05000259/FIN-2009007-01
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Finding | |
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| Title | Suppression Pool Initial Temperature Assumed in the Appendix R Thermo-Hydraulic Analysis May not be the Most Limiting Value |
| Description | The team identified a URI involving a postulated fire scenario in which the initial suppression pool temperature assumed in the licensees Appendix R thermohydraulic analysis may not be the most limiting value for a postulated fire in certain FAs.The licensees Appendix R thermo-hydraulic analysis was based on specific initial plant conditions at the time of entry into the SSIs. During review, the team noted that a fire induced single spurious equipment operation could result in plant parameters being outside the initial conditions assumed in the thermo-hydraulic analysis and SSA prior to entry into the SSIs. This was corroborated by a simulator exercise for a postulated fire in FA 9, which demonstrated the effect on suppression pool temperature of a single main steam safety relief valve (MSRV) spuriously opening at the onset of a fire. During the simulator exercise, suppression pool temperature quickly rose above the 95 degrees Fahrenheit (o F) value assumed in the thermo-hydraulic analysis. Suppression pool temperature above the analyzed value could impact the net positive suction head (NPSH) required for the low pressure coolant injection (LPCI) pumps, which were credited for providing core cooling (if high pressure systems were not available) and suppression pool cooling. This issue was discussed with licensee personnel who initiated problem evaluation report (PER) 169488 to assess the basis for the suppression pool temperature assumed in the Appendix R analysis. The licensee had hourly roving fire watches in place (which were implemented as additional compensatory measures to address the existing noncompliant OMAs) while this issue was being evaluated. This issue is unresolved pending the NRCs review of the licensees assessment of the suppression pool temperature basis during the fall 2009 triennial fire protection inspection (TFPI). This issue is identified as URI 05000259, 260, 296/2009007-01, Suppression Pool Initial Temperature Assumed in the Appendix R Thermo-Hydraulic Analysis May not be the Most Limiting Value |
| Site: | Browns Ferry  |
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| Report | IR 05000259/2009007 Section 1R05 |
| Date counted | Jun 30, 2009 (2009Q2) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.05 |
| Inspectors (proximate) | G Pick K Miller L Suggs M Thomas P Fillion P Qualls R Neaseb Metzgerc Kontz L Suggs M Thomas P Qualls R Nease |
| INPO aspect | |
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Finding - Browns Ferry - IR 05000259/2009007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Browns Ferry) @ 2009Q2
Self-Identified List (Browns Ferry)
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