ENS 52261
ENS Event | |
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06:03 Sep 25, 2016 | |
Title | Actuation of Group 1 Isolation Signal |
Event Description | At 0103 CDT a Group 1 Isolation signal was received on Main Steam Line (MSL) A High Flow while attempting to un-isolate MSL A.
During plant cooldown for refueling outage, all inboard MSIV's were closed to minimize steam flow to control cooldown rate. With all inboard MSIV's closed and all outboard MSIV's open, MSL drains in-service, and reactor pressure at approximately 330 psig, an attempt was made to un-isolate MSL A by opening A inboard MSIV. This resulted in a MSL high flow signal on MSL A as the valve was being opened, resulting in a Group I Isolation and closure of all MSIV's and MSL Drain Valves. Pressure was equalized to less than 200 psid across MSIV A prior to attempting to open the valve in accordance with plant procedures. All valves actuated as expected and the cause of the event is under investigation. There are no indications of a leak. The Group I Isolation has been reset. The licensee notified the NRC Resident Inspector. |
Where | |
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Cooper Nebraska (NRC Region 4) | |
Reporting | |
10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
Time - Person (Reporting Time:+-1.67 h-0.0696 days <br />-0.00994 weeks <br />-0.00229 months <br />) | |
Opened: | Kyle Sayler 04:23 Sep 25, 2016 |
NRC Officer: | Donald Norwood |
Last Updated: | Sep 25, 2016 |
52261 - NRC Website
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Unit 1 | |
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Reactor critical | Not Critical |
Scram | No |
Before | Hot Shutdown (0 %) |
After | Hot Shutdown (0 %) |