ENS 49639

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v t e ENS Event
23:00 Dec 16, 2013
Title	Potential for Spurious Start of Various Pumps During Postulated Fire Events
Event Description	A circuit analysis review for Appendix R Operator Manual Action deficiency extent of condition identified that fire damage to cable ES194-I is not isolated by the local control power transfer switch utilized in the Safe Shut-down Instruction. Fire damage to the non-isolated cable ES194-I in Fire Areas 01-03, 02-01, and 02-03 could cause the RHR Pump 2C to spuriously start (or restart after the Operator local trip action) when 4kV Shutdown Board B is credited for these Fire Areas. An undesired spurious start of RHR Pump 2C could overload the credited Diesel Generator or take away the necessary load capacity to allow operation of other Appendix R fire safe shutdown credited loads. The fire damage postulated would require a short to ES194-I from a separate cable conductor energized with the positive potential of the battery supplying 4kV Shutdown Board B (i.e., normally Shutdown Battery B). It is postulated for a fire-event that the necessary short to ES194-I could come from a cable-to-cable short or from a short to ground as the fire event may cause a separate conductor energized with the positive potential of the associated battery to short to ground. Similar conditions also exist for: RHR Pumps 1A, 1B, 1D, 2A, 2B, 3A, and 3C due to fire damage to cables in one or more Fire Areas. Compensatory actions in the form of an Operator Work Around [OWA] to remove the affected RHR Pump breaker close circuit control power fuses during the affected Safe Shut-down Instructions, a caution order on the appropriate transfer switches referencing the OWA, and fire watches in the affected Fire Areas to mitigate this condition are in place in accordance with the BFNP [Browns Ferry Nuclear Plant] Fire Protection Report. This condition is being reported pursuant to 10CFR50.72(b)(3)(ii)(B) and 10CFR50.72(b)(3)(v). The NRC Resident Inspector has been notified. The licensee is also reporting under 10CFR50.72(b)(3)(v)(D) Accident Mitigation.

ENS 49639 +/-
Where
Browns Ferry Alabama (NRC Region 2)
Reporting

10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material
Time - Person (Reporting Time:+-0.52 h-0.0217 days <br />-0.0031 weeks <br />-7.12296e-4 months <br />)
Opened:	Neel Shukla 22:29 Dec 16, 2013
NRC Officer:	Howie Crouch
Last Updated:	Dec 16, 2013
49639 - NRC Website
v • d • e

v t e Emergency Notification System
Browns Ferry with 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material
WEEKMONTHYEAR2022-10-18T19:40:00 [Table view]
[ENS list for Browns Ferry]

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