15 mai 2013
Le 13 mai 2013, au cours de l’analyse de données ultrasoniques effectuées un an plus tôt (printemps 2012) sur des têtes de pénétrations, il a été découvert une fissure estimée à 7 mm le 15 mai 2013. Selon les spécifications techniques, cette fissure liée à l’érosion du métal par le liquide du circuit primaire imposait la mise à l’arrêt du réacteur pour réparation. La dégradation de cette partie du réacteur, sollicitée en situation "d’ilotage", pouvait empêcher l’accomplissement d’une fonction de sécurité permettant le contrôle des rejets de matières radioactives".
1ère divergence janvier 1987 - P : 900 MW - Type : PWR
Available in english only.
Facility : HARRIS - State : NC - Unit : [1] - RX Type : [1] W-3-LP Event Date : 05/15/2013 - Event Time : 06:49 Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(2)(i) - PLANT S/D REQD BY TS 50.72(b)(3)(ii)(A) - DEGRADED CONDITION 50.72(b)(3)(v)(C) - POT UNCNTRL RAD REL
Initial PWR 100% Current PWR 100%
Event Text
TECHNICAL SPECIFICATION REQUIRED SHUTDOWN DUE TO DISCOVERY OF AN UNACCEPTABLE FLAW DURING DATA REVIEW
"On May 13, 2013, during a secondary review of ultrasonic data of the reactor vessel head penetrations performed during Harris Nuclear Plant spring 2012 refueling outage, it was determined that the results for one of the penetrations appeared to not meet the applicable acceptance criteria. Further evaluation completed on May 15, 2013, characterized the flaw as a 0.26 inch flaw an nozzle 49 that overlaps the J-grove weld and exhibits characteristics of primary water stress corrosion cracking. The original examinations were performed per NRC requirements.
"Initial evaluation indicates that the flaw is not through wall and there is no evidence of leakage based on inspections performed on the top of the reactor vessel head during the spring 2012 refueling outage. Operators are shutting down the unit to make the necessary repairs. There is no impact to the health and safety of employees or the public.
"The NRC resident inspector has been informed.
"This report is being made in accordance with 10 CFR 50.72(b)(3)(ii)(A), discovery of a degraded condition, 10 CFR 50.72(b)(2)(i), plant shutdown required by technical specifications, and 10 CFR 50.72(b)(3)(v)(C), a condition which could have prevented the fulfillment of a safety function to control the release of radioactive material."
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2013/20130516en.html
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