05000368/FIN-2016001-03
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Finding | |
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| Title | Blocked Drain Results in Emergency Feedwater Pump Inoperability |
| Description | The inspectors documented a self-revealing Green finding with an associated non-cited violation of 10 CFR Part 50, Appendix B, Criterion XI, Test Control, for the failure to verify that the floor drains in the Unit 2 turbine-driven emergency feedwater pump room would pass the amount of water added to the drain during operation of the pump in order to prevent the pump from becoming submerged. As a result, the licensee was unaware that the turbine-driven emergency feedwater pump room drain had become blocked until water began pooling in the room during a pump test. Upon discovery, the licensee stopped the pump, declared the train inoperable, and cleared the drain. This finding was entered into the licensees corrective action program as Condition Report CR-ANO-2-2016-0384. The failure to verify that the Unit 2 turbine-driven emergency feedwater pump room drain would pass the water added to the drains during operation of the turbine-driven emergency feedwater pump is a performance deficiency. The finding is more than minor because it adversely affected the protection against external factors (i.e., flood hazard) attribute of the mitigating systems cornerstone to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, the failure to detect a clogged drain affected the availability of the emergency feedwater system by potentially flooding the room and failing the pump. The inspectors evaluated the finding using Manual Chapter 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The inspectors determined that the finding required a detailed risk evaluation because the finding represented an actual loss of function of a single train for greater than its technical specification allowed outage time. A senior reactor analyst performed a detailed risk evaluation and estimated the total increase in core damage frequency to be 7.7E-7/year, and therefore the finding had very low safety significance (Green). The inspectors determined that this finding did not have a cross-cutting aspect because the most significant contributor, inadequate documentation of the pump design requirements during initial plant construction, does not reflect current licensee performance. |
| Site: | Arkansas Nuclear  |
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| Report | IR 05000368/2016001 Section 1R19 |
| Date counted | Mar 31, 2016 (2016Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.19 |
| Inspectors (proximate) | A Barrett B Tindell J Choate M Tobin N O'Keefe |
| Violation of: | 10 CFR 50 Appendix B Criterion XI Technical Specification |
| INPO aspect | |
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Finding - Arkansas Nuclear - IR 05000368/2016001 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Arkansas Nuclear) @ 2016Q1
Self-Identified List (Arkansas Nuclear)
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