05000335/FIN-2014002-04
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Finding | |
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| Title | Latent MV-08-03 Contactor Failure Results in Operation Prohibited by Tech Specs |
| Description | On December 20, 2013, the 1C AFW pump was declared inoperable in order to perform planned maintenance on the pumps trip and throttle valve (MV-08-03). After completion of the maintenance, MV-08-03 failed to open during post maintenance testing. The valve failed due to a stuck open contact in the auxiliary switch for the valves motor line contactor. The failure was unrelated to the valve maintenance. The licensee determined that the auxiliary switch contact failed to return to its standby position following the last successful operation of the valve on December 17, 2013. The licensee concluded that rubbing between the switch operating mechanism and the switch housing had degraded the operation of the auxiliary contact. The licensee properly installed and tested the switch in November 2013. The cause of the contact failure on December 20, 2013, had not previously been recognized as a failure mode for this type of switch. Additionally, there were no symptoms available to operators to indicate the contact had failed to return to its normal standby position. The inspectors concluded that there was no performance deficiency associated with the switch failure. The inspectors utilized available risk-informed tools to assess the safety significance of the 1C AFW pump inoperability. Based on the short amount of time that the 1C AFW pump was inoperable, the inspectors concluded this event was of very low safety significance. St. Lucie Unit 1 TS limiting condition for operation 3.7.1.2, Auxiliary Feedwater System, required at least three independent, operable AFW pumps in plant operating modes one through three. With one AFW pump inoperable, the inoperable pump must be returned to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or Unit 1 placed in hot standby within the next twelve hours. Contrary to the above, Unit 1 operated for 98 hours0.00113 days <br />0.0272 hours <br />1.62037e-4 weeks <br />3.7289e-5 months <br /> from December 17, 2013, until December 20, 2013, with the 1C AFW pump inoperable due to a failed auxiliary contact for the trip and throttle valve. Although a violation of TS occurred; the violation was not attributable to an equipment failure that was avoidable by reasonable licensee quality assurance measures or management controls. Therefore, the TS 3.7.1.2 violation was not associated with a licensee performance deficiency. The inspectors concluded that the violation would normally be characterized as Severity Level IV based on its very low safety significance. The NRC exercised enforcement discretion (Enforcement Action (EA)-14-047) in accordance with Section 2.2.4.d of the Enforcement Policy because the violation was not associated with a licensee performance deficiency; and therefore, it will not be considered in the assessment process or the NRCs Action Matrix. This issue was documented in the licensees corrective action program as AR 1929130. Licensee corrective actions included: 1) installing and testing a new MV-08-03 auxiliary switch, 2) revision of AFW operating procedures to visually inspect the position of all auxiliary contactor switches of the same type following operation of the AFW system; and 3) modifying the contactor preventative maintenance procedure to check for binding of the switch and to verify tightness of the switch housing to prevent any misalignment between the switch and its housing. This LER is closed. |
| Site: | Saint Lucie  |
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| Report | IR 05000335/2014002 Section 4OA3 |
| Date counted | Mar 31, 2014 (2014Q1) |
| Type: | Violation: Severity level Enforcement Discretion |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | D Rich J Reyes J Rivera T Morrissey W Loo W Pursley |
| Violation of: | Technical Specification - Procedures Technical Specification |
| INPO aspect | |
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Finding - Saint Lucie - IR 05000335/2014002 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Saint Lucie) @ 2014Q1
Self-Identified List (Saint Lucie)
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