05000306/FIN-2012003-02
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Finding | |
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| Title | Failure to Properly Assess and Manage Risk |
| Description | A finding of very low safety significance and a non-cited violation (NCV) of 10CFR 50.65(a)(4) was identified by the inspectors due to the licensees failure to properly assess plant risk upon obtaining information which challenged the continued availability of the 21 Residual Heat Removal (RHR) pump. On April 21, 2012, licensee personnel failed to promptly recognize the unplanned orange risk condition when the 21 RHR Pump vibrations exceeded the in-service test (IST) criteria of procedure SP 2092B, Safety Injection Check Valve Test (Head Off) Part B: RWST to RHR Flow Path Verification. Corrective actions for this event included raising the reactor cavity level 20 feet above the reactor vessel flange per TS requirements. The inspectors determined that this issue was more than minor because, if left uncorrected, the failure to properly assess and manage risk could result in a loss of shutdown cooling (a more significant safety concern) due to a loss of the RHR function. Since Unit 2 was shut down in Mode 6, the Senior Risk Analyst (SRA) assessed the risk significance of the event in accordance with IMC 0609, Appendix G, Shut-down Operations Significance Determination Process. The SRAs reviewed Attachment 1, Phase 1 Operational Checklists for Both PWRS and BWRS. The applicable checklist was Checklist 3, PWR Cold Shutdown and Refueling Operation RCS Open and Refueling Cavity Level < 23\' OR RCS Closed and No Inventory in Pressurizer Time to Boiling < 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. The risk result was calculated to be 3.3E-7. Since the total estimated change in core damage frequency was greater than 1.0E-7/yr, the potential risk contribution for this finding from large early release frequency was screened using the guidance of IMC 0609, Appendix H, Containment Integrity Significance Determination Process. The inspectors determined that this issue was of very low safety significance because it was not a design deficiency; it did not represent a loss of system safety function; it did not present a loss of safety function for one train for greater than the TS allowed outage time; and it did not screen as potentially risk significant due to a seismic, flooding or severe weather initiating event. This finding was determined to be cross-cutting in the Human Performance, Work Control area since the licensee did not plan and coordinate work activities consistent with nuclear safety |
| Site: | Prairie Island  |
|---|---|
| Report | IR 05000306/2012003 Section 1R13 |
| Date counted | Jun 30, 2012 (2012Q2) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.13 |
| Inspectors (proximate) | C Moore C Zoia D Betancourt K Riemer K Stoedter P Cardona Morales P Voss P Zurawski S Shah |
| CCA | H.5, Work Management |
| INPO aspect | WP.1 |
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Finding - Prairie Island - IR 05000306/2012003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Prairie Island) @ 2012Q2
Self-Identified List (Prairie Island)
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