05000482/FIN-2009007-04
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Finding | |
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| Title | 345 kV Offsite Power System Compliance with General Design Criterion 17 |
| Description | The 345 kV switchyard currently provides both sources of offsite power to the plant. The original design of the offsite power system included a 345 kV source from the 345 kV switchyard and a separate 69 kV source from the 69 kV switchyard. In April 1982, the NRC concluded that the original design was acceptable because the circuits provided sufficient assurance that redundant and independent sources of offsite power were provided, as required by General Design Criterion 17. The NRC safety evaluation report was in two parts. The first described offsite power inside the Standardized Nuclear Unit Power Plant System design and the second described offsite power to the Wolf Creek specific Standardized Nuclear Unit Power Plant System (i.e., Wolf Creek). In 1983, Wolf Creek Generating Station reanalyzed the offsite power system and determined that changes needed to be made to the Updated Safety Analysis Report. Wolf Creek Generating Station submitted the revised Updated Safety Analysis Report pages to the NRC which described the changes to the switchyard and how General Design Criterion 17 would be met. The significant changes were removing one of the four proposed 345 kV transmission lines coming into the 345 kV switchyard and adding a345/69 kV transformer to connect the 345 and 69 kV switchyards. Thus, both offsite power sources were routed through the common 345 kV switchyard versus from separate switchyards. In 1985 the NRC concluded that the design changes met the requirements of General Design Criterion 17 and were acceptable. The removal of this portion of the USAR was not described in Wolf Creeks submittal and the effective deletion of the NRCs 1983 safety evaluation report were not described in the NRC approval. Thus, this Updated Safety Analysis Report change also effectively removed the second portion of the NRC safety evaluation report from the licensing basis that described how the plants 345 kV and 69 kV switchyards met the independence requirements of General Design Criterion 17.After the NRC approved the offsite power design changes in 1985, Wolf Creek Generating Station installed an additional 345/13.8 kV transformer. The new configuration bypassed the 69 kV switchyard and went directly to the onsite XNB01safety related transformer. In the 10 CFR 50.59 evaluation, Wolf Creek Generating Station determined that this would be a more reliable source of offsite power than the previously approved source, which was routed through the 69 kV switchyard. Wolf Creek Generating Station determined that the new design met General Design Criterion 17. The inspectors were not able to determine if these design changes were submitted to the NRC for approval and if the changes, including those in 1983, would have been accepted as conforming to General Design Criterion 17. Therefore, this issue is unresolved pending more NRC inspection of the General Design Criterion 17acceptance criteria applied by Wolf Creek Generating Station and basis and verification of the removal of the 69 kV system from the offsite power analysis: Unresolved Item 05000482/2009007-04, 345 kV Offsite Power System Compliance with General Design Criterion 17. |
| Site: | Wolf Creek  |
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| Report | IR 05000482/2009007 Section 4OA5 |
| Date counted | Dec 31, 2009 (2009Q4) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 93812 |
| Inspectors (proximate) | C Peabody G Miller J Bashore L Carson L Willoughby N Makris S Alferink C Longc Longc Peabody D Dumbacher G Miller G Tutak J Medoff M Runyan R Deese |
| INPO aspect | |
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Finding - Wolf Creek - IR 05000482/2009007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Wolf Creek) @ 2009Q4
Self-Identified List (Wolf Creek)
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