ENS Event | |
|---|---|
20:00 Apr 8, 2004 | |
| Title | Degraded Condition - Greater than One Percent of Steam Generator Tubes Defective |
| Event Description | On April 08, 2004, during the Unit 1 twelfth refueling outage (1R12), analysis of eddy current data on [Steam Generator] SG 1-4 indicated that greater than one percent of the total tubes inspected in SG 1-4 were defective. Approximately ninety (90) defective tubes in SG 1-4 were detected and are being plugged. Most of the pluggable indications are due to circumferential primary water stress corrosion cracking in the Rows 5 to 8 U-bend region. Results of the SG tube inspection fall into Category C-3, which requires a four-hour non-emergency report in accordance with Technical Specification (TS) Table 5.5.9-2 and 10 CFR 50.72(b)(3)(ii) (an 8-hour requirement replacing the former (b)(2)(iii)(C), 4-hour requirement).
An NRC teleconference in accordance with TS 5.6.10.d to report the results of the voltage-based repair criteria implemented for the tube support plate intersections is currently scheduled for Wednesday April 14, 2004, at 1300 EDT. A Special Report in accordance with TS 5.6.10.a and e will be submitted prior to returning Unit 1 to power operation. A Licensee Event Report in accordance with 10 CFR 50.73(a)(2)(v)(C) will be submitted within 60 days. The Licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
Diablo Canyon  California (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| Time - Person (Reporting Time:+-2.97 h-0.124 days <br />-0.0177 weeks <br />-0.00407 months <br />) | |
| Opened: | Anthony Chitwood 17:02 Apr 8, 2004 |
| NRC Officer: | Bill Gott |
| Last Updated: | Apr 8, 2004 |
| 40659 - NRC Website
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WEEKMONTHYEARENS 561762022-10-23T15:30:00023 October 2022 15:30:00
[Table view]10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Reactor Coolant System (RCS) Pressure Boundary Degradation ENS 425472006-05-03T09:14:0003 May 2006 09:14:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition ENS 421362005-11-11T20:00:00011 November 2005 20:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Report of Degraded Condition Due to Defective Steam Generator Tubes ENS 406892004-04-21T01:10:00021 April 2004 01:10:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition - Greater than One Percent of Steam Generator Tubes Defective ENS 406592004-04-08T20:00:0008 April 2004 20:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition - Greater than One Percent of Steam Generator Tubes Defective 2022-10-23T15:30:00 | |