ENS 42305
ENS Event | |
|---|---|
04:36 Feb 3, 2006 | |
| Title | High Pressure Coolant Injection (Hpci) System Inoperable Due to One Hpci Turbine Exhaust Vacuum Breaker Isolation Valve Failure |
| Event Description | On February 2, 2006 at 23:36 [EST], during testing of the HPCI System per OPT-09.7, HPCI System Valve Operability Test, 1-E41-F079, Turbine Exhaust Vacuum Breaker valve, was given a close signal and failed in the intermediate position. The 1-E41-F079 is one of the two HPCI Turbine Exhaust Line Vacuum Breaker isolation valves. When 1-E41-F079 failed in the intermediate position, the HPCI system was considered inoperable. HPCI is a single-train, safety function system. Approximately two minutes later, the valve was reopened and HPCI was restored to operable status (1-E41-F079 remains inoperable).
The cause of the 1-E41-F079 failing to stroke is being investigated and will be repaired." HPCI will be inoperable after 1-E41-F079 is isolated for maintenance. The licensee notified the NRC Resident Inspector.
The purpose of this call is to retract the notification (Event Number 42305) made by the Brunswick Steam Electric Plant, Unit No. 1, Docket No. 50-325/License No. DPR-71. On February 3, 2006, at 0459 hours0.00531 days <br />0.128 hours <br />7.589286e-4 weeks <br />1.746495e-4 months <br />, the control room Shift Supervisor made a notification (Event Number 42305) to the NRC Operations Center in accordance with 10 CFR 50.72 (b)(3)(v)(D) (i.e., any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident). The event was reported as the HPCI system inoperable due to the HPCI inboard turbine exhaust vacuum breaker isolation valve (1-E41-F079) failure during scheduled testing. Valve 1-E41-F079 is a motor-operated valve that is normally open when the HPCI system is in service. When the valve is closed, it prevents the HPCI turbine exhaust vacuum breakers from operating, and the HPCI system is considered to be inoperable. During the testing, performed under 0PT-09.7, "HPCI System Valve Operability Test," on February 2, 2006, operators observed a dual indication when attempting to stroke the valve 1-E41-F079 closed. An auxiliary operator observed that the thermal overloads on the breaker were not tripped and no overload annunciator was received. The valve was then reopened. During the time that 1-E41-F079 had dual indication until the valve was full open (i.e., 2336 to 2338 hours0.0271 days <br />0.649 hours <br />0.00387 weeks <br />8.89609e-4 months <br />), the operators considered the HPCI system inoperable and the event to be an unplanned inoperability of the HPCI system. Further troubleshooting and evaluation of the valve performance indicates that the valve did not close sufficiently to adversely affect the HPCI system's ability to perform its safety function. Subsequent valve disassembly identified pitting corrosion of the stem. This problem results in increased torque requirements through the first approximately 20 percent of the valve travel as the valve strokes from open to closed. When operators attempted to stroke the valve closed on February 2, 2006, the valve closed less than 20 percent of its stroke when the "closed" torque switch stopped the actuator from further closing the valve. A documented engineering evaluation established that, with valve 1-E41-F079 stroked less than 50 percent closed, enough flow is provided through the valve to allow the vacuum breakers to operate and allow the HPCI system to perform its safety function. Therefore, during the stroking of 1-E41-F079 in accordance with 0PT-09.7 on September 2, 2006, it is reasonable to expect that the performance of the valve did not result in the loss of safety function of the HPCI system. NUREG-1022, Rev. 2, Section 3.2.7 lists types of events or conditions that are generally not reportable under 10 CFR 50.72(b)(3)(v) and 10 CFR 50.73 (a)(2)(v) criteria. The list of not-reportable conditions includes: Removal of a system or part of a system from service as part of a planned evolution for maintenance or surveillance testing when done in accordance with an approved procedure and the plant's TS (unless a condition is discovered that could have prevented the system from performing its function) The performance of 1-E41-F079 did result in the valve being declared inoperable for its PCIV isolation function. This condition resulted in the penetration being isolated under an equipment clearance, which closed the HPCI outboard turbine exhaust vacuum breaker isolation valve (1-E41-F075). Closure of 1-E41-F075 under the equipment clearance process did result in the inoperability of the HPCI system; however, this planned inoperability of the system for maintenance is not reportable (as discussed in NUREG-1022, Rev. 2, Section 3.2.7) and no condition was discovered that could have prevented the HPCI system from performing its safety function. Investigation of this condition and evaluation of other reportability considerations documented in the corrective action program in Action Request (AR) 183102. Carolina Power & Light Company, doing business as Progress Energy Carolina, Inc., has determined that this event does not meet the 10 CFR 50.72 or 10 CFR 50.73 reporting criteria and the notification for Event Number 42305 is retracted. The resident inspector has been notified. NRC R2DO (Tom Decker) notified. |
| Where | |
|---|---|
Brunswick  North Carolina (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:+0.38 h0.0158 days <br />0.00226 weeks <br />5.20524e-4 months <br />) | |
| Opened: | Michael Potter 04:59 Feb 3, 2006 |
| NRC Officer: | Jeff Rotton |
| Last Updated: | Apr 3, 2006 |
| 42305 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Brunswick with 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
WEEKMONTHYEARENS 559972022-07-16T00:20:00016 July 2022 00:20:00
[Table view]10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection (HPCI) Inoperable ENS 557802022-03-10T01:13:00010 March 2022 01:13:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection (HPCI) Inoperable ENS 541162019-06-13T01:27:00013 June 2019 01:27:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection (Hpci) Inoperable ENS 531232017-12-17T08:16:00017 December 2017 08:16:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection (Hpci) System Declared Inoperable ENS 527882017-06-05T17:52:0005 June 2017 17:52:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Control Room Air Conditioning and Emergency Ventilation Systems Inoperable ENS 526792017-04-14T04:15:00014 April 2017 04:15:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - 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Mitigate the Consequences of an Accident High Pressure Coolant Injection (Hpci) System Inoperable Due to Seal Leak ENS 437112007-10-11T02:45:00011 October 2007 02:45:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Unit 2 Hpci Pump Seal Failure ENS 431972007-02-28T03:26:00028 February 2007 03:26:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection (Hpci) Inoperability ENS 429062006-10-13T17:57:00013 October 2006 17:57:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection (Hpci) System Declared Inoperable Due to Potential Turbine Exhaust Diaphragm Failure ENS 424882006-04-10T20:30:00010 April 2006 20:30:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Control Room Emergency Ventilation System Declared Inoperable Due to Design Deficiency ENS 423052006-02-03T04:36:0003 February 2006 04:36:00 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 Due to One Hpci Turbine Exhaust Vacuum Breaker Isolation Valve Failure ENS 422542006-01-12T14:20:00012 January 2006 14:20:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Control Room Air Conditioning and Control Room Emergency Ventilation Systems Inoperable ENS 418952005-08-05T22:40:0005 August 2005 22:40:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Inoperability of All Emergency Diesel Generators ENS 416922005-05-12T08:11:00012 May 2005 08:11:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.73(a)(1), Submit an LER Technical Specification Required Shutdown Due to Loss of Emergency Bus E1 ENS 408332004-06-22T13:00:00022 June 2004 13:00:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Presure Coolant Injection System Inoperable Due to Maintenance ENS 407142004-04-29T02:30:00029 April 2004 02:30:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Hpci System Inoperable Following Planned Maintenance ENS 406362004-04-03T08:00:0003 April 2004 08:00:00 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 403182003-11-13T03:22:00013 November 2003 03:22:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection System Isolation During Testing 2022-07-16T00:20:00 | |