ENS 42906
ENS Event | |
|---|---|
17:57 Oct 13, 2006 | |
| Title | High Pressure Coolant Injection (Hpci) System Declared Inoperable Due to Potential Turbine Exhaust Diaphragm Failure |
| Event Description | On October 13, 2006 at 1357 (EST) Unit 2 HPCI system was declared inoperable due to indications of a leaking rupture diaphragm in the turbine steam exhaust line.
This determination was made when water was discovered in the E41-PSH-N012A and E41-PSH-N012C instrument lines during the performance of 0MST- HPCI23Q (HPCI Turbine Exhaust Diaphragm High Pressure Instrument Channel Calibration). TS LCO 3.5.1. 'ECCS - Operating,' Condition D was entered for the HPCI system being declared inoperable. The Reactor Core Isolation Cooling (RCIC) system was verified operable per Required Action D.1. Required Action D.2 of TS LCO 3.5.1 requires the HPCI system to be returned to operable status within 14 days. The initial safety significance of this condition is considered to be minimal. The RCIC system and all other required ECCS, are operable at this time. HPCI has been isolated and will be placed under clearance to allow the turbine exhaust diaphragm to be inspected and replaced if necessary The [NRC] Resident Inspector has been notified.
Upon further review, it has been determined that the HPCI system was not rendered inoperable as a result of the condition identified on October 13, 2006. The HPCI system is equipped with two rupture diaphragms on the steam exhaust line installed in series. Between the rupture discs are four instrument lines leading to pressure switches (i.e., E41-PSH-N012A, N012B, N012C, and N012D) and a header vent line that vents to the HPCI room atmosphere. The HPCI Turbine Exhaust Diaphragm Pressure - High signals are initiated from these pressure switches; which are required to be operable per Technical Specification 3.3.6.1, 'Primary Containment Isolation Instrumentation,' to isolate the HPCI exhaust line in the event of a degraded inner rupture disc, before the redundant outer disc is significantly challenged. This isolation provides equipment protection and [is] not assumed in any transient or accident analysis. The suspected leaking inner rupture diaphragm was confirmed to be fully intact and, as such, not a source of the water (i.e., approximately 1.125 quarts) in the E41-PSH-N012A and E41-PSH-N012C instrument lines. The most likely source of this water is residual water remaining from a rupture disc failure that occurred in November 2003. Engineering has evaluated the potential impact of the residual water and determined that both the HPCI system and the HPCI Turbine Exhaust Diaphragm Pressure - High isolation function remained operable. There was not sufficient water in the lines to affect the function of the HPCI rupture diaphragms if required. In addition, the quantity of water discovered would not have prevented a HPCI initiation, if required, as evidenced by successful operation of the Unit 2 HPCI system on at least 10 occasions since November 2003. The Technical Specification required function of the pressure switches was not impacted by the presence of residual water. Investigation of this condition is documented in the corrective action program is Nuclear Condition Report (NCR) 209265. On this basis, the HPCI system was capable of performing its function to mitigate the consequences of an accident and the issue is not reportable under 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector was notified of this retraction. Notified R2DO (Landis). |
| 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:+-1.03 h-0.0429 days <br />-0.00613 weeks <br />-0.00141 months <br />) | |
| Opened: | Michael Potter 16:55 Oct 13, 2006 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Dec 5, 2006 |
| 42906 - NRC Website | |
Unit 2 | |
|---|---|
| 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 Inoperable Due to Erratic Governor Operation ENS 474932011-12-01T18:44:0001 December 2011 18:44:00 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 467632011-04-17T02:52:00017 April 2011 02:52:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Hpci Inoperable Due to Lube Oil Pressure Low Out of Band ENS 467402011-04-07T21:40:0007 April 2011 21:40:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Loss of the Control Room Emergency Ventilation System ENS 452642009-08-14T23:58:00014 August 2009 23:58:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Hpci Inoperable Due to Automatic Closure of Inboard Isolation Valve ENS 448102009-01-28T01:07:00028 January 2009 01:07:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Unit 2 Hpci System Inoperable for Two Hours Due to Condensate in Exhaust Line ENS 447932009-01-21T18:00:00021 January 2009 18:00:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Loss of Control Room Air Conditioning and Emergency Ventilation System ENS 447482009-01-01T19:30:0001 January 2009 19:30:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Two Emergency Diesel Generators Declared Inoperable Due to Component Failure ENS 443092008-06-19T21:35:00019 June 2008 21:35:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Control Room Ventilation Inoperable ENS 442622008-06-03T17:13:0003 June 2008 17:13:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Loss of Control Room Emergency Ventillation System for 12 Minutes ENS 441792008-04-30T03:13:00030 April 2008 03:13:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection (Hpci) 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 | |