05000338/FIN-2011003-03
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Finding | |
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| Title | Failure to Comply with Technical Specifications for Alignment of the Refueling Water Storage Tank to the Non-Seismic Refueling Purification System. |
| Description | The inspectors identified a non-cited violation of Technical Specification (TS) 3.5.4, Refueling Water Storage Tank (RWST), for the failure to comply with the Limiting Conditions for Operation (LCO), while the Units 1 and 2 RWSTs were aligned to the non-seismic Refueling Purification (RP) system for purification during Mode 1, causing the RWSTs to be inoperable. Specifically, when the RP system was aligned to the RWST, the licensee did not declare the RWST inoperable. The licensee entered the problem into their corrective action program as condition report 397144 and suspended the use of procedures, 1-OP-16.4, Purification Operations of Unit 1 Storage Tank, and 2-OP-16.4, Purification Operations of Unit 2 Storage Tank, for purification of the RWST in Modes 1-4 until further review has been completed. The licensee had originally modified their procedures to allow this activity in 1996. The failure to comply with the actions of TS LCO 3.5.4 while the Units 1 and 2 RWSTs were aligned to the non-seismic RP system for purification on September 4, 2010, and January 7, 2010, respectively, resulting in the inoperability of the RWSTs was a performance deficiency (PD). The PD was more than minor because it affected the design control attribute of the mitigating system cornerstone objective of ensuring the availability, reliability and capability of systems that respond to initiating events to prevent undesirable consequences. In accordance with NRC IMC 0609, Significant Determination Process, the inspectors performed a Phase 1 analysis and determined that this finding was within the mitigating systems cornerstone and was potentially risk significant due to a seismic external event and therefore required a Phase 3 SDP analysis. A phase 3 risk assessment was performed by a regional SRA using the NRC SPAR model. A bounding one year exposure period was utilized. The non-seismic RP piping was assumed to fail at the same seismic input as that assumed for a loss of offsite power. The dominant sequence was a seismically induced non-recoverable loss of offsite power with a failure of the AFW system due to loss of the emergency condensate storage tank and failure of feed and bleed due to loss of the RWST leading to core damage. The risk was mitigated by the low probability of a seismic event and the use of a dedicated operator for isolation of the non-seismic piping. The analysis determined that the risk increase of the performance deficiency was an increase in core damage frequency less than 1E- 6/year yielding a GREEN finding of very low safety significance. The finding had no cross-cutting aspects due to its legacy nature. |
| Site: | North Anna  |
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| Report | IR 05000338/2011003 Section 1R18 |
| Date counted | Jun 30, 2011 (2011Q2) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.18 |
| Inspectors (proximate) | A Alen A Sengupta C Sanders D Mas G Mccoy J Reece R Carrion R Clagg S Sandal |
| INPO aspect | |
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Finding - North Anna - IR 05000338/2011003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (North Anna) @ 2011Q2
Self-Identified List (North Anna)
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