ENS Event | |
|---|---|
23:01 Apr 30, 2012 | |
| Title | |
| Event Description | Grand Gulf Nuclear Station is currently in Mode 4 (less than 200 degrees F) executing Refueling Outage 18 (RF-18) including in-service inspections.
General Electric notified Entergy of a weld indication that was detected by automated ultrasonic testing. The indication is in the weld root area of N06B-KB Reactor Coolant System Pressure Boundary weld. The N06B nozzle connects Residual Heat Removal System 'C' to the Reactor Pressure Vessel. The dimension of the indication is approximately 0.9 inches in length, approximately 0.5 inches in depth and with no discernible width. Nominal wall thickness is 1.3 inches. The indication does not penetrate the entire thickness of the pipe wall and there is no leakage at the indication. There has been no release of radioactive material due to the indication. No systems were actuated due to this event. There are currently no other systems affected. The cause is under investigation and corrective action plans are being explored. The weld defect has been evaluated by Entergy Engineering and determined to meet the criteria for reporting identified in NUREG-1022: Welding or material defects in the primary coolant system that cannot be found acceptable under ASME Section XI, IWB-3600, 'Analytical Evaluation of Flaws,' or ASME Section XI, Table IWB-3410-1, 'Acceptable Standards'. The NRC Resident Inspector has been informed. |
| Where | |
|---|---|
Grand Gulf  Mississippi (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| Time - Person (Reporting Time:+-0.45 h-0.0188 days <br />-0.00268 weeks <br />-6.1641e-4 months <br />) | |
| Opened: | Leroy Purdy 22:34 Apr 30, 2012 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Apr 30, 2012 |
| 47880 - NRC Website
Loading map... | |
Unit 1 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |
WEEKMONTHYEARENS 533352018-04-13T17:08:00013 April 2018 17:08:00
[Table view]10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Two Cracks Identified at the Feed Water Line 'B' Containment Concrete Penetration ENS 478802012-04-30T23:01:00030 April 2012 23:01:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Weld Defect Indication Found in Residual Heat Removal System to Reactor Pressure Vessel Nozzle 2018-04-13T17:08:00 | |