16 octobre 2017
Un défaut traversant sur l’évent de ligne de communication du système de refroidissement de mise à l’arrêt du réacteur a été repéré suite à la découverte d’acide borique humide sur un mur. La fuite était non quantifiable. Alors que le réacteur est en mode 5, la fuite a été repérée en mode 4.
Type : PWR - Puissance : 1 667 MWth - Première divergence : 12 / 1974 -
Available in english only
Event Number : 53019
Facility : PRAIRIE ISLAND
State : MN - Unit : [2] - RX Type : [2] W-2-LP
NRC Notified By : PHILIP SNIDER
Event Date : 10/16/2017 - Event Time : 14:25 [CDT]
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(3)(ii)(A) - DEGRADED CONDITION
Initial PWR : 0 % - Current PWR 0 %
Event Text :
REACTOR COOLANT SYSTEM SHUTDOWN COMMUNICATION LINE VENT THROUGH WALL DEFECT
"At 1425 CDT on 10/16/17, investigation into a boric acid indication was determined to be a through wall leak at the socket weld that joins the 3/4 inch line 2RC-92 to valve 2RC-8-37. Unit 2 is currently in Mode 5 with Reactor Coolant system (RCS) Operational Leakage limits not applicable. The leak is downstream of two first off RCS isolation valves that are normally closed. The leak is not quantifiable as it only consists of a small amount of dry boric acid at the location. This failure constitutes welding or material defects in the primary coolant system that cannot be found acceptable under ASME Section Xl.
"Therefore, this is a degraded condition reportable under 10 CFR 50.72(b)(3)(ii)(A).
"At the time of this notification, the Prairie Island Nuclear Generating Plant Unit 2 is in Mode 5 for a planned refueling outage. The identified defect will be repaired prior to entering Mode 4.
"This condition does not affect the health and safety of the public or station employees. The NRC Resident Inspector has been notified."
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