ML110840459

Summary of Telephone Conference Calls Held on 2/28/11 and 3/17/11 Btw the USNRC and Pacific Gas and Electric Company Concerning RAIs Related to the Diablo Canyon Nuclear Power Plant, Units 1 and 2, LRA

ML110840459
Person / Time
Site:	Diablo Canyon
Issue date:	04/11/2011
From:	Ferrer N License Renewal Projects Branch 2
To:	Pacific Gas & Electric Co
Ferrer, N B, NRR/DLR, 415-1045
References
TAC ME2896, TAC ME2897
Download: ML110840459 (6)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 April 11, 2011 LICENSEE:

Pacific Gas and Electric Company FACILITY:

Diablo Canyon Nuclear Power Plant, Units 1 and 2

SUMMARY

OF TELEPHONE CONFERENCE CALLS HELD ON FEBRUARY 28 AND MARCH 17,2011, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND PACIFIC GAS AND ELECTRIC COMPANY CONCERNING REQUESTS FOR ADDITIONAL INFORMATION RELATED TO THE DIABLO CANYON NUCLEAR POWER PLANT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION (TAC NOS. ME2896 AND ME2897)

The U.S. Nuclear Regulatory Commission (NRC or the staff) and representatives of Pacific Gas and Electric Company (PG&E or the applicant) held telephone conference calls on February 28 and March 17, 2011, to obtain clarification on the applicant's response to requests for additional information (RAls) regarding the Diablo Canyon Nuclear Power Plant license renewal application.

By letters dated January 7 and 12, 2011, PG&E responded to RAls regarding the Flux Thimble Tube Program and Metal Fatigue. The subjects of these RAls are open items concerning the Diablo Canyon Nuclear Power Plant safety evaluation report. The staff requested a telephone conference call for clarification regarding the applicant's response. Enclosure 1 provides a listing of the participants. Enclosure 2 provides discussions on the RAls for which the staff requested clarification. The applicant will submit applicable supplements within 30 days of the issuance of this summary.

The applicant had an opportunity to comment on this summary.

~--

Nathaniel B. Ferrer, Project Manager Projects Branch 2 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-275 and 50-323

Enclosures:

As stated cc w/encls: Listserv

TELEPHONE CONFERENCE CALL DIABLO CANYON NUCLEAR POWER PLANT, UNITS 1 AND 2 LICENSE RENEWAL APPLICATION LIST OF PARTICIPANTS FEBRUARY 28 AND MARCH 17,2011 PARTICIPANTS:

Nate Ferrer Allen Hiser Jim Medoff Yogen Garud Terry Grebel Mike Wright Kyle Duke Kevin Braico Dan Hardesty Michelle Albright Brett Lynch Brandy Sizemore Dave Kunsemiller Chalmer Myer AFFILIATIONS:

U.S. Nuclear Regulatory Commission (NRC)

NRC NRC Argonne National Laboratory (contractor)

Pacific Gas and Electric Company (PG&E)

PG&E PG&E PG&E PG&E PG&E PG&E PG&E Strategic Teaming And Resource Sharing (STARS)

STARS ENCLOSURE 1

DIABLO CANYON NUCLEAR POWER PLANT, UNITS 1 AND 2 LICENSE RENEWAL APPLICATION REQUEST FOR ADDITIONAL INFORMATION FLUX THIMBLE TUBE INSPECTION PROGRAMITIME-LiMITED AGING ANALYSES RAI4.1-7 In a response dated January 12, 2011, the applicant submitted the cumulative usage factor calculation for the baffle and former bolts as a time-limited aging analysis (TLAA). The applicant dispositioned the TLAA in accordance with 10 CFR 54.4(c)(1)(iii), stating that it would manage fatigue of the components with the Reactor Vessel Internals Aging Management Program.

Discussion:

The response was not clear on how the inspection frequency for the baffle and former bolts would be determined and justified. The applicant agreed to supplement its response to clarify how it would validate the inspection frequency for the components.

RAI4.3-15 In a response dated January 7, 2011, the applicant committed to performing an evaluation to determine whether the NUREG/CR-6260-based components that have been evaluated for the effects of reactor coolant environment on fatigue usage are the limiting components. The applicant stated that if more limiting components are identified, then an evaluation will be performed in accordance with the Metal Fatigue of Reactor Coolant Pressure Boundary Program. In its response, the applicant also provided details discussing the assumed dissolved oxygen (DO) content for the derivation of environmentally-assisted fatigue factors. The applicant stated, in part, that for a pressurized-water reactor environment, the DO content is less than 0.05 ppm.

Discussion:

The response was unclear with regard to how nickel-alloy components would be evaluated, if they are determined to be one of the most limiting components. The staff noted that the applicant's Metal Fatigue of Reactor Coolant Pressure Boundary Program does not address nickel-alloy components. Additionally, the response did not specify whether the DO content at Diablo Canyon Nuclear Power Plant is less than 0.05 ppm. The applicant agreed to supplement its response to RAI4.3-15 to address the staff's concerns.

RAls 82.1.21-2 In a supplemental response dated January 12, 2011, the applicant submitted justification for why the acceptance criteria for its Flux Thimble Tube Program are adequate. The applicant provided additional details on its operating experience related to flux thimble tubes, and clarified how it accounts for measurement uncertainties. Additionally, the applicant provided justification ENCLOSURE 2

- 2 for why the program's wear projection methodology was conservative and why the program was adequate. Additionally, during a conference call held on February 4, 2011, the applicant agreed to make flux thimble tube wear data available for the staff to audit.

Discussion:

The staff agreed that acceptance criteria are adequate and that they account for measurement uncertainties. However, the staff could not determine, based on the wear data, whether the program's wear projection was conservative. The applicant agreed to supplement its response to address the staff's concern with respect to program's the wear projection methods.

April 11, 2011 LICENSEE:

Pacific Gas and Electric Company FACILITY:

Diablo Canyon Nuclear Power Plant, Units 1 and 2

SUMMARY

OF TELEPHONE CONFERENCE CALLS HELD ON FEBRUARY 28 AND MARCH 17, 2011, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND PACIFIC GAS AND ELECTRIC COMPANY CONCERNING REQUESTS FOR ADDITIONAL INFORMATION RELATED TO THE DIABLO CANYON NUCLEAR POWER PLANT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION (TAC NOS. ME2896 AND ME2897)

The U.S. Nuclear Regulatory Commission (NRC or the staff) and representatives of Pacific Gas and Electric Company (PG&E or the applicant) held telephone conference calls on February 28 and March 17, 2011, to obtain clarification on the applicant's response to requests for additional information (RAls) regarding the Diablo Canyon Nuclear Power Plant license renewal application.

By letters dated January 7 and 12, 2011, PG&E responded to RAls regarding the Flux Thimble Tube Program and Metal Fatigue. The subjects of these RAls are open items concerning the Diablo Canyon Nuclear Power Plant safety evaluation report. The staff requested a telephone conference call for clarification regarding the applicant's response. Enclosure 1 provides a listing of the participants. Enclosure 2 provides discussions on the RAls for which the staff requested clarification. The applicant will submit applicable supplements within 30 days of the issuance of this summary.

The applicant had an opportunity to comment on this summary.

IRA!

Nathaniel B. Ferrer, Project Manager Projects Branch 2 Division of License Renewa I Office of Nuclear Reactor Regulation Docket Nos. 50-275 and 50-323

Enclosures:

As stated cc w/encls: Listserv DISTRIBUTION:

See next page ADAMS Accession Number: ML110840459

• concurrence via e-mail OFFICE LA:DLR*

PM: RPB2:DLR BC:RPB2:DLR PM:RPB2:DLR NAME IKing NFerrer DWrona NFerrer DATE 3/28/2011 3/31/2011 4/05/2011 4/11/2011 OFFICIAL RECORD COpy

Memorandum to Pacific Gas and Electric Company from N. Ferrer dated April 11, 2011 SUB..IECT:

SUMMARY

OF TELEPHONE CONFERENCE CALLS HELD ON FEBRUARY 28 AND MARCH 17,2011, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND PACIFIC GAS AND ELECTRIC COMPANY CONCERNING REQUESTS FOR ADDITIONAL INFORMATION RELATED TO THE DIABLO CANYON NUCLEAR POWER PLANT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION (TAC NOS. ME2896 AND ME2897)

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