22 juillet 2014
Un défaut d’ouverture de vanne est à l’origine du problème. Toutes les pompes d’injection d’eau en urgence dans le générateur de vapeur ont correctement fonctionné. Le cœur étant critique, les systèmes de protection du réacteur se sont enclenchés. Les barres de contrôles se sont insérées normalement dans le cœur.
Type PWR - Puissance : 2 900 MWth - Première divergence : 10/1982
Available in english only.
Event Number : 50293
Facility : SUMMER - State : SC
Unit : [1] - RX Type : [1] W-3-L
Event Date : 07/22/2014 - Event Time : 04:14
Last Update Date : 07/22/2014 - 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 : 48 % Current PWR : 0 %
Event Text
AUTOMATIC REACTOR TRIP DUE TO LOW STEAM GENERATOR LEVEL
"At 0414 [EDT on 7/22/2014], VC Summer Nuclear Station automatically tripped due to decreasing water level in the ’C’ Steam Generator. The trip occurred when valve XVB-09210 WI System Condensate Bypass Valve failed to open as required while the station was removing the Condensate Polishing System during startup. The Condensate Polishing System is used to purify and filter the condensate from the non-nuclear, secondary side of the plant. This valve failure caused low level in the Deaerator Storage Tank, which consequently tripped all feedwater pumps. This loss of feedwater led to Lo-Lo Steam Generator level in the ’C’ Steam Generator. All Emergency Feedwater pumps automatically started on Lo-Lo Steam Generator level and all control rods inserted fully. The Steam Generator levels recovered quickly.
"Presently the plant is in Mode 3. Decay heat is being removed by dumping steam to the condenser. A station response team is actively investigating the cause of the event.
"The NRC Resident Inspector has been notified."
The licensee will notify the State and local governments.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2014/20140723en.html#en50293
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