ENS 52049
ENS Event | |
|---|---|
14:55 Jun 28, 2016 | |
| Title | Both a & B Trains Hpi Inoperable Due to Void in Common Suction Line Resulting in Loss of Safety Function |
| Event Description | At 1055 [EDT] on 06/28/16 a gas void was found during the monthly surveillance inspection located in the common suction line to the High Pressure Injection / Makeup (HPI / MU) pumps. At 1150 on 06/28/16 the HPI suction line cross-connect valves were closed to isolate and separate the 'A' & 'B' Trains of HPI. The 'A' train of HPI was declared degraded and initiated a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> LCO [Limiting Condition of Operation] under TS [Technical Specification] 3.3.2. Investigation and analysis by Engineering determined that the size of the void did not meet the acceptance criteria for system operability. Due to the size of the void and location at time of discovery, both trains of HPI were determined to be inoperable until the suction cross connect valves were closed.
This condition is reportable under 10 CFR 50.72(b)(3)(v)(D) as a Condition That Could Have Prevented Fulfillment of a Safety Function to mitigate the consequences of an accident. The void is being vented to restore a water-solid condition. The last successful surveillance was conducted on 05/31/16. The cause of the void is being investigated. The NRC Resident Inspector has been informed.
Following the 8-hour 10 CFR 50.72 notification made on 06/28/16 (EN 52049), further engineering analysis determined that the as-found void size was insufficient to cause the high pressure injection pumps to become inoperable or unable to fulfill their safety function. The cause for the void continues to be under investigation including the development of actions to prevent recurrence. Void checks are being performed at an increased frequency until cause is determined, and actions to prevent recurrence are in place. As determined through analysis, both trains of HPl were operable and available such that the safety function was never lost. Therefore, this event notification is being retracted as it is not reportable pursuant to 10 CFR 50.72(b)(3)(v)(D). The licensee notified the NRC Resident Inspector. Notified R1DO (Dimitriadis). |
| Where | |
|---|---|
Three Mile Island  Pennsylvania (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+2.92 h0.122 days <br />0.0174 weeks <br />0.004 months <br />) | |
| Opened: | William Craddock 17:50 Jun 28, 2016 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Aug 22, 2016 |
| 52049 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Three Mile Island with 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
WEEKMONTHYEARENS 531062017-12-06T14:58:0006 December 2017 14:58:00
[Table view]10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Diesel Fuel Oil Tank Supply Non-Conforming with Licensing Basis for Tornado Generated Missiles ENS 520492016-06-28T14:55:00028 June 2016 14:55:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Both a & B Trains Hpi Inoperable Due to Void in Common Suction Line Resulting in Loss of Safety Function ENS 431392007-02-02T18:50:0002 February 2007 18:50:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Low Pressure Injection (Lpi) Net Positive Suction Head Flow Requirements Not Met for Certain Accident Sequences ENS 424752006-04-05T12:04:0005 April 2006 12:04:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Both Trains of High Pressure Injection (Hpi) Declared Inoperable Due to Potential Air Binding of Pumps ENS 414442005-02-16T01:55:00016 February 2005 01:55:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Possible Failure to Meet Design Basis Requirements of Positive Pressure in the Control Tower Envelope Following a Design Basis Accident. 2017-12-06T14:58:00 | |