05000456/FIN-2012005-03
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Finding | |
|---|---|
| Title | Inadequate Operability Evaluation of Block Walls for High Energy Line Break Loads |
| Description | The inspectors identified a finding of very low safety significance (Green) when licensee personnel failed to perform an adequate technical review to determine the operability of auxiliary building safety-related block walls affected by High Energy Line Break (HELB) pressure loading. The licensee entered this issue in their CAP as IR 1454143. Corrective actions included a significant revision to the Operability Evaluation to address each of the inspectors concerns. The finding was determined to be more than minor because it was associated with the Equipment Performance attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective of ensuring the reliability, availability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e. core damage). Additionally, More than Minor Example 3.j of IMC 0612, Appendix E, Examples of Minor Issues, was used to inform the answer to this more than minor screening question. Specifically, the licensee used non-conservative allowable stress values for masonry and steel support columns that, at the time of discovery, resulted in reasonable doubt of the operability of the affected walls. In accordance with IMC 0609, Significance Determination Process, Attachment 4, Initial Characterization of Findings, Table 2, the inspectors determined the finding affected the Mitigating Systems Cornerstone. As a result, the inspectors determined the finding could be evaluated using Appendix A, The SDP for Findings At Power, Exhibit 2, for the Mitigating Systems Cornerstone. Because the finding did not ultimately affect the operability or functionality of any equipment, the inspectors answered Yes to Screening Question 1 and determined the 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 used non-conservative assumptions in an operability evaluation of auxiliary building block walls. Specifically, the licensee used non-conservative assumptions for masonry and steel allowable stresses in the evaluation of safety-related walls, which could not be justified. |
| Site: | Braidwood  |
|---|---|
| Report | IR 05000456/2012005 Section 1R15 |
| Date counted | Dec 31, 2012 (2012Q4) |
| Type: | Finding: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | M Bielby M Holmberg M Perry R Baker R Ng T Go V Meghani A Garmoe E Duncan J Benjamin J Robbins J Steffesm Holmbergm Perry N Feliz Adorno R Ng T Go V Meghani A Garmoe B Bartlett C Moore C Zoia D Szwarc E Duncan J Benjamin J Jandovitz J Laughlin J Robbins |
| CCA | H.14, Conservative Bias |
| INPO aspect | DM.2 |
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Finding - Braidwood - IR 05000456/2012005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Braidwood) @ 2012Q4
Self-Identified List (Braidwood)
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