ENS 48209
ENS Event | |
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16:00 Aug 20, 2012 | |
Title | Minor Thru-Wall Leak at Weld in Safety Injection Suction Piping |
Event Description | While working In the vicinity of valve SI-3, the isolation valve between the Boric Acid Storage Tanks and the common Safety Injection (SI) pump suction piping header, plant staff discovered a thru-wall leak at the weld between the SI-3 valve body and the piping upstream of SI-3. Minor leakage (less than 1 drop per minute) was observed at the flaw location. Upon being informed of this condition, plant operators closed SI-3 at 1109 [CDT] to isolate the affected portion of the piping from the SI suction piping. The time period from when the leak was discovered until it was isolated from the SI piping was less than 10 minutes.
As part of the immediate operability determination, plant staff attempted to characterize the flaw to determine the degradation mechanism. Because the flaw could not be readily characterized, the common SI suction piping exposed to the leakage was considered to have been inoperable from the time of discovery until valve SI-3 was closed. This condition resulted in both Safety Injection Train A and Safety Injection Train B being inoperable per LCO 3.5.2, ECCS - Operating, Condition A, due to an inoperable common suction line. Since the flaw could not be readily characterized, required ECCS flow was conservatively deemed to not be available and LCO 3.0.3 was conservatively entered per Condition C of LCO 3.5.2 during this brief period (less than 10 minutes) until valve SI-3 was closed. This event is reportable under 10CFR50.72(b)(3)(ii)(B) as an unanalyzed condition that significantly degrades plant safety. Closing SI-3 restored both Safety Injection Train A and Safety Injection Train B to Operable status and LCO 3.0.3 was exited at 1109 CDT on 8/20/2012. The NRC Resident Inspector has been notified. |
Where | |
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Kewaunee ![]() Wisconsin (NRC Region 3) | |
Reporting | |
10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
LER: | 05000305/LER-2012-007 Regarding Minor Thru-Wall Leak at Weld in Safety Injection Suction Piping |
Time - Person (Reporting Time:+0.43 h0.0179 days <br />0.00256 weeks <br />5.89014e-4 months <br />) | |
Opened: | Mike Terry 16:26 Aug 20, 2012 |
NRC Officer: | John Knoke |
Last Updated: | Aug 20, 2012 |
48209 - NRC Website
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Unit 1 | |
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Reactor critical | Critical |
Scram | No |
Before | Power Operation (100 %) |
After | Power Operation (100 %) |