Successful decommissioning of a nuclear plant

1. Successful decommissioning of a nuclear plant Evelyn HooftBart Thieren 20 june 2008

2. Introduction • 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

3. Introduction • 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

4. Foto site 1

5. Eurochemic

6. 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

7. 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.

8. History 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

9. History of Eurochemic • 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

10. Pilot 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

11. Before and after

12. Main lessons learned • Emphasis should be put on: • Decontamination of metal components • Automation of concrete decontamin-ation

13. Clean-up of Eurochemic

14. Clean-up of Eurochemic • 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

15. Clean-up of Eurochemic • 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

16. Used techniques • Removal of metal components • Decontamination of concrete surfaces • Removal of contamination in depth • Removal of pipe penetrations • Techniques for working on heights

17. Removal of metal components

18. Removal of metal components

19. Decontamination of concrete surfaces

20. Decontamination of floor

21. Removal of contamina-tion in depth

22. Removal of pipe penetrations

23. Working at height

24. Working at height

25. To decontaminate • Main streams • Metal • Concrete

26. To decontaminate • Main streams • Metal 1.494 ton • Concrete 2.913 ton (incl. barytes blocs) (period 1988 – 2007)

27. Metal decontamination

28. Before and after

29. Concrete sampling

30. Clearance 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

31. Clearance measurement

32. Safety • Top priority for Belgoprocess • Radiation dose • Contamination risque • Conventional safety

33. Safety • 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

34. Protective clothes

35. Protective clothes

36. Isolation of a module

37. Demolition • Method

38. Result: • Production streams • Men-hours • Budget • Planning

39. Result: production DECOMMISSIONING & CONTAMINATED MATERIAL & & & UNCONTAMINATED MATERIAL DECONTAMINATION OF MATERIALS RADIOACTIVE WASTE & & & & RECYCLING WASTE PROCESSING

40. Result: production 4.588 t DECOMMISSIONING (31/12/2007) & 2.501 t CONTAMINATED MATERIAL 1.530 t 557 t & & & 2.356 t 145 t UNCONTAMINATED MATERIAL DECONTAMINATION OF MATERIALS RADIOACTIVE WASTE & & & & 2.913 t 63% 1.675 t RECYCLING WASTE PROCESSING

41. Result: production 4.588 t DECOMMISSIONING (31/12/2008) +9.552 t & 2.501 t CONTAMINATED MATERIAL 1.530 t 557 t & & & 2.356 t 145 t UNCONTAMINATED MATERIAL DECONTAMINATION OF MATERIALS RADIOACTIVE WASTE & & & & 2.913 t 63% -> 88% 1.675 t +9.552 t RECYCLING WASTE PROCESSING

42. Result: 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

43. Result: budget Forced decontamination till clearance Less treatment, interim storage and disposal End result remains equal

44. Result: planning • Conventional demolition • East part: september 2008 • Central part: einde 2010 • West part : einde 2012 • Distribution of water, air, steam,.. for neighbouring buildings remains

45. Result: planning 2008 2010 2012

46. Ambitions • Safety • Environment • Socio-economical • Exploitation of the disposal site for category-A waste • International partner

47. Conclusion • 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

48. More information • Websites • Eurochemic www.eurochemic.be • Belgoprocess www.belgoprocess.be • NIRAS www.nirond.be