ENS 42162
ENS Event | |
|---|---|
19:15 Nov 21, 2005 | |
| Title | Postulated Fire Scenario Affecting Reactor Makeup from a Charging Pump |
| Event Description | On November 21, 2005, continued engineering evaluation determined that the Beaver Valley Power Station Unit No. 1 (BV-1) charging pump used to provide make-up to the Reactor Coolant System (RCS) may not perform its credited safety function during all postulated fire scenarios. This potential issue was first identified by a condition report on November 18, 2005. The BV1 Primary Plant Component Cooling Water System (CCR) is not credited during any postulated fire scenario. However, two postulated fire scenarios were identified where the absence of CCR could lead to elevated temperature of the water entering the charging pump suction, which could result in pump cavitation and subsequent pump damage. One scenario involves continued normal letdown entering the Volume Control Tank (VCT) at elevated temperatures raising VCT outlet water temperatures above 250 degree Fahrenheit which then goes to the charging pump suction. Another scenario involves elevated suction temperatures during a minimum flow scenario when charging flow to the RCS may be normally isolated by procedure.
Hourly fire tours were immediately initiated as interim measures on November 18, 2005 in applicable areas to reduce the risk of an initiating fire to support continued plant operation. Plant procedure changes are being developed which will address these two scenario issues. These plant procedure revisions, expected shortly, will return the plant into compliance with the current fire protection licensing and design bases. Preliminary engineering evaluation also determined that the complete loss of RCS make-up during the two identified scenarios will not lead to core damage. This event is reportable pursuant to 10 CFR 50.72(b)(3)(v)(A) since the make-up function to the RCS may not be available during a postulated fire event which is credited for maintaining the reactor in a safe shutdown condition. The Beaver Valley Power Station Unit No. 2 (BV-2) Component Cooling Water System is credited and evaluated in its fire design bases. BV-2 operator action currently exists to protect the BV-2 charging pump during a fire event. The NRC resident inspector has been notified. |
| Where | |
|---|---|
| Beaver Valley Pennsylvania (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor | |
| LER: | 05000334/LER-2005-002 |
| Time - Person (Reporting Time:+-0.35 h-0.0146 days <br />-0.00208 weeks <br />-4.7943e-4 months <br />) | |
| Opened: | Dan Schwer 18:54 Nov 21, 2005 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Nov 21, 2005 |
| 42162 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Beaver Valley with 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor | |
WEEKMONTHYEARENS 525712017-02-23T15:40:00023 February 2017 15:40:00
[Table view]10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Tornado Missile Vulnerabilities ENS 462082010-08-26T20:49:00026 August 2010 20:49:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 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 Both Trains of High Head Safety Injection Pumps Declared Inoperable ENS 421622005-11-21T19:15:00021 November 2005 19:15:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor Postulated Fire Scenario Affecting Reactor Makeup from a Charging Pump 2017-02-23T15:40:00 | |