ML072420116

Evaluation of Finite Element Analysis in Support of Alloy 82/182 Pressurizer Butt Weld Inspections in 2008 as Provided by CAL NRR-07-007 (Tac MD4150)

ML072420116
Person / Time
Site:	Diablo Canyon
Issue date:	09/07/2007
From:	Catherine Haney NRC/NRR/ADRO/DORL/LPLIV
To:	Keenan J Pacific Gas & Electric Co
Wang, A B, NRR/DORL/LPLIV, 415-1445
References
TAC MD4150, NRR-07-007
Download: ML072420116 (4)

Text

September 7, 2007Mr. John S. KeenanSenior Vice President and Chief Nuclear Officer Pacific Gas and Electric Company Diablo Canyon Power Plant P.O. Box 770000, Mail Code B32 San Francisco, CA 94177-0001

SUBJECT:

DIABLO CANYON POWER PLANT, UNIT NO. 2 - EVALUATION OF FINITEELEMENT ANALYSIS IN SUPPORT OF ALLOY 82/182 PRESSURIZER BUTT WELD INSPECTIONS IN 2008 AS PROVIDED BY CONFIRMATORY ACTION LETTER NRR-07-003 (TAC NO. MD4150)

Dear Mr. Keenan:

On March 15, 2007, the U.S. Nuclear Regulatory Commission (NRC) issued ConfirmatoryAction Letter (CAL) No. NRR-07-003 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML070670425) regarding dissimilar metal welds in the pressurizer surge, spray, and safety/relief nozzle-to-safe end welds at Diablo Canyon Power Plant (DCPP), Unit No. 2. The CAL and the supporting commitment letter (ADAMS AccessionNo. ML070580128) indicate that inspection and mitigation actions may be conducted duringyour spring 2008 refueling outage, contingent on the industry providing an analysis thatdemonstrates an acceptable level of safety to the NRC for the operation of these welds untilspring 2008. This letter acknowledges receipt of your letter dated August 7, 2007 (ADAMS Accession No. ML072410199), informing the NRC that the analysis referred to by this CAL andthe supporting commitment letter has been completed, and that the analysis is applicable to your plant.The NRC received MRP-216, Rev. 1, "Materials Reliability Program: Advanced FEA [FiniteElement Analysis] Evaluation of Growth of Postulated Circumferential PWSCC [Primary Water Stress-Corrosion Cracking] Flaws in Pressurizer Nozzle Dissimilar Metal Welds," on August 13,2007 (ADAMS Accession No. ML072410235). Based on our review of this report, the NRC concludes that the analysis provides adequate justification to permit inspections during yourspring 2008 refueling outage, and that the analysis is applicable to DCPP, Unit No. 2. The results of the staff's review are contained in a safety assessment dated August 31, 2007(ADAMS Accession No. ML072400199), and the associated contractor report (ADAMS Accession No. ML072470394).Based on the above, the NRC concludes that a plant shutdown by December 31, 2007, is nolonger required. Therefore, the pressurizer surge, spray, and safety/relief nozzle-to-safe end Alloy 82/182 butt weld inspections for DCPP, Unit No. 2 must be performed prior to exiting your scheduled spring 2008 refueling outage. All other requirements of the CAL and the supporting commitment letter regarding enhanced inspection and leakage monitoring requirements for thereactor coolant system and associated reports remain valid.

J. S. Keenan-2-The CAL will remain open until all CAL commitments pertaining to DCPP, Unit No. 2 arecomplete. Current NRC guidance regarding CALs is contained in the NRC Enforcement Policy and theNRC Enforcement Manual, which are available at the NRC web site at http://www.nrc.gov/about-nrc/regulatory/enforcement.html (click on Enforcement Policy orEnforcement Guidance) or by contacting the Government Printing Office (GPO) toll-free at 1-888-293-6498. The GPO is open from 7:00 a.m. to 9:00 p.m. EST, Monday through Friday (except Federal holidays).In accordance with Section 2.390 of Title 10 of the Code of Federal Regulations, of the NRC's"Rules of Practice," a copy of this letter will be made available electronically for public inspection in the NRC Public Document Room or from the NRC's document system (ADAMS),

accessible from the NRC Web site at http://www.nrc.gov/reading-rm.html

.Sincerely,/RA/Catherine Haney, Director Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket No. 50-323 cc: See next page

ML072420116OFFICEDCI/CPNBDCI/CPNBLPL4/PMLPL4/LALPL4/BCNAMETLupoldTChanAwang, JND forJBurkhardtThiltz, BKS for DATE9/6/079/6/079/6/079/5/079/6/07 OFFICEDCI/DDRP/D, RGN4DORL/D NAMEMEvansDChamberlainCHaney DATE9/7/079/7/07 WJones for9/7/07 August 2007Diablo Canyon Power Plant, Units 1 and 2 cc:NRC Resident Inspector Diablo Canyon Power Plant c/o U.S. Nuclear Regulatory Commission P.O. Box 369 Avila Beach, CA 93424Sierra Club San Lucia ChapterATTN: Andrew Christie P.O. Box 15755 San Luis Obispo, CA 93406Ms. Nancy CulverSan Luis Obispo Mothers for Peace P.O. Box 164 Pismo Beach, CA 93448ChairmanSan Luis Obispo County Board of Supervisors 1055 Monterey Street, Suite D430 San Luis Obispo, CA 93408Mr. Truman BurnsMr. Robert Kinosian California Public Utilities Commission 505 Van Ness, Room 4102 San Francisco, CA 94102Diablo Canyon Independent Safety Committee Attn: Robert R. Wellington, Esq.

Legal Counsel 857 Cass Street, Suite D Monterey, CA 93940Regional Adminstrator, Region IVU.S. Nuclear Regulatory Commission Harris Tower & Pavillion 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064Jennifer Post, Esq.Pacific Gas & Electric Company P.O. Box 7442 San Francisco, CA 94120City EditorThe Tribune 3825 South Higuera Street P.O. Box 112 San Luis, Obispo, CA 94306-0112Director, Radiologic Health BranchState Department of Health Services P.O. Box 997414, MS 7610 Sacramento, CA 95899-7414Mr. James Boyd, CommissionerCalifornia Energy Commission 1516 Ninth Street MS (31)

Sacramento, CA 95831Mr. James R. Becker, Vice PresidentDiablo Canyon Operations and Station Director Diablo Canyon Power Plant P.O. Box 56 Avila Beach, CA 93424Jennifer TangField Representative United States Senator Barbara Boxer 1700 Montgomery Street, Suite 240 San Francisco, CA 94111Mr. John T. ConwaySite Vice President Diablo Canyon Power Plant P. O. Box 56 Avila Beach, California 93424