05000395/FIN-2014005-01
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Finding | |
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Title | Licensee-Identified Violation |
Description | 10 CFR Part 50 Criterion XVI, Corrective Actions, requires in part that measures be established to assure that conditions adverse to quality are promptly identified and corrected. Contrary to this, the licensee failed to correct the valve packing friction and the degradation of the valve opening springs associated with the SW system outlet header component cooling loop B cross-connect Valve, XVG090627B-CC after the valve failed surveillance testing on October 30, 2012. In addition, the licensee failed to correct this condition adverse to quality during a mini-outage on March 30, 2013. This degraded condition resulted in the failure to stroke open of both valves XVG090627B-CC and XVG09627A-CC during the 2014 refueling outage and resulted in violations of Technical Specifications 4.0.5, Inservice Testing Surveillance, 3.7.3, Component Cooling Water System, and 3.7.4, Service Water System. The conditions adverse to quality were identified by the licensee and entered in the licensees corrective action program as CR- 13-00930, CR-14-01926, and CR-14-02282. The failure to correct a condition adverse to quality related to the service water (SW) system outlet header component cooling water (CCW) system loop cross-connect valves, XVG09627B-CC and XVG09627A-CC was a PD. Both valves XVG09627A-CC and XVG09627B-CC failed surveillance tests and both trains of the CCW system were simultaneously rendered past inoperable during the 2014 refueling outage. The PD was screened in accordance with NRC Inspection Manual Chapter (IMC) 0609.04 and was determined to impact the Mitigating Systems Cornerstone. Significance Determination Process (SDP) screening performed in accordance with NRC IMC 0609, Appendix A, Exhibit 2, determined that the PD represented a loss of system function and required a Detailed Risk Evaluation. A Detailed SDP risk evaluation was performed by a regional SRA in accordance with the guidance of NRC IMC 0609, Appendix A, using the latest NRC Virgil C. Summer SPAR risk model. The major analysis assumptions included: Both valves considered simultaneously inoperable for a one year exposure period; Random or seismically induced pipe failure in combination with failure of the normal CCW supply, the Demineralized Water (DW) System, would be required to yield a demand for valves XVG09627A/B to open to fill the CCW system; Operator action was credited to identify and isolate leakage and restart the standby CCW train and re-align components per annunciator and abnormal operating procedures; EPRI generic pipe rupture frequency data was utilized. The dominant sequence was a seismic initiator which resulted in a loss of offsite power, loss of the DW system, and seismically induced leakage in the CCW system; failure of the Backup SW fill function due to the PD; failure of the operator to recover the CCW system resulting in a loss of seal cooling which led to a seal loss of coolant accident and core damage. The risk was mitigated by the low probability of the associated rupture initiators and the ability to manually operate the valves or start the alternate CCW train components. The Detailed SDP Risk Evaluation determined that the risk increase due to the PD was an increase in core damage frequency of <1 E-6/year, a GREEN finding of very low safety significance. |
Site: | Summer ![]() |
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Report | IR 05000395/2014005 Section 4OA7 |
Date counted | Dec 31, 2014 (2014Q4) |
Type: | NCV: Green |
cornerstone | Mitigating Systems |
Identified by: | Licensee-identified |
Inspection Procedure: | |
Inspectors (proximate) | D Bacon E Coffman G Macdonald J Reece S Ninh S Rose |
Violation of: | Technical Specification - Procedures Technical Specification 10 CFR 50 Appendix B Criterion XVI |
INPO aspect | |
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Finding - Summer - IR 05000395/2014005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Summer) @ 2014Q4
Self-Identified List (Summer)
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