ML24205A067

OEDO-24-00083 - 10 CFR 2.206 - FRN Diablo Canyon Units 1 and 2 Seismic Core Damage Frequency - (EPID L-2024-CRS-0000) - Federal Register Notice

ML24205A067
Person / Time
Site:	Diablo Canyon
Issue date:	08/27/2024
From:	Mike Franovich NRC/NRR/DORL/LPL2-2
To:
Lee S, 301-415-3158
Shared Package
ML24074A328	List: ML24162A079 ML24198A105 ML24205A066 ML24205A067 ML24218A164 ML24235A203
References
EPID L-2024-CRS-0000, OEDO-24-00083, NRC-2024-0148, 89FR71432
Download: ML24205A067 (5)

Text

[7590-01-P]

NUCLEAR REGULATORY COMMISSION

[Docket Nos. 50-275 and 50-323; NRC-2024-0148]

Pacific Gas & Electric Company; Diablo Canyon Power Plant, Unit Nos. 1 and 2; Petition AGENCY: Nuclear Regulatory Commission.

ACTION: 10 CFR 2.206 request; receipt.

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) is giving notice that by petition dated March 4, 2024, as supplemented on June 7, 2024, San Luis Obispo Mothers for Peace, Friends of the Earth, and Environmental Working Group (the petitioners) requested that the NRC exercise its supervisory authority to order the immediate closure of Diablo Canyon Nuclear Power Plant, Unit Nos. 1 and 2 (Diablo Canyon) due to the unacceptable risk of a seismically induced severe accident. The Commission referred the request to the enforcement petition process under NRC regulations. The petitioners request is included in the SUPPLEMENTARY INFORMATION section of this document.

DATES: September 3, 2024.

ADDRESSES: Please refer to Docket ID NRC-2024-0148 when contacting the NRC about the availability of information regarding this document. You may obtain publicly available information related to this document using any of the following methods:

Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2024-0148. Address questions about Docket IDs in Regulations.gov to Stacy Schumann; telephone: 301-415-0624; email:

2 Stacy.Schumann@nrc.gov. For technical questions, contact the individual listed in the For Further Information Contact section of this document.

NRCs Agencywide Documents Access and Management System (ADAMS): You may obtain publicly available documents online in the ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html. To begin the search, select Begin Web-based ADAMS Search. For problems with ADAMS, please contact the NRCs Public Document Room (PDR) reference staff at 1-800-397-4209, at 301-415-4737, or by email to PDR.Resource@nrc.gov. For the convenience of the reader, instructions about obtaining materials referenced in this document are provided in the Availability of Documents section.

NRCs PDR: The PDR, where you may examine and order copies of publicly available documents, is open by appointment. To make an appointment to visit the PDR, please send an email to PDR.Resource@nrc.gov or call 1-800-397-4209 or 301-415-4737, between 8 a.m. and 4 p.m. eastern time (ET), Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Perry Buckberg, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington DC 20555-0001; telephone: 301-415-1383; email: Perry.Buckberg@nrc.gov.

I. SUPPLEMENTARY INFORMATION:

On March 4, 2024, the petitioners filed a petition requesting that the NRC exercise its supervisory authority to order the immediate closure of Diablo Canyon due to the unacceptable risk of a seismically induced severe accident. An order was issued on March 12, 2024, referring the request to the enforcement petition process under section 2.206 of title 10 of the Code of Federal Regulations (10 CFR), Requests for action under this subpart.

3 The specific concerns expressed in the March 4, 2024, petition, as supplemented on June 7, 2024, now include:

1. Thrust faulting is neglected by Pacific Gas & Electric Companys (PG&Es) 2012 Seismic Source Characterization (SSC) model, because the model assumes that a majority of large earthquakes affecting Diablo Canyon are strike-slip and disregards the significant contribution of thrust faulting earthquake sources under the Diablo Canyon site and the adjacent Irish Hills. In addition, PG&E did not use a hanging-wall term for the modeling of potential ground motions from the Los Osos and San Luis Bay thrust faults.

2. The January 2024 magnitude 7.5 (moment magnitude) earthquake centered in the Noto Peninsula (Japan), with an average slip of 2 meters on the fault, is analogous to future potential thrust mechanism earthquakes beneath Diablo Canyon. Based on the slip rate of the Irish Hills adjacent to Diablo Canyon and the slip of the Noto earthquake, large thrust fault earthquakes will occur, on average, every 715 years near the Diablo Canyon site.

3. PG&Es 2012 SSC model does not account for an inferred offshore thrust fault that has a slip rate of 2.8 millimeters per year (mm/yr) and the potential for producing a magnitude 7.5 earthquake.

4. Seismic core damage frequency estimated by PG&E in 2018 to be 3x10-5, should be 1.4x10-3 per year (about once every 715 years) based on this higher recurrence rate for thrust earthquakes.

The NRC staff assembled a Petition Review Board (PRB) in accordance with NRC Management Directive (MD) 8.11, Review Process for 10 CFR 2.206 Petitions, and its associated Directive Handbook 8.11,Section III. In an email dated May 15, 2024, the petition manager informed the petitioners that the PRBs initial assessment was to

4 not accept the petition for review. The PRBs position was that the petition did not meet the criteria in MD 8.11 for accepting petitions under 10 CFR 2.206 because the issues raised have previously been the subject of a facility specific or generic NRC staff review and the petition does not provide significant new information that the staff did not consider in a prior review.

On May 15, 2024, along with the initial assessment, the petition manager offered the petitioners an opportunity to address the PRB in a public meeting, which was accepted by the petitioners.

The June 7, 2024, supplement to the petition responded to the PRBs initial assessment.

The NRC then held the public meeting on July 17, 2024. During the meeting, the petitioners presentation discussed and expounded on information from the supplement dated June 7, 2024, and included graphics to represent their position. The transcript of that meeting is considered a supplement to the petition.

Following the public meeting, the PRB met to consider what had been presented during the meeting. The PRB determined that the concerns as previously described in this notice, which were raised in the original petition and supplements, meet the criteria in MD 8.11, Sections III.C.1(a) and (b) and will be accepted into the 10 CFR 2.206 process for further review by the PRB in accordance with MD 8.11. The PRB also determined that there is no imminent safety concern that warrants immediate shutdown of Diablo Canyon. On August 22, 2024, the petition manager informed the petitioners of this outcome.

II. Availability of Documents The documents identified in the following table are available to interested persons through ADAMS.

5 DOCUMENT DESCRIPTION ADAMS ACCESSION NO.

Petition submitted by San Luis Obispo Mothers for Peace, Friends of the Earth, and Environmental Working Group, dated March 4, 2024.

ML24067A066 NRC SECY Order referring the petition to the 10 CFR 2.206 process, dated March 12, 2024.

ML24072A529 Petition Supplement, dated June 7, 2024. ML24162A079 NRC Management Directive 8.11, Review Process for 10 CFR 2.206 Petitions, dated March 1, 2019.

ML18296A043 Email from the NRC to the Petitioners re Diablo Canyon Seismic Core Damage 2.206 petition - Initial Assessment, dated May 15, 2024.

ML24136A162 July 17, 2024, Public Meeting Petitioner Presentation to the PRB.

ML24198A105 July 17, 2024, Public Meeting Official Transcript of Proceedings.

ML24218A164 Email from the NRC the Petitioners re Diablo Canyon Seismic Core Damage 2.206 petition - Accepted, dated August 22, 2024.

ML24235A203 Dated: August 27, 2024.

For the Nuclear Regulatory Commission.

/RA/

Michael X. Franovich, Acting Deputy Director, Office of Nuclear Reactor Regulation.