ML063250099

Summary of 11/6/2006 Meeting with Pacific Gas and Electric Company on Digital Upgrade Project

ML063250099
Person / Time
Site:	Diablo Canyon
Issue date:	01/29/2007
From:	Wang A NRC/NRR/ADRO/DORL/LPLIV
To:
Wang A, NRR/DORL/LPL4, 301-415-1445
Shared Package
ML063250103	List: ML063170445 ML063250099
References
TAC MD0386, TAC MD0387
Download: ML063250099 (5)

Text

January 29, 2007 LICENSEE Pacific Gas and Electric Company FACILITY: Diablo Canyon Power Plant, Unit Nos. 1 and 2

SUMMARY

OF NOVEMBER 6, 2006, MEETING WITH PACIFIC GAS AND ELECTRIC COMPANY ON DIGITAL UPGRADE PROJECT (TAC NOS. MD0386 AND MD0387)

On November 6, 2006, the U.S. Nuclear Regulatory Commission (NRC) staff conducted an open meeting with Pacific Gas and Electric Company (PG&E) to discuss a digital upgrade project for Diablo Canyon Power Plant, Units 1 and 2 (DCPP).

PG&E stated that this was the second meeting with the NRC staff to discuss its digital upgrade project for the DCPP. Based on NRC staff comments from the last meeting, PG&E had revised its design approach and schedule. PG&E wanted to keep the NRC informed of the progress and schedule it was pursuing in this effort. The NRC staff stated that the NRC encourages the industry to have such meetings to assure that the licensees expectations are achievable and that the licensee has the guidance to provide a quality product that the NRC staff can review in a timely manner. The Nrc staff also noted that no decisions about the scope or acceptability of the project would be made as a result of this meeting.

PG&E proposes to replace the legacy analog process protection system (combined reactor trip system (RTS) and engineered safety features actuation system (ESFAS)) with a solid-state protection system. In previous designs, PG&E proposed to combine the RTS and ESFAS in one digital module. The NRC staff did not approve of this design because a postulated digital common cause failure could disable the RTS and ESFAS functions concurrent with an FSAR Chapter 15 accident or event. To mitigate this issue, PG&E proposes a new design so that the RTS and ESFAS utilizes different processors. While these two safety functions will use different processors, PG&E will request to use the same platform for the control systems, the RTS, and the ESFAS. This will be a first-of-its-kind request by the industry. PG&E proposed a two-step approach where it would submit a plant-specific topical report that will provide an evaluation, for NRC approval, of the potential for a common design error that could disable redundant channels of the protection systems through a common-cause failure. Upon this approval, PG&E would submit a license amendment to implement the change referencing the topical report. PG&E wanted to know if the NRC staff felt that the proposed approach using a common platform and operating systems in multiple echelons violated regulations. The general understanding was that the approach could be reviewed and approved. However, the NRC staff stated this would be a very complicated review and completion on the proposed schedule would be highly dependent on the thoroughness of the licensees submittal. The licensee proposed to submit the topical report in early 2007 with the amendment application to follow in 2008. The NRC staff stated that a detailed design in the topical report will enhance the review process. The NRC staff stated that when PG&E was prepared to issue the topical report, a kick-off meeting would be beneficial.

The NRC staff thanked the licensee for the presentation and agreed that a follow-up meeting would be appropriate. A list of attendees is enclosed. The licensee presented information and the non-proprietary presentation slides are available in the Agencywide Documents Access and Management System under Accession Number ML063170445.

Please direct any inquiries to me at 301-415-1445, or abw@nrc.gov.

/RA/

Alan B. Wang, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Licensing Docket Nos. 50-275 and 50-323

Enclosure:

List of Attendees cc w/encl: See next page

Pkg ML063250103 (Summary/Attendees ML063250099, Handouts ML063170445)

OFFICE NRR/LPL4/PM NRR/LPL4/LA ADES/EICB/BC NRR/LPL4/BC NAME AWang LFeizollahi AHowe - HCG for AH DTerao DATE 12/1/07 12/6/07 1/26/07 1/29/07 MEETING WITH PACIFIC GAS AND ELECTRIC (PG&E)

LIST OF ATTENDEES November 6, 2006 PG&E Westinghouse INVENSYS Altran, et al. NRC K. Schrader L. Erin J. Murray J. Hefler A. Howe E. Quinn J. Mauck W. Kemper S. Patterson K. Keithline A. Wang M. Waterman P. Loeser D. Zhang M. Chiramal

Diablo Canyon Power Plant, Units 1 and 2 cc:

NRC Resident Inspector Antonio Fernández, Esq.

Diablo Canyon Power Plant Pacific Gas & Electric Company c/o U.S. Nuclear Regulatory Commission P.O. Box 7442 P.O. Box 369 San Francisco, CA 94120 Avila Beach, CA 93424 City Editor Sierra Club San Lucia Chapter The Tribune ATTN: Andrew Christie 3825 South Higuera Street P.O. Box 15755 P.O. Box 112 San Luis Obispo, CA 93406 San Luis Obispo, CA 93406-0112 Ms. Nancy Culver Director, Radiologic Health Branch San Luis Obispo State Department of Health Services Mothers for Peace P.O. Box 997414, MS 7610 P.O. Box 164 Sacramento, CA 95899-7414 Pismo Beach, CA 93448 Mr. James D. Boyd, Commissioner Chairman California Energy Commission San Luis Obispo County 1516 Ninth Street (MS 31)

Board of Supervisors Sacramento, CA 95814 1055 Monterey Street, Suite D430 San Luis Obispo, CA 93408 Mr. James R. Becker, Vice President Diablo Canyon Operations Mr. Truman Burns and Station Director Mr. Robert Kinosian Diablo Canyon Power Plant California Public Utilities Commission P.O. Box 56 505 Van Ness, Room 4102 Avila Beach, CA 93424 San Francisco, CA 94102 Jennifer Tang Diablo Canyon Independent Safety Field Representative Committee United States Senator Barbara Boxer ATTN: Robert R. Wellington, Esq. 1700 Montgomery Street, Suite 240 Legal Counsel San Francisco, CA 94111 857 Cass Street, Suite D Monterey, CA 93940 Mr. John S. Keenan Senior Vice President - Generation Regional Administrator, Region IV and Chief Nuclear Officer U.S. Nuclear Regulatory Commission Pacific Gas and Electric Company Harris Tower & Pavillion Diablo Canyon Power Plant 611 Ryan Plaza Drive, Suite 400 P.O. Box 770000, Mail Code B32 Arlington, TX 76011-8064 San Francisco, CA 94177-0001 January 2007