ENS 49639: Difference between revisions
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| event date = 12/16/2013 17:00 CST | | event date = 12/16/2013 17:00 CST | ||
| last update date = 12/16/2013 | | last update date = 12/16/2013 | ||
| title = Potential | | title = Potential for Spurious Start of Various Pumps During Postulated Fire Events | ||
| event text = 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. | | event text = 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. | 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. | ||
Latest revision as of 21:52, 1 March 2018
| 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
| |
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 | |