05000348/FIN-2012004-03
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Finding | |
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| Title | LER 05000348/2012-0015-00 Unit Shutdown Required by Technical Specification 3.8.1 |
| Description | The inspectors reviewed information contained in the licensees submittal of LER 05000348/2012-0015-00. The inspectors monitored the plant shutdown prior to the expiration also of LCO 3.8.1 during the 1B EDG maintenance outage on July 26, 2012. The inspectors monitored repair activities for the 1B EDG #12 engine cylinder failure and associated post maintenance testing. The inspectors reviewed the immediate extent of condition review to determine if other EDGs were affected. The inspectors also reviewed the condition of temperature actuated valves installed in other portions of the 1B EDG system as well as the other similar diesel generators in the plant. On July 20, 2012, during the post-maintenance testing following a 24 month maintenance outage, oscillations in power output occurred on the 1B EDG and within minutes, the 1B EDG unexpectedly shutdown. The initial investigation determined the #12 cylinder failed. The licensees requested the NRC exercise discretion and not enforce compliance with the actions required in TS 3.8.1. The request was verbally denied on July 26, 2012 (ML12213A310). The region concluded that relying on a single alternate AC power source for a station blackout in one unit and an inoperable DG in the adjacent unit erodes the defense-in-depth aspects of the plant\\\'s design and operation and thereby reduces the safety margins due to a planned extended allowed outage time and that the request was not acceptable. On July 26, 2012, at 2151 hours0.0249 days <br />0.598 hours <br />0.00356 weeks <br />8.184555e-4 months <br /> CDT with Unit 1 at 100% power, a reactor shutdown was conducted in accordance with TS Condition H, for LCO 3.8.1, following expiration of the completion time allowed for compliance with TS Condition B.4, of the same LCO. The Unit was stabilized in Mode 5 to effect necessary repairs to the 1B EDG. The licensees investigation determined the immediate cause of the 1B EDG shutdown was a high crankcase pressure trip. The underlying cause of the engine shutdown was the malfunction of the engine\\\'s intercooler thermostatic bypass valve (Q1R43V0561) due to the failure of one of three thermal actuating devices. Although the preliminary causes of the failure were determined, the licensee had not completed their root cause evaluation. Additional reviews of the root cause evaluation and corrective actions will need to be completed prior to closure of this LER. This item is identified as URI 05000348/2012004-03: LER 05000348/2012-0015- 00 Unit Shutdown Required by Technical Specification 3.8.1. This issue was entered into the licensees CAP as CR 487817. |
| Site: | Farley  |
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| Report | IR 05000348/2012004 Section 4OA5 |
| Date counted | Sep 30, 2012 (2012Q3) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | |
| Inspectors (proximate) | D Lanyi E Crowe F Ehrhardt G Croon G Laska J Sowa M Miller T Lightyb Caballeroe Crowe F Ehrhardt J Laughlin J Sowa M Coursey M Riley |
| INPO aspect | |
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Finding - Farley - IR 05000348/2012004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Farley) @ 2012Q3
Self-Identified List (Farley)
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