15 mai 2015
Perte de refroidissement d’un système de secours. Suite à cette indisponibilité, de nombreuses alimentations électriques de matériels de secours se retrouvent indisponibles (4 160 v, 480 v, 120 v AC, 125 v DC...). Malgré leur disponibilité, tous ces systèmes restaient indisponibles suite à la perte du refroidissement de leur local. Le réacteur doit être arrêté en mode 3 avant 4 h 36. Mise à jour du 18 mai : Le contrôleur de pression d’huile ayant été strappé et la pression étant correcte, le refroidissement a pu être rétabli en mode dégradé en attendant une réparation.
Type : PWR - Puisssance : 3 565 MWth - première divergence : 05 / 1985 -
Available in english only
Event Number : 51074
Facility : WOLF CREEK - State : KS Unit : [1] - RX Type : [1] W-4-LP
Event Date : 05/15/2015 - Event Time : 21:48
Last Update Date : 05/18/2015
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(2)(i) - PLANT S/D REQD BY TS
Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode 1 N Y 100 Power Operation 99 Power Operation
Event Text
TECHNICAL SPECIFICATION REQUIRED SHUTDOWN DUE TO 2 AC INVERTERS INOPERABLE
"Class 1E A/C Unit SGK05A cools safety related electrical train ’A’ and was found tripped at 2148 [CDT]. As a result, the following supported safety related electrical equipment were declared inoperable : 4.16 KV Bus NB01, 480 Volt Buses NG01 and NG03, 120 volt Instrument AC Inverters and Buses NN11, NN13, NN01 and NN03, 125 VDC Chargers and Buses NK11, NK13, NK01 and NK03. T/S 3.0.3 was entered from T/S 3.8.7 due to two out of four 120 volt AC Inverters (NN11 and NN13) being inoperable. All electrical systems listed above remain available but are declared inoperable due to inadequate room cooling capability. Plant shutdown to mode 5 commenced at 2244 [CDT]. No major equipment is out-of-service. All systems have functioned normally. Plant is currently at 99% with power ramping down. Plant must be in mode 3 by 0448 CDT. No compensatory measures have been established.
"The NRC Resident Inspector has been notified."
See EN #51071 for an earlier T/S required shutdown required at 0436 CDT on 5/15/15, due to the same conditions.
* * * UPDATE FROM BRET DAVIS TO VINCE KLCO ON 5/18/15 AT 1600 EDT * * *
"For both EN 51071 and 51074, the low lube oil pressure switch tripped the SGK05A unit. Oil pressures were verified to be normal and the SGK05A unit was successfully started. The plant shutdown each time was terminated. A fault in the Electronic Oil Pressure control which monitors the low lube oil pressure switch was identified. A jumper has been installed that bypasses the oil switch while maintenance is being conducted. The unit was declared functional but degraded. Indication of low oil pressure is still provided. "
The licensee notified the NRC Resident Inspector.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2015/20150519en.html#en51074
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