19 juin 2014
Les circuits découverts non protégés par fusible pourraient occasionner un départ de feu secondaire par échauffement des câbles d’alimentation. Les équipements concernés sont des alimentations de lubrification de matériel d’intervention sur les situations d’urgence.
Type : BWR Mark 3 - Puissance : 3758 MWth - Première divergence : 06/1986
Available in english only.
Event Number : 50213 - Facility : PERRY - State : OH -
Unit : [1] - RX Type : [1] GE-6
Event Date : 06/19/2014 - Event Time : 16:28
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(3)(ii)(B) - UNANALYZED CONDITION Person (Organization) :
Initial PWR : 100 % Current PWR : 100 %
Event Text
UNANALYZED CONDITION DUE TO A POSTULATED HOT SHORT THAT COULD AFFECT SAFE SHUTDOWN EQUIPMENT
"A review of industry operating experience regarding the impact of unfused Direct Current (DC) circuits has determined the described condition to be applicable to the Perry Nuclear Power Plant (PNPP) resulting in an unanalyzed condition with respect to fire safe shutdown requirements.
"In the postulated event, a fire induced hot short could adversely impact safe shutdown equipment. The potential exists for a secondary fire to occur due to unfused DC control circuits associated with the Turbine Emergency Bearing Oil Pump, Reactor Feed Pump Turbine ’A’ Emergency Lube Oil Pump, Turbine Emergency Seal Oil Pump, and Reactor Feed Pump Turbine ’B’ Emergency Lube Oil Pump. These circuits are routed from the respective equipment to other plant areas including the Unit 1 Control Room, Division 1 Cable Spreading, and Division 1 Cable Chase.
"Without overcurrent protection for these circuits, the potential exists that an initial fire event affecting these circuits could cause short circuits without protection that would cause excessive current through the circuit beyond the capacity rating of the conductors. This could lead to a secondary fire in another plant area where these circuits are routed challenging the ability to achieve and maintain safe shutdown.
"This condition is being reported in accordance with 10 CFR 50.72(b)(3)(ii)(B). Interim compensatory measures (i.e., fire watches) have been implemented for affected areas of the plant.
"The licensee has notified the NRC Resident Inspector."
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2014/20140620en.html#en50213