Refurbishment of the tritium laboratories at SCKCEN

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Refurbishment of the tritium laboratories at
SCKCEN

• Johan Braet, Kris Dylst, Sven Vanderbiesen

8th International Conference on Tritium Science
and Technology September 16-21, 2007 Rochester,
New York
2
Agenda
Introduction
Strategy
DD Figures
Economics
Conclusions

• Introduction
• Strategy
• Dismantling and decontamination figures
• Economics
• Conclusions

3
The SCK Tritium laboratory is in use for more
than 30 years
Introduction
Strategy
DD Figures
Economics
Conclusions

• The tritium laboratories at SCKCEN were
  commissioned in 1975 for a maximum tritium
  inventory of 37 TBq tritium.
• A number of major tritium projects have been
  executed
• Detritiation of atmospheres 0.5 TBq
• Detritiation of water (CECE) 2.0 TBq
• Detritiation of solvents 18.0 TBq
• Various detritiation projects 2.5 TBq
• LPCE catalyst testing
• Detritiation of steel
• Detritiation of concrete
• 22.5 TBq

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The new layout provides more and better work
areas
Introduction
Strategy
DD Figures
Economics
Conclusions
New layout
Old layout

• 100 m² controlled area
• 3 process cells 19 m²
• 2 gloveboxes
• 3 Fume Hoods
• Extraction rate 10,758 m³/h
• Max. Tritium inventory of 37 TBq

• 100 m² controlled area
• 1 process cell 15 m²
• 6 gloveboxes (ETHEL)
• 5 1 Fume hoods
• Extraction rate 15,350 m³/h
• Max. Tritium inventory of 370 TBq

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Refurbishment plan
Introduction
Strategy
DD Figures
Economics
Conclusions

• Continue working in room 1 decommission room 2
• Reinstall room 2
• Commission room 2
• Decommission room 1 start working in room 2
• Reinstall room 1
• Commission room 1

? Busy ? ? ? ?
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Decommissioning requires a strategy for disposal
or free release
Introduction
Strategy
DD Figures
Economics
Conclusions

• Room 2 needed to be cleared for decommissioning.
• Equipment in room 2 meters, pumps,
• To be reused
• Move to working lab
• Move to warehouse
• Infrastructure room 2 process cell, fume hoods,
  furniture
• Not to be reused
• Several tons of material need to be disposed/
  free released
• A disposal / free release strategy is necessary

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The free release limit is a key factorin the
disposal / free release strategy
Introduction
Strategy
DD Figures
Economics
Conclusions
Decontaminate
Yes
BelowFRL?
Further decont.?
Clean up
Dispose as nuclear waste
No
No
Yes
Recycle
Free release
Dispose as nonnuclear waste
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Tritium limits
Introduction
Strategy
DD Figures
Economics
Conclusions
Contamination ? Activation

• Belgian law 100 Bq/g

Destructive measurement
Total surface contamination limits Bq/dm²
Removable surface contamination limits Bq/dm²
200 000 000 CEA 1 000 000 European
Commission 16 667U.S. Department of
Energy 2 500
SCKCEN
2 000 000CEA 250 SCKCEN
167 U.S. Department of Energy
4Interpretation of IAEA transport norm for ß,?
emitters
Indirect measurement
Direct measurement
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The infrastructure was decommissioned in 3 main
phases
Introduction
Strategy
DD Figures
Economics
Conclusions

• Probably not contaminated equipment 1.2 t
• Furniture
• Possibly contaminated equipment 5.3 t
• Process cells / glovebox / fume hoods
• Ventilation / pulsation
• Covering of floor, wall and ceiling 10.6 m³

0.3 t
0.3 t
0.9 t
0.6 m³
10 m³
0.9 t
4.1 t
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Decontamination generates secondary radioactive
waste
Introduction
Strategy
DD Figures
Economics
Conclusions
ProbablyContaminated
Prob. notContaminated
Floor, Walland ceiling

• Free released
• Nuclear metal recycling
• Disposed radioactive waste
• Secondary radioactive waste
• Compressible waste
• Scintillation liquid
• Air filters

0.9 t 0.3 t 7 kg 10 L
4.1 t 0.3 t 0.9 t 131 kg 20 L 48 kg
10 m³ 0.6 m³ 6 kg 3 L
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Safety measures prevented personnel to receive
measurable tritium dose
Introduction
Strategy
DD Figures
Economics
Conclusions

• Safety measures during project
• PPE
• PEDI suits
• Gloves, dust masks, overalls
• Infrastructural
• Ventilation
• Airborne tritium monitoring
• Dosimetry
• Regular analyses of urine samples
• The tritium concentration in all urine samples
  were below the detection limit to calculate the
  received dose.

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The low release limit made decontamination labour
intensive
Introduction
Strategy
DD Figures
Economics
Conclusions

• Example Process cells
• 2.8 Tons of painted metal
• Underlying paint layers can contain up to 47000
  Bq/dm² (fixed)
• Decontamination method
• Scouring off paint from floor and walls in cell
• Scouring off thin metal layer
• Washing cell
• 31 of the total manhours have been spent on the
  decontamination of the process cells.
• Could disposing of metals to a nuclear melting
  facility a valid alternative?

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Cost balanceFree release Nuclear melting
facility
Introduction
Strategy
DD Figures
Economics
Conclusions
Free Release
Nuclear meltingFacility

• Entry
• Manhours
• Equipment
• Radioactive waste
• Nuclear melting facility
• Total

EUR 213 000 13 000 64 000 2 000 292 000
EUR 146 000 13 000 48 000 21 000 228 000

• Disposing metals to a nuclear melting facility
  could have saved 22 of the costs.
• Free release socially more acceptable?

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Conclusions
Introduction
Strategy
DD Figures
Economics
Conclusions

• One room has been decommissioned and
  reinstallation activities are taken place.
• For free release purposes tritium was classified
  as regular ß,? emitter which leads to too
  restrictive free release limits and a very labour
  intensive decontamination process.
• Decontamination also generates secondary nuclear
  waste.
• Most of the materials have been denuclearised
  without personnel receiving measurable tritium
  dose.
• Disposing metals to a nuclear melting facility
  would have saved 22 of the costs, but free
  release might be socially more accepted

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Tritium 2007
refurb
tritium
Thank you for your attention
lab