ML24205A066

OEDO-24-00083 - 10 CFR 2.206 - Ack Letter - Diablo Canyon Units 1 and 2 Seismic Core Damage Frequency -

ML24205A066
Person / Time
Site:	Diablo Canyon
Issue date:	08/27/2024
From:	Mike Franovich NRC/NRR/DORL/LPL2-2
To:	Curran D, Leary C, Templeton H Environmental Working Group, Friends of the Earth, Harmon, Curran, Harmon, Curran, Spielberg & Eisenberg, LLP
Lee S, 301-415-3158
Shared Package
ML24074A328	List: ML24162A079 ML24198A105 ML24205A066 ML24205A067 ML24218A164 ML24235A203
References
EPID L-2024-CRS-0000, OEDO-24-00083
Download: ML24205A066 (10)

Text

August 27, 2024

Diane Curran, Esq.

Harmon, Curran, Spielberg, & Eisenberg, LLP 1725 DeSales Street, NW, Suite 500 Washington, DC 20036

Hallie Templeton, Esq.

Friends of the Earth 1101 15th Street, 11th Floor Washington, DC 20005

Caroline Leary, Esq.

Environmental Working Group 1250 I St N.W.

Washington, DC 20005

SUBJECT:

2.206 PETITION REGARDING SEI SMIC CORE DAMAGE FREQUENCY FOR DIABLO CANYON NUCLEAR POWER PLANT, UNITS 1 AND 2 (EPID L-2024-CRS-0000)

Dear Diane Curran,

Hallie Templeton, and Caroline Leary:

On March 4, 2024, the San Luis Obispo Mothers for Peace, Friends of the Earth, and Environmental Working Group filed a petition requesting that the U.S. Nuclear Regulatory Commission (NRC) exercise its supervisory autho rity to order the immediate closure of Diablo Canyon Nuclear Power Plant, Units 1 and 2 (Diablo Canyon), due to the unacceptable risk of a seismically induced severe accident (Agencywide Documents Access and Management System Accession No. ML24067A066). On March 12, 2024 (ML24072A529), the request was referred to the enforcement petition process under Title 10 of the Code of Federal Regulations (10 CFR) 2.206, Requests for action under this subpart.

The specific concerns in the March 4, 2024, petition, as supplemented, include:

1. Thrust faulting is neglected by Pacific Gas & Electric Companys (PG&E) 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 D. Curran, et al.

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, dated March 1, 2019, and its associated Directive Handbook 8.11, section III (ML18296A043). In an email dated May 15, 2024 (ML24136A162), the petition manager informed you that the PRBs initial assessment was to not accept your 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 you an opportunity to address the PRB in a public meeting, which you accepted.

The June 7, 2024, supplement to the petition responded to the PRBs initial assessment (ML24162A079).

The NRC then held the public meeting on July 17, 2024. During the meeting, your presentation (ML24198A105) discussed and expounded on information from the supplement dated June 7, 2024, and included graphics to represent your position. The transcript of that meeting (ML24218A164) 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 described above, which you raised in your 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 (ML24235A203), the petition manager informed you of this outcome. As provided by 10 CFR 2.206, we will take action on your request within a reasonable time.

D. Curran, et al.

For your information, I have enclosed a copy of the draft Federal Register notice that acknowledges the receipt of the petition. In addition, MD 8.11, and the associated NRC Office of Nuclear Reactor Regulation brochure titled, Enforcement Petition Process, issued March 2019 can be found in ADAMS (ML18296A043 and ML19070A037, respectively). I would like to express my appreciation for your effort in bringing these matters to the NRCs attention.

Sincerely,

/RA/

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

Docket Nos. 50-275 and 50-323

Enclosure:

Federal Register Notice

ENCLOSURE

FEDERAL REGISTER NOTICE

[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: [INSERT DATE OF PUBLICATION IN THE FEDERAL REGISTER].

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:

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.nr c.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 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

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 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.

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.

5

ML24074A328 (Package)

ML24205A066 (Letter)

ML24205A067 (FRN) NRR-106 OFFICE NRR/DORL/LPL22/PM NRR/DORL/LPL22/LA NRR/DEX RES/DE/SGSEB NAME PBuckberg ABaxter CMunson TWeaver DATE 07/24/2024 07/25/24 07/30/2024 08/02/2024 OFFICE NRR/DRA/APLC NRR/DRA/APLC NRR/DORL/LPL4/PM OGC - NLO NAME SAlferink SPark SLee RCarpenter DATE 07/30/2024 07/30/2024 07/26/2024 08/07/2024 OFFICE NRR/DORL/LPL22/BC QTE/Tech. Editor NRR/DORL/DD NRR/D NAME DWrona JDougherty ARivera-Varona MFranovich DATE 08/07/2024 08/09/2024 08/13/2024 08/27/2024 OFFICE NRR/DORL/LPL22/PM NAME PBuckberg DATE 08/27/2024