05000298/FIN-2017003-03
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Finding | |
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Title | Loss of Control Room Ventilation Due to Inadequate Post-Maintenance Testing Activities |
Description | The inspectors identified a non-cited violation of 10 CFR Part 50, Appendix B, Criterion XI, Test Control, for the licensees failure to assure that all testing required to demonstrate that the control room emergency filter system would perform satisfactorily in service was identified and performed in accordance with written test procedures. Specifically, on May 25, 2017, following corrective maintenance to replace bent positioning rods for the A and B discharge dampers for the control room supply fans, the licensee failed to ensure that all testing described in Maintenance Procedure 7.0.5, CNS Post-Maintenance Testing, Revision 53, was identified and performed, in order to assure that the control room filter system would be able to perform its safety function. As a result, on May 26, 2017, after the licensee restored the system back to service, the in-service B discharge damper was found partially closed, resulting in the supply fan failing to meet minimum flow requirements and the control room emergency filter system being declared inoperable. Corrective actions to restore compliance included replacement of the damper positioning arm, interim actions requiring post-maintenance testing after each repositioning of the dampers, and long term actions to modify the damper control arms to prevent bending and improve position verification methods. The licensee entered this deficiency into the corrective action program as Condition Report CR-CNS-2017-05794.The licensees failure to assure that adequate post-maintenance testing was identified and performed for work on the control room supply fan discharge dampers was a performance deficiency. Using Inspection Manual Chapter 0612, Appendix B, Issue Screening, dated September 7, 2012, the inspectors determined the performance deficiency was more than minor, and therefore a finding, because it was associated with the structure, system, and component, and barrier performance attribute of the Barrier Integrity Cornerstone and adversely affected the cornerstone objective to provide reasonable assurance that physical design barriers (control room envelope) protect the public from radionuclide releases caused by accidents or events. Specifically, the finding resulted in control room supply fan B failing to meet minimum flow requirements and the control room emergency filter system being declared inoperable. Using Inspection Manual Chapter 0609, Appendix A, The Significance Determination Process (SDP) for Findings at Power, dated June 19, 2012, the inspectors determined that the finding had very low safety significance (Green) because it did not represent a degradation of the barrier function of the control room against smoke or a toxic atmosphere. The finding had a cross-cutting aspect in the area of problem identification and resolution associated with evaluation. Specifically, the licensee failed to ensure that the organization thoroughly evaluated indications of degraded supply fan flow that occurred during testing, and failed to properly assess bent discharge damper positioning rod deficiencies discovered during the maintenance activities, to ensure that resolutions addressed causes and extent of conditions were commensurate with their safety significance [ P. 2]. |
Site: | Cooper |
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Report | IR 05000298/2017003 Section 4OA3 |
Date counted | Sep 30, 2017 (2017Q3) |
Type: | NCV: Green |
cornerstone | Barrier Integrity |
Identified by: | NRC identified |
Inspection Procedure: | IP 71153 |
Inspectors (proximate) | P Voss C Henderson C Young M Stafford C Jewett L Brookhart E Simpson J Kozal |
Violation of: | 10 CFR 50 Appendix B 10 CFR 50 Appendix B Criterion XI |
CCA | P.2, Evaluation |
INPO aspect | PI.2 |
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Finding - Cooper - IR 05000298/2017003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Cooper) @ 2017Q3
Self-Identified List (Cooper)
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