ENS 49800
ENS Event | |
|---|---|
13:18 Dec 11, 2013 | |
| Title | Invalid Actuation of Primary Containment Isolation System (Pcis) Valves During I&C Maintenance |
| Event Description | This 60-day report, as allowed by 10 CFR 50.73(a)(1 ), is being made per 10 CFR 50.73(a)(2)(iv)(A) to describe an unplanned, invalid closure of Unit 2 Primary Containment Isolation System (PCIS) valves.
On December 11, 2013, at 0818 EST, an instrument technician was adjusting the output voltage of the 'A' 120-volt Reactor Protection System (RPS) motor-generator (MG) set, which is the normal power supply for the 'A' RPS bus. As the adjustment potentiometer was being moved, output voltage momentarily dropped below the setpoint of an Electrical Protection Assembly (EPA) on the 'A' RPS bus. The EPA tripped and removed power from the 'A' RPS bus. Removing power from the RPS bus resulted in PCIS valves receiving a close signal. Affected valves or systems were a Reactor Water Sample valve, Main Steam Line Drain valves, Containment Atmospheric Control System valves, Drywell Equipment Drain and Floor Drain valves, and a Reactor Water Cleanup System valve. Other systems affected were Standby Gas Treatment, Control Room Emergency Ventilation, and Radiation Monitoring on Main Steam Lines, Main Stack, Reactor Building Vent, and Main Condenser. All actuations that resulted from the loss of power to RPS Bus 'A' were completed as expected. This event resulted from the attempt to adjust the voltage control potentiometer on the RPS MG set. When a technician attempted to adjust the potentiometer, the movement caused the RPS MG set to momentarily and unexpectedly experience a low voltage on the output, tripping the output breakers. Power was restored to the affected RPS bus by 0858 EST on December 11, 2013, and all affected systems were subsequently returned to service. Since no actual plant or process conditions existed which would have caused the various actuations described above, this event is being reported per 10 CFR 50.73(a)(1) as an invalid actuation. This issue has been entered into the site Corrective Action Program (CR 651284) for evaluation and implementation of further corrective actions. The NRC Resident Inspector has been informed of this notification. |
| Where | |
|---|---|
Brunswick  North Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1365.7 h56.904 days <br />8.129 weeks <br />1.871 months <br />) | |
| Opened: | Stephen W. Reed 11:00 Feb 6, 2014 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Feb 6, 2014 |
| 49800 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 569872024-01-02T04:33:0002 January 2024 04:33:00
[Table view]10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Containment Isolation Valves ENS 569882023-12-28T13:15:00028 December 2023 13:15:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Emergency Diesel Generators ENS 562872022-11-09T14:06:0009 November 2022 14:06:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Containment Isolation Valves ENS 561382022-08-06T10:28:0006 August 2022 10:28:00 10 CFR 50.73(a)(1), Submit an LER 60-DAY Optional Telephonic Notification of Invalid Actuation of Containment Isolation Valves ENS 558592022-03-07T04:40:0007 March 2022 04:40:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation 60-DAY Telephone Notification ENS 557562022-01-04T18:16:0004 January 2022 18:16:00 10 CFR 50.73(a)(1), Submit an LER 60-DAY Optional Telephonic Notification for Invalid Actuation of Containment Isolation Valves ENS 551912021-02-17T19:07:00017 February 2021 19:07:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Containment Isolation Valves ENS 546752020-03-05T14:25:0005 March 2020 14:25:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Telephonic Notification of an Invalid Specified System Actuation ENS 541442019-05-10T00:00:00010 May 2019 00:00:00 10 CFR 50.73(a)(1), Submit an LER 60 Day Optional Notification Due to Actuation of an Emergency Diesel Generator ENS 527782017-04-06T16:12:0006 April 2017 16:12:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Emergency Diesel Generators ENS 520512016-05-09T10:26:0009 May 2016 10:26:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Primary Containment Isolation Valves (Pcivs) ENS 517392016-01-09T14:46:0009 January 2016 14:46:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Emergency Diesel Generator ENS 515052015-09-10T01:03:00010 September 2015 01:03:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of a General Containment Isolation Signal Affecting More than One System ENS 498002013-12-11T13:18:00011 December 2013 13:18:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Primary Containment Isolation System (Pcis) Valves During I&C Maintenance ENS 491682013-05-08T01:14:0008 May 2013 01:14:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Emergency Diesel Generators ENS 489722013-03-04T13:04:0004 March 2013 13:04:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Emergency Diesel Generators ENS 442132008-03-15T20:35:00015 March 2008 20:35:00 10 CFR 50.73(a)(1), Submit an LER Invalid Primary Containment Isolation System (Pcis) Actuation ENS 437912007-09-21T18:10:00021 September 2007 18:10:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Emergency Diesel Generators ENS 416922005-05-12T08:11:00012 May 2005 08:11:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.73(a)(1), Submit an LER Technical Specification Required Shutdown Due to Loss of Emergency Bus E1 ENS 413572004-12-13T21:15:00013 December 2004 21:15:00 10 CFR 50.73(a)(1), Submit an LER Invalid System Actuation ENS 405412004-01-11T11:37:00011 January 2004 11:37:00 10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation ENS 404962003-12-22T03:04:00022 December 2003 03:04:00 10 CFR 50.73(a)(1), Submit an LER Invalid Reactor Building Exhaust Radiation Monitor Signal Resulting in Pcis Isolations 2024-01-02T04:33:00 | |