05000456/FIN-2012004-02
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Finding | |
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| Title | |
| Description | The inspectors identified a finding of very low safety significance (Green) when licensee personnel failed to adhere to Corrective Action and Operability Determination Program standards after identifying a non-conforming condition associated with reduced steam generator (SG) power-operated relief valve (PORV) flow capacities. Specifically, in April 2012, the licensee identified that the station SG PORV relief capacities were lower than what was assumed in the CLB. This condition was identified during laboratory testing to support a power uprate application. Throughout the licensees operability assessment spanning from April to September 2012, the inspectors identified that the licensee did not adequately and effectively utilize station standards to evaluate Unit 2 CST operability after initially identifying the issue in April 2012; when processing a formal Operability Evaluation; after receiving new information from a sensitivity study performed by a contractor; and after the inspectors directly identified an issue of concern to the licensee that was addressed through the CAP. Specifically, the licensee did not ensure that the Unit 2 CST was capable of performing its TS function after identifying a non-conservative condition that ultimately resulted in requiring nearly double the CST volume from what was assumed in the CLB. The inspectors determined that such a significant decrease in available margin provided a cause for reasonable doubt of Unit 2 CST operability. Corrective actions include a revision to the Operability Evaluation that addressed the deficiency and re-confirmed CST operability. The inspectors determined the failure to evaluate the effect the reduced Unit 2 SG PORV flow rate capacities would have on the Unit 2 CSTs ability to perform its specified TS function was a performance deficiency. The inspectors determined that the performance deficiency was more than minor because it was associated with the Design Control attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e. core damage). The inspectors evaluated this finding using the SDP in accordance with IMC 0609, Attachment 4, Initial Characterization of Findings, which directed the finding to be screened using IMC 0609, Appendix A, The Significance Determination Process (SDP) for Findings at Power. The inspectors determined that because the CST maintained its operability and functionality within the CLB that this finding was of very low safety significance (Green). This finding had a cross-cutting aspect in the Decision- Making component of the Human Performance cross-cutting area because the licensee failed to use conservative decision-making and verify the validity of underlying assumptions when evaluating the effect of reduced Unit 2 SG PORV flow capacities on CST operability. |
| Site: | Braidwood  |
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| Report | IR 05000456/2012004 Section 1R15 |
| Date counted | Sep 30, 2012 (2012Q3) |
| Type: | Finding: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | A Garmoe B Bartlett D Szwarc E Duncan J Benjamin J Robbins M Perry R Langstaff R Ng T Go V Meghani |
| CCA | H.14, Conservative Bias |
| INPO aspect | DM.2 |
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Finding - Braidwood - IR 05000456/2012004 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Braidwood) @ 2012Q3
Self-Identified List (Braidwood)
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