12 septembre 2014
Une enquête a été menée pour déterminer la raison de l’enclenchement du système de ventilation d’urgence lors de la phase finale de chargement de fûts. Du krypton 85, produit de fission, a été découvert dans les échantillons analysés. Tous les assemblages combustibles chargés ont pourtant été contrôlés pour vérifier qu’ils étaient bien intacts, et donc en conformité avec les exigences réglementaires. La présence de krypton 85 indique que les assemblages ne seraient pas intacts.
Type : PWR - Puissance : 2 568 MWth - Première divergence : 08/1974
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Event Number : 50454
Facility : ARKANSAS NUCLEAR
State : AR - Unit : [1] - Type : [1] B&W-L-LP
Event Date : 09/12/2014 - Event Time : 15:47
Emergency Class : NON EMERGENCY 10 CFR Section : OTHER UNSPEC REQMNT
Initial PWR : 100 % - Current PWR : 100 % -
Event Text
STORED FUEL MAY NOT MEET FUEL SPECIFICATIONS OR LOADING CONDITIONS FOR HI-STORM 100 CASK SYSTEM
"Arkansas Nuclear One (ANO) identified the potential for stored fuel that does not meet the fuel specifications or loading conditions of the Certificate of Compliance (CoC) for the HI-STORM 100 Cask System. Investigation into the cause of a Control Room Emergency Ventilation System (CREVS) actuation on the morning of 9/12/2014 led to sampling of helium circulating through the Multi-Purpose Canister (MPC-24-060) as part of the Forced Helium Dehydration process in the final stages of cask loading. Sample results indicated the presence of Kr-85. Kr-85 is a fission product that indicates the potential for the fuel that does meet the selection criteria for the HI-STORM 100 Cask System.
"All fuel assemblies loaded into MPC-24-060 were checked to confirm their intact status (a cask Certificate of Conformance requirement) as part of the selection process. Each assembly’s status as intact is based on in-mast sipping and/or ultrasonic testing performed subsequent to their final operating cycle. Results of these sipping and ultrasonic test campaigns are maintained in a comprehensive engineering report used to verify assembly status during cask fuel selection.
"Per the CoC for the Hi-STORM 100 Cask System, Appendix B, Section 1.0, the definition of ’INTACT FUEL ASSEMBLY’ is a fuel assembly without known or suspected cladding defects greater than pinhole leaks or hairline cracks, and which can be handled by normal means. Given the presence of Kr-85 along with the fuels history, it cannot be confirmed that all fuel assemblies meet the definition of ’Intact’ and would not meet the CoC Requirements for Fuel to be stored in the HI-STORM 100 SFSC System (Section 2.1.1)."
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2014/20140915en.html#en50454
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