Transnubel
Experience dry storage of spent fuel
Belgium NPP Doel
20/05/2014
Xavier Van MierlooWorkshop IAEA May 2014
Experience dry storage of spent fuel Belgium
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20/05/2014
Spent fuel Belgium
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
Experience dry storage of spent fuel Belgium
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Spent fuel Belgium
• 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!
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• 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
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Dry storage spent fuel Doel
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• 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)
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Dry storage spent fuel Doel
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• 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
• …Experience dry storage of spent
fuel Belgium6
Dry storage spent fuel Doel
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TN24 spent fuel cask
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Experience dry storage of spent fuel Belgium
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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
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Experience dry storage of spent fuel Belgium
TN 24 Entity # assemblies
Assembly size
Assembly
length
SH Doel 1-2 37 14x14 2900
D Doel 3 28 17x17 4030
DH Doel 3 28 17x17 4030
XL Doel 4 24 17x17 4795.4
XLH Doel 4 24 17x17 4795.4
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Dry storage spent fuel Doel
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Experience dry storage of spent fuel Belgium
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Dry storage spent fuel Doel
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Experience dry storage of spent fuel Belgium
TN 24 # casks stored
Cooling time (av)
Years
Max. burnhup
GWd/t
Max. enrichment
%
SH 27 5 55 4.55
D 10 8 36 3.4
DH 24 7 55 4.5
XL 8 8 40 3.3
XLH 18 7 55 4.36
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Storage in SCG Doel
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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?
12Experience dry storage of spent fuel Belgium
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Incidents
Experience dry storage of spent fuel Belgium
• 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
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Conclusion
Experience dry storage of spent fuel Belgium
• 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
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Thank you for your attention
20/05/2014
Transnubel
Experience dry storage of spent fuel Belgium
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