ENS 42915
ENS Event | |
|---|---|
18:15 Oct 17, 2006 | |
| Title | Pressure Boundary Leakage Identified During an Outage |
| Event Description | On October 14th V.C. Summer Nuclear Station shut down for a routine refueling outage. At 1415 on October 17, 2006 during an inspection of the reactor vessel upper head, personnel identified a small leak in a weld in the Reactor Vessel Level Instrumentation System (RVLIS). This weld is located in a 3/4 inch stainless steel instrumentation line. The line is attached to, and is approximately three feet from the reactor vessel head. This leak resulted in a small amount of boron accumulation in an isolated area. There is no indication that any safety systems were affected.
The licensee notified the NRC Resident Inspector.
EN#42915 was submitted by South Carolina Electric & Gas Company based on the initial indication of a pressure boundary leak in the Reactor Vessel Level Instrumentation System (RVLIS). South Carolina Electric & Gas Company retracts EN#42915 based on the following discussion. During subsequent cleaning and inspection of the suspect weld, which was preserved in its as-found condition for root cause analysis, no flaw in the analyzed RVLIS piping or pipe coupling was found. Further investigation was conducted of the area under the Control Rod Drive Mechanism (CRDM) shroud near the RVLIS line. The source was determined to be leakage through the lower canopy seal weld of CRDM No. 25, which resulted in accumulation of boric acid on the suspect RVLIS line. Since the RVLIS line was not leaking and the CRDM canopy connection is a mechanical (screwed) fitting with a seal weld, there has been no pressure boundary leakage as defined by Technical Specifications. The canopy seal weld is neither a structural weld nor a pressure retaining weld comprising the reactor coolant system pressure boundary. A permanent plant design was developed and the canopy seal was repaired using a standard canopy seal clamping process. A 100 % bare metal visual inspection of the reactor vessel head was completed during this refueling outage. The results confirmed that there has been no degradation. The licensee will notify the NRC Resident Inspector. Notified the R2DO (Evans) |
| Where | |
|---|---|
Summer  South Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| Time - Person (Reporting Time:+-0.42 h-0.0175 days <br />-0.0025 weeks <br />-5.75316e-4 months <br />) | |
| Opened: | Robert Sweet 17:50 Oct 17, 2006 |
| NRC Officer: | Pete Snyder |
| Last Updated: | Nov 4, 2006 |
| 42915 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |
WEEKMONTHYEARENS 500442014-04-19T00:39:00019 April 2014 00:39:00
[Table view]10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition Due to Reactor Head Vessel Penetration Indications ENS 484352012-10-23T23:22:00023 October 2012 23:22:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition Due to Reactor Head Vessel Penetration Indications ENS 429152006-10-17T18:15:00017 October 2006 18:15:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Pressure Boundary Leakage Identified During an Outage ENS 406282004-03-30T16:29:00030 March 2004 16:29:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Automatic Reactor Trip Due to Lo-Lo Steam Generator Level ENS 402612003-10-20T11:00:00020 October 2003 11:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Rcs Through-Wall Leakage Found on Seal Injection Piping 2014-04-19T00:39:00 | |