05000458/FIN-2012002-04
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Finding | |
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| Title | Failure to Appropriately Set Reactor Core Isolation Cooling Flow Controller High Output Limit |
| Description | The inspectors identified a self-revealing non-cited violation of 10 CFR Part 50, Appendix B, Criterion V, Procedures, when the reactor core isolation cooling turbine tripped on mechanical over speed. Troubleshooting determined the cause was an improperly tuned flow controller. This issue has been entered into the licensees corrective action program as Condition Reports CR-RBS-2012-01188 and CR-RBS-2012-01262 The failure to provide specific flow controller tuning instructions for the reactor core isolation cooling turbine flow controller was a performance deficiency. The finding was more than minor in accordance with Appendix B, Issue Screening, of Inspection Manual Chapter IMC 0612, Power Reactor Inspection Reports, because the finding was associated with the equipment performance attribute of the Mitigating Systems cornerstone and affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, improper tuning of the reactor core isolation cooling controller impacted operability and availability of the reactor core isolation cooling system. The inspectors performed a Phase 1 significance determination process review of this finding per Inspection Manual Chapter IMC 0609, Attachment 4, Initial Screening and Characterization of Findings. In accordance with Table 4a, Characterization Worksheet for IE, MS, and BI Cornerstones, the finding represented a loss of system safety function. Therefore, a Region IV senior reactor analyst used Inspection Manual Chapter IMC 0609, Appendix A, Determining the Significance of Reactor Inspection Findings for At-Power Situations, to review the finding using the Standardized Plant Analysis Risk (SPAR) model for River Bend Station. The Phase 3 analysis determined the Delta-CDF was 4.68E-7/yr. For a 7-month exposure, the incremental conditional core damage probability is 2.73E-7. The majority of the risk came from sequences involving a loss of feedwater (48 percent) and a loss of offsite power (33 percent). Consequently, the analyst determined that the risk associated with the performance deficiency was very low (green). The inspectors determined the apparent cause of this finding was the failure to perform a post maintenance test to identify that the high output limit was not properly set by the maintenance work instruction. Therefore, this finding has cross-cutting aspect in the area of human performance associated with the resources component due to less than adequate work package testing instruction. |
| Site: | River Bend  |
|---|---|
| Report | IR 05000458/2012002 Section 1R19 |
| Date counted | Mar 31, 2012 (2012Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.19 |
| Inspectors (proximate) | W Sifre R Hagar G Larkin V Gaddy S Makor D Reinert C Alldredge L Carson S Garchow A Barrett |
| CCA | H.7, Documentation |
| INPO aspect | WP.3 |
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Finding - River Bend - IR 05000458/2012002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (River Bend) @ 2012Q1
Self-Identified List (River Bend)
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