05000456/FIN-2013002-03
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Finding | |
|---|---|
| Title | Failure to Establish an Adequate Quality Instruction for Determining Pressurizer Power Operated Relief Valve Operability |
| Description | The inspectors identified a finding of very low safety significance (Green) and an associated NCV of 10 CFR 50, Appendix B, Criterion III, Design Control, when licensee personnel failed to account for pressurizer (PZR) power operated relief valve (PORV) accumulator system leakage when establishing a design operability limit. Specifically, procedures BwAR 1-12-D7 (Unit 1) and BwAR 2-12-D7 (Unit 2), PZR PORV Supply Pressure High/Low, established a minimum PZR PORV air accumulator operability pressure limit of 85 pounds per square inch gauge (psig). However, this pressure limit did not account for allowable accumulator system leakage, which could be as high as 15 psig per hour, during a postulated Steam Generator Tube Rupture (SGTR) event with a loss of the nonsafety-related air supply to the valves. The licensee entered this issue into their CAP as IR 1493170. Corrective actions to address this issue included a revision to Unit 1 BwAR 1-12-D7 and Unit 2 BwAR 2-12-D7 to require Operations to declare the PZR PORVs inoperable at a higher minimum accumulator pressure limit of 94 psig. The finding was determined to be 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). Specifically, the operability limit of 85 psig failed to account for the licensing basis conditions of a postulated Chapter 15 SGTR event, loss of nonsafety-related instrument air to the containment and PZR PORVs, and acceptable loss of air from the safety-related accumulators through normal leakage and valve strokes. The finding was evaluated using IMC 0609, Significance Determination Process. Using Appendix A, The Significance Determination Process for Findings At-Power, Exhibit 2, Mitigating Systems Screening Questions, the inspectors answered No to Questions 1, 2, 3 and 4 and, as a result, determined the finding was of very low safety significance (Green). There was no cross-cutting aspect associated with the finding because it was not indicative of current licensee performance. |
| Site: | Braidwood  |
|---|---|
| Report | IR 05000456/2013002 Section 1R04 |
| Date counted | Mar 31, 2013 (2013Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.04 |
| Inspectors (proximate) | A Garmoe E Duncan J Benjamin M Holmberg M Perry R Jickling R Ng T Daun |
| Violation of: | 10 CFR 50 Appendix B Criterion III, Design Control |
| INPO aspect | |
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Finding - Braidwood - IR 05000456/2013002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Braidwood) @ 2013Q1
Self-Identified List (Braidwood)
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