ENS 42883
ENS Event | |
|---|---|
10:57 Oct 7, 2006 | |
| Title | Hpci Declared Inoperable |
| Event Description | A division 2 Primary Containment Isolation Instrument System component inoperable required the manual isolation of High Pressure Coolant Injection (HPCI) outboard Primary Containment Isolation valves (PCIV). This isolation was required by T/S action 3.3.2.b.1.
This report made pursuant to 10CFR 50,72 (b)(3)(v)(D) for the inability of single train system to mitigate the consequences of an accident. At approximately midnight on 10/7/06, Control Room Operators received a Div 2 Steam Leak Detection Trouble Alarm. Troubleshooting identified the failure as associated with the GE NUMAC drawer where temperature inputs are processed. The applicable 14-day T/S LCO Action Statement requires completion of repairs within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> or isolation of HPCI 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> later. HPCI was isolated at 0657 EDT. There was no I&C work in progress at the time of the failure. Repair parts are available and onsite. The licensee informed the NRC Resident Inspector.
This is a retraction of the event notification made on 10/07/06 at 11:05 hours. This event (#42883) was initially reported as a safety system functional failure under the requirement of 10CFR50.72(b)(3)(v)(D). Unit 2 High Pressure Coolant Injection (HPCI) system was declared inoperable due to a manual closure of the HPCI steam line outboard primary containment isolation valve (PCIV). The PCIV was closed to support the maintenance on an inoperable steam leak detection (SLD) channel and to satisfy the Technical Specification (TS) 3.3.2 Isolation Actuation Instrumentation action statement. The event was initiated at 00:06 hours by a trouble alarm due to a 'self test fault' condition on the Division 2 SLD instrument channel. Troubleshooting determined that the instrument channel was inoperable. TS 3.3.2 Action 'b.1' requires the channel to be restored to operable status within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Since this action could not be completed Table 3.3.2-1 Action 23 was applicable. Action 23 required the affected system isolation valves to be closed within one hour and the system (HPCI) to be declared inoperable. This action was completed at 06:57 hours. Two modules were replaced in the SLD instrument chassis. The instrument channel was tested satisfactorily and returned to service, Unit 2 HPCI was restored to operable status at 23:48 hours. The system was removed from service as part of a planned evolution to conduct maintenance in accordance with an approved procedure and the plant's Technical Specifications. The system was secured for the purpose of conducting maintenance on an inoperable SLD instrument channel and completing the TS action. The failed instrument did not adversely affect the HPCI system's capability of performing its safety function. HPCI remained capable of automatic initiation until the PCIV was manually closed to support maintenance by completing the TS actions. A condition did not exist at the time of discovery that could have prevented the fulfillment of the HPCI safety function. The licensee notified the NRC Resident Inspector. Notified R1DO(Sykes). |
| Where | |
|---|---|
Limerick  Pennsylvania (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+0.13 h0.00542 days <br />7.738095e-4 weeks <br />1.78074e-4 months <br />) | |
| Opened: | J. E. Thompson 11:05 Oct 7, 2006 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Dec 4, 2006 |
| 42883 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |