05000461/FIN-2013005-05
Finding | |
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| Title | Failure to Assess and Manage Risk Associated with the Performance of Surveillance Testing on Average Power Range Monitors |
| Description | Inspectors reviewed a self-revealing NCV of 10 CFR 50.65(a)(4) for failing to manage risk when the Division 4 Nuclear System Protection System (NSPS) inverter unexpectedly transferred from its normal direct current (DC) power source to its alternate alternating current (AC) power source during the Average Power Range Monitor (APRM) D surveillance test. Specifically, the installed operational barrier failed to protect a fus
block when a test cable connector was inadvertently dropped. This caused a momentary electrical short and resulted in the inverter to transfer power sources. The licensee documented this issue in the CAP as IR 01476647 and performed (1) a standdown with instrument maintenance craftsmen to discuss the event and lessons learned, (2) changes to the licensees risk/hazards assessment process to include a checklist designed to aid in challenging jobsite conditions, (3) conduct of paired observations by maintenance department managers on use of the checklist, and (4) a case study with the maintenance shops using this event to highlight determining risk perception and robust protective barriers. The inspectors determined that the licensees failure to adequately manage the risk associated with performance of surveillance testing for APRM D was a performance deficiency. The performance deficiency is more than minor because it was associated with the configuration control attribute of the MS cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The performance deficiency involved the licensees assessment and management of risk associated with performing maintenance in accordance with 10 CFR 50.65(a)(4); therefore the inspectors used IMC 0609, Attachment 4 Initial Characterization of Findings, and Appendix K, Maintenance Risk Assessment and Risk Management Significance Determination Process, and determined that a detailed risk evaluation would be required since the issue represented an actual loss of safety function of a system. The Region III Senior Reactor Analyst (SRA) completed a detailed risk evaluation using the NRCs Standardized Plant Analysis Risk (SPAR) model for Clinton Power Station (CPS), Version 8.17 and SAPHIRE Version 8.09 to calculate an Incremental Core Damage Probability Deficit (ICDPD) for the unevaluated condition. The SRA ran the SPAR model conservatively assuming that High Pressure Core Spray System (HPCS) was unavailable during the 6-hour time. The result was an ICDPD of less than 2E-08/year. In accordance with IMC 0609, Appendix K, because the ICDPD was not greater than 1E-06/year, the finding was determined to be of very low safety significance (i.e. Green). The finding was determined to have a cross-cutting aspect in the area of huma performance, associated with the work practices component, in that personnel wor practices are used commensurate with the risk of the assigned task, such that wor activities are performed safely. Specifically, the technicians did not perform adequat self or peer checks after installation of the barrier to ensure the barrier would provid protection from shorting. |
| Site: | Clinton  |
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| Report | IR 05000461/2013005 Section 4OA3 |
| Date counted | Dec 31, 2013 (2013Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | A Boland D Jones D Lords J Laughlin R Walton S Bell S Mischke W Schaup |
| Violation of: | 10 CFR 50.65(a)(4) 10 CFR 50.65 |
| CCA | H.12, Avoid Complacency |
| INPO aspect | QA.4 |
| Finding closed by | |
| IR 05000461/2013005 (11 February 2014) | |
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Finding - Clinton - IR 05000461/2013005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Clinton) @ 2013Q4
Self-Identified List (Clinton)
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