05000266/FIN-2012004-03
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Finding | |
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Title | Plant Operation with an Unacceptable ASME Code Class 2 Pressure Boundary Flaw |
Description | The inspectors identified a finding of very low safety significance and associated non-cited violation of 10 CFR 50.55a(g)(4) because the licensee failed to identify and evaluate an American Society of Mechanical Engineers (ASME) Code Class pressure boundary flaw. Specifically, between May 22 and June 26, 2012, the licensee did not identify that leakage in the Unit 2 containment from an unknown source was from a weld in the steam generator A blow-down line, an ASME Section XI Code Class 2 high energy component. The issue was entered into the licensees corrective action program as action requests AR01789202 and AR01797798 for evaluation and development of corrective actions. The finding was determined to be more than minor in accordance with IMC 0612, Power Reactor Inspection Reports, Appendix B, Issue Screening, dated September 7, 2012, because it was associated with the Initiating Events Cornerstone attribute of equipment performance and adversely affected the reliability of the steam generation systems (steam generator, feedwater, or main steam); thereby, directly impacting the cornerstone objective to limit the likelihood of events that upset plant stability during power operations. Specifically, the inspectors determined that any potential (and subsequently actual) failure location represented both a containment barrier during a loss of coolant accident and a reactor pressure system boundary during a steam generator tube failure event, in addition to being a potential transient initiator if the leakage became more significant. The inspectors evaluated the finding using IMC 0609, Significance Determination Process, Attachment 0609.04, Initial Characterization of Findings, Tables 2 and 3, dated June 19, 2012, and Appendix A, The Significance Determination Process (SDP) for Findings At-Power, Exhibit 1 for the Initiating Events Cornerstone, dated June 19, 2012. The inspectors answered No to the Exhibit 1 questions in Appendix A for transient initiators and support system initiators. Therefore, the inspectors determined the finding to be of very low safety significance. This finding has a cross-cutting aspect in the area of human performance, conservative assumptions. Specifically, the licensee failed to use conservative assumptions in decision-making because it developed an operability evaluation demonstrating that continued full power operation was acceptable without reasonable assurance that the leakage was from a mechanical joint, rather than developing reasonable assurance or providing physical evidence, either indirectly or by observation, that the leakage was not pressure boundary leakage |
Site: | Point Beach |
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Report | IR 05000266/2012004 Section 1R15 |
Date counted | Sep 30, 2012 (2012Q3) |
Type: | NCV: Green |
cornerstone | Initiating Events |
Identified by: | NRC identified |
Inspection Procedure: | IP 71111.15 |
Inspectors (proximate) | C Zoia J Jandovitz M Kunowski S Burton R Krsek V Meghani M Learn M Thorpe-Kavanaugh P Cardona-Morales K Carrington |
CCA | H.14, Conservative Bias |
INPO aspect | DM.2 |
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Finding - Point Beach - IR 05000266/2012004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Point Beach) @ 2012Q3
Self-Identified List (Point Beach)
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