ML23122A236

Review of the Post-Shutdown Decommissioning Activities Report

ML23122A236
Person / Time
Site:	Diablo Canyon   (DPR-080, DPR-082)
Issue date:	06/20/2023
From:	Samson Lee Plant Licensing Branch IV
To:	Gerfen P Pacific Gas & Electric Co
Lee S, 301-415-3158
References
EPID L 2019-LRL-0004, EPID L-2019-LRL-0005, EPID L-2019-LRL-0006
Download: ML23122A236 (13)

Text

June 20, 2023 Ms. Paula Gerfen Senior Vice President, Generation and Chief Nuclear Officer Pacific Gas and Electric Company Diablo Canyon Power Plant P.O. Box 56, Mail Code 104/6 Avila Beach, CA 93424

SUBJECT:

DIABLO CANYON NUCLEAR POWER PLANT, UNITS 1 AND 2 - REVIEW OF POST-SHUTDOWN DECOMMISSIONING ACTIVITIES REPORT (EPID L-2019-LRL-0004, EPID L-2019-LRL-0005, AND EPID L-2019-LRL-0006)

Dear Ms. Gerfen:

On December 4, 2019, Pacific Gas and Electric Company (PG&E, the licensee) submitted to the U.S. Nuclear Regulatory Commission (NRC, the Commission) letters enclosing the post-shutdown decommissioning activities report (PSDAR), the site-specific decommissioning cost estimate (SSDCE), and the irradiated fuel management plan (IFMP) for the Diablo Canyon Nuclear Power Plant, Units 1 and 2 (Diablo Canyon). These submittals were made pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.82(a)(4)(i) in relation to the licensees intent to decommission Diablo Canyon in the future. The purpose of this letter is to inform you that the NRC staff has completed its review of the Diablo Canyon PSDAR, SSCDE, and IFMP and finds that these submittals contain the information required by 10 CFR 50.82(a)(4)(i) related to plans and costs for decommissioning the facility. The NRC staff also notes that, consistent with 10 CFR 50.82(a)(6), PG&E shall not perform any decommissioning activities that would result in significant impacts to cultural, historical, or archeological environmental resources without prior NRC review through a license amendment request.

Subsequent to its December 4, 2019, submissions, PG&E submitted a notification of changes to the Diablo Canyon PSDAR, SSDCE, and IFMP on October 19, 2021, in accordance with 10 CFR 50.82(a)(7) and 10 CFR 50.54(bb). The Diablo Canyon PSDAR, IFMP, and notification of changes are available in the NRCs Agencywide Documents Access and Management System (ADAMS) under Accession Nos. ML19338F173, ML19338F260, and ML21293A120, respectively. The publicly available version of the SSDCE is available in ADAMS at ML19345D344 and ML19345D345. The non-publicly available, proprietary version of the SSDCE is in ADAMS at ML19345D348. The PSDAR, including the SSDCE and IFMP, provides an overview of the planned activities, schedule, projected costs, and potential environmental impacts for the decommissioning of Diablo Canyon. PG&E selected the decontamination and dismantlement (DECON) method for decommissioning Diablo Canyon.

By letters dated October 12, 2022, PG&E submitted Revision 1 to the Diablo Canyon PSDAR, SSDCE, and IFMP. Revision 1 to the PSDAR and IFMP are available in ADAMS at ML22293A419 and ML22293A304, respectively. The publicly available version of Revision 1 to

the SSDCE is available in ADAMS at ML22293A405. The non-publicly available, proprietary version of Revision 1 to the SSDCE is in ADAMS at ML22293A406.

On November 27, 2018, PG&E notified the NRC that it would permanently cease power operations at Diablo Canyon upon the expiration of the facility operating licenses (ML18331A553). The facility operating license for Unit 1 expires on November 2, 2024, and the facility operating license for Unit 2 expires on August 26, 2025. Upon the docketing of the certifications for permanent cessation of operations and permanent removal of fuel from the reactor vessels for Diablo Canyon, in accordance with 10 CFR 50.82(a)(1)(i) and (ii), the 10 CFR Part 50 licenses will no longer authorize operation of the reactors or emplacement or retention of fuel in the reactor vessels in accordance with 10 CFR 50.82(a)(2). However, the NRC staff notes that, by letter dated October 31, 2022 (ML22304A691), the licensee requested that the NRC issue to the licensee an exemption, as is permitted by the NRCs regulations at 10 CFR 50.12, Specific exemptions, and 10 CFR 54.15, Specific exemptions, from the timely renewal requirement of 10 CFR 2.109(b). Specifically, the licensee requested this exemption such that if the licensee were to submit a license renewal application by December 31, 2023, then the licensee would still receive timely renewal protection under 10 CFR 2.109(b). By letter dated March 2, 2023 (ML23026A115), the NRC staff granted this exemption request. As of the date of this letter, no license renewal application has been submitted for Diablo Canyon.

The purposes of the Diablo Canyon PSDAR, including the SSDCE and IFMP, are to: (1) inform the public of the licensees planned decommissioning activities, (2) assist in the scheduling of NRC resources necessary for the appropriate oversight activities during decommissioning, (3) ensure that the licensee has considered all of the costs for the planned decommissioning activities and has considered the funding necessary for the decommissioning process, and (4) ensure that the environmental impacts of the planned decommissioning activities are bounded by those considered in existing environmental impact statements for the site.

Pursuant to 10 CFR 50.82(a)(4)(i), the PSDAR must contain a description of the planned decommissioning activities along with a schedule for their accomplishment, a discussion that provides the reasons for concluding that the environmental impacts associated with site-specific decommissioning activities will be bounded by appropriate previously issued environmental impact statements, and an SSDCE, including the projected cost of managing irradiated fuel.

Additionally, pursuant to 10 CFR 50.82(a)(3), decommissioning is to be completed within 60 years of permanent cessation of operations. The regulations do not require the NRC to approve a licensees PSDAR; rather, NRC approval is required later in the decommissioning process for a license termination plan in accordance with 10 CFR 50.82(a)(9)-(a)(10). The NRC staffs review of the PSDAR consists of determining if the PSDAR contains the information required by 10 CFR 50.82(a)(4)(i).

Consistent with 10 CFR 50.82(a)(4)(ii), the public was offered opportunities to comment on the Diablo Canyon PSDAR. An initial notice of receipt of the PSDAR was published in the Federal Register (FR) (85 FR 10200) on February 21, 2020. The NRC staff requested that all comments on the PSDAR be submitted by June 22, 2020. Additionally, pursuant to 10 CFR 50.82(a)(4)(ii),

the NRC staff had planned to hold a public meeting in the vicinity of Diablo Canyon on March 19, 2020, to discuss the PSDAR and to receive comments on it; however, this meeting was cancelled due to concerns regarding the coronavirus disease 2019 (COVID-19) public health emergency (85 FR 15505; March 18, 2020). No public comments were submitted.

By notice published in the Federal Register (87 FR 37533) on June 23, 2022, the NRC staff rescheduled the Diablo Canyon PSDAR public meeting for July 21, 2022, and requested that all comments on the PSDAR be submitted by October 19, 2022. The NRC staff held the public meeting at the San Luis Obispo County Government Building, 1055 Monterey Street, San Luis Obispo, California, on July 21, 2022, as planned. This was a hybrid meeting where attendees could participate in person or through a webinar. A summary of the public meeting is available in ADAMS at ML22238A345. Public questions and comments on the Diablo Canyon PSDAR and other matters related to the sites decommissioning are available for review in the transcript of the meeting (ML22238A346). Five public comments were submitted in response to the Federal Register notice and are available in ADAMS at ML22202A424, ML22203A045, ML22203A046, ML22208A010, and ML22228A164. Comments that were submitted electronically can also be viewed at www.regulations.gov by searching for Docket ID NRC-2022-0132.

Public comments from the July 21, 2022, meeting and in response to the June 23, 2022, Federal Register notice generally fell into two categories: (1) comments that are within the regulatory purview of the NRC staffs review of a PSDAR and (2) comments that, upon review, were found to be outside of the regulatory authority of the NRC or not relevant to the review performed by the NRC staff (i.e., whether the PSDAR contains the information required by 10 CFR 50.82(a)(4)(i)). Details of the specific questions or comments can be found in the documents referenced above.

The general topics of public comments potentially within the regulatory purview of the NRC staffs review of the PSDAR are summarized below:

Managing irradiated materials and debris.

Evolving decommissioning plan.

Protecting cultural resources at the site.

Shortening timeline to move spent fuel to dry cask storage.

Storing spent fuel and the robustness of casks.

Flooding and seismic risk to dry cask canisters.

Shipping decommissioning waste offsite by barge.

Transferring spent fuel to a permanent repository.

NRC inspections at Diablo Canyon during decommissioning.

The general topics of public comments that, upon review, were found to be outside of the NRCs regulatory purview or outside of the scope of the NRC staffs review of the Diablo Canyon PSDAR, as defined in 10 CFR 50.82(a)(4)(i), are summarized below:

Continuing operation and relicensing of Diablo Canyon.

Lowering the NRCs radiological criteria for unrestricted site release, which, in accordance with 10 CFR 20.1402, Radiological criteria for unrestricted use, are residual radioactivity that does not exceed 25 millirem per year, including from groundwater sources of drinking water, and that has been reduced to levels that are as low as reasonably achievable.

Effects on electric grid resilience and carbon emissions in California after Diablo Canyon is decommissioned.

San Onofre Nuclear Generating Station decommissioning activities.

Land use after decommissioning is completed.

The NRC staffs review process for a PSDAR does not require responding to comments.

However, the NRC staff identified a number of similar, potentially in-scope comments that pertained to the same topic. Generic responses related to some of the topics are provided below:

With respect to comments related to the Diablo Canyon independent spent fuel storage installation (ISFSI), the NRC staff notes that the NRC has authorized the storage of spent fuel at the ISFSI under the provisions of a site-specific license in accordance with the requirements in 10 CFR Part 72, Licensing Requirements for the Independent Storage of Spent Fuel, High-Level Radioactive Waste, and Reactor-Related Greater Than Class C Waste, which is separate from the Diablo Canyon facility operating licenses. The site-specific ISFSI license authorizes the licensee to store spent fuel in an ISFSI at the site.

The changes to the PSDAR dated October 19, 2021, indicate that PG&E was evaluating available alternate dry casks storage systems, as compared to those currently approved for use under the Diablo Canyon site-specific ISFSI license that may reduce the spent fuel cooling time required in the spent fuel pools prior to transfer to the ISFSI. Revision 1 to the Diablo Canyon PSDAR indicates that PG&E has executed a contract with Orano TN Americas (Orano) for storage of spent fuel and Greater Than Class C waste in Orano dry cask storage systems. It also indicates that PG&E plans to employ the Orano NUHOMS-EOS system to store spent fuel at Diablo Canyon under Certificate of Compliance (CoC) No. 1042, which will be amended via an NRC licensing action.

A request for approval of this CoC amendment will be submitted by Orano in the 2022-2024 timeframe. This licensing action will provide the opportunity for NRC review and approval of the use of the NUHOMS-EOS system before it is placed into service at Diablo Canyon. Specifically, evaluations are required to be performed of the Diablo Canyon site to demonstrate that it is adequate for storing spent fuel in dry casks under the requirements of the NUHOMS-EOS system. These evaluations must show that the cask CoC conditions and associated technical specifications can be met, including analysis of earthquake events and tornado missiles. The licensee must also review its security program, emergency plan, quality assurance program, training program, and radiation protection program and make any necessary changes before it may incorporate the new CoC for use at the ISFSI site. These evaluations are reviewed by the NRC staff as part of the approval process for amending the CoC for the NUHOMS-EOS system.

An NRC-approved cask is one that has undergone a technical review of its safety aspects and been found to be adequate to store spent fuel at a site that has been evaluated by the licensee to meet all of the NRCs requirements in 10 CFR Part 72. The NRC issues a CoC for a cask design to a cask vendor if the review of the design finds that it is technically adequate. The CoC is valid for up to 40 years from the date of issuance.

With respect to comments related to the safety of the plant during decommissioning, the NRC staff notes that the NRC maintains inspection oversight at decommissioning power plants in accordance with NRC Inspection Manual Chapter (IMC) 2561, Decommissioning Power Reactor Inspection Program, which was revised in January 2021 (ML20358A131).

The objectives of IMC 2561 are:

To obtain information through direct observation and verification of licensee activities to determine whether the power reactor is being decommissioned safely, that spent fuel is safely and securely stored onsite or transferred to another licensed location, and that site operations and license termination activities are in conformance with applicable regulatory requirements, the facility licensing basis, licensee commitments, and management controls; To verify that (1) the licensees procedures, processes, and programs for post-operational transition, decommissioning, and license termination are adequate, (2) necessary programs continue from the period of operation into decommissioning in accordance with the applicable regulatory requirements, and (3) the safety culture established during reactor operations is maintained. These decommissioning programs are assessed by inspection of the following areas: plant status; modifications, maintenance, and surveillances; problem identification and resolution; fire protection; and radiation protection; To identify declining trends in performance and perform inspections to verify that the licensee has resolved the issue(s) before performance declines below an acceptable level; and To provide for effective allocation of resources for the inspection of nuclear power reactors following permanent cessation of operations.

With respect to comments related to PSDAR changes, a licensee may make changes to its planned decommissioning activities, such as to consider new alternatives or technologies, or to the proposed schedule for their accomplishment. The October 12, 2022, letter submitting Revision 1 to the Diablo Canyon PSDAR states:

The updated PSDAR reflects PG&Es current plans for decommissioning; however, the plans may change as [Diablo Canyon] progress[es] closer to permanent cessation of operations.

Section 1.1, Introduction, of Revision 1 to the PSDAR also states:

This report is based on currently available information and the plans discussed herein may be modified as additional information becomes available or conditions change.

PG&E is required to notify the NRC in writing when making significant changes to the PSDAR in accordance with 10 CFR 50.82(a)(7), which states:

In taking actions permitted under [10 CFR 50.59, Changes, tests, and experiments,] following submittal of the PSDAR, the licensee shall notify the NRC, in writing and send a copy to the affected State(s), before performing any decommissioning activity inconsistent with, or making any significant schedule change from, those actions and schedules described

in the PSDAR, including changes that significantly increase the decommissioning cost.

In addition, the December 4, 2019, letter submitting the PSDAR states:

In response to public input provided during the NRC pre-submittal meeting, PG&E will provide the NRC an updated PSDAR within six months following submittal of each Nuclear Decommissioning Cost Triennial Proceeding (in addition to the notification required by 10 CFR 50.82(a)(7)).

Since submitting the PSDAR, including the SSDCE and IFMP, on December 4, 2019, PG&E has submitted a notification of changes on October 19, 2021, and Revision 1 to the PSDAR, including the SSDCE and IFMP, by letter dated October 12, 2022. These documents are publicly available in ADAMS, except for proprietary information.

The NRC staff reviewed the Diablo Canyon PSDAR, including the SSDCE and IFMP, as updated in a notification of changes dated October 19, 2021, and Revision 1 submitted by letter dated October 12, 2022, to determine whether it contains the information required by 10 CFR 50.82(a). In addition, the NRC staff used the guidance in Regulatory Guide (RG) 1.185, Revision 1, Standard Format and Content for Post-Shutdown Decommissioning Activities Report, dated June 2013 (ML13140A038), in conducting its review and considered public comments.

Based on this review, the NRC staff concludes the following:

1. Section 2, Description of Planned Decommissioning Activities, of the PSDAR and the SSDCE provide the applicable information identified in section C.1, Description of the Licensees Planned Decommissioning Activities, of RG 1.185. The NRC staffs review found that the licensee adequately described the activities associated with the major periods or milestones related to decommissioning, as required by 10 CFR 50.82(a)(4)(i) and consistent with RG 1.185. These periods include: pre-shutdown planning, power block modifications, wet storage, building demolition, site restoration, ISFSI operations, and ISFSI demolition and restoration.

2. Section 3, Schedule of Planned Decommissioning Activities, of the PSDAR and the SSDCE provide the estimated dates for the initiation and completion of major decommissioning activities, as required by 10 CFR 50.82(a)(4)(i) and consistent with section C.2, Schedule of Planned Decommissioning Activities, of RG 1.185. The NRC staff finds that the schedule for decommissioning activities is adequate to achieve license termination within 60 years of permanent cessation of operations, as required by 10 CFR 50.82(a)(3).

3. Section 4, Estimate of Expected Decommissioning Costs and Associated Funding, of the PSDAR and the SSDCE provide an estimate of the expected costs for decommissioning Diablo Canyon, including the Diablo Canyon ISFSI. The IFMP provides an estimate of the expected costs for the management of the spent fuel. Using the formula in 10 CFR 50.75(c) and the methodology provided in NUREG-1713, Standard Review Plan for Decommissioning Cost Estimates for Nuclear Power Reactors, dated December 2004 (ML043510113), and NUREG-1307, Revision 19, Report on Waste Burial Charges: Changes in Decommissioning Waste Disposal Costs

at Low-Level Waste Burial Facilities, dated February 2023 (ML23044A207), the NRC staff independently calculated the 2023 minimum decommissioning financial assurance formula amount to be $804.4 million per unit (in 2023 dollars). PG&E opted to provide a site-specific decommissioning cost amount in lieu of using the minimum decommissioning financial assurance formula amount. As reported in the SSDCE, Revision 1, the licensees 2022 site-specific decommissioning cost estimate is greater than the NRC minimum decommissioning financial assurance formula amount.

Therefore, the NRC staff finds that the SSDCE amount conforms to the guidance in NUREG-1713 and meets the regulations in 10 CFR 50.75, Reporting and recordkeeping for decommissioning planning.

The NRC staff considered the adequacy of available funding to safely decommission Diablo Canyon, including the Diablo Canyon ISFSI. In the PG&E decommissioning trust fund report dated March 28, 2023 (ML23087A117), the licensee stated that the trust fund balance for Diablo Canyon, Unit 1 as of December 31, 2022, was $1.583 billion, and that the trust fund balance for Diablo Canyon, Unit 2 as of December 31, 2022, was $2.075 billion. In order to determine whether adequate funds would be available for radiological decommissioning, the NRC staff performed a cash flow analysis using the costs listed by year in the SSDCE and the balances in the trust funds as of December 31, 2022. This analysis also assumed a conservative 2-percent real rate of return on the trust fund balances, as prescribed by 10 CFR 50.75(e)(1)(ii), and contributions in future years that have been requested by the licensee from the California Public Utilities Commission.

Based on this analysis, the NRC staff determined that a positive ending balance in the trust funds is achieved in the last year of spent fuel management assumed in the PDSAR and SSDCE (i.e., 2076), indicating that sufficient funding is available to decommission Diablo Canyon, including the Diablo Canyon ISFSI, using the DECON method. The NRC staff also reviewed estimates for major spent fuel management activities and funding requirements, including capital for spent fuel management infrastructure; spent fuel pool operation, maintenance, and isolation costs; ISFSI expansion and operating costs; emergency planning costs; security and utility staffing costs; and spent fuel transfer costs. The NRC staff determined that the activities and associated costs related to the Diablo Canyon spent fuel management program appear reasonable.

Based on its review of the Diablo Canyon SSDCE, the NRC staff finds that the licensee has demonstrated reasonable assurance that funding will be available to decommission Diablo Canyon, including the Diablo Canyon ISFSI, pursuant to the DECON method.

The NRC staff verified that the SSDCE amount is more than the decommissioning financial assurance formula amount required by 10 CFR 50.75(c). The SSDCE included an up-to-date listing of major factors that could affect the cost to decommission Diablo Canyon, and these factors were assessed by the licensee as required by 10 CFR 50.75(f)(3). The SSDCE also provided plans to adjust the level of funding and costs as required by 10 CFR 50.75(c)(2), 10 CFR 50.75(f)(5), and 10 CFR 50.82(a)(8)(iv). Finally, the SSDCE included the cost for ISFSI decommissioning consistent with 10 CFR 72.30. The NRC staff also concludes that the activities and associated costs of the Diablo Canyon spent fuel management program appear reasonable and that the preliminary approval of the Diablo Canyon IFMP is appropriate in accordance with 10 CFR 50.54(bb).

4. Section 5, Environmental Impacts, of Revision 1 of the PSDAR provides a discussion of the potential environmental impacts associated with the planned Diablo Canyon decommissioning activities, as required by 10 CFR 50.82(a)(4)(i) and consistent with section C.4, Environmental Impacts, of RG 1.185. The PSDAR includes a comparison of the potential environmental impacts from the planned Diablo Canyon decommissioning activities with impacts from similar activities provided in NUREG-0586, Supplement 1, Generic Environmental Impact Statement [GEIS] on Decommissioning of Nuclear Facilities, dated November 2002, Volumes 1 and 2 (ML023470327 and ML023500228, respectively) (also called the Decommissioning GEIS). A licensee is required to address the site-specific environmental impacts associated with planned decommissioning activities in both its PSDAR, in accordance with 10 CFR 50.82(a)(4)(i),

as well as before performing the decommissioning activities per 10 CFR 50.82(a)(6).

PG&E also relied on the final environmental statement issued by the Atomic Energy Commission, titled, Final Environmental Statement related to the Nuclear Generating Station Diablo Canyon Units 1 & 2, dated May 1973 (ML15043A481).

The environmental impacts associated with decommissioning activities are generically evaluated in the Decommissioning GEIS. In the Decommissioning GEIS, the NRC staff explains the significance of the impacts and whether the environmental impacts of decommissioning activities are considered generic to all nuclear power plants or site-specific to the decommissioning facility. The Decommissioning GEIS also identifies activities that can be bounded by the generic evaluations presented in the GEIS. The licensee can therefore rely on the information in the Decommissioning GEIS as a basis for meeting the bounding impacts requirement in 10 CFR 50.82(a)(4)(i). For environmental impacts that the Decommissioning GEIS classifies as site-specific, or for decommissioning activities that could exceed the generic environmental impacts analyzed by the Decommissioning GEIS, the licensee cannot rely on the Decommissioning GEIS. If the environmental impacts of a decommissioning activity fall outside the range of impacts considered in the Decommissioning GEIS or are not bounded by other appropriate previously issued environmental impact statements (i.e.,

unbounded impacts), then the activity cannot be performed until a site-specific analysis is completed through the submission of a license amendment request to the NRC for prior approval. As discussed below, the applicable site-specific issues for Diablo Canyon include threatened and endangered species, environmental justice, and cultural, historical, and archaeological resources.

Generic Issues In the Diablo Canyon PSDAR, Revision 1, PG&E provided a summary of the reasons for reaching the conclusion that the environmental impacts for generic issues associated with the planned Diablo Canyon decommissioning activities are bounded by the Decommissioning GElS. For generic issues, except for cultural, historical, and archeological resources, the NRC staff has concluded that the PSDAR is well reasoned and supports the conclusion reached that the environmental impacts of the planned decommissioning activities are bounded by the Decommissioning GEIS.

The Decommissioning GEIS identifies cultural, historical, and archeological resources environmental impacts for decommissioning activities within the operational area as generic. However, as discussed below, site disturbances to onsite historic properties during decommissioning at Diablo Canyon are likely to result in destruction or alteration that would impair their significance and exceed the threshold of SMALL as described in

the Decommissioning GEIS. If a licensee identifies environmental impacts associated with planned decommissioning activities that are not bounded by appropriate previously issued environmental impact statements, then, pursuant to 10 CFR 50.82(a)(6), the licensee shall not perform those decommissioning activities until their environmental impacts have been reviewed through the NRCs prior approval of a license amendment request regarding the activities.

Site-Specific Issues Threatened and Endangered Species On September 18, 2006, the National Marine Fisheries Service (NMFS) issued a biological opinion under the authority of the Endangered Species Act of 1973, as amended (ESA), for Diablo Canyon (ML063000348). The opinion pertains to four species of sea turtles: green (Chelonia mydas); leatherback (Dermochelys coriacea);

loggerhead (Caretta caretta); and olive ridley (Lepidochelys olivacea). The biological opinion allows for the incidental take of specified numbers of these species subject to PG&Es adherence to three reasonable and prudent measures and nine terms and conditions. The NMFS addresses the operation of Diablo Canyon in the biological opinion but does not address the shutdown or decommissioning of the plant.

In Revision 1 of the Diablo Canyon PSDAR, PG&E stated that the federally listed black abalone (Haliotis cracherodii) and its critical habitat, the southern sea otter (Enhvdra lutris nereis), and the green sea turtle could experience impacts from planned decommissioning activities that may include direct mortality from in-water demolition and disturbances as well as impacts from runoff, sedimentation, dust generation, and noise.

The PSDAR finds that the California sea lion (Zalophus californianus) and harbor seal (Phoca vitulina), which are protected under the Marine Mammal Protection Act, also occur in the area, and may be affected by planned Diablo Canyon decommissioning activities. The PSDAR does not discuss impacts to leatherback, loggerhead, or olive ridley sea turtles, although these species are present in the area and included in the NMFSs 2006 biological opinion.

Title 50 of the Code of Federal Regulations (50 CFR) Part 402, Interagency CooperationEndangered Species Act of 1973, as Amended, implements section 7 of the ESA. The regulation at 50 CFR 402.16, Reinitiation of consultation, requires, in part, that Federal agencies reinitiate consultation where discretionary Federal involvement or control over the action has been retained or is authorized by law and the identified action is subsequently modified in a manner that causes an effect to the listed species or critical habitat that was not considered in the biological opinion or written concurrence or if a new species is listed or critical habitat designated that may be affected by the identified action. The Diablo Canyon PSDAR discusses the planned transition of the plant from operating to decommissioning and the environmental impacts of decommissioning activities on the black abalone and its critical habitat, as well as the southern sea otter. However, the licensee did not discuss the necessary permits to exempt the incidental take of these species during the decommissioning period.

By email dated February 10, 2020 (ML20041E601), the NRC staff issued to PG&E a request for additional information (RAI) related, in part, to the above-described issues.

By letter dated March 11, 2020 (ML20071L136), PG&E responded stating that during operations, it will continue to implement the reasonable and prudent measures and

terms and conditions outlined in the 2006 biological opinion. PG&E also recognized that consultation under ESA section 7 would be appropriate to address the impacts of the planned Diablo Canyon shutdown and decommissioning. PG&E therefore requested that the NRC reinitiate ESA section 7 consultations with the NMFS and the U.S. Fish and Wildlife Service (FWS) to address environmental impacts of planned decommissioning activities and amend the biological opinion, as appropriate. Such reinitiated consultations would consider the effects to federally listed species and critical habitat resulting from the planned shutdown and decommissioning of Diablo Canyon. The consultations would fulfill both the NRCs and PG&Es obligation under the ESA and would provide a basis for PG&E to satisfy 10 CFR 50.82(a)(4)(i) with respect to concluding that the environmental impacts to threatened and endangered species will be bounded.

On March 22, 2022, the NRC staff held a virtual meeting with the U.S. Army Corps of Engineers (USACE) to discuss NRCs and USACEs roles and authorities over planned Diablo Canyon decommissioning activities and to determine which agency should assume the primary responsibility for initiating and leading ESA section 7 consultations with the NMFS and the FWS. During that meeting, PG&E personnel explained the permits that PG&E would seek to obtain from the USACE to support decommissioning.

Those permits included permits under Clean Water Act (CWA) section 404 and Rivers and Harbors Act (RHA) section 10. USACE staff confirmed that the review of these applications would require environmental review under the National Environmental Policy Act and the ESA, among other relevant statutes. USACE staff explained that its review of the permit applications would also require USACE to consult with the NMFS under the Magnuson-Stevens Fishery Conservation and Management Act and the Marine Mammal Protection Act. USACE typically conducts these consultations concurrent with ESA consultation. The scope of USACEs review and consultations under these statutes would likely encompass the entirety of the planned Diablo Canyon decommissioning activities. Therefore, the NRC staff proposed that USACE lead the ESA section 7 consultations because the activities that are likely to affect listed species will be activities permitted by USACE. The two agencies agreed that, given the scope of the effects to listed species, it is preferable for USACE to lead the ESA section 7 consultations. The NRC staff offered to support the consultations as a Federal agency partner. USACE will initiate these consultations once it receives CWA and RHA permit applications for Diablo Canyon decommissioning activities.

Environmental Justice Section 5.1.13, Environmental Justice, of Revision 1 of the Diablo Canyon PSDAR addresses environmental justice. PG&E conducted a site-specific analysis for environmental justice and examined the geographic distribution of minority and low-income populations within a 50-mile radius of the Diablo Canyon site using the 2016 American Community Survey Five-Year Summary data. PG&E concluded that there can be no disproportionately high and adverse impact or effects on minority and low-income populations as a result of the planned Diablo Canyon decommissioning activities.

Cultural, Historical, and Archeological Resources Revision 1 of the Diablo Canyon PSDAR indicates that a number of archaeological sites are likely to experience adverse effects from planned decommissioning activities.

Specifically, site disturbances to two historic properties (CA-SLO-2 and CA-SLO-61) during decommissioning are likely to result in destruction or alteration that would impair

their significance, and thus exceed the threshold of SMALL as described in the Decommissioning GEIS. In Revision 1 of the Diablo Canyon PSDAR, P&GE concluded that impacts to cultural, historical, and archaeological resources from planned decommissioning activities within the Diablo Canyon operational area would be MODERATE to LARGE.

The requirements in 10 CFR 50.82(a)(6)(ii) state that licensees shall not perform any decommissioning activities that result in significant environmental impacts not previously reviewed. In order to obtain prior review of the environmental impacts of a decommissioning activity such that it may be performed consistent with 10 CFR 50.82(a)(6)(ii), a licensee would have to submit a license amendment request regarding the activity and the NRC would have to approve that request. Furthermore, section 4.2.2, Preservation of Archaeological Resources Requirements, of Appendix B, Environmental Protection Plan (Non-Radiological), to the Diablo Canyon operating licenses (ML053140349 and ML053140353) states that [t]he licensee shall avoid disturbances to the [CA-]SLO-2 site in accordance with the Archaeological Resources Management Plan. In accordance with the provisions of 10 CFR 50.90, Application for amendment of license, construction permit, or early site permit, if a licensee desires to amend an operating license, the licensee must submit a license amendment request regarding proposed changes to the license. The licensee must also submit an environmental report that describes and evaluates the environmental impacts of the proposed changes to the license and of the planned decommissioning activities that result in environmental impacts not previously reviewed. The NRC would then review the environmental report in conjunction with its review of the license amendment request.

Based on its review, the NRC staff finds that the Diablo Canyon PSDAR, including the SSDCE and IFMP, as updated in a notification of changes dated October 19, 2021, and Revision 1 submitted by letter dated October 12, 2022, contain the information required by 10 CFR 50.82(a)(4)(i). The NRC staff also finds that PG&E cannot perform the planned decommissioning activities that will have significant environmental impacts to cultural, historical, and archeological resources without approval from the NRC via a license amendment request.

As required by 10 CFR 50.82(a)(7), PG&E must notify the NRC in writing and send a copy to the State of California before performing any decommissioning activity inconsistent with, or making any significant schedule change from, the planned decommissioning activities and schedules described in Revision 1 of the PSDAR, including changes that significantly increase the decommissioning costs. In accordance with NRC regulations, PG&E is required to verify, prior to their performance, that decommissioning activities meet the requirements of 10 CFR 50.82(a)(6)(i) through 10 CFR 50.82(a)(6)(iii) or seek appropriate regulatory approval if needed.

The NRC will continue to conduct inspections at Diablo Canyon throughout decommissioning under IMC 2561 to ensure that decommissioning activities are performed safely and in compliance with the Commissions rules and regulations, and the conditions of the license.

In accordance with 10 CFR 2.390, Public inspections, exemptions, requests for withholding, a copy of this letter will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records component of the NRCs ADAMS.

ADAMS is accessible from the NRC website at https://www.nrc.gov/reading-rm/adams.html.

If you have any questions regarding this letter, please contact me at 301-415-3168 or by email to Samson.Lee@nrc.gov.

Sincerely,

/RA/

Samson S. Lee, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-275 and 50-323 cc: Listserv

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