15 octobre 2014
La procédure manuelle pour démarrer cette pompe ne prenait pas en compte le risque d’incendie qui est susceptible d’engendrer la perte de ses alimentations électriques (125 VDC ou 120 VAC). Ce problème empêcherait de répondre aux critères de sûreté dans les délais impartis. La mise en place d’une procédure de contournement du problème est en cours.
Type : PWR - Puissance : 3 459 MWth - Première divergence : 01/1996
Available in english only.
Event Number : 50540
Facility : WATTS BAR - State : TN
Unit : [1] - RX Type : [1] W-4-LP
Event Date : 10/15/2014 - Event Time : 17:00
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(3)(ii)(B) - UNANALYZED CONDITION Person (Organization) : DAVID AYRES (R2DO)
Initial PWR : 100 % Current PWR : 100 %
Event Text
APPENDIX R UNANALYZED CONDITION AFFECTING THE TURBINE DRIVEN AUX FEEDWATER PUMP
"WBN U1 [Watts Bar Nuclear Unit-1] Appendix R (APP R) procedures do not include all the required operator manual actions to ensure manual control of the Unit 1 Turbine Driven Auxiliary Feed (TDAFW) Pump during a fire in room 713-A1A or 737-A1A. The current APP R procedure includes actions to transfer the Unit 1 TDAFW Pump to local control, but does not account for the potential loss of 125 VDC or 120 VAC to the Unit 1 TDAFW pump controls.
"Without procedural guidance to transfer the 120 VAC and 125 VDC supplies, the operation of the Unit 1 TDAFW pump may not be completed within the required time. Failure to take all the required actions to control the Unit 1 TDAFW Pump places WBN Unit 1 in an unanalyzed condition.
"WBN has instituted a fire impairment for the affected rooms and established an hourly roving fire watch.
"The NRC Resident Inspector has been notified of this condition."
The affected components are the trip throttle valve and the local control panel. Procedures should be in place by 10/16/2014 to rectify this situation.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2014/20141016en.html
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