surveys to characterise pre- and post-spreading radiation levels around platforms are measures to control the impact on the marine environment.

< 5 Bq[226Raeq]/g[solid]

Cleanup criteria for soil contamination. Scraping of contaminated soil, leaving remnant (residual) radioactivity levels.

< 5 Bq[226Raeq]/g[soil]

Dilution into the Environment

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Land based burial with unrestricted site re-use may occupy any available land area with minimal or no groundwater(flow). There may be some requirements like de-watering/oiling, solidification, consolidation, packaging (crates, boxes, drums) or compaction, before the waste is actually buried in (lined) trenches, more than 2.5 m deep (intrusion limit). After burial the trenches generally are capped with clay or other low-permeability cover material, gravel drainage layers and a topsoil layer. Capping the waste with concrete prevents erosion or water leaching. In arid climates, measures may be taken (e.g. dumping of large rock material on top) to discourage temporarily dwelling construction (e.g. Bedouins), while in other climates sites are contoured and replanted with vegetation for drainage and erosion control. This disposal method may also be applied to NOR-contaminated items.

Strongly related option is burial of “NORM” sludge and scale in (deep) surface mines. Possibly with some pre-treatment requirements “NORM” is placed at the bottom of mine excavations and is subsequently buried by accumulated earthen overburden. Typical burial depths are 15 m or greater, and areas are sufficient to accommodate relatively large volumes of wastes. Because of the significant burial depths, the potential for erosion or intrusion into the wastes is remote.

Other designated (municipality, oilfield waste, hazardous material, low level) waste sites may take NORM waste.

5 <> 200 Bq[226Raeq]/g

“Controlled Disposal”

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Deep Geological Disposal

Engineered deep underground geological disposal facilities for high or intermediate level waste final disposal may be available. These facilities are used c.q. have been proposed due to their inherent isolation of the wastes from groundwater and from the surrounding environment.

Salt provides impermeable containment of wastes at depths of 1,000 m or more. The salt formation tends to self-anneal any containment defects that may occur, further assuring containment of the wastes. NOR-contaminated sludge, scale and/or gas/oil field items can also be placed in salt domes. Salt caverns have been used to store various hydrocarbon products and to dispose normal oilfield waste.

Matrix injection consists of injecting produced water into a deep permeable formation below underground sources of drinking water with no fresh water or mineral value. The formation is confined by impermeable layers that are likely to remain intact.

Fracturing injection consists of adding sludges and pulverised scales to a carrier fluid (typically brine) and pumping the mixture into a well of sufficiently high pressure to create a fracture in a permeable formation below underground sources of drinking water with no fresh water or mineral value. The fracture formed by this process is normally vertical, confined above and below by impermeable shale formations. After the sludge-scale water mixture is displaced into the fracture, pressure is reduced and the fracture closes and NORM becomes trapped.

Fill a well to be abandoned with NORM encapsulated in connected tubulars (encapsulation), after well is plugged and abandonded.

1,000 Bq[226Raeq]/g[solid]

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Iso

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q[226Ra]/g

• “Spreading (with dilution)” $ 402

• Sludge farming $ 102

• Burial with Unrestricted Site Reuse5

• Non-Retrieval of Surface Pipe50

• NORM Disposal Facility $ 20200

• Commercial Oil Industrial Waste Facility $ 45200

• Commercial Low Level Waste Disposal Site $ 400200

• Burial in Surface Mine500

• Well Injection $ 120> 1000

• Plugged and Abandoned Well $ 200> 1000

• Hydraulic Fracturing> 1000

• Salt Dome Disposal $ 10> 1000

NORM FINAL DISPOSAL OPTIONS(approximate CRL´s and costs/drum [1997/9 US data])

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Sustainable Environment

Backup Slides

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Risk Assessment MatrixCONSEQUENCE INCREASING LIKELIHOOD

A B C D E

Sev

erit

y

Peo

ple

Ass

ets

Env

iron

men

t

Rep

utat

ion

Neverheard ofin …..

industry

Heard ofin ….

industry

Incidenthas

occurredin our

Company

Happensseveral

times peryear in

ourCompany

Happensseveral

times peryear in alocation

0 No healtheffect/injury

No damage No effect No impact

1 Slight healtheffect/injury

Slightdamage

Slight effect Slight impact

2 Minor healtheffect/injury

Minordamage

Minor effect Limitedimpact

Manage for continuousimprovement

3 Major healtheffect/injury

Localiseddamage

Localisedeffect

Consider-able impact

Incorporate riskreduction

4 PTD or 1 to 3fatalities

Majordamage

Major effect Nationalimpact

measures &demonstrate

5 Multiplefatalities

Extensivedamage

Massiveeffect

Internationalimpact

ALARP Intolerable

Risk Assessment Matrix

The level of control should depend on the level or risk !

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Additional DoseRestrictions

Individual Dose Limit(1,000 Sv/a)

Source Constraint(300 – 100 Sv/a)

Exemption(10 Sv/a)

InterventionAlways

Justifiable

InterventionRarely

Justifiable

Intervention May Be

Justifiable

source

very high100,000 Sv/a

Typical10,000 Sv/a

background2,400 Sv/a

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RISKLikelihood of Fatal Cancer

DOSE


EXPOSURE

External & Internal

CONCENTRATION(air, water, soil)


ESTABLISHMENT OF GENERAL EXEMPT LIMITS

Source Dose Constraintto be endorsed by the Competent Authority

Derived Limitsto be endorsed by the Competent Authorityfor any circumstance

(Unconditional) “Fo

rwar

d”

Cal

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tio

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App

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for

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(E

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for

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ose

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HIERARCHY OF DOSE QUANTITIES

Absorbed Dose (Gy)

Equivalent Dose (Sv)

Effective (Whole Body) Dose (Sv)

Collective Effective Dose (manSv)

energy imparted by radiation to unit of mass of tissue (J/kg)

absorbed dose weighted for harmfulness of different radiations (wR)

equivalent dose weighted for susceptibility to harm of different tissues (wT)

effective dose to all people exposed to a source of radiation

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EXPOSURE OF NATURAL ‘BACKGROUND’ RADIATION

Everyone is Exposed to Natural Background RadiationWorldwide Population Averaged Natural Radiation Dose: 2,400 µSv/y

Internal Terrestrial(excl radon/thoron)

12%

Internal Cosmogenic

1%

Terrestrial21%

Cosmic17%

Internal Radon47%

Internal Thoron3%

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Yes

Yes

No

No

Yes

Yes

No

No

Yes

Yes

No

Yes

No No Health Effects

to theIndividual

Radiation hits a molecule of a living cell. Was that molecule a DNA molecule?

Damage to a DNA molecule normally corrects itself. Was the damage corrected?

No

An error remained in the molecule. Was that error of any significance to the cell?

A malignant disease will develop.

Cellular reproduction rate may be too slow for cancer to develop during the lifetime of the individual. Is that so?

Radiation may or may not cause damage to the molecule. Was the DNA molecule damaged?

The changed characteristics of the new cells may be harmless or harmful. Are they harmful?

IONISING RADIATION & CANCER DEVELOPMENT

Cancer cells may be destroyed by the normal immune system of the body. Are these cancer cells destroyed?

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RADIATION RISKS “CONSUMER GOODS”(comparison of risks expressed in dose units: Sv{/a})

Record static eliminator 0.01Radioactive lightning rod 0.5Gas camping lantern mantle (NORM) 2.5Cooking on Natural Gas (Radon) 5Tritium wrist watch 5Ionisation smoke detector 10Exempt level (PRACTICE IAEA/EU) 10Radium wrist watch 30Flight Amsterdam-Houston (~ 10 h) v.v. 70 Building masonry (NORM) 70X-Ray Photograph (Chest) 100Exempt level (WORK ACTIVITY EU, ICRP-2005) 300Living in a Dutch Dwelling (Radon) 950Public Limit (ICRP-2005) 1000(World average) Natural Background Dose 2400(radioisotopes) Nuclear Medicine (kidney) 2500X-Ray Photograph (Barium meal) 3500X-Ray Computed Tomography (CT body) 8500Worker Limit (ICRP-2005) 20000

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COMPARISON OF RISKS OF (WORKING) LIFE (fatalities per million per year)

Exempt level - PRACTICE (10 Sv – IAEA/EU) 0.5Clothing & Footwear 3.5Timber & Furniture 10Exempt level - WORK ACTIVITY (300 Sv – EU/ICRP) 15Textiles 35Accidents at Work (UK) 50Public dose limit (1,000 Sv/a – ICRP) 50Metal Manufacture 60Accidents at Home (UK) 100Natural Background (world average 2,400 Sv/a) 120Construction 200Road Accidents (UK) 200Coal Mining 250Radiation worker Dose limit (20,000 Sv/a - ICRP) 1000Deep Sea Fishing 2000Smoker (10 cigarettes/day) 5000

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Risk to People – What Is Reasonable?

10-3

10-4

10-5

10-6

10-7

Smokingall accidental (non disease)all accidental (non-disease, non transport)E&P contractors

car driving

accidents at homeE&P company staffaccidents at work (average all industries – US ’86)playing football/rock climbingFireWorkers in safest industryLight manufacturing

air transportLiving near nuclear installations

insect bites/flooding in the Netherlandslightning strikesexplosion of pressure vessel

RSSG upper bound forvoluntary risk

HSE upper bound forinvoluntary risk

public acceptance ofvoluntary risk

RSSG/HSE insignificantpublic acceptance of Natural disasters

public tolerance of man-made disasters

Intolerable

Too high

Compareoptions

Maintainprecautions(due care)

Negligible*

* Proposed by Health & Safety Executive, UK

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to be issued and endorsed by the competent authority for radiation

workers, workforce/public at largesource constraint for dose control

radiation workers 20,000 Sv/aworkers (2,000 h/a) 1,000 Sv/apublic 1,000 Sv/aNORM- source constraint 300 Sv/a

DOSEannual limits


competent authority enveloping scenario's URL’s

set of enveloping exposure scenario’s encompassing all industrial uncontrolled

work with “NORM” leading to workforce/public exposure

set of NOR-specific Unconditional Release Limits

(URL’s; may be applied under all circumstances)

CONCENTRATION(limits for air, water, soil)


EXPOSUREscenarios

External & Internal

Unconditional Release Limits (URL)

226Ra 210Pb 228Ra 228ThEU BSS 0.5 5 1 0.5ICRP 2005 1 1 1 1

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Dose Assessment Study Conditional Release Limit (referenced against the NORM Source Constraint set by the Competent Authority)

Collection/compilation of site specific data characterising the geohydrological setting, background radiation levels and radioactivity concentration in various environmental media including soil, subsoil, surface water, ground water, airborne dusts, fauna and flora.

Identification and quantification of the source terms (input of NORM for intended final disposal option), the chemical and physical form of the radionuclides the points of release, and the time distribution of release.

Identification of the potential environmental pathways.

Identification of the critical population.

Assessment of the individual dose using a computer modelling.

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Risk of Radiation DosesCompare with Natural Background Dose

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norm final disposal options (risk & cost considerations) gert jonkers engineering &...

Documents

deposits norm

ep norm workshop muscat

ep norm disposal urls

bn amsterdam

enveloping exposure

internal dose

sva workers

workforcepublic exposure