05000289/FIN-2014002-03
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Finding | |
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| Title | Failure to Restore Station Blackout Diesel Generator Cooling Water Lineup following Maintenance and Testing Activities |
| Description | A self-revealing non-cited violation (NCV) of 10 CFR 50.63, Loss of All Alternating Current Power, was identified for Exelons failure to properly restore the station blackout (SBO) diesel generator system following maintenance and testing activities, rendering the SBO diesel generator unable to be available in 10 minutes of and cope for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> after a postulated SBO event. Specifically, during the restoration from SBO switchgear maintenance during the previous Fall 2013 refueling outage, operators failed to remove a blocking device (gag) from the SBO diesel generator fire service water cooling isolation valve (FS-V-646) as part of its restoration to an automatic, standby configuration. As a result the SBO diesel generator was not in the configuration required by 10 CFR 50.63 (c)(2), which describes acceptable capability standards for alternate AC power systems. Exelon entered this issue into their corrective action program as IR 1608625. Exelon restored the valve configuration and revised affected and related procedures. The inspectors determined this performance deficiency in that Exelon failed to remove the blocking devise from FS-V-646 prior to restoring the SBO diesel to service was more than minor because it is associated with the mitigating systems affecting the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, in the event of a station blackout, the SBO diesel generator was not able to be started and operated from the control room with no local operations required to allow the prompt restoration of electrical power to at least one vital bus as assumed in the TMI SBO analysis. The inspectors evaluated the finding using IMC 0609, Attachment 4, Initial Characterization of Findings, and Appendix A, The Significance Determination Process for Findings At-Power, and determined that this finding required a detailed risk evaluation because, with FS-V-646 gagged, the SBO diesel was not capable of performing its safety function. The detailed risk evaluation determined the finding to be of very low safety significance (Green). This finding has a cross-cutting aspect in the area of Human Performance, Documentation, because Exelons procedure for restoration from the maintenance and testing (OP-TM-731- 510, Rev. 5) was not adequate to specify actions to return the cooling water isolation valve (FS-V-646) to its normal automatic condition [H.7]. |
| Site: | Three Mile Island  |
|---|---|
| Report | IR 05000289/2014002 Section 1R22 |
| Date counted | Mar 31, 2014 (2014Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.22 |
| Inspectors (proximate) | C Cahill D Werkheiser E Burket J Heinly K Mangan R Rolph S Barr T O'Hara W Cook |
| Violation of: | 10 CFR 50.63 |
| CCA | H.7, Documentation |
| INPO aspect | WP.3 |
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Finding - Three Mile Island - IR 05000289/2014002 | |||||||||||||||||||||||||||||||
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Finding List (Three Mile Island) @ 2014Q1
Self-Identified List (Three Mile Island)
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