05000400/FIN-2010005-07
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Finding | |
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Title | Licensee-Identified Violation |
Description | During Mode 4 operation, TS 3.5.3 requires that one complete train of Emergency Core Cooling System (ECCS) shall be operable. During Mode 3 operation, TS 3.5.2 requires that two complete trains of ECCS shall be operable. Additionally, TS 3.0.4 prohibits transitioning into a Mode when the licensee has not met all of the limiting conditions for operation when the TS action would require a shutdown. Contrary to these requirements, between November 9, 2010 and November 10, 2010, the licensee operated in Mode 4 and transitioned to Mode 3 with both trains of ECCS inoperable. The licensee determined that the root cause of this issue was an operating procedure which incorrectly directed the operator to remove control power to both of the Residual Heat Removal Header Isolation Valves which provided suction to the Charging Safety Injection Pump. As corrective action, the licensee restored control power to the affected valves and revised the procedure. The licensee determined that this issue was reportable and will issue a Licensee Event Report which will be addressed in a future inspection report. This issue was identified in the licensees CAP as AR 432567. A regional Senior Reactor Analyst evaluated the performance deficiency under the Phase 3 protocol of the Significance Determination Process. Based upon the results of that evaluation, the performance deficiency was characterized as of very low safety significance (Green). The NRC\'s most current Probabilistic Risk Assessment model for the Harris plant was used. The surrogates for the performance deficiency were basic events RHR-MOV-CC-25 and RHR-MOV-CC-26, i.e., the piggyback motor operated valves, which were set to always be closed for the evaluation. The resulting dominant accident sequence was a Small Break Loss of Coolant Accident with operators failing to depressurize the Reactor Coolant System allowing core cooling via low pressure recirculation and high pressure recirculation failing due to the performance deficiency. The major assumptions for the evaluation included a thirty six hour exposure time and no recovery credit from the performance deficiency. |
Site: | Harris |
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Report | IR 05000400/2010005 Section 4OA7 |
Date counted | Dec 31, 2010 (2010Q4) |
Type: | NCV: Green |
cornerstone | Mitigating Systems |
Identified by: | Licensee-identified |
Inspection Procedure: | |
Inspectors (proximate) | R Kellner A Nielsen J Rivera-Ortiz R Hamilton W Loo J Austin M Bates S Walker R Musser D Mas-Penaranda M Coursey P Lessard J Eargle N Childs |
INPO aspect | |
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Finding - Harris - IR 05000400/2010005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Harris) @ 2010Q4
Self-Identified List (Harris)
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