05000354/LER-2004-003, Both Trains of Control Room Emergency Filtration (CREF) Declared Inoperable
| ML041250357 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 04/23/2004 |
| From: | Hutton J Public Service Enterprise Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LR-N04-0176 LER 04-003-00 | |
| Download: ML041250357 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 3542004003R00 - NRC Website | |
text
PSEG Nuclear LLC P.O. Box 236, Hancocks Bridge, New Jersey 08038-0236 APR 2 3 2004 ON PSEG N~uclearlLC LR-N04-01 76 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 LER 354104-003-00 HOPE CREEK GENERATING STATION FACILITY OPERATING LICENSE NO. NPF-57 DOCKET NO. 50-354 This Licensee Event Report entitled 'Both Trains of Control Room Emergency Filtration (CREF) Declared Inoperable" is being submitted pursuant to the requirements of 1 OCFR50.73(a)(2)(v)(D).
Sincerely, ames Hutton Plant Manager - Hope Creek Attachment BJT C
Distribution LER File 3.7
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95-2168 REV. 7/99
Abstract
On February 23, 2004, at 0152 hours0.00176 days <br />0.0422 hours <br />2.513228e-4 weeks <br />5.7836e-5 months <br />, a high delta pressure alarm was received for the 'A' and 'B' Station Service Water (SSW) strainers. The appropriate abnormal operating procedures were entered in response to the alarms.
The high delta pressure condition was cleared on the 'B' SSW strainer ensuring the 'B' SSW loop remained operable. The 'A' SSW strainer high delta pressure condition remained. At 0212 hours0.00245 days <br />0.0589 hours <br />3.505291e-4 weeks <br />8.0666e-5 months <br />, the 'A' SSW loop was declared inoperable, along with the 'A' Safety Auxiliary Cooling System (SACS) loop and the 'A' Control Room Emergency Filtration (CREF) train. The 'B' CREF train was inoperable for planned maintenance on the associated chiller. Technical Specification 3.0.3 was entered since both the 'A' and 'B' CREF trains were inoperable. A shutdown brief was conducted and the operating procedure for shutdown from rated power to cold shutdown was entered at 0305 hours0.00353 days <br />0.0847 hours <br />5.042989e-4 weeks <br />1.160525e-4 months <br />. At 0407, shutdown of the unit commenced. At 0424, the unit shutdown was halted at 94.5% Reactor power when the 'A' CREF train was returned to operable status and TS 3.0.3 was exited.
The cause of this event is still under investigation and will be updated in the supplement of this LER. Preliminary investigation identified the failure of the 'A' SSW strainer was due to backing off of the restraining nut holding the main shaft that caused the strainer internals to lower and come in contact with the rim of the strainer body. Additionally, the preliminary investigation identified a contributing cause was incorrect decision making in permitting emergent work in the work schedule and proceeding with planned maintenance. Corrective actions consist of changes to maintenance procedures, equipment operator rounds and the development of an operational risked based strategy for Operations personnel.
This event is being report in accordance with 1 OCFR50.73(a)(2)(v)(D), any event that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.
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SAFETY CONSEQUENCES AND IMPLICATIONS
There was no impact to the health and safety of the public. Although the 'A' CREF train was declared inoperable due to the trip of the 'A' SSW strainer and reduced cooling flow in the 'A' SSW loop, the 'A' CREF was still capable of starting and pressurizing the control room with the 'B' CREF train out of service. However, an assessment of how long the 'A' CREF train could operate with the reduced cooling flow capacity was not performed. Both trains of CREF were inoperable simultaneously for approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. During this time period no design basis accidents occurred that would have required the system to operate. Further, actions were being implemented to remove Hope Creek from service and place the plant in a mode where CREF was no longer required until restoration of at least one train of CREF to operable status.
A review of this event determined that a Safety System Functional Failure (SSFF) as defined in Nuclear Energy Institute (NEI) 99-02 has occurred.
CORRECTIVE ACTIONS
The below corrective actions are based on the preliminary root cause evaluation. Upon completion of the root cause evaluation, additional corrective actions or modifications to the below corrective actions will be discussed in the supplement to this LER.
- 1. The 'A' SSW strainer was repaired and returned to service.
- 2. Equipment operator rounds will be revised to inspect the position of the restraining nut on the SSW strainers to ensure they are not backing off.
- 3. Appropriate maintenance procedures will be revised to specify the proper torque values for fastening the restraining nut on the SSW strainers and to mark the lock nut position so that it can be readily monitored.
- 4. An information distribution notice pertaining to operational decision making and proper risk assessment associated with planning or deferring work activities that may impact safe and reliable operation has been developed. The notice will be distributed to the appropriate personnel.
- 5. An operational risk based decision strategy for Operations personnel will be developed.
The actions specified above are being tracked in accordance with PSEG Nuclear's Corrective Action Program.
COMMITMENTS
The corrective actions cited in this LER are voluntary enhancements and do not constitute
commitments