Experience dry storage of spent fuel Belgium NPP Doel

Transcription

1 Transnubel Experience dry storage of spent fuel Belgium NPP Doel Xavier Van Mierloo Workshop IAEA May

2 Spent Introductory remarks Experience of dry spent fuel storage in Belgium Presentation is for information purposes only Spent fuel management is a cooperation of different partners Synatom, Electrabel, Tractebel, Transnubel 2

3 Spent Moratorium on reprocessing of Belgian spent fuel since 93 Spent fuel elements of the NPPs of Tihange are stored on-site in dedicated spent fuel pools SF is transported in a wet transfer cask from the units to the spent fuel pool Spent fuel elements of the NPPs of Doel are temporary stored on-site in a dedicated building with dry dual purpose casks The Belgian operators are awaiting the decision of their definitive destination: Transport followed by reprocessing Transport followed by conditioning for final disposal As long as this decision is not taken, these fuel assemblies are not considered to be waste! 3

4 Dry storage spent fuel Doel Storage on-site in a dedicated storage building Storage of spent fuel in type B(U)F or B(M)F transport casks Transport on-site with transport license Storage authorization is coupled to the package approval Problem: Renewal of package approval certificate is getting more difficult over time Maintain full conformity of loaded cask with package design could be difficult over time (small evolution in design) taking into account the evolution of the transport regulations 4

5 Dry storage spent fuel Doel Solution : Disconnect storage authorization from package design approval : proposed new requirements: 1. Valid package design approval at the time of loading 2. Maintain on-site transferability during storage (availability of procedure and equipment to transfer, if requested to manage an incident on a cask, the Spent Fuel dual purpose cask to pool s unit in a safe way evaluated every 5 years) 3. Every 10 years (safety review of NPP) : assessment of possibilities to transport for final disposal (package design approval still possible or transfer to an other cask (hot cell or pool) or transport under special arrangement) 5

6 Dry storage spent fuel Doel Easy way to comply with new approach : continue to renew the certificate for as long as it is possible How to apply this if a prolongation of the package design approval certificate is no longer possible? : Integrated Transport and Storage Safety Case for Dual Purpose Casks for Spent Nuclear Fuel on basis of : Safety Analysis Report (SAR) Storage safety file (TSAR) Gap analysis 6

7 TN24 spent fuel cask 7

8 Filling of dry storage Loading, drying and conditioning of casks Transfer on site to storage building SCG Vertical storage No shock absorbers No secondary lid Anti-missile shield Storage pad Leak tightness control Thermal control Visual inspections Experience dry storage 8 of spent

9 Dry storage spent fuel Doel TN 24 Entity # assemblies Assembly size Assembly length SH Doel x D Doel x DH Doel x XL Doel x XLH Doel x

10 This image cannot This currently image cannot be displayed. currently be displayed. Dry storage spent fuel Doel Experience dry storage of spent 10

11 Storage in SCG Doel TN 24 # casks stored Cooling time (av) Years Max. burnhup GWd/t Max. enrichment SH D DH XL XLH % 11

12 This image cannot currently be displayed. Storage in SCG Doel TOTAL: 87 loaded storage casks Capacity Storage building SCG First part: 56 containers Second part: 112 containers TOTAL: 165 positions (3 obligatory empty) Storage building is half full Extension of storage capacity? 12

13 This image cannot currently be displayed. Incidents Detection of leaking fuel at cask loading Water sample Defective second seal for one cask Leak tightness was always guaranteed Transport to fuel pool of D4 Reflooding of cask Changing lid and seals Loosening of silicons Intervention on pressure monitors Configuration of pressure gauges has changed Radiation level locally above expected value 13

14 Conclusion The dry storage of spent fuel at Doel is stable and safe Only minor incidents Storage is half full Renewal of packaging approval certificate Transport after storage can be a challenge Closing of Doel 1-2 Cooling time for spent fuel Capacity per packaging 14

15 Transnubel Thank you for your attention 15