ENS 49491
ENS Event | |
|---|---|
21:22 Oct 31, 2013 | |
| Title | Postulated Fire Event Could Result in a Hot Short That Could Adversely Impact Safe Shutdown Equipment |
| Event Description | Per review of OE INPO ICES-305419, 'Unfused remote DC ammeter circuit could result in a secondary fire due to multiple fire induced faults' from Davis-Besse and Cooper Condition Report CR CNS-2013-07413; it has been determined that JAF [James A. Fitzpatrick] is potentially susceptible to the same condition.
The condition in the Davis-Besse OE is described as follows: The wiring design for the ammeters contains a shunt in the current flow from each direct current (DC) battery or charger. Bolted on the shunt bar are two IEEE 383 qualified leads to a current meter in the main control room (MCR). The small difference in voltage between the two taps on the shunt is enough to deflect the current gauge in the MCR when current flows from the battery or charger through the shunt. The ammeter wiring attached to the shunt does not have fuses. It is postulated that a fire could cause one of these ammeter wires to short to ground at the same time the fire causes another DC wire from the opposite polarity on the same battery to also short to ground. This would cause a ground loop through the unfused ammeter cable. With enough current going through the cable, the potential exists that the cable could self-heat to the point of causing a secondary fire in the electrical tray at some point along the path of the cable (including the Control Room) or possibly heat up to the point of causing damage to adjacent cables that may be required for safe shutdown. TRM 3.7.M, Fire Barrier Penetrations, is applicable. The functional integrity of the fire barrier penetration seals ensures that fires will be confined or adequately retarded from spreading to adjacent portions of the facility. This design feature minimizes the possibility of a single fire rapidly involving several areas of the facility prior to detection and extinguishment. The fire barrier penetration seals are a passive element in the facility fire protection program and are subject to periodic inspections. The issue identified is with the potential of a fire starting in another location other than the original fire location bypassing fire barriers due to a fire induced electrical short. Per engineering, the areas with the deficient fire barriers are the DC Switchgear Rooms A and B, Cable Spreading Room, Relay Room and Control Room. An active LCO will track the TRM action for the non-functionality of those fire barriers. This condition is being reported under 10CFR50.72 (b)(3)(ii)(B) as a condition that results in the plant being in an unanalyzed condition which significantly degrades plant safety. The licensee has notified the NRC Resident Inspector. |
| Where | |
|---|---|
Fitzpatrick  New York (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| LER: | 05000333/LER-2013-003 |
| Time - Person (Reporting Time:+-0.68 h-0.0283 days <br />-0.00405 weeks <br />-9.31464e-4 months <br />) | |
| Opened: | David Richardson 20:41 Oct 31, 2013 |
| NRC Officer: | Howie Crouch |
| Last Updated: | Oct 31, 2013 |
| 49491 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 554272021-08-24T18:06:00024 August 2021 18:06:00
[Table view]10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Appendix R Hot Short Unanalyzed Condition ENS 545332020-02-20T17:40:00020 February 2020 17:40:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition - Unprotected Dc Control Circuits ENS 541302019-06-24T22:15:00024 June 2019 22:15:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition En Revision Imported Date 10/1/2019 ENS 523292016-10-28T13:40:00028 October 2016 13:40:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Fire Barrier/Helb Door Inoperable ENS 494912013-10-31T21:22:00031 October 2013 21:22:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated Fire Event Could Result in a Hot Short That Could Adversely Impact Safe Shutdown Equipment 2021-08-24T18:06:00 | |