ENS 47907
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ENS Event | |
|---|---|
20:04 Mar 13, 2012 | |
| Title | 60-Day Optional Report - Invalid Primary Containment Isolation System Actuation |
| Event Description | This 60-day report, as allowed by 10 CFR 50.73(a)(1), is being made under the reporting requirement in 10CFR50.73(a)(2)(iv)(A) to describe an unplanned, invalid actuation of specified systems, specifically the Unit 2 Primary Containment Isolation System (PCIS). On 3/13/12, at approximately 1604 hours0.0186 days <br />0.446 hours <br />0.00265 weeks <br />6.10322e-4 months <br />, Unit 2 experienced an invalid PCIS partial isolation. An equipment operator was in the process of making an adjustment to the Reactor Protection System (RPS) MG Set output voltage during daily rounds. As the rheostat was beginning to be rotated to increase the voltage, output voltage quickly dropped below the MG Set undervoltage trip setpoint. The BC757B and BC757D MG Set output breakers opened, resulting in the loss of the 2B RPS bus causing a half scram. The half scram signal resulted in closure of the instrument nitrogen primary containment isolation valve, secondary containment normal ventilation isolation valves and start of the 'B' Standby Gas Treatment supply fan.
The invalid PCIS isolation was a result of the failure of the voltage adjustment rheostat for the MG Set output voltage. This issue has been entered into the site Corrective Action Program (AR 1340452) for evaluation and implementation of further corrective actions. The NRC Resident Inspector has been informed of this notification. |
| Where | |
|---|---|
Peach Bottom  Pennsylvania (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1336.48 h55.687 days <br />7.955 weeks <br />1.831 months <br />) | |
| Opened: | Dan Dullum 12:33 May 8, 2012 |
| NRC Officer: | Donald Norwood |
| Last Updated: | May 8, 2012 |
| 47907 - NRC Website | |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 562802022-11-12T04:33:00012 November 2022 04:33:00
[Table view]10 CFR 50.73(a)(1), Submit an LER 60-DAY Telephonic Notification ENS 548202020-06-08T08:24:0008 June 2020 08:24:00 10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation ENS 529612017-07-14T18:53:00014 July 2017 18:53:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Containment Isolation Valves ENS 519622016-03-28T17:20:00028 March 2016 17:20:00 10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation ENS 500892014-03-09T21:13:0009 March 2014 21:13:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephonic Notification for an Invalid Actuation of an Emergency Service Water System ENS 479072012-03-13T20:04:00013 March 2012 20:04:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Report - Invalid Primary Containment Isolation System Actuation ENS 449402009-03-02T15:55:0002 March 2009 15:55:00 10 CFR 50.73(a)(1), Submit an LER Invalid Primary Containment Isolation Signal Due to Maintenance Error ENS 444652008-07-24T03:25:00024 July 2008 03:25:00 10 CFR 50.73(a)(1), Submit an LER Invalid System Actuation Due to Loss of One Offsite Power Circuit to Safety Buses ENS 439102007-12-11T21:45:00011 December 2007 21:45:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Notification of an Invalid Actuation of Units 2 and 3 Primary Containment Isolation Systems ENS 411932004-09-28T06:00:00028 September 2004 06:00:00 10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation Due to Bus Voltage Dip During Recirc Mg Start ENS 411922004-09-18T08:57:00018 September 2004 08:57:00 10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation Due to Off Site Power Source Fast Transfer ENS 408192004-04-25T05:05:00025 April 2004 05:05:00 10 CFR 50.73(a)(1), Submit an LER Invalid System Actuation ENS 401982003-09-25T04:00:00025 September 2003 04:00:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.73(a)(1), Submit an LER Initiation of a Technical Specification Required Shutdown at Peach Bottom 2 ENS 401042003-07-27T22:39:00027 July 2003 22:39:00 10 CFR 50.73(a)(1), Submit an LER 60 Day Optional Report 2022-11-12T04:33:00 | |
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