ENS 45737
ENS Event | |
|---|---|
12:30 Mar 2, 2010 | |
| Title | Pressurizer Safety Nozzle Weld Degradation |
| Event Description | A Unit-1 Pressurizer Safety Relief Valve Nozzle to Safe-end Weld, (#4SR-1006-1) was discovered to have an indication not acceptable under ASME Section XI, IWB-3600. The weld is on a 4 inch diameter line to the pressurizer safety relief valve (RV-201). The weld is in our dissimilar metal weld inspection program and was scheduled to be examined this RFO [refueling outage] in accordance with MRP-139 requirements. Initial inspections on 3/1/10 found an indication and the indication was confirmed by a second NDE level 3 examiner. Indication is circumferential, initiated at ID and propagates approximately 1.8 inches circumferentially to about approximately 70% through wall. ASME IWB-3500 allows up to 12.5% through wall for class 1 welds. The defect was found using phased array Ultrasonic Testing (UT). The NDE report is being reviewed and characterized at this time.
At this time, we believe the most probable cause of the indication is primary water stress corrosion cracking. No active leaks have been identified, the defect is not through wall. Unit 1 is in Mode 6. A team has been established and repair options are being investigated. The licensee notified the NRC Resident Inspector.
On March 7, 2010, manually indexed phased-array ultrasonic examination of the U1 Pressurizer Safety Relief Valve Nozzle to Safe-end Weld was performed. Based on these inspections, it was determined on March 13, 2010 that the indication does not exhibit stress corrosion cracking characteristics and is not consistent with ultrasonic responses associated with inside diameter (ID) connected geometry. Therefore, the U1 Pressurizer Safety Relief Valve Nozzle to Safe-end Weld is acceptable from an ASME Code Section XI perspective. On this basis, the indication did not result in the condition of the nuclear power plant, including its principal safety barriers, being seriously degraded and the issue is not reportable under 10 CFR 50.72(b)(3)(ii)(A). The NRC resident was notified of this retraction. Notified the R1DO (Chris Cahill) |
| Where | |
|---|---|
Calvert Cliffs  Maryland (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| Time - Person (Reporting Time:+-1 h-0.0417 days <br />-0.00595 weeks <br />-0.00137 months <br />) | |
| Opened: | Charles Morgan 11:30 Mar 2, 2010 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Mar 15, 2010 |
| 45737 - NRC Website | |
WEEKMONTHYEARENS 551222021-03-04T08:23:0004 March 2021 08:23:00
[Table view]10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Notification of Degraded Condition ENS 517472016-02-20T08:30:00020 February 2016 08:30:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition Discovered on Pressurizer Safety Relief Valve Weld ENS 503072014-07-25T03:15:00025 July 2014 03:15:00 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 Reactor Coolant System Pressure Boundary Leakage ENS 487632013-02-17T18:45:00017 February 2013 18:45:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Pressure Boundary Leakage Discovered During Containment Walkdown ENS 481242012-07-21T16:10:00021 July 2012 16:10:00 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 Instrument Line Leakage ENS 481162012-07-17T04:00:00017 July 2012 04:00:00 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 Small Rcs Pressure Boundary Instrument Line Leak ENS 473162011-10-03T14:35:0003 October 2011 14:35:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Technical Specification (Ts) Required Shutdown Due to Both 'A' Train Edg'S Inoperable ENS 466232011-02-18T05:51:00018 February 2011 05:51:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Inactive Leak Identified on Presurizer Heater Well ENS 457372010-03-02T12:30:0002 March 2010 12:30:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Pressurizer Safety Nozzle Weld Degradation ENS 457192010-02-23T20:12:00023 February 2010 20:12:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition - Weld Leak Due to Vibrating Valve Attachment Wire ENS 440062008-02-25T06:40:00025 February 2008 06:40:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition Due to Leakage on a Pressurizer Heater Sleeve ENS 414482005-02-27T20:00:00027 February 2005 20:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition of Reactor Coolant Boundary Weld ENS 414452005-02-26T20:30:00026 February 2005 20:30:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition of Reactor Coolant Boundary Weld 2021-03-04T08:23:00 | |