05000335/FIN-2007006-04
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Finding | |
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| Title | Unit 1 Compliance With Failure To Comply With The Requirements Of The 10 Cfr 50.63, Sbo Rule |
| Description | During the review of the operator actions and procedure to cross-connect the 4KV vital bus between units, the team identified licensee issues regarding compliance with 10 CFR 50.63, SBO Rule, for Unit 1. In particular, questions were raised regarding the SBO rule requirement to verify by testing the capability to restore AC power to Unit 1 within 10 minutes of a SBO or perform a coping analysis if the time to restore AC power exceeded 10 minutes. Unit 1 coping strategy for SBO was to restore AC power in 10 minutes. Unit 2 SBO coping strategy was as a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> coping plant. The licensees Unit 1 response to the SBO rule, and subsequently accepted by the NRC in the SER, dated 9/12/1991, stated the coping strategy for Unit 1 SBO was to provide alternate AC (AAC) source within 10 minutes of the SBO event. The AAC was to be provided by a modification to install hardware between the Unit 1 and Unit 2 vital buses. 20 Enclosure The hardware was installed; however, there was no testing documented to verify the 10 minute restoration of AC power capability. On 9/7/1993, the licensee amended the UFSAR to state that the AAC would be provided in 25 minutes. The applicable operations procedures and JPM performance times in 2006 and 2007 reflect this 25 minute restoration time. The SBO rule [10 CFR 50.63(c)(2)] required AAC plants to perform a coping analysis to address how the plant would cope without AC power for one hour if AC power could not be restored in 10 minutes. No coping analysis was performed initially nor after the 25 minute time was amended to the UFSAR. During the inspection, the licensee provided technical information to demonstrate that Unit 1 could adequately respond to an SBO event, maintaining the reactor core cooled and maintaining containment integrity, success criteria for SBO in 10 CFR 50.63, during the 25 minutes it takes to restore AC power to the Unit. Additionally, the team observed an SBO scenario on the plant simulator and noted that reactor core cooling and containment integrity were not challenged in the time taken to restore AC power. The team concluded there was no apparent immediate safety issue associated with this noncompliance with the SBO Rule. Not withstanding, this issue is unresolved pending licensee actions to verify compliance with 10 CFR 50.63. This would include any of the following actions: 1. Verify by testing the 10 minutes restoration of AC power capability. 2. Performance and submission to the NRC of the required coping analysis if AC recovery cannot be verified to occur in 10 minutes. This item is identified as URI 05000335/2007006-04, Unit 1 Compliance with the Requirements of 10 CFR 50.63, SBO Rule |
| Site: | Saint Lucie  |
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| Report | IR 05000335/2007006 Section 1R21 |
| Date counted | Sep 30, 2007 (2007Q3) |
| Type: | URI: |
| cornerstone | Initiating Events |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | D Jones R Aiello T Hoeg S Sanchez M Sykesr Taylor R Moore D Jones S Kobylarz M Yeminy C Even J Hamma |
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Finding - Saint Lucie - IR 05000335/2007006 | |||||||||||||||||||||
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Finding List (Saint Lucie) @ 2007Q3
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