10 juillet 2014
Le générateur diesel de secours d’urgence a été déclaré inopérant suite à la découverte d’une fuite sur son système de refroidissement. La mise à l’arrêt du réacteur a été engagée conformément aux prescriptions techniques. Le refroidissement du diesel ayant été retrouvé 3h40 après l’alerte, le réacteur qui était descendu à 98 % de sa puissance a été relancé.
Type : Fukushima 1 (BWR Mark 1) - Puissance : 3 458 MWth - Première divergence : 07/1974 (soit 40 ans)
Available in english only.
Event Number : 50265
Facility : BROWNS FERRY - State : AL - Unit : [2] GE-4
Event Date : 07/10/2014 - Event Time : 04:45
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(2)(i) - PLANT S/D REQD BY TS
Initial PWR : 100 % Current PWR : 98 %
Event Text TECHNICAL SPECIFICATION REQUIRED SHUTDOWN
"At 0445 [CDT] on July 10, 2014, Browns Ferry Unit 2 initiated actions to commence a reactor shutdown to comply with TS LCO 3.0.3. TS LCO 3.0.3 was entered at 0355 [CDT] and was required due to the ’C’ Emergency Diesel Generator becoming inoperable after isolating a leak on the Emergency Equipment Cooling Water System. Currently, a 7 day TS LCO Action 3.5.1.A is in effect due to ongoing scheduled Core Spray Loop I maintenance outage. The declaration of inoperability of the equipment supported by the ’C’ Emergency Diesel Generator, Core Spray Loop II, along with the redundant Core Spray system inoperable for maintenance resulted in TS LCO 3.0.3 for Unit 2. TS LCO 3.0.3 requires actions to be initiated within one hour ; to place the unit in MODE 2 within 10 hours ; MODE 3 within 13 hours ; and MODE 4 within 37 hours.
"This event requires a 4 hour report lAW 50.72(b)(2)(i), ’The initiation of any nuclear plant shutdown required by the plant’s Technical Specifications.’
"Actions were taken to restore the Core Spray System to Operable status and LCO 3.0.3 was exited at 0735 [CDT] on July 10, 2014.
"The NRC Resident Inspector has been notified.
"This event was entered into the Corrective Action Program."
Browns Ferry Unit 2 had reduced power to 98% when LCO 3.0.3 was exited, the power reduction was suspended, and preparations are being made to return power to 100%. There is no impact on Units 1 or 3.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2014/20140711en.html#en50265