ENS 45324
ENS Event | |
|---|---|
06:38 Jul 10, 2009 | |
| Title | Electrical Short Circuit Resulted in Partial High Pressure Injection |
| Event Description | This event is being reported via a telephone notification to the NRC Operations Center within 60 days after discovery of the event instead of submitting a written LER. In this case, the telephone report is not considered an LER. This report is being made under 10 CFR 50.73(a)(2)(iv)(A).
During a maintenance activity to replace an Engineered Safeguards Actuation System (ESAS) relay, one of the two High Pressure Injection (HPI) valves (MU-V-16C) in the 'B' train partially opened. The HPI system consists of the 'A' and 'B' trains, with each train containing two HPI valves. The cause of the partial opening of the HPI valve was inadvertent contact with adjacent energized circuits during the replacement of the ESAS relay. This resulted in a momentary short circuit, which bypassed the normal actuation logic, causing the HPI valve to open approximately 0.17 inches before blowing the control power fuse that stopped the valve movement. The event resulted in the inadvertent transfer of approximately 1000 gallons of water from the Make-up Tank into the Reactor Coolant System (RCS), before the valve could be restored to the closed position. No other valves or components actuated as a result of the inadvertent short circuit. RCS volume and pressure were stabilized and returned to normal. The 'B' HPI train had been declared inoperable and the unit entered a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> LCO at 1:03 AM on 7/10/2009 due to configuration requirements needed for the planned ESAS relay replacement. The inadvertent partial 'B' train HPI did not impact the 'A' HPI train, and the unit remained at full power during this event. Following troubleshooting and replacement of the control power fuse, MU-V-16C was tested and restored to OPERABLE at 4:59 AM on 7/11/2009. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
Three Mile Island  Pennsylvania (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1322.43 h55.101 days <br />7.872 weeks <br />1.811 months <br />) | |
| Opened: | Adam Miller 09:04 Sep 3, 2009 |
| NRC Officer: | Dong Park |
| Last Updated: | Sep 3, 2009 |
| 45324 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 527672017-03-24T18:25:00024 March 2017 18:25:00
[Table view]10 CFR 50.73(a)(1), Submit an LER Invalid System Actuation During Testing ENS 516952015-12-02T02:19:0002 December 2015 02:19:00 10 CFR 50.73(a)(1), Submit an LER Invalid Emergency Feedwater Actuation ENS 453242009-07-10T06:38:00010 July 2009 06:38:00 10 CFR 50.73(a)(1), Submit an LER Electrical Short Circuit Resulted in Partial High Pressure Injection ENS 447152008-10-24T18:18:00024 October 2008 18:18:00 10 CFR 50.73(a)(1), Submit an LER Inadvertent Actuation of Engineered Safeguards System from Relay Sensing Circuit ENS 434982007-06-27T12:28:00027 June 2007 12:28:00 10 CFR 50.73(a)(1), Submit an LER Failed Relay Starts One Train of the Decay Heat River Water System 2017-03-24T18:25:00 | |