IR 05000530/2010010

Followup of License Renewal Unresolved Item - Inspection Report 05000528; 05000529; 05000530-10-010

ML102180239
Person / Time
Site:	Palo Verde
Issue date:	08/05/2010
From:	O'Keefe N NRC/RGN-IV/DRS/EB-2
To:	Edington R Arizona Public Service Co
References
IR-10-010
Download: ML102180239 (10)

Text

UNITED STATES NUC LE AR RE G UL AT O RY C O M M I S S I O N ust 5, 2010

SUBJECT:

PALO VERDE NUCLEAR GENERATING STATION - FOLLOWUP OF LICENSE RENEWAL UNRESOLVED ITEM - INSPECTION REPORT 05000528; 05000529; 05000530/2010010

Dear Mr. Edington:

On July 29, 2010, the U.S. Nuclear Regulatory Commission (NRC) completed review of two unresolved items documented in Inspection Report 05000528; 05000529; 05000530/2010007.

These unresolved items related to concerns regarding whether your staff had accounted for industry operating experience related to metal-enclosed bus ducts and the frequency and scope of your structures monitoring program. The enclosed report documents the inspection findings which were discussed with Ms. A. Krainik, Project Manager, License Renewal, and other members of your staff.

This inspection examined activities related to your application for a renewed license for Palo Verde Nuclear Generating Station. The inspection evaluated the completion of baseline structural inspections and the frequency for performing these inspections. In addition, the inspection evaluated whether a recent failure of your metal-enclosed bus ducts should have resulted in a change to your aging management programs. As part of the inspection, the NRC examined procedures and representative records and interviewed personnel.

As a result of our review we have concluded that the accelerated reviews to identify the current condition of your structures and the changes that increased the frequency of monitoring of structures provided reasonable assurance that you had established processes that would manage the effects of aging of your structures. Further, we have concluded the failure of the metal enclosed bus ducts resulted in no required changes to your management programs.

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 component of NRCs document system (ADAMS). ADAMS

Arizona Public Service Company -2-is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).

Sincerely,

/RA/

Neil O'Keefe, Chief Engineering Branch 2 Division of Reactor Safety Dockets: 50-528; 50-529; 50-530 Licenses: NPF-41; NPF-51; NPF-74 NRC Inspection Report 50-528; 50-529; 50-530/2010010

w/Attachment:

Supplemental Information

REGION IV==

Docket: 05000528; 050000529; 05000530 License: NPF-41; NPF-51; NPF-74 Report: 05000528/2010010; 05000529/2010010; 05000530/2010010 Licensee: Arizona Public Service Company Facility: Palo Verde Nuclear Generating Station Location: 5951 S. Wintersburg Rd Tonopah, Arizona Dates: May 1 through July 29, 2010 Inspector: G. Pick, Senior Reactor Inspector Approved By: Neil O'Keefe, Chief Engineering Branch 2 Division of Reactor Safety-1- Enclosure

SUMMARY OF FINDINGS

IR 05000528/2010010; 05000529/2010010; 05000530/2010010; 05/01/2010 - 07/29/2010; Palo

Verde Nuclear Generating Station, Followup of License Renewal Unresolved Items The report covered a 3-month period of inoffice review and evaluation by a senior regional inspector.

Cornerstone: Mitigating Systems

No findings were identified.

Licensee-Identified Violations

No findings were identified.

REPORT DETAILS

4OA5 Other - License Renewal

.1 (Closed) Unresolved Item 05000528; 05000529; 05000530/2010007-01: Impact of

Recent Operating Experience on Metal-Enclosed Bus Program Subsequent to completing the onsite portion of the license renewal inspection, on March 7, 2010, Unit 1 tripped when a ground fault occurred on Bus 1E-NAN-A03 connecting the Nonclass 1E 13.8 kV Bus 1E-NAN-S01 to Breaker 1E-NAN-S03B.

Because of heavy rains, water intruded past the cover protecting the nonsegregated bus. The applicant preliminarily concluded the fault resulted from an improperly installed bus duct cover and a breakdown in the Noryl insulation because of aging mechanisms.

The applicant had not completed their evaluation of this event, which included the cause(s).

During this inspection, the inspector reviewed the laboratory evaluation report of the remaining portions of the bus duct and the applicants root cause evaluation report. The inspector interviewed the team leader and personnel responsible for the Metal-Enclosed Bus Aging Management Program.

The inspector concluded that the causes identified for the failure in this bus duct would not have changed the methods employed by the applicant to monitor for the effects of aging since aging was not a contributing cause of the fault. Further, from review of the root cause analysis report planned corrective actions, the inspector determined that the applicant had corrective maintenance work orders scheduled to be implemented during future refueling outages to replace the Noryl insulation.

This unresolved item is closed.

.2 (Closed) Unresolved Item 05000528; 05000529; 05000530/2010007-02: Structures

Monitoring Frequency and Scope During the onsite inspection, the license renewal inspection team had identified concerns related to the proposed inspection frequency and scope of the structures inspections. The applicant had not established an inspection program that reflected the frequencies specified in American Concrete Institute 349.3R-96, Evaluation of Existing Nuclear Safety-Related Concrete Structures, and NUREG-1801, Generic Aging Lessons Learned (GALL) Report - Tabulation of Results, Volume 2, Revision 1. These standards specified that structures exposed to the elements and those inside primary containment should be inspected every 5 years, and that other interior structures should be inspected every 10 years. In addition, the license renewal inspection team had

concerns because the applicant had not completed a 100 percent inspection of all structures to establish a baseline for comparison to future inspection results. The applicant documented these concerns in Condition Report Disposition Request 3441953.

In response to the teams concern, the applicant provided a supplemental response to Request for Additional Information B2.1.32-1, as documented in License Renewal Application Amendment 13, dated April 1, 2010. The applicant revised Commitment 34 in Table A.4-1, License Renewal Commitments, to state that prior to the period of extended operation, the Palo Verde Structures Monitoring program will be enhanced to inspect structures within the scope of license renewal at 10-year intervals. The team concluded that the applicant had provided an appropriate response for internal structures, excluding primary containment. However, the team continued to have concerns with the applicants assessment regarding external structures and structures inside containment and concerns with a lack of baseline inspection.

During this inspection, the inspector reviewed the applicants supplemental responses, reviewed corrective action documents and discussed plans for completing the baseline inspections with the applicant.

As reflected in Letter 102-06194, Responses to April 28, 2010, Request for Additional Information (RAI) and Follow-up RAIs, for the Review of the PVNGS [Palo Verde Nuclear Generating Station] License Renewal Application, and License Renewal Application Amendment No. 15, dated May 21, 2010, the applicant revised their structures monitoring program commitment to inspect external structures and those structures inside containment at 5-year intervals with the exception of a specific list of nonsafety-related structures. The inspector found this response satisfied the original concerns regarding the inspection frequency.

The inspector reviewed the applicants plans to complete the inspection and evaluation of their structures onsite prior to the period of extended operation. In Condition Report Disposition Request 3439970, the applicant established an action plan to inspect the remaining structures by the end of 2015. In addition, the applicant established a plan to complete a second 100 percent inspection of the onsite structures during the subsequent 10-year period that would end in 2025 prior to entry into the period of extended operation.

The inspector found that these corrective actions appropriately addressed the identified concerns.

This unresolved item is closed.

4OA6 Meetings

Exit Meeting Summary

On July 29, 2010, the inspector presented the results of the in-office inspection of the structural inspection program reviews to Ms. A. Krainik, Project Manager, License Renewal and other members of the applicants staff. The applicant acknowledged the issues presented. The inspector asked the licensee whether any materials examined during the inspection should be considered proprietary. No proprietary information was identified.

SUPPLEMENTAL INFORMATION

KEY POINTS OF CONTACT

Licensee Personnel

A. Krainik, Project Manager, License Renewal

F. Oreshack, Licensing Engineer

K. Schrecker, Section Leader

LIST OF ITEMS

CLOSED

Closed

05000528,

05000529, URI Impact of Recent Operating Experience on

05000530/2010007-01 Metal-Enclosed Bus Program (Section 4OA5.1)

05000528,

05000529, URI Structures Monitoring Frequency and Scope

05000530/2010007-02 (Section 4OA5.2)