ML15125A186

April 28, 2015, Summary of Category 1 Public Meeting with Pacific Gas and Electric Company to Discuss Diablo Canyon'S Seismic Hazard Reevaluation Associated with Implementation of Japan Lessons-Learned Near-Term Task Force Recommendation 2.

ML15125A186
Person / Time
Site:	Diablo Canyon
Issue date:	05/27/2015
From:	Nicholas Difrancesco Japan Lessons-Learned Division
To:
DiFrancesco N, NRR/JLD, 415-1115
References
Download: ML15125A186 (7)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 27, 2015 LICENSEE: Pacific Gas and Electric Company FACILITY: Diablo Canyon Power Plant, Unit Nos. 1 and 2

SUMMARY

OF APRIL 28, 2015, CATEGORY 1 PUBLIC MEETING WITH PACIFIC GAS AND ELECTRIC COMPANY TO DISCUSS DIABLO CANYON POWER PLANT, UNIT NOS. 1 AND 2 SEISMIC HAZARD REEVALUATION ASSOCIATED WITH IMPLEMENTATION OF JAPAN LESSONS-LEARNED NEAR-TERM TASK FORCE RECOMMENDATION 2.1, SEISMIC On April 28, 2015 1 , the U. S. Nuclear Regulatory Commission (NRC) staff held a Category 1 public meeting with the Pacific Gas and Electric Company (PG&E, the licensee) at NRC Headquarters, Two White Flint North, 11545 Rockville Pike, Rockville, Maryland. The purpose of this meeting was to discuss Diablo Canyon Power Plant, Unit Nos. 1 and 2 (Diablo Canyon)

Seismic Hazard Reevaluation 2 associated with the implementation of Near-Term Task Force (NTTF) Recommendation 2.1: Seismic of the March 12, 2012, NRC request for information issued pursuant to Title 10 to the Code of Federal Regulations Part 50, Section 50.54(f)

(hereafter referred to as the 50.54(f) letter) 3 .

During the meeting, the NRC staff provided an overview of NTTF Recommendation 2.1 "Seismic" including specifics of the review process as it relates to the Western United States (WUS) sites4 . Additionally, PG&E representatives provided an overview of Diablo Canyon's seismic hazard reevaluation which included specific discussions of several focus areas identified by the staff and conveyed to PG&E before the public meeting 5 .

NRC staff and PG&E representatives' discussions included the following meeting highlights:

• NRC staff presented an overview of NTTF Recommendation 2.1 "Seismic" review process which included specifics on how the process would be applied to the review of the WUS submittals.

• NRC staff provided the overall schedules for Recommendation 2.1 seismic hazard and risk evaluation activities. The staff stated that the screening and prioritization results letter for the WUS reviews would be issued by mid May 2015. Specifically, for Diablo Canyon, the plant has screened-in for further risk evaluation as a higher priority group.

Subsequently, by letter dated May 13, 2015 6 , NRC placed Diablo Canyon into the 1

The meeting notice is available via the Agencywide Documents Access and Management System (ADAMS) under Accession No. ML15105A528.

2 Diablo Canyon's Seismic Hazard Reevaluation is available via ADAMS under Accession No. ML15070A607.

3 The 50.54(f) letter and Enclosure 1 are available under ADAMS Accession Nos. ML12053A340 and ML12056A047, respectively.

4 NRC's slide presentation is available via ADAMS under Accession No. ML15117A226.

5 PG&Es slide presentation is available via ADAMS under Accession No. ML15117A069.

6 The screening and prioritization results for the WUS sites can be found via ADAMS under Accession No. ML151136344.

highest priority group (Group 1) for the reevaluated seismic hazard review along with 11 other reactor sites.

• The staff described the main differences between the Central and Eastern United States (CEUS) and WUS submittals. The staff emphasized the complexity of the WUS reviews and explained the reasons for anticipating that the WUS reviews may take longer to be completed than those for the CEUS.

• PG&E provided an overview of their seismic hazard reevaluation. Specifically, PG&E responded to a series of potential issues or focus areas that the staff had identified and conveyed to PG&E before the meeting 7 . These discussions helped the staff better understand PG&E approaches and added clarity to assist in the staff's review.

• PG&E provided additional clarification on Diablo Canyon's seismic design and licensing basis. Specifically, PG&E described their Long-Term Seismic Program margin assessment in order to demonstrate additional seismic margin and ensure plant safety while the updated risk evaluations are in progress.

• PG&E stated that they are moving forward with the seismic probabilistic risk assessment update and are currently coordinating with the Electric Power Research Institute to be one of the first licensees to complete these evaluations.

• The staff asked for clarifications in areas of the seismic reevaluation report where information appeared to be in conflict or incomplete.

• The staff indicated its plan to request from PG&E free field recordings for the Parkfield and San Simeon earthquakes used to develop the ground motion model. PG&E indicated that it will work with the staff to supplement the report with this information.

Requests for additional information by the staff are also expected.

• The staff is currently evaluating PG&E's intentions not to perform the Expedited Seismic Evaluation Process and will provide a formal response.

No regulatory decisions or commitments were made during the meeting. The public was invited to observe the meeting and was given an opportunity to communicate with the NRC during the public meeting before adjourning. The NRC staff received several public comments, which were addressed during the meeting and no meeting feedback forms were received.

The staff received a comment from Dr. Gene Nelson (Physical Sciences professor at Cuesta College and Government Liaison for Californians for Green Nuclear Power) via email during the meeting. The NRC staff inadvertently missed the opportunity to acknowledge Dr. Nelson's comment during the meeting. According to Dr. Nelson, Diablo Canyon has favorable site conditions, which attenuate or dissipate earthquake energy over relatively short distances. Due to these favorable conditions, the primary earthquake forces seen by the plant would be dominated by nearby earthquake sources and energy transmitted to the plant would be 7

NRG Technical Focus Areas for Support of Public Meeting on April 28 can be found via ADAMS under Accession No. ML151138360

dominated by the small section of the earthquake rupture closest to the plant. Dr. Nelson stated that when considering the information presented at the meeting of overall plant ruggedness and the seismic hazard insights discussed above, Diablo Canyon will continue to operate safely -

with generous safety margins - during anticipated earthquakes.

The staff received a comment via email from Rochelle Becker (Alliance for Nuclear Responsibility) after the meeting on May 12, 2015 8 . Mrs. Becker summarized several concerns identified by the California Public Utilities Commission's Independent Peer Review Panel (IPRP) and emphasized the need for the staff to consider this information as part of its review process.

The IPRP has expressed concerns regarding the modeling assumption used by PG&E to characterize soil conditions beneath the plant. In response to the comment, the staff stated that it is aware and following the IPRP activities and will consider this information as part of its review of the Diablo Canyon Seismic Hazard Screening Report supporting NTTF Recommendation 2.1: Seismic.

8 Rochelle Becker's (Alliance for Nuclear Responsibility) written concerns can be found via ADAMS under Accession No. ML15134A258

Please direct any inquiries to me at 301-415-1115 or by e-mail at Nicholas.DiFrancesco@nrc.gov.

Nicholas J. DiFran sco, Senior Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket Nos. 50-275 and 50-323

Enclosure:

List of Attendees cc w/encl: Distribution via Listserv

List of Attendees U.S. Nuclear Regulatory Commission Public Meeting with Pacific Gas and Electric Company to discuss Diablo Canyon's seismic hazard reevaluation associated with implementation of Japan Lessons-Learned Near-Term Task Force Recommendation 2.1, Seismic April 28, 2015 Name Organization Lisa Walsh NRC/NRO Clifford Munson NRC/NRO Diane Jackson NRC/NRO Scott Stoval NRG/RES Jon Ake NRG/RES Nicholas DiFrancesco NRC/NRR Mohamed Shams NRC/NRR Vladimir Graizer NRC/NRO Frankie Vega NRC/NRR Meralis Plaza Toledo NRC/NRO Thomas Weaver NRG/RES David Heeszel NRC/NRO Alice Stieve NRC/NRO Nilesh Chokshi NRC/NRO Mike Tschiltz NEI (continues to next page)

Abbreviations:

NEI - Nuclear Energy Institute NMSS - Nuclear Material Safety and Safeguards NRO - Office of New Reactors NRR - Office of Nuclear Reactor Regulation RES - Office of Nuclear Regulatory Research Enclosure

Name Organization Steve Wyman NRC/NRR Richard Rivera-Lugo NRC/NRO Siva P. Lingam NRC/NRR Meraj Rahimi NRC/NMSS Mike Markley NRC/NRR Tom Hipschman NRC/RIV Ryan Alexander NRC/RIV Wayne Walker NRC/RIV Tom Farnholtz NRC/RIV Farhanf Ostadan Bechtel Dennis Damon NRC/NMSS Damon Maslen Friends of the Earth Norm Abrahamson PG&E Nozar Jahangir PG&E Jearl Strickland PG&E Tom Jones PG&E

ML15125A186 *concurrence via e-mail OFFICE NRR/JLD/JHMB/PM NRR/JLD/LA NRO/DSEA/RGS/BC NAME FVega Slent DJackson DATE 05/15/15 05/05/15 05/19/15 OFFICE NRR/JLD/JHMB/BC OGG (NLO) NRR/JLD/PMB/PM NAME MS hams BHarris NDiFrancesco DATE 05/27/15 05/20/15 05/27/15