ENS 51910
ENS Event | |
|---|---|
12:00 May 5, 2016 | |
| Title | High Pressure Safety Injection Valve Bonnet Leakage Identified During Refueling Outage |
| Event Description | The following event description is based on information currently available. If through subsequent reviews of this event additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via the ENS or under the reporting requirements of 10 CFR 50.73.
At 0500 MST on May 5, 2016, engineering personnel determined that leakage from the bonnet seal weld of the Train B High Pressure Safety Injection (HPSI) system loop 2A injection valve, SIBUV0616, constituted reactor coolant system pressure boundary leakage. This is being reported as a degradation of a principal safety barrier pursuant to 10 CFR 50.72(b)(3)(ii)(A). The leak was identified during a planned activity in which Operations was filling the refueling pool using HPSI pump B. Leakage was stopped when a plant operator closed SIBUV0616. PVNGS Unit 1 was shut down for its 19th refueling outage (1R19) on April 9, 2016, at 0000 MST and is in Mode 6. The NRC Resident Inspectors have been informed of this condition.
Subsequent engineering evaluation of the leak condition concluded the leakage from the bonnet seal weld of SIBUV0616 was not reportable reactor coolant system pressure boundary leakage. This conclusion was based on further reviews of the PVNGS licensing bases, ASME Code requirements, and design features of the valve with vendor assistance, which determined that the body-to-bonnet threads provide the structural support for the mechanical joint and the seal weld is not required for structural integrity of the component. Based on the above information, PVNGS has determined the leakage did not represent a degraded condition of a principal safety barrier as defined by 10 CFR 50.72(b)(3)(ii)(A) and Event Notification 51910 is hereby withdrawn. The NRC Resident Inspectors have been informed. Notified R4DO (Werner) |
| Where | |
|---|---|
Palo Verde  Arizona (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| Time - Person (Reporting Time:+3.65 h0.152 days <br />0.0217 weeks <br />0.005 months <br />) | |
| Opened: | David Heckman 15:39 May 5, 2016 |
| NRC Officer: | Bethany Cecere |
| Last Updated: | Jun 29, 2016 |
| 51910 - NRC Website
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WEEKMONTHYEARENS 567852023-10-09T22:07:0009 October 2023 22:07:00
[Table view]10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Reactor Coolant System Pressure Boundary Degraded ENS 523092016-10-20T01:30:00020 October 2016 01:30:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Safety Injection Piping Weld Flaw ENS 519102016-05-05T12:00:0005 May 2016 12:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded High Pressure Safety Injection Valve Bonnet Leakage Identified During Refueling Outage ENS 518612016-04-11T12:35:00011 April 2016 12:35:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Reactor Pressure Bounday Leakage ENS 509682015-04-08T10:30:0008 April 2015 10:30:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Reactor Coolant System Pressure Boundary Leakage Identified ENS 494162013-10-07T09:19:0007 October 2013 09:19:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Potential Reactor Coolant System Pressure Boundary Leakage Identified ENS 428862006-10-07T18:40:0007 October 2006 18:40:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Axial Indications Identified on Pressure Boundry ENS 417832005-06-17T18:00:00017 June 2005 18:00:00 10 CFR 21.21, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Potential Degraded Condition Due to Pressurizer Heater Element Non-Conformance ENS 416292005-04-23T07:00:00023 April 2005 07:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Discovered Two Axial Indications on Inside Diameter of Reactor Vessel Head Penetration ENS 405562004-02-29T07:00:00029 February 2004 07:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Boric Acid Residue Found on Pressurizer Heater Sleeve ENS 405032004-02-03T22:35:0003 February 2004 22:35:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Technical Specification Required Shutdown Due to Rcs Pressure Boundary Leakage ENS 397142003-03-29T11:00:00029 March 2003 11:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded 2023-10-09T22:07:00 | |