05000361/FIN-2010005-04
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Finding | |
|---|---|
| Title | Failure to Properly Store C-Panels in the Radwaste Building |
| Description | Specifically, in October, 2010, plant personnel failed to follow Procedure SO23-XX-31, Control of Work and Storage Areas within the Protected Area during Unit Outages at SONGS 2 and 3, Revision 0, by improperly storing portable electrical equipment panels outside an approved laydown area. The portable electrical equipment panels were tied-off near a hydrogen supply line which could have been damaged during a seismic event. Consequently, a hydrogen fire could have damaged trains A and B safety related equipment cables in the overhead, but sufficient train A cables were free of the area to permit a safe shutdown. A hydrogen fire was not analyzed in the San Onofre Units 2 and 3 Fire Hazards Analysis Report, because the hydrogen line was designed to withstand a seismic event. The licensee captured this performance deficiency in their corrective action program as Nuclear Notifications NNs 201142972 and 201140052. This finding was more than minor because it could adversely affect the protection against fires attribute of the initiating events cornerstone objective. The Initiating Events Cornerstone objective is to limit the likelihood of those events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. The inspectors performed the initial significance determination for the finding using the NRC Inspection Manual 0609, Attachment 0609.04, Phase 1 Initial Screening and Characterization of Findings. The inspectors transitioned to NRC Inspection Manual Chapter 0609, Appendix F, Fire Protection Significance Determination Process. However, this guidance was not well suited for this finding. A Region IV senior reactor analyst completed a Phase 3 significance determination and found that the finding was of very low safety significance. The bounding change to core damage frequency was 4E-8/year. The dominant core damage sequence included a loss of offsite power initiating event and failure of a safety relief valve to seat. The relatively low frequency of a seismic induced loss of offsite power event coupled with the remaining available equipment helped to limit the findings significance. The finding had a crosscutting aspect in the area of human performance associated with the work practices component and the self-checking theme, because personnel failed to properly check the procedural requirements prior to staging C-panels near the hydrogen line H.4(a) (Section 4OA5). |
| Site: | San Onofre  |
|---|---|
| Report | IR 05000361/2010005 Section 4OA5 |
| Date counted | Dec 31, 2010 (2010Q4) |
| Type: | NCV: Green |
| cornerstone | Initiating Events |
| Identified by: | NRC identified |
| Inspection Procedure: | |
| Inspectors (proximate) | L Ricketson G Guerra P Elkmann L Carson S Garchow D Allen G Replogle J Reynoso S Alferink C Osterholtz R Telson B Larson S Makor P Capehart M Bloodgood I Anchondo G Tutak C Alldredge T Hedigan N Greene L Micewski Z Hollcraft F Sanchez M Jimenez S Achen |
| CCA | H.12, Avoid Complacency |
| INPO aspect | QA.4 |
| ' | |
Finding - San Onofre - IR 05000361/2010005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (San Onofre) @ 2010Q4
Self-Identified List (San Onofre)
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