05000352/FIN-2013005-01
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Finding | |
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| Title | Failure to Properly Plan Work for Failed Airlock Door Magnetic Switch |
| Description | The inspectors identified a self-revealing finding (FIN) of very low safety significance (Green) for Exelons failure to appropriately prioritize work activities associated with a degraded Unit 2 magnetic switch for a secondary containment airlock door in accordance with Exelon procedure WC-AA-106, Work Screening and Processing. This resulted in both airlock doors being opened simultaneously due to equipment degradation and resulted in a momentary loss of reactor enclosure secondary containment integrity. The failure of the station to properly prioritize the work order for the defective magnetic switch for the Unit 2 313 elevation reactor building-to-reactor building air supply room access airlock doors was a performance deficiency that was reasonably within Exelons ability to foresee and correct and could have been prevented. This was caused by not performing a site impact review of reportability clarifications made by NUREG 1022, Event Report Guidelines 10 CFR 50.72 and 50.73, Revision 3. The performance deficiency was also contrary to Exelons procedure for work screening and processing. The finding was determined to be more than minor because it was associated with the Barrier Integrity cornerstone attribute of structures, systems, and components (SSC) and Barrier Performance (doors and instrumentation) and affected the cornerstone objective of providing reasonable assurance that physical design barriers (secondary containment) protect the public from radionuclide releases caused by accidents or events. Specifically, opening two reactor building airlock doors at the same time did not maintain reasonable assurance that the secondary containment would be capable of performing its safety function in the event of a reactor accident. The finding was determined to be self-revealing because it was revealed through the receipt of an alarm in the main control room which required no active and deliberate observation by Exelon personnel. The finding was determined to be of very low safety significance (Green) in accordance with Appendix A of IMC 0609, Significance Determination Process for Findings At-Power. Specifically, the finding only represents a degradation of the radiological barrier function provided by the secondary containment airlock doors. Exelon entered the issue into the corrective action program (CAP) as Issue Report (IR) 1553563. Corrective actions performed or planned included repairing the magnetic switch, verifying that the corrective maintenance backlog did not contain any other issues involving the airlock door indicating lights, developing a periodic routine test of the airlock door indicating circuits, and performing a site impact review of the changes in NUREG 1022, Revision 3. This finding had a cross-cutting aspect in the area of Human Performance, Resources, because Exelon did not ensure that resources were available to minimize preventative maintenance deferrals and ensure maintenance and engineering backlogs were low enough to ensure that safety is maintained H.2(a). Specifically, Exelon deferred implementation of the work order several times over a three year period which resulted in secondary containment becoming inoperable on September 3, 2013. |
| Site: | Limerick  |
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| Report | IR 05000352/2013005 Section 4OA3 |
| Date counted | Dec 31, 2013 (2013Q4) |
| Type: | Finding: Green |
| cornerstone | Barrier Integrity |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | A Turilin E Dipaolo F Bower J Ayala J Bream R Montgomery R Nimitzj Hawkinsk Mangan R Nimitz S Chaudhary T Burns A Alen B Fuller E Dipaolo F Bower J Ayala J D'Antoniob Fullere Dipaolo F Bower J Ayala J D'Antonio J Hawkins K Mangan R Nimitz S Chaudhary T Burns |
| CCA | , |
| INPO aspect | LA.5, WP.2 |
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Finding - Limerick - IR 05000352/2013005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Limerick) @ 2013Q4
Self-Identified List (Limerick)
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