05000456/FIN-2009003-06
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Finding | |
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Title | Failure to Promptly Identify Bryozoa Infestation Caused 2A SX subsystem to be inoperable |
Description | The inspectors identified a Green NCV of 10 CFR 50, Appendix B, Criterion XVI, Corrective Action Program, associated with the licensee\'s failure to promptly identify that the 2A Essential Service Water (SX) subsystem was inoperable and hence, entry into Braidwood Improved Technical Specification (TS) 3.7.8, Essential Service Water (SX) System, Condition A was appropriate. Following the failure of the Unit 1A SX pump due to indications of discharge strainer fouling from Bryozoan infestation in the lake screenhouse the operators failed to properly evaluate possible common mode failures associated with the 2A SX subsystem. This resulted in an approximately 45 hour5.208333e-4 days <br />0.0125 hours <br />7.440476e-5 weeks <br />1.71225e-5 months <br /> delay in recognizing that the 2A SX subsystem was inoperable and therefore delayed actions to recover the subsystem. The licensee entered this performance deficiency into their corrective action program. The finding is greater than minor because the lack of prompt identification of the common failure affected the Mitigating Systems Cornerstone objective of ensuring the availability, capability and reliability of the Unit 1 and Unit 2 SX trains to respond to initiating events to prevent undesirable consequences. The finding is of very low safety significance because based on the results of an analysis performed by the licensee, which concluded that, even under severely degraded flow conditions, the affected trains of SX would have provided sufficient cooling to components served by the SX system following a reactor trip, a loss of coolant accident, or a loss of offsite power. The primary cause of the finding was related to the cross-cutting element of Human Performance and the associated attribute of decision making (H.1(b)). |
Site: | Braidwood ![]() |
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Report | IR 05000456/2009003 Section 4OA3 |
Date counted | Jun 30, 2009 (2009Q2) |
Type: | NCV: Green |
cornerstone | Mitigating Systems |
Identified by: | NRC identified |
Inspection Procedure: | IP 71153 |
Inspectors (proximate) | A Garmoe B Dickson M Holmberg M Mitchell M Perry M Thorpe Kavanaugh R Jones R Ng R Skokowski T Hartman |
CCA | H.14, Conservative Bias |
INPO aspect | DM.2 |
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Finding - Braidwood - IR 05000456/2009003 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Braidwood) @ 2009Q2
Self-Identified List (Braidwood)
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