15 janvier 2015
Mauvais scellement de pénétrations de tuyauteries dans la galerie de vannes et de tuyaux du système de retrait de chaleur résiduelle du réacteur (RHR : Residual Heat Removal). Ce problème, découvert après 86 ans cumulés de fonctionnement des deux réacteurs, aurait pu affecter les deux pompes du circuit (RHR). Des mesures d’atténuation d’inondation ont été prises.
Type : PWR - Puissance : 1 800 MWth - Première divergence n° 1 : 11/1970 ; n° 2 : 05/1972
Available in english only.
Event Number : 50740
Facility : POINT BEACH - State : WI
Unit : [1] [2] - RX Type : [1] W-2-LP,[2] W-2-LP
Event Date : 01/15/2015 - Event Time : 17:04
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(3)(ii)(B) - UNANALYZED CONDITION 50.72(b)(3)(v)(B) - POT RHR INOP
Initial PWR Current PWR
1 N Y 100 % Power Operation 100 % Power Operation 2 N Y 100 % Power Operation 100 % Power Operation
Event Text
INADEQUATELY SEALED PIPING PENETRATIONS AND POSTULATED FLOODING EVENT
"On November 19, 2014, inadequately sealed piping penetrations were discovered in the Residual Heat Removal (RHR) piping and valve gallery walls that could have allowed a postulated flooding event to potentially impact both RHR pumps. The same configuration was identified on both Units. Following analysis of the postulated flooding leakage sources and flow paths, it was discovered that there was a time when an unacceptable volume of flood water could have entered the pipe and valve gallery areas. This condition was found to have been previously corrected on 12/16/14, following changes to Operations flood mitigation strategies and installation of seals in upstream pipeway trenches. Therefore, this issue is reported as an unanalyzed past condition that had the potential to adversely impact the RHR pumps.
"This condition was determined to be reportable per 50.72(b)(3)(ii)(B) and 50.72(b)(3)(v)(B)."
The licensee has informed the NRC Resident Inspector.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2015/20150116en.html#en50740