ML15364A530
| ML15364A530 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 01/28/2016 |
| From: | Nicholas Difrancesco Japan Lessons-Learned Division |
| To: | Halpin E Pacific Gas & Electric Co |
| DiFrancesco, Nicholas NRR/JLD 415-1115 | |
| References | |
| CAC MF5275, CAC MF5276 | |
| Download: ML15364A530 (3) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Edward D. Halpin Senior Vice President and Chief Nuclear Officer Pacific Gas and Electric Company P.O. Box 56 Mail Code 104/6 Avila Beach, CA 93424 January 28, 2016
SUBJECT:
DIABLO CANYON POWER PLANT, UNIT NOS. 1AND2-PRELIMINARY ASSESSMENT OF THE REEVALUATED SESIMIC HAZARD SUBMITTED IN RESPONSE TO TITLE 10 OF THE CODE OF FEDERAL REGULATIONS 50.54(f) INFORMATION REQUEST (CAC NOS. MF5275 AND MF5276)
Dear Mr. Halpin:
The purpose of this letter is to inform Pacific Gas and Electric Company (PG&E, the licensee) of the U.S. Nuclear Regulatory Commission's (NRC) preliminary results of the review of the reevaluated seismic hazard information, submitted in March 2015 for Diablo Canyon Power Plant, Unit Nos. 1 and 2 (DCPP). As explained below, the reevaluated seismic hazard information submitted in March 2015, as updated, is suitable for use in the development of a seismic probabilistic risk assessment (SPRA) for DCPP.
BACKGROUND On March 12, 20121, the NRC issued a request for information pursuant to Title 1 O of the Code of Federal Regulations, Part 50, Section 50.54(f) (hereafter referred to as the 50.54(f) letter).
The purpose of the 50.54(f) letter was to gather information concerning, in part, the seismic hazard at operating reactor sites to enable the NRC staff to determine whether licenses should be modified, suspended, or revoked. The "Required Response" section of Enclosure 1 indicated that licensees should provide a seismic hazard evaluation and screening report within 3 years for Western United States (WUS) plants. The 50.54(f) letter, following submittal of the reevaluated hazard, indicated that the NRC would identify sites where an SPRA is warranted to evaluate the impact of the reevaluated hazard. By letters2 dated March 11, 2015, August 12, 2015, September 16, 2015, December 2, 2015, and December 21, 2015, PG&E submitted for NRC review, its Seismic Hazard and Screening Report (SHSR) and supplemental information, in response to the 50.54(f) letter for DCPP.
PRELIMINARY ASSESMENT OF SEISMIC HAZARD The NRC staff has reviewed the areas that have the most significant impact on the results 1 The letter can be found under Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340.
2 The letters can be found under ADAMS Accession Nos. ML15071A046, ML152248575, ML15259A600, ML15349A874, and ML15362A569, respectively.
provided in DCPP's SHSR, including information discussed during a public meeting held on April 28, 2015,3 the licensee's supplements and responses to the NRC's request for additional information, and the results of regulatory audits4 on August 26 and 27, 2015, September 11, 2015, and December 3, 2015, to assess and review the licensee's seismic evaluation models for DCPP. Based on the NRC staff's review of the licensee's characterization of the seismic hazard for DCPP, the staff has no further questions at this time. The staff has determined that the reevaluated seismic hazard information, as documented in the SHSR, is of sufficient quality and suitable for use in the development of a SPRA for DCPP and in other assessments associated with Near-Term Task Force Recommendation 2.1 "Seismic."
NEXT STEPS This letter serves as preliminary feedback to the licensee concerning the NRC's review of the March 2015 SHSR and the suitability of the licensee's hazard characterization for use in the SPRA. Additional confirmatory sensitivity analyses are still in progress and if clarification is needed to complete its review, the NRC staff will notify the licensee. The NRC staff plans to issue a staff assessment documenting its review no later than September 2016. Consistent with a letter dated December 10, 20145, the NRC does not plan to re-review the seismic hazard as part of reviewing the SPRA unless significant modifications are made to the seismic hazard inputs following this staff acceptance.
By letters6 dated May 13, 2015, and October 27, 2015, the NRC staff determined that DCPP would need to submit a SPRA. The expected SPRA submittal date for DCPP is September 30, 2017. If you have any questions regarding this letter, please contact me at 301-415-1115 or via e-mail at Nicholas.DiFrancesco@nrc.gov.
Docket Nos. 50-275 and 50-323 cc: Distribution via ListseN Sincerely, Nicholas DiFrancesco, Senior reject Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation 3 The public meeting summary can be found under ADAMS Accession No. ML15125A186.
4 The audit reports can be found under ADAMS Accession Nos. ML15345A021 and ML15345A093, respectively.
5 The letter can be found under ADAMS Accession No. ML 1431 OA033.
6 The letter can be found under ADAMS Accession No. ML151138344 and ML15194A015, respectively.
ML15364A530 OFFICE NRR/JLD/JHMB/PM NRR/JLD/JHMB/LA NRO/DSEA/RGS2 NAME NDiFrancesco SLent MMcCoooin DATE 12/30/2015 1/05/2016 1/21/2016 OFFICE NRR/JLD/JHMB/BC OGC (NLO w/ comments)
NRR/JLD/JHMB/PM NAME MShams BHarris NDiFrancesco DATE 1/27/2016 1/14/2016 1/28/2016