IR 05000032/2006005
| ML070940259 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon, 05000032  |
| Issue date: | 04/03/2007 |
| From: | Vincent Gaddy NRC/RGN-IV/DRP/RPB-B |
| To: | Keenan J Pacific Gas & Electric Co |
| References | |
| IR-06-002, IR-06-005 | |
| Download: ML070940259 (8) | |
Text
April 3, 2007John S. KeenanSenior Vice President - Generation and Chief Nuclear Officer Pacific Gas and Electric Company P.O. Box 770000 Mail Code B32 San Francisco, CA 94177-0001
Dear Mr. Keenan:
SUBJECT:ERRATA FOR DIABLO CANYON POWER PLANT - NRC INSPECTIONREPORT 05000275/2006005; 05000323/2006005 AND 07200026/2006002 Please insert the enclosed corrected pages of NRC Inspection Report 05000275/2006005;05000323/2006005, and 0700026/2006002. The subject inspection report included inspection related activities associated with the Diablo Canyon Independent Spent Fuel Storage Installation (ISFSI) project. NRC Inspection Report 07200026/2006002, used for inspection of the ISFSI, was not included with the originally issued inspection report. In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and itsenclosure will be available electronically for public inspection in the NRC Public DocumentRoom or from the Publicly Available Records (PARS) component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).
Sincerely,
/RA/
Vince G. Gaddy, ChiefProject Branch B Division of Reactor ProjectsDockets: 50-275 50-323 72-026Licenses: DPR-80 DPR-82 SNM-2511
Enclosure:
As stated Pacific Gas and Electric Company- 2 -
REGION IVDockets:50-275, 50-323,72-026 Licenses:DPR-80, DPR-82, SNM-2511 Report:05000275/200600505000323/2006005 07200026/2006002Licensee:Pacific Gas and Electric Company Facility:Diablo Canyon Power Plant, Units 1 and 2 Location:7 1/2 miles NW of Avila Beach Avila Beach, CaliforniaDates:October 1 through December 31, 2006 Inspectors:T. Jackson, Senior Resident InspectorT. McConnell, Resident Inspector M. Brown, Resident Inspector M. Peck, Senior Resident Inspector - Callaway Plant J. Dodson, Regional Operations Officer J. Drake, Operation Engineer P. Goldberg, Reactor Inspector R. Kellar, Health Physicist R. Lantz, Senior Emergency Preparedness InspectorApproved By:V. G. Gaddy, Chief, Projects Branch BDivision of Reactor Projects Enclosure-3-SUMMARY OF FINDINGSIR 05000275/2006005, 05000323/2006005; 07200026/2006002; 10/1/06 - 12/31/06; DiabloCanyon Power Plant Units 1 and 2; Maintenance Risk Assessments and Emergent Work Control, Problem Identification and Resolution, Operability Evaluations, and Other Activities.This report covered a 13-week period of inspection by resident inspectors and Region-basedhealth physics and reactor inspectors. Three NRC-identified violations and one self-revealing, Green, noncited violation were identified. The significance of most findings is indicated by theircolor (Green, White, Yellow, or Red) using Inspection Manual Chapter 0609 "Significance Determination Process." Findings for which the Significance Determination Process does not apply may be Green or be assigned a severity level after NRC management review. The NRC's program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, "Reactor Oversight Process," Revision 3, dated July 2000.A.NRC-Identified and Self-Revealing FindingsCornerstone: Initiating Events
- Green. A self-revealing, noncited violation of 10 CFR Part 50, Appendix B,Criterion III, "Design Control," was identified for the failure to apply adequatedesign control measures regarding the installation of thimble tubes with chrome-plated bands. Specifically, Pacific Gas and Electric Company installed thimble tubes with chrome-plated bands at the fuel assembly bottom nozzle/lower core plate interface to address flow-induced vibration wear. Due to the failure of engineering personnel to account for the chrome-plated bands in the thimble tube relocation procedure, the chrome-plated band on Thimble Tube L-13 was removed from its designed location at the fuel assembly bottom nozzle, thereby increasing the potential for thimble tube through-wall wear. This issue was entered into Pacific Gas and Electric Company's corrective action program as Nonconformance Report N0002211.The finding is greater than minor because it is associated with the Initiating EventsCornerstone attribute of design control and affects the associated cornerstone objective to limit the likelihood of those events that upset plant stability and challenge critical safety functions during shutdown as well as power operations.
Using the Inspection Manual Chapter 0609, "Significance Determination Process,"
Phase 1 Worksheet, the finding is determined to have very low safety significance because, assuming the worst-case degradation, the finding would not result in exceeding the Technical Specification limit for identified reactor coolant system leakage or affect mitigating systems. Specifically, the inspectors verified the worst-case leakage, i.e., guillotine break, from a thimble tube at the fuel assembly bottom nozzle/lower core plate interface to be approximately 7 gpm versus the Technical Specification reactor coolant system identified leakage limit of 10 gpm.
The finding has a crosscutting aspect in the area of problem identification andresolution associated with the corrective action program because Pacific Gas and Electric Company removed a corrective action to prevent recurrence of significant thimble tube wear (Section 4OA5.5).