ENS 41629
ENS Event | |
|---|---|
07:00 Apr 23, 2005 | |
| Title | Discovered Two Axial Indications on Inside Diameter of Reactor Vessel Head Penetration |
| 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 will be made via the ENS or under the reporting requirements of 10CFR50.73.
On April 23, 2005, at approximately 11:35 Mountain Standard Time (MST) engineering personnel performing preplanned in-service examinations of reactor vessel head vent penetration in accordance with procedure requirements discovered two axial indications in the Palo Verde Nuclear Generating Station Unit 2 reactor vessel head vent penetration. The indications are located on the inner diameter surface of the pipe adjacent to the J-weld to the head and are part of the RCS pressure boundary. The indications are characterized as axial, estimated less than 0.080 inch deep, approximately 0.1 inch long, and oriented at approximately 90 degrees from each other. The indications are not through-wall. There is no evidence of RCS pressure boundary leakage. Technical Specifications (TS) Limiting Condition for Operation (LCO) 3.4.14 permits no reactor coolant system (RCS) pressure boundary leakage and there is no evidence of pressure boundary leakage. Nevertheless, the indications are being conservatively identified as abnormal degradation of the reactor coolant system pressure boundary and will necessitate taking corrective action to restore the barrier's capability. Therefore, the ENS notification of this event is in accordance with 10CFR50.72(b)(3)(ii)(A). The Unit had been shutdown for its 12th refueling outage and was being maintained de-fueled for maintenance. No ESF actuations occurred and none were required. There were no structures, systems, or components that were inoperable at the time of discovery that contributed to this condition. There were no failures that rendered a train of a safety system inoperable and no failures of components with multiple functions were involved. The event did not result in the release of radioactivity to the environment and did not adversely affect the safe operation of the plant or health and safety of the public. An investigation of this event will be conducted in accordance with PVNGS corrective action program. The NRC Resident Inspector was notified of this event by the licensee. |
| Where | |
|---|---|
Palo Verde  Arizona (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| LER: | 05000529/LER-2005-001 |
| Time - Person (Reporting Time:+11.72 h0.488 days <br />0.0698 weeks <br />0.0161 months <br />) | |
| Opened: | John Aronson 18:43 Apr 23, 2005 |
| NRC Officer: | John Mackinnon |
| Last Updated: | Apr 23, 2005 |
| 41629 - NRC Website | |
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, Notification of failure to comply or existence of a defect and its evaluation, 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 | |