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NORM Final Disposal Options (risk & cost considerations) Gert Jonkers Engineering & Analytical - GSEA/4 “ Problem Solving ” (Shell E&P Ionising Radiation/NORM HSE Expert CHP) location Shell Research & Technology Centre, Amsterdam P.O. 38000 NL-1030 BN Amsterdam the Netherlands . g.

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NORM Final Disposal Options

(risk & cost considerations)

Gert Jonkers

Engineering & Analytical - GSEA/4 “Problem Solving”

(Shell E&P Ionising Radiation/NORM HSE Expert CHP)

location

Shell Research & Technology Centre, Amsterdam

P.O. 38000

NL-1030 BN Amsterdam

the Netherlands


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g

NORM after abandonment - Internal & External Radiation Hazard

TARGETReducing 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.

a

b

g


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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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Isolationfrom Environment

NORM FINAL DISPOSAL OPTIONS

Dilution into the Environment

Controlled Surface Storage

Injection in Sealed Reservoir

Immobilisation & Sealed Subsurface Storage


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Conditional Release Limits (CRL)

DOSE

annual limits

Effective Dose in Sievert

EXPOSURE

scenarios

External & Internal

CONCENTRATION

(limits for air, water, soil)

Becquerel per m3, L or g

radiation workers 20,000 mSv/a

workers (2,000 h/a) 1,000 mSv/a

public 1,000 mSv/a

NORM- source constraint 300 mSv/a

to be issued and endorsed by the

competent authority for radiation workers, workforce/public at large

source constraint for dose control

set of enveloping exposure scenario’s encompassing all industrial uncontrolled work with “NORM” leading to workforce/public exposure

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)

set of NOR-specific Unconditional Release Limits (URL’s; may be applied under all circumstances)

Generic EP or Group operating unit specific scenario’s competent authority enveloping scenario's

Generic CRL’s for EP NORM disposal URL’s

CRL (Bq[…]/g) 226Ra210Pb 228Ra 228Th

Condition

Spreading

Sludge farming

Shallow disposal

Deep hole disposal

226Ra 210Pb 228Ra 228Th

EU BSS 0.5 5 1 0.5

ICRP 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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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

  • Specific & In-house (Shell)

  • flat source (external radiation, microshield),

  • sludge farming (external & dust)

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

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

  • In-house (Shell)

  • Mores,

  • FORDAM


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Dilution into the Environment

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]


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“Controlled Disposal”

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


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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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NORM FINAL DISPOSAL OPTIONS

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

Isolationfrom Environment

  • B q[226Ra]/g

  • “Spreading (with dilution)”$ 40 2

  • Sludge farming $ 10 2

  • Burial with Unrestricted Site Reuse 5

  • Non-Retrieval of Surface Pipe 50

  • NORM Disposal Facility $ 20 200

  • Commercial Oil Industrial Waste Facility $ 45 200

  • Commercial Low Level Waste Disposal Site $ 400 200

  • Burial in Surface Mine 500

  • Well Injection$ 120 > 1000

  • Plugged and Abandoned Well $ 200 > 1000

  • Hydraulic Fracturing > 1000

  • Salt Dome Disposal $ 10 > 1000




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Risk Assessment Matrix

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


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Intervention

Always

Justifiable

Intervention

May Be

Justifiable

Intervention

Rarely

Justifiable

very high

100,000 mSv/a

Additional Dose

Restrictions

Individual Dose Limit

(1,000 mSv/a)

Source Constraint

(300 – 100 mSv/a)

Exemption

(10 mSv/a)

Typical

10,000 mSv/a

background

2,400 mSv/a

source


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ESTABLISHMENT OF GENERAL EXEMPT LIMITS

RISK

Likelihood of Fatal Cancer

Source Dose Constraint

to be endorsed by the

Competent Authority

DOSE

“Forward” Calculation - Applied

for Deriving Unconditional Release (Exempt) Limits or

for Determining Compliance with

Dose or Risk Standards

Effective Dose in Sievert

EXPOSURE

Derived Limits

to be endorsed by the

Competent Authority

for any circumstance

(Unconditional)

External & Internal

CONCENTRATION

(air, water, soil)

Becquerel per m3, L or g


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HIERARCHY OF DOSE QUANTITIES

Absorbed Dose (Gy)

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

Equivalent Dose (Sv)

absorbed dose weighted for harmfulness of different radiations (wR)

Effective (Whole Body) Dose (Sv)

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

Collective Effective Dose (manSv)

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 Radiation

Worldwide Population Averaged Natural Radiation Dose: 2,400 µSv/y

Internal Terrestrial

(excl radon/thoron)

12%

Internal Radon

47%

Internal Thoron

3%

Internal Cosmogenic

1%

Terrestrial

21%

Cosmic

17%


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IONISING RADIATION & CANCER DEVELOPMENT

No

Health Effects

to the

Individual

No

Yes

No

Yes

Yes

No

No

Yes

No

Yes

Yes

No

No

Radiation hits a molecule of a living cell.

Was that molecule a DNA molecule?

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

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

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

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

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

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

Yes

A malignant disease will develop.


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RADIATION RISKS “CONSUMER GOODS”

(comparison of risks expressed in dose units: mSv{/a})

Record static eliminator 0.01

Radioactive lightning rod 0.5

Gas camping lantern mantle (NORM) 2.5

Cooking on Natural Gas (Radon) 5

Tritium wrist watch 5

Ionisation smoke detector 10

Exempt level (PRACTICE IAEA/EU) 10

Radium wrist watch 30

Flight Amsterdam-Houston(~ 10 h) v.v. 70

Building masonry (NORM) 70

X-Ray Photograph (Chest) 100

Exempt level (WORK ACTIVITY EU, ICRP-2005) 300

Living in a Dutch Dwelling (Radon) 950

Public Limit (ICRP-2005) 1000

(World average) Natural Background Dose 2400

(radioisotopes) Nuclear Medicine (kidney) 2500

X-Ray Photograph (Barium meal) 3500

X-Ray Computed Tomography (CT body) 8500

Worker Limit (ICRP-2005) 20000


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COMPARISON OF RISKS OF (WORKING) LIFE

(fatalities per million per year)

Exempt level - PRACTICE (10 mSv – IAEA/EU) 0.5

Clothing & Footwear 3.5

Timber & Furniture 10

Exempt level - WORK ACTIVITY (300 mSv – EU/ICRP) 15

Textiles 35

Accidents at Work (UK) 50

Public dose limit (1,000 Sv/a – ICRP) 50

Metal Manufacture 60

Accidents at Home (UK) 100

Natural Background (world average 2,400 Sv/a) 120

Construction 200

Road Accidents (UK) 200

Coal Mining 250

Radiation worker Dose limit (20,000 Sv/a - ICRP) 1000

Deep Sea Fishing 2000

Smoker (10 cigarettes/day) 5000


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-

3

10

-

4

10

-

5

10

-

6

10

-

7

10

Risk to People – What Is Reasonable?

Smoking

all accidental (non disease)

all accidental (non-disease, non transport)

E&P contractors

RSSG upper bound for

voluntary risk

Intolerable

Too high

Compareoptions

Maintainprecautions(due care)

Negligible*

car driving

accidents at home

E&P company staff

accidents at work (average all industries – US ’86)

playing football/rock climbing

Fire

Workers in safest industry

Light manufacturing

HSE upper bound for

involuntary risk

public acceptance of

voluntary risk

air transport

Living near nuclear installations

RSSG/HSE insignificant

public acceptance of

Natural disasters

insect bites/flooding in the Netherlands

lightning strikes

explosion of pressure vessel

public tolerance of

man-made disasters

* Proposed by Health & SafetyExecutive, UK


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Unconditional Release Limits (URL)

DOSE

annual limits

Effective Dose in Sievert

EXPOSURE

scenarios

External & Internal

CONCENTRATION

(limits for air, water, soil)

Becquerel per m3, L or g

radiation workers 20,000 mSv/a

workers (2,000 h/a) 1,000 mSv/a

public 1,000 mSv/a

NORM- source constraint 300 mSv/a

to be issued and endorsed by the

competent authority for radiation workers, workforce/public at large

source constraint for dose control

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)

competent authority enveloping scenario's

URL’s

226Ra 210Pb 228Ra 228Th

EU BSS 0.5 5 1 0.5

ICRP 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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The End

The End

Risk of Radiation Doses

Compare with Natural Background Dose


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