05000305/FIN-2011002-03
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Finding | |
|---|---|
| Title | Unintended Voiding of the Reactor Vessel Closure Head |
| Description | A finding of very low safety-significance and associated non-cited violation (NCV) of Technical Specification 5.4.1, Procedures, was identified by the inspectors for the failure to establish, implement, and maintain procedures for shutdown operations involving the draining of reactor coolant system (RCS) inventory. Specifically, on March 21, 2011, during a pressurizer draindown evolution, licensed operators unknowingly created a gas void in the reactor vessel closure head (RVCH) that displaced water to a level near the RVCH flange. Subsequent evaluation determined that the procedure for draining the RCS did not contain adequate guidance to ensure that an unacceptable void in the RVCH was not present prior to or formed during operations draindown activities. The licensee subsequently entered the issue into its corrective action program as CR418537 and performed a remedial corrective action of removing the gas void that accumulated in the RVCH. At the end of the inspection period, the licensee was performing an apparent cause evaluation to determine the causes of the event and develop additional corrective actions. The finding was determined to be more than minor because the finding was associated with the Mitigating Systems Cornerstone attribute of operating procedure quality and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, the formation of the gas void in the RVCH displaced RCS inventory and could have challenged the ability to remove decay heat in the event of a loss of shutdown cooling. The Region III senior reactor analyst determined that this issue is best characterized as a finding of very low safety significance (Green). The finding has a cross-cutting aspect in the areas of human performance, work practices, because operations personnel did not follow or implement the guidance contained in plant procedures. Specifically, procedure OP-KW-AOP-RC-002 prescribed actions to take if a gas void formed in the RVCH that resulted in RVLIS level readings less than 88 percent, which had occurred several hours prior to the start of a pressurizer draining evolution (H.4(b)). |
| Site: | Kewaunee  |
|---|---|
| Report | IR 05000305/2011002 Section 1R20 |
| Date counted | Mar 31, 2011 (2011Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.2 |
| Inspectors (proximate) | A Shaikh E Sanchez-Santiago M Holmberg R Langstaff R Winter J Jandovitz J Cassidy M Kunowski R Krsek K Barclay R Jones |
| CCA | H.8, Procedure Adherence |
| INPO aspect | WP.4 |
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Finding - Kewaunee - IR 05000305/2011002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Kewaunee) @ 2011Q1
Self-Identified List (Kewaunee)
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