ML16176A058

NRC Report for the Audit of Pacific Gas and Electric Company'S Flood Hazard Reevaluation Report Submittal Relating to the Near-Term Task Force Recommendation 2.1-Flooding for Diablo Canyon Power Plant, Unit Nos. 1 and 2 (CAC Nos. MF6039 and

ML16176A058
Person / Time
Site:	Diablo Canyon
Issue date:	12/01/2016
From:	Robert Bernardo Japan Lessons-Learned Division
To:	Halpin E Pacific Gas & Electric Co
References
CAC MF6039, CAC MF6040
Download: ML16176A058 (6)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 December 1, 2016 Mr. Edward D. Halpin Senior Vice President, Generation and Chief Nuclear Officer Pacific Gas and Electric Company P.O. Box 56 Mail Code 104/6 Avila Beach, CA 93424

SUBJECT:

NUCLEAR REGULATORY COMMISSION REPORT FOR THE AUDIT OF PACIFIC GAS AND ELECTRIC COMPANYS FLOOD HAZARD REEVALUATION REPORT SUBMITTAL RELATING TO THE NEAR-TERM TASK FORCE RECOMMENDATION 2.1-FLOODING FOR DIABLO CANYON POWER PLANT, UNIT NOS. 1 AND 2 (CAC NOS. MF6039 AND MF6040)

Dear Mr. Halpin:

By letter dated June 10, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15148A207), the U.S. Nuclear Regulatory Commission (NRC) informed you of the staffs plan to conduct a regulatory audit of Pacific Gas and Electric Companys (the licensees) Flood Hazard Reevaluation Report (FHRR) submittal related to the Near-Term Task Force Recommendation 2.1-Flooding for Diablo Canyon Power Plant, Unit Nos.1 and 2. The audit was intended to support the NRC staff review of the licensees FHRR and the subsequent issuance of a staff assessment.

The audit was conducted on March 17, 2016, and was performed consistent with NRC Office of Nuclear Reactor Regulation, Office Instruction LIC-111, Regulatory Audits, dated December 29, 2008 (ADAMS Accession No. ML082900195). The purpose of this letter is to provide you with the final audit report which summarizes and documents the NRCs regulatory audit of the licensees FHRR submittal.

E. Haplin If you have any questions, please contact me at (301) 415-2621 or by e-mail at Robert.Bernardo@nrc.gov.

Sincerely,

/RA/

Robert Bernardo, Project Manager Office of Nuclear Reactor Regulation Japan Lessons-Learned Division Hazards Management Branch Docket Nos. 50-275 and 50-323

Enclosure:

Audit Report cc w/encl: Distribution via Listserv

E. Haplin If you have any questions, please contact me at (301) 415-2621 or by e-mail at Robert.Bernardo@nrc.gov.

Sincerely,

/RA/

Robert Bernardo, Project Manager Office of Nuclear Reactor Regulation Japan Lessons-Learned Division Hazards Management Branch Docket Nos. 50-275 and 50-323

Enclosure:

Audit Report cc w/encl: Distribution via Listserv DISTRIBUTION:

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DATE 6/23/2016 6/24/2016 9/2/2016 11/28/2016 OFFICE NRO/DSEA/RHM1/BC NRR/JLD/JHMB/BC NRR/JLD/JHMB/PM NAME CCook* GBowman RBernardo DATE 11/28/2016 6/27/2016 12/1/2016 OFFICAL RECORD COPY

NUCLEAR REGULATORY COMMISSION AUDIT REPORT PACIFIC GAS AND ELECTRIC COMPANYS FLOOD HAZARD REEVALUATION REPORT SUBMITTALS RELATING TO THE NEAR-TERM TASK FORCE RECOMMENDATION 2.1-FLOODING FOR DIABLO CANYON POWER PLANT, UNIT NOS. 1 AND 2 BACKGROUND AND AUDIT BASIS By letter dated March 12, 2012, the U.S. Nuclear Regulatory Commission (NRC) issued a request for information to all power reactor licensees and holders of construction permits in active or deferred status, pursuant to Title 10 of the Code of Federal Regulations (10 CFR),

Section 0.54(f) Conditions of license (hereafter referred to as the 50.54(f) letter). The request was issued in connection with implementing lessons-learned from the 2011 accident at the Fukushima Dai-ichi nuclear power plant, as documented in the Near-Term Task Forces review of insights from the Fukushima Dai-ichi accident. Recommendation 2.1 in that document recommended that the NRC staff issue orders to all licensees to reevaluate seismic and flooding for their sites against current NRC requirements and guidance. Subsequent staff requirements memoranda associated with SECY-11-0124 and SECY-11-0137, instructed the NRC staff to issue requests for information to licensees pursuant to 10 CFR 50.54(f).

By letter dated March 11, 2015, Pacific Gas and Electric Companys (PG&E, the licensee) submitted its Flood Hazard Reevaluation Report (FHRR) Diablo Canyon Power Plant, Unit Nos. 1 and 2 (Diablo Canyon) (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15071A045). The NRC is in the process of reviewing the aforementioned submittal and has completed a regulatory audit of the licensee to better understand the development of the submittal, identify any similarities/differences with past work completed and ultimately aid in its review of the licensees FHRR. This audit summary is being completed in accordance with the guidance set forth in NRC Office of Nuclear Reactor Regulation, Office Instruction LIC-111, Regulatory Audits, dated December 29, 2008 (ADAMS Accession No. ML082900195).

AUDIT LOCATION AND DATES The audit was completed by document review via a webinar session in conjunction with the use of the licensees established electronic reading room and teleconference on March 17, 2016.

Enclosure

AUDIT TEAM The NRC audit team, and audit participants were as follows:

NRC AUDIT TEAM Organization Victor Hall, Team Leader NRR Kevin Quinlan, Technical Lead NRO Chris Cook NRO Hosung Ahn NRO Mike Lee NRO Aida Rivera-Varona NRO Michael Willingham NRO John Quinn, et. al. Argonne National Laboratories AUDIT PARTICIPANTS Organization Helene Finger PG&E Terence Grebel PG&E Hossein Hamzehee PG&E Mike McCoy PG&E Michelle Olsofsky PG&E Philippe Soenen PG&E DOCUMENTS AUDITED The documents reviewed by the NRC staff were located in an electronic reading room during the NRC staffs review. Documents used by the NRC staff to support the technical analysis will be referenced in the staff assessment.

AUDIT ACTIVITIES In response to the 50.54(f) request, the licensee submitted its FHRR for the Diablo Canyon site on March 11, 2015. Through the course of the staffs FHRR review, the staff identified a series of questions (information need requests) for the licensee. The staffs information need requests were discussed during the audit and are briefly summarized below.

LIP-Related Questions: In connection with the local intense precipitation (LIP) flood hazard analysis, the licensee notified the staff that it had identified one or more inconsistencies in the original 50.54(f) FHRR related to LIP and indicated its plans to resubmit the LIP analysis to the NRC staff. By letter dated February 8, 2016 (ADAMS Accession Nos. ML16039A366 and ML16039A367), the revised LIP analysis was provided to the staff, and included the submission of the applicable FLO-2D-related input/output files. The licensees re-submittal addressed the staffs LIP-related questions. A more detailed discussion of the staffs review and conclusion of the revised LIP analysis will be included in the staff assessment.

Current Design-Basis vs. Current Licensing Basis (CLB): In response to this particular information need request, the staff were advised by the licensee that the intent was to describe water surface elevations as CDB.

In light of this information, the NRC staff determined that no further action in this area was necessary.

Flood Event Duration Parameters: The licensees 50.54(f) response was expected to include flood event duration parameters (FEDs) needed to perform the additional assessment of plant response for flood hazards not bounded by the CDB. The licensee confirmed that they did not provide complete FED parameter values for LIP. The licensee is expected to develop FED parameter values and applicable flood-related associated effects, if needed, in order to conduct future additional assessments of plant response per Appendix G of Nuclear Energy Institute (NEI) guidance document NEI 12-06, Revision 2, Diverse and Flexible Coping Strategies (Flex)

Implementation Guide (ADAMS Accession No. ML16005A625), as discussed in COMSECY-15-0019, Closure Plan for the Reevaluation of Flooding Hazards for Operating Nuclear Power Plants (ADAMS Accession No. ML15153A104).

In light of these facts, the staff determined that no further action on this matter was necessary.

EXIT MEETING/BRIEFING By letter dated March 30, 2016, the NRC staff issued a summary of the reevaluated flood-causing mechanisms (ADAMS Accession No. ML16083A551). That letter concluded that the licensee's reevaluated flooding hazard information is a suitable input for assessments associated with Near-Term Task Force Recommendation 2.1 "Flooding," thus closing out the discussion of the technical topics described above.