ENS 49490

v t e ENS Event
22:12 Oct 31, 2013
Title	Postulated Fire Event Could Result in a Hot Short That Could Adversely Impact Safe Shutdown Equipment
Event Description	While performing a review of industry OE [operating experience] concerning unfused ammeter circuits on station batteries, it was discovered that the ammeter circuits for all of the non-1E batteries are of a similar design to that described in the OE. Also, while reviewing additional DC circuits, it was discovered that the control circuit for the Turbine Generator Emergency Lube Oil pump is unfused, protected only by the motor circuit breaker with a trip setting of 350 amps. The concern is that under the fire safe shutdown rules it is postulated that a fire in one fire area can damage these circuits and cause short circuits without protection that would overheat the cables and possibly result in secondary fires in other fire areas where the cables are routed. The secondary fires could adversely affect safe shutdown equipment and potentially cause the loss of the ability to conduct a safe shutdown as required by 10CFR50 Appendix R. This condition is being reported in accordance with 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition that significantly degrades plant safety. Compensatory measures (fire watches) have been implemented for affected areas of the plant. The NRC Resident Inspector has been notified.

ENS 49490 +/-
Where
South Texas Texas (NRC Region 4)
Reporting

10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
LER:	05000498/LER-2013-003 Regarding Unanalyzed Condition - Direct Current Ammeter Circuits Without Overcurrent Protection
Time - Person (Reporting Time:+-2.62 h-0.109 days <br />-0.0156 weeks <br />-0.00359 months <br />)
Opened:	Billy Herzog 19:35 Oct 31, 2013
NRC Officer:	Howie Crouch
Last Updated:	Oct 31, 2013
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v t e Emergency Notification System
South Texas with 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition
WEEKMONTHYEAR2019-09-06T02:15:00 [Table view]
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