05000220/FIN-2010003-01
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Finding | |
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| Title | Excessive Reactor Pressure Vessel Drain Down due to Inadequate Procedure |
| Description | A self-revealing finding of very low safety significance associated with a non-cited violation (NCV) of Technical Specification (TS) 5.4, \"Procedures,\" was identified when Nine Mile Point Nuclear Station (NMPNS) Unit 2 operators used an inadequate procedure for reactor cavity drain down, which resulted in water being drained from the reactor pressure vessel (RPV) to a level that was significantly lower than had been planned. As a result, the steam dryer was partially uncovered, which produced elevated radiation levels on the refueling floor. As immediate corrective action, the control room operators took actions to raise water level back to the RPV flange. The event was entered into the corrective action program as condition report (CR) 2010-4408. The finding was more than minor because it was associated with the procedure quality attribute of the Mitigating Systems cornerstone and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The finding was evaluated in accordance with Inspection Manual Chapter (IMC) 0609, Appendix G, \"Shutdown Operations Significance Determination Process.\" The change in core damage frequency (!\'.CDF) was determined to be of very low safety significance because of the multiple methods to inject water into the vessel and the time available to align these systems. The finding had a cross-cutting aspect in the area of human performance, resources, because NMPNS did not ensure that the RPV drain down procedure was adequate to assure nuclear safety (H.2.c per IMC 0310). |
| Site: | Nine Mile Point  |
|---|---|
| Report | IR 05000220/2010003 Section 1R20 |
| Date counted | Jun 30, 2010 (2010Q2) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.2 |
| Inspectors (proximate) | D Dempsey B Haagensen J Furia E Gray G Dentel J Krafty E Knutson N Perry S Sloan D Molteni |
| CCA | H.7, Documentation |
| INPO aspect | WP.3 |
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Finding - Nine Mile Point - IR 05000220/2010003 | |||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Nine Mile Point) @ 2010Q2
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