ENS Event | |
|---|---|
04:33 Jan 2, 2024 | |
| Title | Invalid Actuation of Containment Isolation Valves |
| Event Description | The following information was provided by the licensee via phone and email:
This 60-day optional telephone notification is being made in lieu of a Licensee Event Report (LER) submittal as allowed by 10 CFR 50.73(a)(1). This notification is made pursuant to the reporting requirements specified in 10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation of one of the systems listed in 10 CFR 50.73(a)(2)(iv)(B). At approximately 2333 EST on January 1, 2024, an invalid actuation of group 6 primary containment isolation valves (PCIVs) (i.e., containment atmospheric control/monitoring (CAC/CAM) and post-accident sampling system (PASS) isolation valves) occurred. Reactor building ventilation isolated and standby gas treatment started per design. No manipulations associated with the isolation or reset logic were ongoing at the time. Troubleshooting determined that the group 6 isolation signal resulted from spurious relay contact actuation in the main stack radiation high-high isolation logic due to relay contact oxidation. The main stack radiation monitor is a shared component that sends isolation signals to Unit 1 and Unit 2. There were no Unit 1 actuations. Only the relay contacts associated with Unit 2 actuated. The relay has been replaced. The actuation was not initiated in response to actual plant conditions. It was not an intentional manual initiation and there were no parameters satisfying the requirements for initiation of the system. Therefore, this event has been determined to be an invalid actuation. During this event the PCIVs functioned successfully, and the actuations were complete. This event did not result in any adverse impact to the health and safety of the public. The NRC Resident Inspector had been notified. |
| Where | |
|---|---|
Brunswick  North Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | |
| Time - Person (Reporting Time:+1228.37 h51.182 days <br />7.312 weeks <br />1.683 months <br />) | |
| Opened: | Chris Denton 08:55 Feb 22, 2024 |
| NRC Officer: | Ernest West |
| Last Updated: | Feb 26, 2024 |
| 56987 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 574542024-12-04T21:40:0004 December 2024 21:40:00
[Table view]10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Inoperable ENS 569872024-01-02T04:33:0002 January 2024 04:33:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Invalid Actuation of Containment Isolation Valves ENS 528882017-08-04T19:11:0004 August 2017 19:11:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Inoperable Due to Opening in Service Water Piping ENS 500462014-04-20T06:15:00020 April 2014 06:15:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Loss of Secondary Containment Due to Opening in Reactor Building Roof Drain Piping ENS 499212014-03-17T11:50:00017 March 2014 11:50:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Airlock Door Interlock Malfunction ENS 499102014-03-13T13:37:00013 March 2014 13:37:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Apparent Secondary Containment Airlock Door Interlock Malfunction ENS 498802014-03-06T21:05:0006 March 2014 21:05:00 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Secondary Containment Airlock Door Interlock Malfunction 2024-12-04T21:40:00 | |