05000259/FIN-2009003-02
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Finding | |
|---|---|
| Title | Failure to Perform an Adequate Risk Assessment During Severe Weather Conditions |
| Description | A Green non-cited violation of 10 CFR Part 50.65 (a)(4), Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, was identified when the licensee failed to consider the impact of severe weather conditions on plant risk. Specifically, on May 1 and again on May 2, 2009, the licensee removed the A Emergency Diesel from service for planned maintenance during severe weather conditions (i.e., Tornado Warning and Tornado Watch, respectively) without reevaluating the potential adverse affect upon the existing on-line risk assessment. The severe weather conditions only lasted about an hour each day. This issue was entered into the licensee\'s corrective action program as problem evaluation report 171402. The finding was determined to be greater than minor because the licensees risk assessment failed to consider unusual external conditions that were present or imminent (e.g., severe weather, offsite power instability). According to Inspection Manual Chapter 0609, Appendix K, Maintenance Risk Assessment and Risk Management Significance Determination Process, the significance of this finding was determined to be of very low safety significance (Green) based on an initiating events frequency of <1.0E-7, and a very low risk deficit due to the number of redundant emergency diesels and the short duration of the severe weather. The cause of this finding was directly related to the crosscutting aspect of complete and accurate procedures in the area of Human Performance because the licensees sitespecific guidelines for assessing on-line risk did not require severe weather to be considered when determining plant risk nor did they require personnel to determine if severe weather is imminent prior to removing an emergency diesel generator from service (H.2.c) |
| Site: | Browns Ferry  |
|---|---|
| Report | IR 05000259/2009003 Section 1R13 |
| Date counted | Jun 30, 2009 (2009Q2) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.13 |
| Inspectors (proximate) | R Hamilton W Loo H Gepford E Guthrie K Korth R Williams |
| CCA | H.7, Documentation |
| INPO aspect | WP.3 |
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Finding - Browns Ferry - IR 05000259/2009003 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Browns Ferry) @ 2009Q2
Self-Identified List (Browns Ferry)
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