05000443/FIN-2013004-01
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Finding | |
|---|---|
| Title | Inadequate Operability Determination Regarding Service Water Leakage and Associated TS Violation |
| Description | The inspectors identified an NCV of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, and an associated violation of technical specification (TS) 3.7.4, because NextEra did not follow the requirements of station procedure EN-AA-203-1001, Operability Determinations/ Functionality Assessments. Specifically, NextEra did not properly evaluate and document an adequate basis for operability, when relevant information was available that would have challenged the reasonable expectation of operability threshold for a service water (SW) through-wall leak that degraded incrementally from weepage on August 7, 2013, to a significantly larger leak on August 28, 2013. NextEra completed a temporary non-code repair of the flaw with the installation of a weldolet on September 1, 2013, following NRC review and approval of a relief request. Additionally, under the corrective action process, NextEra completed apparent cause evaluations for the piping flaw, as well as engineering decision-making during the non-destructive examinations and evaluations, and are currently evaluating the fundamental issue of decision-making regarding TS operability and TS compliance. This performance deficiency is more than minor because it is associated with the equipment performance attribute of the Mitigating Systems Cornerstone and affected its objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the prompt operability determination incorrectly concluded the B cooling tower (CT) SW header and the B SW (ocean) pumps were operable, but degraded, versus inoperable. IMC 0609, Appendix A, Exhibit 2, Mitigating Systems Screening Questions, and Exhibit 4, External Events Screening Questions, were used to assess this issue and a detailed risk evaluation was completed. The inspectors assumed that functionality of the SW system, based upon the as-found wall thinning, would only be challenged when aligned to the cooling tower basin when the SW piping is subjected to a higher overall sytem pressure. This system configuration is used to mitigate a seismic event following the loss of the normal SW intake structure. Based on low probability of SW piping system failure due to a seismic event and the overall low likelihood of a seismic event of a magnitude sufficient to cause structure, system, and component (SSC) damage, this finding was determined to be of very low safety significance (Green). This finding has a cross-cutting aspect in the area of human performance associated with the decision making component because NextEra failed to use conservative assumptions in decision-making and adopt a requirement to demonstrate that the proposed action is safe in order to proceed rather than a requirement to demonstrate it is unsafe in order to disapprove the action. Specifically, NextEra personnel had not considered relevant information in the form of UT data and actual leak propagation to conclude that they no longer had reasonable assurance of operability and did not declare the B header of ocean and CT SW systems inoperable. |
| Site: | Seabrook  |
|---|---|
| Report | IR 05000443/2013004 Section 1R15 |
| Date counted | Sep 30, 2013 (2013Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | P Cataldo S Barr G Dentel J Laughlin H Gray J Gilliam J Rady S Hammann N Floyd B Dionne M Jennerich |
| Violation of: | 10 CFR 50 Appendix B Criterion V Technical Specification Technical Specification - Procedures |
| CCA | H.14, Conservative Bias |
| INPO aspect | DM.2 |
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Finding - Seabrook - IR 05000443/2013004 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Seabrook) @ 2013Q3
Self-Identified List (Seabrook)
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