IR 05000032/2006005

Errata for Diablo Canyon Power Plant - NRC Inspection Report 05000275-06-005; 0500032-06-005 and 07200026-06-002

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, 2007

SUBJECT:

DIABLO CANYON POWER PLANT - NRC INTEGRATED INSPECTION REPORT 05000275/2006005; 05000323/2006005 AND 07200026/2006002

Dear Mr. Keenan:

On December 31, 2006, the U.S. Nuclear Regulatory Commission completed an inspection at your Diablo Canyon Power Plant, Units 1 and 2, facility. The enclosed integrated report documents the inspection findings that were discussed on January 10, 2007, with Ms. Donna Jacobs and members of your staff.

This inspection examined activities conducted under your licenses as they relate to safety and compliance with the Commission's rules and regulations and with the conditions of your licenses. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel.

There were three NRC-identified findings and one self-revealing finding of very low safety significance (Green) identified in this report. These findings involved violations of NRC requirements. However, because of their very low risk significance and because they are entered into your corrective action program, the NRC is treating these four findings as noncited violations (NCVs) consistent with Section VI.A of the NRC Enforcement Policy. If you contest any NCV in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, U.S. Nuclear Regulatory Commission, Region IV, 611 Ryan Plaza Drive, Suite 400, Arlington, Texas 76011-4005; the Director, Office of Enforcement, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; and the NRC Resident Inspector at the Diablo Canyon Power Plant.

Pacific Gas and Electric Company-2-In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and its enclosure will be available electronically for public inspection in the NRC Public Document Room 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, Chief Project Branch B Division of Reactor Projects Dockets: 50-275 50-323 72-026 Licenses: DPR-80 DPR-82 SNM-2511

Enclosure:

NRC Inspection Report 05000275/2006005; 05000323/2006005 and 0700026/2006002 w/attachment: Supplemental Information

REGION IV==

Dockets:

50-275, 50-323,72-026 Licenses:

DPR-80, DPR-82, SNM-2511 Report:

05000275/2006005 05000323/2006005 07200026/2006002 Licensee:

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, California Dates:

October 1 through December 31, 2006 Inspectors:

T. Jackson, Senior Resident Inspector T. 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 Inspector Approved By:

V. G. Gaddy, Chief, Projects Branch B Division of Reactor Projects

Enclosure-3-SUMMARY OF FINDINGS IR 05000275/2006005, 05000323/2006005; 07200026/2006002; 10/1/06 - 12/31/06; Diablo Canyon 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-based health 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 their color (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 NRCs 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 Findings Cornerstone: 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 adequate design 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 Companys corrective action program as Nonconformance Report N0002211.

The finding is greater than minor because it is associated with the Initiating Events Cornerstone 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 and resolution 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).