14 septembre 2013
Le réacteur a été placé manuellement en arrêt d’urgence suite à l’enclenchement des pompes d’injection d’eau primaire. Ces pompes, chargées de contrôler le flux, ont été arrêtées manuellement car elles ont entraîné un dépassement de 1,40 m du niveau d’eau dans le réacteur. L’arrêt du réacteur s’est déroulé normalement sauf pour le système d’isolation "Reactor Core Isolation Cooling System " (RCIC) qui a du être mis en route, puis arrêté manuellement. Le cœur étant critique, les systèmes de protection du réacteur se seraient correctement enclenchés.
Type : BWR Mark 2 - Première divergence : 05 1984 - Puissance thermique : 3952 MWth
Available in english only.
Event Number : 49342
Facility : SUSQUEHANNA - State : PA - Unit : [2] - RX Type : [2] GE-4 -
Event Date : 09/14/2013 - Event Time : 03:30 -
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
Initial PWR : 14 % - Current PWR : 0 %
Event Text
MANUAL REACTOR SCRAM DUE TO FEEDWATER TRANSIENT DURING SHUTDOWN
"At approximately 0330 hours on September 14, 2013, Susquehanna Steam Electric Station Unit 2 reactor was manually scrammed while transitioning the ’A’ reactor feed pump from flow control mode to discharge pressure mode. Reactor water level rose to +54 inches causing a trip of reactor feedpumps. Subsequently the mode switch was taken to shutdown to manually scram the Unit 2 reactor.
"All control rods inserted. Reactor water level lowered to approximately +18 inches. There were no automatic emergency core cooling system initiations. No steam relief valves opened during the event. No containment isolations occurred. All safety systems operated as expected. RCIC system was manually initiated for level control until a reactor feedpump was recovered, then RCIC was manually shutdown. The cause of the feedwater flow transient and trip of the reactor feedwater pumps is under investigation.
"This report is being made per 10CFR50.72(b)(2)(iv)(B) for a 4 hour report, and 10CFR50.72(b)(3)(iv)(A) for an 8 hour report.
Decay heat is being removed via the turbine bypass valve to the condenser. Offsite power remains stable, and there was no impact on Unit 1.
The licensee has notified the NRC Resident Inspector. The Pennsylvania Emergency Management Agency will be notified, and the licensee will be making a press release.
Source : https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2013/20130916en.html#en49342
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