ENS 40824
ENS Event | |
|---|---|
09:21 Jun 17, 2004 | |
| Title | High Pressure Coolant Injection (Hpci) Declared Inoperable |
| Event Description | While changing out a light bulb in the Unit 1 HPCI room, the surveillance operator noticed that the bolts for the HPCI pump discharge check valve, 1E41-F005, bonnet on pressure seal were loose. All six bolts could be turned by hand. HPCI was declared inoperable until an investigation is performed. The bolts were properly torqued and HPCI pump run is complete and sat. Licensee entered Technical Specification 3.5.1 (14 day Limiting Condition of Operation). All other Emergency Core Cooling Systems are fully operable including the Reactor Core Isolation Cooling System.
The NRC Resident Inspector was notified of this event by the licensee.
The following information was obtained from the licensee via facsimile: A subsequent investigation revealed that a hot torque of the Unit 1 HPCI pump discharge check valve (1E41-F005) was performed during the 165 psig pump operability surveillance test which was performed following reassembly during the Unit 1 refueling outage. During this surveillance, the pump discharge pressure and thus internal pressure on the pressure seal cover, is maintained between 265 and 305 psig. However, during the rated pressure run, the pump discharge pressure achieved is required to be greater than or equal to 1135 psig. This difference in internal pressure (1135-305 = 830 psig minimum), acting on the bottom of the pressure seal cover, forced the pressure seal cover to move upward toward the cover retainer, compressing the pressure seal more tightly. As the pressure seal cover moved toward the cover retainer, the retainer bolts also moved upward, but the cover retainer remained stationary, due to gravity. Therefore, the retainer bolts were no longer torqued against the retainer cover, creating the 'as found' condition. It is site and vendor (Flowserve) experience that once the pressure seal cover is wedged upward, sufficient friction exists between the pressure seal cover, the pressure seal, and the valve body to prevent the pressure seal cover from relaxing the sealing force on the pressure seal once the valve internal (system) pressure is removed. Furthermore, no gap existed between the head of any of the retainer bolts and the retainer cover. The sealing function of the pressure seal was never lost, and the valve would have performed its design function while the retainer bolts were in the 'as found' 'finger tight' condition. Therefore, the valve remained operable at all times when the HPCI system was required to be operable following the Unit 1 refueling outage. This was further substantiated by the fact that no leakage was observed during the rated pressure pump operability run on 3/14/04. Following discovery of the 'finger tight' condition, the retainer bolts were cold torqued to the appropriate value (370 ft-lbs) by Maintenance personnel on 6/17/04. A HPCI pump surveillance was then performed and a hot torque of 370 ft-lbs was performed immediately after the system was shutdown. Tampering was considered as a possible cause for the loosened bolts, but no evidence could be found to support these bolts being loosened intentionally. All evidence available suggests that the bolts were loosened by internal pressure, which is consistent with vendor experience. Based on the above information this event is not reportable, and this notification serves to withdraw the previous notification made on 6/17/2004. The licensee has notified the NRC Resident Inspector. The Headquarters Operations Officer notified R2DO (Bonser). |
| Where | |
|---|---|
Hatch  Georgia (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+-3.07 h-0.128 days <br />-0.0183 weeks <br />-0.00421 months <br />) | |
| Opened: | Barry Coleman 06:17 Jun 17, 2004 |
| NRC Officer: | John Mackinnon |
| Last Updated: | Oct 28, 2004 |
| 40824 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Hatch with 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
WEEKMONTHYEARENS 568962023-12-18T07:23:00018 December 2023 07:23:00
[Table view]10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection System Inoperable ENS 554482021-09-08T05:59:0008 September 2021 05:59:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Unit 1 High Pressure Coolant Injection (HPCI) System Inoperable ENS 546772020-04-22T14:15:00022 April 2020 14:15:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection System (Hpci) Inoperable ENS 542372019-08-23T02:34:00023 August 2019 02:34:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection (Hpci) System Inoperable ENS 539442019-03-19T05:40:00019 March 2019 05:40:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection System Inoperable ENS 525432017-02-08T16:51:0008 February 2017 16:51:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection System Inoperable Due to Degraded Dc to Ac Inverter ENS 500802014-05-02T00:45:0002 May 2014 00:45:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Loss of Hpci Operability Due to Water Accumulation in the Hpci Turbine ENS 488272013-03-18T13:10:00018 March 2013 13:10:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection Inoperable Following Refueling Outage ENS 455412009-12-05T15:59:0005 December 2009 15:59:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Hpci Out of Service Due to the Loss of the Suction Auto-Swap Function ENS 448492009-02-12T17:30:00012 February 2009 17:30:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection Suction Source Instrument Malfunction ENS 438842008-01-06T16:00:0006 January 2008 16:00:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Hpci Declared Inoperable Due to Failed Surveillance Test ENS 433742007-05-18T21:45:00018 May 2007 21:45:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Inoperable Hpci Pump ENS 432422007-03-15T19:32:00015 March 2007 19:32:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Hpci Declared Inoperable During Startup Testing ENS 432212007-03-08T01:50:0008 March 2007 01:50:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Hpci Declared Inoperable Following Surveillance Testing ENS 431532007-02-08T09:32:0008 February 2007 09:32:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection (Hpci) System Inoperable ENS 431522007-02-07T21:40:0007 February 2007 21:40:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolent Injection (Hpci) Declared Inoperable ENS 429142006-10-17T15:21:00017 October 2006 15:21:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Accident Mitigation - Hpci System Inoperable ENS 426572006-06-21T04:15:00021 June 2006 04:15:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection (Hpci) Declared Inoperable Due Excessvie Aux Oil Pump Motor Current ENS 425782006-05-16T13:38:00016 May 2006 13:38:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Hpci Inoperable Due to Hpci Discharge Check Valve Body Leak ENS 422622006-01-16T23:31:00016 January 2006 23:31:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Hpci System Isolated Due to Atts Card Failure ENS 408242004-06-17T09:21:00017 June 2004 09:21:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection (Hpci) Declared Inoperable 2023-12-18T07:23:00 | |