ENS 41369
ENS Event | |
|---|---|
00:19 Feb 4, 2005 | |
| Title | 4160 Volt Relaying and Metering Single Failure Vulnerability |
| Event Description | The licensee provided the following report via facsimile:
On February 3, 2005 at 1819 hours0.0211 days <br />0.505 hours <br />0.00301 weeks <br />6.921295e-4 months <br />, Quad Cities Nuclear Power Station (QCNPS) confirmed a vulnerability with a 4160 VAC relaying and metering current transformer (CT) associated with the Unit and Reserve Auxiliary Transformers (i.e., the UAT and RAT) on both Unit 1 and Unit 2. Although the CT is currently fully operable, failure of the CT circuitry could cause the neutral overcurrent relay to trip and lockout the circuit breakers supplying feeds to safety related buses 13 (23) and 14 (24), isolating them from their normal and emergency power sources. Emergency power (i.e., the emergency diesel generator) would still be available to supply power to safety related buses 13-1 (23-1) and 14-1 (24-1), but the Residual Heat Removal Service Water (RHRSW) system may be without a source of power. If this failure occurred during a LOCA, then the RHRSW pumps may not be started within the ten minute requirement. A modification is in progress to eliminate this vulnerability. This event is being reported as a potential loss of safety function (10CFR50.72(b)(3)(v)(B)) and as a degraded or unanalyzed condition (10CFR50.72(b)(3)(ii)(B)). The NRC Resident Inspector has been notified. See similar events #41362 (Crystal River), #41366 (LaSalle), and #41370 (Dresden). |
| Where | |
|---|---|
Quad Cities  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat | |
| Time - Person (Reporting Time:+-0.52 h-0.0217 days <br />-0.0031 weeks <br />-7.12296e-4 months <br />) | |
| Opened: | Terry Gallentine 23:48 Feb 3, 2005 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Feb 4, 2005 |
| 41369 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (85 %) |
| After | Power Operation (85 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (85 %) |
| After | Power Operation (85 %) |
Quad Cities with 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 | |
WEEKMONTHYEARENS 558912022-05-10T18:59:00010 May 2022 18:59:00
[Table view]10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Both Trains of LOW Pressure Coolant Injection (LPCI) Inop ENS 536932018-10-24T05:00:00024 October 2018 05:00:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(iv)(A), System Actuation 1/2 Edg Auto Started and Lpci/Core Spray Inoperable Due to Loss of Safety Bus ENS 532352018-03-01T18:10:0001 March 2018 18:10:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition En Revision Imported Date 11/8/2019 ENS 508822015-03-13T06:00:00013 March 2015 06:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Fuel Assembly Mis-Oriented Resulting in a Unanalyzed Condition ENS 450922009-05-25T21:50:00025 May 2009 21:50:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Inoperable Rcic Primary Containment Isolation Valves ENS 415312005-03-28T01:30:00028 March 2005 01:30:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Electrical Safety Bus Trip During Quad Cities Unit 1 Refueling Outage ENS 413692005-02-04T00:19:0004 February 2005 00:19:00 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 4160 Volt Relaying and Metering Single Failure Vulnerability 2022-05-10T18:59:00 | |