ENS 52767
ENS Event | |
|---|---|
18:25 Mar 24, 2017 | |
| Title | Invalid System Actuation During Testing |
| Event Description | On March 24, 2017, at 1425 EDT, while performing Engineered Safeguards Actuation System (ESAS) quarterly High Pressure Injection/Low Pressure Injection Logic and Component testing, an unintended test signal was generated when a test switch was moved to the OFF position but went slightly past this position and engaged contacts for the Test no. 1 position. When examined, the test switch was found to be degraded which allowed the switch to move past the center position and engage the test no. 1 contacts. This resulted In a partial actuation of 'B'- train ESAS components. It also resulted in an injection to the reactor coolant system (RCS). The test signal was immediately removed by operators and the inadvertently started equipment secured.
The plant was operating at 100% power when the event occurred. There were no valid signals or plant conditions present to warrant the safety system actuation. The 'B' Emergency Diesel Generator rolled on air start but did not get up to full speed. Decay Heat Removal Pump 'B' started and the Decay Heat Removal Injection valve 4B opened, Make-Up Pump 'C' started, Make-Up Pump suction valve 14B opened, Make-Up pump discharge valves 16C and 16D opened, Spent Fuel Pump 1B tripped off, Air Handling Fan 18 tripped off and Air Handling Fan 1C trip tripped off. These components properly functioned from the inadvertent test signal and were secured prior to any adverse impact to plant operation. There was a small injection of borated water into the RCS. The plant remained stable at 100% power operation. Pursuant to 10 CFR 50.73(a)(1) the following information is provided as a sixty (60) day telephone notification to the NRC. This notification, reported under 50.73(a)(2)(iv)(A), is being provided in lieu of the submittal of a written LER to report a condition that resulted in an invalid partial actuation of the 'B' train of the Engineered Safeguards Actuation System (ESAS) as it was not part of a pre-planned sequence. 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:+1433.15 h59.715 days <br />8.531 weeks <br />1.963 months <br />) | |
| Opened: | Michael Hoffmaster 11:34 May 23, 2017 |
| NRC Officer: | Dong Park |
| Last Updated: | May 23, 2017 |
| 52767 - 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 | |