05000285/FIN-2009007-04
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Finding | |
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| Title | Failure to report a potential defect of breaker trip bars per 10 CFR Part 21 |
| Description | The team identified an unresolved item concerning the extent of a deviation originally discovered in a failed safety-related breaker. An inadequate evaluation of the deviation was performed that could result in an event or condition not being properly reported under 10 CFR Part 21, 10 CFR Part 50.72, 10 CFR Part 50.73or 10 CFR Part 73.71.Description. On August 24, 2007, safety-related Breaker MCC-4B1-B01, Pressurizer Backup Heaters Bank 3 Group 8 failed its instantaneous trip setting on one phase. The failure analysis determined the failure to be curvature of the trip bar, likely due to a material defect. This failure was a deviation as defined by 10 CFR Part 21 (a departure from the technical requirements included in a procurement document) and the licensees governing procedure SO-R-1, Reportability Determinations. In order for this deviation to be reportable under 10 CFR Part 21, 10 CFR 50.72, 10 CFR 50.73 or 10 CFR 73.71, the deviation must be determined to be a defect. As defined by 10 CFR Part 21, a defect includes deviations in a basic component delivered to a purchaser for use in a facility or an activity subject to the regulations in this part if, on the basis of an evaluation, the deviation could create a substantial safety hazard. In evaluating the deviation, the licensee arbitrarily determined that the deviation only applied to breakers with the same date code as the failed breaker. This conclusion was reached with no engineering basis and without consultation with the vendor of the breaker. In evaluating deviations, only the vendor can fully determine the extent of the deviation and its potential effect on other plant components. Since Procedure SO-R-1does not direct vendor notification unless the initial deviation is potentially associated with a substantial safety hazard, it was not possible to determine whether the deviation existed in other components. The licensee determined there were no other breakers with the same date code located anywhere on site, thus the only breaker assumed to have the deviation was the initial breaker that failed. Due to safety-related function of the particular breaker, it was determined that there was no substantial safety hazard, and the event was not reportable under 10 CFR Part 50.72 or 10 CFR Part 50.73. Thus the licensee determined that any reporting requirements required under Part 21 were satisfied, as described in 10 CFR Part 21.2(c). However, since the extent of the deviation was measured against breakers only with the same date code, and without consultation with the vendor, the evaluation was inadequate to determine if the event was reportable under 10 CFR Part 50.72 or 10 CFR Part 50.73. In addition, a proper evaluation of components stored in the warehouse could not be made resulting in an inadequate evaluation to determine if the condition was reportable under 10 CFR Part 21.On November 14, 2007, safety-related breaker MCC-3C1-B01, Pressurizer Backup Heaters Bank 2 Group 4 failed its 300 percent thermal test, instantaneous trip setting, on all three phases. This breaker was the same make and model as the breaker that failed on August 24, 2007, but was a different date code. The failure analysis of this breaker was documented in the same report as the initial breaker failure. While the failure mechanism of this breaker was different than the previous breaker failure, the failure analysis noted that the trip bar was curved, though it did not contribute to the failure. The first breaker failure was determined to be curvature of the trip bar, and the second breaker was exhibiting the same characteristics. Since the two failures occurred so close together in time and the failure analyses were documented in the same report, the licensee could have reasonably questioned the extent to which the deviation present in the first breaker occurred. After a review of the two breaker failure events, the team asked the licensee to determine if other breakers were installed in the plant or stored in the warehouse that contained the same deviation. This issue is unresolved pending review of potentially affected breakers after the licensee consults with the vendor to determine if a substantial safety hazard exits (Unresolved Item 05000285/2009007-04) |
| Site: | Fort Calhoun  |
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| Report | IR 05000285/2009007 Section 4OA2 |
| Date counted | Jun 30, 2009 (2009Q2) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | C Osterholtz G Guerra J Clark J Kirkland L Brookhart L Willoughby P Elkman W Schaupp Elkmang Guerra J Kirkland L Willoughby J Clark C Osterholtz W Schaup L Brookhartj Kirklandg Werner M Vasquez P Goldberg |
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Finding - Fort Calhoun - IR 05000285/2009007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Fort Calhoun) @ 2009Q2
Self-Identified List (Fort Calhoun)
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