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 regar ding 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:

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 (P DR) 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.

2 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 faul ting 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

3 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 ex pounded 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.

4 DOCUMENT DESCRIPTION ADAMS ACCESSION NO.

Petition submitted by San Luis Obispo ML24067A066 Mothers for Peace, Friends of the Earth, and Environmental Working Group, dated March 4, 2024.

NRC SECY Order referring the petition to ML24072A529 the 10 CFR 2.206 process, dated March 12, 2024.

Petition Supplement, dated June 7, 2024. ML24162A079 NRC Management Directive 8.11, ML18296A043 Review Process for 10 CFR 2.206 Petitions, dated March 1, 2019.

Email from the NRC to the Petitioners re ML24136A162 Diablo Canyon Seismic Core Damage 2.206 petition - Initial Assessment, dated May 15, 2024.

July 17, 2024, Public Meeting Petitioner ML24198A105 Presentation to the PRB.

July 17, 2024, Public Meeting Official ML24218A164 Transcript of Proceedings.

Email from the NRC the Petitioners re ML24235A203 Diablo Canyon Seismic Core Damage 2.206 petition - Accepted, dated August 22, 2024.

Dated: August 27, 2024.

For the Nuclear Regulatory Commission.

/RA/

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

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