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Successful Successful decommissioning of a decommissioning of a

nuclear plantnuclear plant

Evelyn HooftBart Thieren

20 june 2008

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IntroductionIntroduction

■NIRAS: public institute responsible for the safe management of radioactive waste in Belgium. Has developped a coherent and central management system

■Belgoprocess: industrial daughter of NIRAS, main activities are treatment and storage of radioactive waste and decommissioning of shut down nuclear installations

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IntroductionIntroduction

■NIRAS is charged by the belgian State with the clean up of nuclear liabilities = task of public benefit

~ 1986 : site BP 1 (Eurochemic)~ 1989 : site BP 2 (Ex waste department

of SCK.CEN)~ 1991 : installations and fission products

originated from research reactors and other installations of the SCK.CEN

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Foto site 1Foto site 1

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EurochemicEurochemic

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Eurochemic Eurochemic

■ First reprocessing plant in Europe■ Goal

~ Research and development in the field of reprocessing spent fuel originated from nuclear reactors

~ Construction of a pilot plant

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Reprocessing ?Reprocessing ?

■ Definition: Reprocessing = recycling

~ Spent fuel (nuclear fuel) can be recycled■ 97% of the material can be reused for

electricity production (U and Pu)■ 3% is waste and is vitrified, interim stored

awaiting for disposal.

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History of EurochemicHistory of Eurochemic

■ 1957 Constitution of Eurochemic■ 1960 Start construction■ 1966 Start up and active operation■ 1974 Shutdown■ 1978 Take-over by the Belgian State

with the intention to continue reprocessing

■ 1984 Constitution of Belgoprocess■ 1985 Belgoprocess takes over the

personnel

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■ 1986 Decision to end reprocessing in Belgium Transfer actions to NIRAS

■ 1987 Start decommissioning studies■ 1989 Start decommissioning pilot

project ■ 1990 Start decommissioning

Eurochemic■ 2008 Start conventional demolition

History of EurochemicHistory of Eurochemic

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Pilot projectPilot project

■ Decommissioning of two smaller buildings for endproducts originated from reprocessing ~ To demonstrate that decommissioning

is feasible~ To demonstrate that costs can be

managed~ To develop and optimise dismantling

techniques~ To train personnel

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Before and afterBefore and after

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Main lessons learnedMain lessons learned

■ Emphasis should be put on:

~ Decontamination of metal components~ Automation of concrete decontamin-

ation

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Clean-up of EurochemicClean-up of Eurochemic

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■ Main data~ Length 90 m, width 27 m,

height 27 m~ Volume: 56.000 m³~ Concrete volume: 12.500 m³~ Concrete surface: 55.000 m²~ Metal: 1.500 ton

■ 7 levels, 40 main cells■ 106 cell structures

Clean-up of EurochemicClean-up of Eurochemic

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■ Radiological status in 1981

~ Contamination level up to 200 Bq/cm² (alpha) and 125 Bq/cm² (beta)

~ Sometimes contamination in depth~ Hot spots up to several mSv/h~ No activation

Clean-up of EurochemicClean-up of Eurochemic

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Used techniquesUsed techniques

■ Removal of metal components■ Decontamination of concrete surfaces■ Removal of contamination in depth■ Removal of pipe penetrations■ Techniques for working on heights

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Removal of metal Removal of metal componentscomponents

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Removal of metal Removal of metal componentscomponents

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Decontamination of Decontamination of concrete surfacesconcrete surfaces

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Decontamination of floorDecontamination of floor

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Removal of contamina-Removal of contamina-tion in depthtion in depth

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Removal of pipe Removal of pipe penetrationspenetrations

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Working at heightWorking at height

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Working at heightWorking at height

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To decontaminateTo decontaminate

■ Main streams~ Metal~ Concrete

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To decontaminateTo decontaminate

■ Main streams~ Metal 1.494 ton~ Concrete 2.913 ton (incl. barytes blocs)

(period 1988 – 2007)

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Metal decontaminationMetal decontamination

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Before and afterBefore and after

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Concrete samplingConcrete sampling

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Clearance measuresClearance measures

■ 100 % surface measurement ■ Taking samples and analyses■ Procedure is representative and

approved by the department of fysical control

■ Control organism (Bel-V) subsidiary of FANC

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Clearance measurementClearance measurement

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SafetySafety

■ Top priority for Belgoprocess

■ Radiation dose■ Contamination risque■ Conventional safety

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SafetySafety

■ Top priority for Belgoprocess

■ Radiation dose (average < 2 mSv/year.person over 1990-2007)

■ Contamination risque (Protective clothes including full-face mask)

■ Conventional safety~ Circumstances as on a construction

warf~ Vibration stress

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Protective clothesProtective clothes

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Protective clothesProtective clothes

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Isolation of a moduleIsolation of a module

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DemolitionDemolition

■ Method

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Result:Result:

■ Production streams■ Men-hours■ Budget■ Planning

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Result: productionResult: production

CONTAMINATED MATERIAL

DECONTAMINATION OF MATERIALS

RADIOACTIVE WASTE

UNCONTAMINATED MATERIAL

RECYCLING WASTE PROCESSING

&

&

& &

&&

& &

DECOMMISSIONING

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Result: productionResult: production

CONTAMINATED MATERIAL

DECONTAMINATION OF MATERIALS

RADIOACTIVE WASTE

UNCONTAMINATED MATERIAL

RECYCLING WASTE PROCESSING

&

&

& &

&&

& &

557 t 1.530 t

2.356 t 145 t

2.913 t 1.675 t63%

DECOMMISSIONING (31/12/2007)4.588 t

2.501 t

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Result: productionResult: production

CONTAMINATED MATERIAL

DECONTAMINATION OF MATERIALS

RADIOACTIVE WASTE

UNCONTAMINATED MATERIAL

RECYCLING WASTE PROCESSING

&

&

& &

&&

& &

557 t 1.530 t

2.356 t 145 t

2.913 t 1.675 t63% -> 88%

DECOMMISSIONING (31/12/2008)+9.552 t

+9.552 t

4.588 t

2.501 t

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Result: men-hoursResult: men-hours

■ Initial estimation: 403 man-year■ Current estimation: 600 man-year■ Difference explained by:

~ Decontamination until clearance~ Differences with the initial inventory~ Labour-intensive clearance

measurements and procedures

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Result: budgetResult: budget

Initial estimation

M€1992 M€2008

1990 - 2007

M€2008

after 2007M€2008

Total

M€2008 Ratio

Decommissioning costs

54,8 73,9 115,1 30,0 145,1 1,96

Treatment (tarif 2008)

68,7 92,6 25,7 4,2 29,9 0,32

Totaal 123,5 166,5 140,8 34,2 175,0 1,05

Forced decontamination till clearance

Less treatment, interim storage and disposal

End result remains equal

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Result: planningResult: planning

■ Conventional demolition~ East part: september 2008~ Central part: einde

2010~ West part : einde 2012

~ Distribution of water, air, steam,.. for neighbouring buildings remains

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Result: planningResult: planning

20082010

2012

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AmbitionsAmbitions

■ Safety■ Environment■ Socio-economical■ Exploitation of the disposal site for

category-A waste■ International partner

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ConclusionConclusion

■ Start of the conventional demolition of Eurochemic

■ In 2012 completely demolished■ Cleaned-up historical heritage■ Know-how to recycle >90%

Belgoprocess and NIRAS decommission succesfully a nuclear plant

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More informationMore information

■ Websites~ Eurochemic

www.eurochemic.be~ Belgoprocess

www.belgoprocess.be~ NIRAS www.nirond.be