05000277/FIN-2011005-03
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Finding | |
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| Title | Licensee-Identified Violation |
| Description | TS b.4.1 states, in part, that written procedures shall be implemented a1d maintained as recommended in RC 1.33, Appendix A, November 1972. RG 1\'33, Appendix A\' Section l, procedures for Performing Maintenance, subsection 1, states the following: Maintenance which can affect the performance of safety-related Equipment should be properly preplanned and performed in accordance with written procedures, documented instructions, or drawings appropriate to the circumstances\' Skill, notably possessed by qualified maintenance personnel may not require detailed step--by-step delineation in a procedure. Contrary to the above,. PBAPS did not properly preplan and perform maintenance which affected the E-1 EDG\' Specifically, PBAPS determined that a damaged lubricating oil drain line should have been identified and replaced during planned maintenance activities prior to the occurrence of leakage. As a consequence of not identifying and replacing the damaged drain line, PBAPS determined that the E-1 EDG was unable to perform its 24-hour mission time, and therefore was inoperable, during the period of time between April27 , 2011, and September 23, 2011\' The finding was determined to be of very low safety significance, for both Peach Bottom Units 2 and 3, in accordance with lMC 0609, Appendix A, Determining the Significance of Reactor Inspection Findings for At-Power Situations (lMC 06094) using SDP phase s 1,2 and 3. Phase 1 screened the finding to Phase 2 because it represented a loss of the E-1 EDG safety function, between April27 and September 23, 2011 (149 days), longer than the TS limiting condition for operation (LCO) of 14 days. A Region I senior Reactor Analyst (SRA) conducted a Phase 3 analysis because the Phase 2 analysis, conducted by the inspectors using- the Peach Bottom pre-solved Risk-Informed Inspection Notebook, indicated that the finding could be more than very low significance\' The SRA used the peach Bottom Standardized Plant Analysis Risk (SPAR) model, Revision 8.19 and 8.17, for units 2 and 3 respectively and SAPHIRE 8 to conduct the phase 3 analysis, with the conservative assumption that the E-1 EDG would not have operated at all for its 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> mission time over the 149 day exposure period\' This analysis was conservative given the EDG could have operated for over two hours assuming that the drain line broke and the potential that operators could have temporarily limited the leakage from the supercharge lube oil drain line. This analysis indicated an increase in core damage frequency (CDF) for internal initiating events in the range of one core damage accident in 2,500,000 years of reactor operation, in the low E-7 range per year for each unit. The dominate core damage sequences included losses of offsite power with the failure of all EDGs resulting in a station blackout (SBO), followed by the failure of operators to reduce direct current loading to allow extended operation of the RCIC system and - depressurize the realtor, and with inability to recover offsite power, the SBO source of power from the Conowingo Dam or an EDG in two hours. In accordance with IMC 0609A, for a finding with an internal events ACDF above 1E-7, the SRA assessed the impact of the finding on: 1) External events such as fire, seismic and flooding, determining, using the external events portion of the Peach Bottom Unit 2 and 3 SPAR models, that the total ACDF (internal plus external) would not be above the 1 E-6 threshold; and 2) the increase in large early release frequency (ALERF)\' determining that given the operators ability, following core damage, to recover offsite power and depressurize and inject water to the reactor from low pressure sources and to flood the containment that the ALERF was in the low E-8 per year range\' Because this finding is of very low safety significance and has been entered into Exelon\'s CAP under lR 1266b37, this violation is being treated as a Green, licensee identified NCV consistent with the NRC Enforcement Policy. |
| Site: | Peach Bottom  |
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| Report | IR 05000277/2011005 Section 4OA7 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | E Miller J Tomlinson K Young P Krohn R Nimitz S Barr S Hansell A Ziedonis |
| INPO aspect | |
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Finding - Peach Bottom - IR 05000277/2011005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Peach Bottom) @ 2011Q4
Self-Identified List (Peach Bottom)
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