ENS 45719
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ENS Event | |
|---|---|
20:12 Feb 23, 2010 | |
| Title | Degraded Condition - Weld Leak Due to Vibrating Valve Attachment Wire |
| Event Description | On 2/22/10, we determined that there was pressure boundary leakage on Unit 2 from the leak off line associated with a pressurizer spray valve (2-RC-220). The source of leakage associated with a boron deposit discovered earlier on 2/18/10. The boron deposit formed based on a leak in a Class 1 manual valve packing leak-off line. The leak location was determined to be in the packing leak-off pipe fillet weld to the stem retaining structure of the valve in the packing gland area. The valve (2-RC-220) is a Class 1 pressure boundary. The packing leak-off line is considered an auxiliary connection in the stem retaining structure of the valve.
At this time, we believe the most probable cause of the 2-RC-220 leak-off line socket weld leak was based on two factors, a small pore in the original socket weld metal and the location of a valve tag attachment wire. The leak location coincided with the location where a valve tag attachment wire laid across the weld. It is possible this wire, vibrating against the weld, opened up a subsurface pore in the weld metal which began to leak sometime after startup from the 2009 RFO [Refueling Outage] (March 2009). Since the failure may have occurred due to a material problem that resulted in abnormal degradation of a principal safety barrier (i.e., it is necessary to take corrective actions to restore the weld's integrity), this event is reportable pursuant to 10 CFR 50.72(b)(3)(ii)(A). The valve was overhauled in the 2009 RFO and subsequently passed VT-2 inspection. The overhaul did not include any welding on the affected joint. Unit 2 is in Mode 5 to allow repairs to be made to this weld. The licensee will notify the NRC Resident Inspector. |
| Where | |
|---|---|
Calvert Cliffs  Maryland (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| LER: | 05000318/LER-2010-002 |
| Time - Person (Reporting Time:+-3.23 h-0.135 days <br />-0.0192 weeks <br />-0.00442 months <br />) | |
| Opened: | Robert Martin 16:58 Feb 23, 2010 |
| NRC Officer: | Dan Livermore |
| Last Updated: | Feb 23, 2010 |
| 45719 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |
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 | |
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