ML17346A157

Residual Heat Removal Suction Weld Joint Flaw Evaluation

ML17346A157
Person / Time
Site:	Diablo Canyon
Issue date:	12/19/2017
From:	Balwant Singal Plant Licensing Branch IV
To:	Halpin E Pacific Gas & Electric Co
Singal B, 301-415-3016
References
CAC MF9711, EPID L-2017-LRO-0015
Download: ML17346A157 (3)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 December 19, 2017 Mr. Edward D. Halpin Senior Vice President, Generation and Chief Nuclear Officer Pacific Gas and Electric Company Diablo Canyon Power Plant P.O. Box 56, Mail Code 104/6 Avila Beach, CA 93424

SUBJECT:

DIABLO CANYON POWER PLANT, UNIT 2-RESIDUAL HEAT REMOVAL SUCTION WELD JOINT FLAW EVALUATION (CAC NO. MF9711; EPID L-2017-LR0-0015)

Dear Mr. Halpin:

By letter dated May 18, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML171388138), Pacific Gas and Electric Company (the licensee),

submitted a flaw evaluation of the Diablo Canyon Power Plant, Unit 2, residual heat removal suction weld joint, WIB-245. The submittal was made in accordance with paragraph IWB-3134(b) of the American Society of Mechanical Engineer's Boiler and Pressure Vessel Code,Section XI, 2001 Edition through 2003 Addenda, which states:

Analytical evaluation of examination results as required by IWB-3132.3 shall be submitted to the regulatory authority having jurisdiction at the plant site.

Typically, licensees provide these analyses to the U.S. Nuclear Regulatory Commission (NRC) as part of the lnservice Inspection Summary Report or the Owner's Activity Report. However, in this instance, the licensee identified the uniqueness of the indication in the subject stainless steel weld under certain degradation mechanism(s), and provided the flaw analysis separately by letter dated May 18, 2017. The NRC staff would like to acknowledge the attention to safety shown by the licensee in the formal submittal of this analysis. Further, the NRC staff did not identify any questions or concerns as a result of the review of the report.

Please note that the NRC staff utilized the information provided by the flaw evaluation report to support the review of the following relief requests and resulted in efficient use of the licensee and the NRC resources.

• Relief request submitted by letter dated May 18, 2017 (ADAMS Accession No. ML17139C628}, "Request for Approval of an Alternative to the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Section XI Examination Requirements for Class 1 and 2 Piping Welds."

E. Halpin

• Relief request submitted by letter dated September 26, 2017 (ADAMS Accession No. ML17269A220), "Request for Approval of Alternative for Application of Full Structural Weld Overlay, REP-RHR-SWOL, Units 1 and 2."

If you have any questions, please contact me at 301-415-3016 or via e-mail at Balwant.Singal@nrc.gov.

Sincerely, Bt?n~S~r*?i*;tager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-323 cc: Listserv

ML17346A157 OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL4/LA NRR/DMLR/MPHB/BC NAME BSingal PBlechman DAIiey (JTsao for)

DATE 12/19/17 12/19/17 12/19/17 OFFICE NRR/DORL/LPL4/BC NRR/DORL/LPL4/PM NAME RPascarelli BSingal DATE 12/19/17 12/19/17