Southern Nuclear Operating Company; Edwin I. Hatch Nuclear Plant Units 1 and 2; Independent Spent Fuel Storage Installation; Environmental Assessment and Finding of No Significant Impact

SUPPLEMENTARY INFORMATION:

I. Introduction

The NRC is reviewing an exemption request from SNC, dated June 25, 2024, and supplemented on July 26, 2024. SNC is requesting an exemption, pursuant to section 72.7 of title 10 of the Code of Federal Regulations (10 CFR), “Specific exemptions,” in paragraphs 72.212(a)(2), 72.212(b)(3), 72.212(b)(5)(i), 72.212(b)(11), and 72.214 that require SNC to comply with the terms, conditions, and specifications of the CoC No. 1014, Amendment No. 11. If approved, the exemption would allow SNC to maintain three loaded and to load five new MPC-68M-CBS in the HI-STORM 100 Cask System at the Hatch ISFSI in a storage condition where the terms, conditions, and specifications in the CoC No. 1014, Amendment No. 11, are not met.

II. Environmental Assessment

Background

Hatch is 32 kilometers (20 miles) east of Vidalia, Georgia. The plant is located on the southwest side of the Altamaha River. Unit 1 began operating in 1975 and Unit 2 began operating in 1979. SNC has been storing spent fuel in the Hatch ISFSI under a general license as authorized by 10 CFR part 72, subpart K, “General License for Storage of Spent Fuel at Power Reactor Sites.” SNC currently uses the HI-STORM 100 Cask System under CoC No. 1014, Amendment No. 11 for dry storage of spent nuclear fuel in a specific MPC ( i.e., MPC-68M) at the Hatch ISFSI.

Description of the Proposed Action

The CoC is the NRC-approved design for each dry cask storage system. The proposed action would exempt the applicant from the requirements of 10 CFR 72.212(a)(2), 72.212(b)(3), 72.212(b)(5)(i), 72.212(b)(11), and 72.214 only as these requirements pertain to the use of the MPC-68M-CBS in the HI-STORM 100 Cask System. The exemption would allow SNC to maintain three loaded and to load five new MPC-68M-CBS in the HI-STORM 100 Cask System at the Hatch ISFSI, despite the MPC-68M-CBS in the HI-STORM 100 Cask System not being in compliance with the terms, conditions, and specifications in the CoC No. 1014, Amendment No. 11.

The HI-STORM 100 Cask System CoC provides the requirements, conditions, and operating limits necessary for use of the system to store spent fuel. Holtec International (Holtec), the designer and manufacturer of the HI-STORM 100 Cask System, developed a variant of the design with CBS for the MPC-68M, known as MPC-68M-CBS. Holtec originally implemented the CBS variant design under the provisions of 10 CFR 72.48, which allows licensees to make changes to cask designs without a CoC amendment under certain conditions (listed in 10 CFR 72.48(c)). After evaluating the specific changes to the cask designs, the NRC determined that Holtec erred when it implemented the CBS variant design under 10 CFR 72.48, as this was not the type of change allowed without a CoC amendment. For this reason, the NRC issued three Severity Level IV violations to Holtec. However, SNC had previously loaded three MPC-68M-CBS in the HI-STORM 100 Cask System and plans to load five MPC-68M-CBS in the HI-STORM 100 Cask System beginning in April 2025. This exemption considers the storage of the three already loaded systems and the planned loading of the five canisters with the CBS variant basket design.

Need for the Proposed Action

SNC requested this exemption because SNC is currently out of compliance with NRC requirements, resulting from the previous loading of spent fuel into a storage system with the CBS variant basket design. This exemption would allow three already loaded MPC-68M-CBS in the HI-STORM 100 Cask System to remain in storage at the Hatch ISFSI. The exemption would also allow SNC to load five new MPC-68M-CBS in HI-STORM 100 Cask System at the Hatch ISFSI for the future loading campaign scheduled to begin in April 2025.

Approval of the exemption request would allow SNC to effectively manage the spent fuel pool margin and capacity to enable refueling and offloading fuel from the reactor. It would also allow SNC to effectively manage the availability of the specialized resources and equipment needed to support competing fuel loading and operational activities at Hatch.

Environmental Impacts of the Proposed Action

This EA evaluates the potential environmental impacts of granting an exemption from the terms, conditions, and specifications in CoC No. 1014, Amendment No. 11. The exemption would allow three already loaded MPC-68M-CBS in the HI-STORM 100 Cask System to remain loaded at the Hatch ISFSI. The exemption would also allow five new MPC-68M-CBS to be loaded in the HI-STORM 100 Cask System in loading campaigns and maintained in storage at the Hatch ISFSI.

The potential environmental impacts of storing spent nuclear fuel in NRC-approved storage systems have been documented in previous assessments. On July 18, 1990 (55 FR 29181), the NRC amended 10 CFR part 72 to provide for the storage of spent fuel under a general license in cask designs approved by the NRC. The EA for the 1990 final rule analyzed the potential environmental impacts of using NRC-approved storage casks. The EA for the HI-STORM 100 Cask System, CoC No. 1014, Amendment No. 11, published in 2018 tiers off of the EA issued for the July 18, 1990, final rule (83 FR 63794). “Tiering” off earlier EAs is a standard process encouraged by the regulations implementing the National Environmental Policy Act of 1969 (NEPA) that entails the use of impact analyses of previous EAs to bound the impacts of a proposed action where appropriate. The Holtec HI-STORM 100 Cask System is designed to mitigate the effects of design basis accidents that could occur during storage. Considering the specific design requirements for the accident conditions, the design of the cask would prevent loss of containment, shielding, and criticality control. If there is no loss of containment, shielding, or criticality control, the environmental impacts would not be significant.

The exemptions requested by SNC at the Hatch site as they relate to CoC No. 1014, Amendment No. 11, for the HI-STORM 100 Cask System are limited to the use of the CBS variant basket design only for the three previously loaded canisters and planned loading of five canisters utilizing the CBS variant basket design. The staff has determined that this change in the basket will not result in either radiological or non-radiological environmental impacts that significantly differ from the environmental impacts evaluated in the environmental assessment supporting the issuance of CoC No. 1014, Amendment No. 11. If the exemption is granted, there will be no significant change in the types or amounts of any effluents released, no significant increase in individual or cumulative public or occupational radiation exposure, and no significant increase in the potential for or consequences from radiological accidents. Accordingly, the Commission concludes that there would be no significant environmental impacts associated with the proposed action.

Alternative to the Proposed Action

The staff considered the no-action alternative. The no-action alternative (denial of the exemption request) would require SNC to unload spent fuel from the MPC-68M-CBS in the HI-STORM 100 Cask System to bring it in compliance with the CoC terms, conditions, and specifications in the CoC No. 1014, Amendment No. 11. Unloading the cask would subject station personnel to additional radiation exposure, generate additional contaminated waste, increase the risk of a possible fuel handling accident, and increase the risk of a possible heavy load handling accident. Furthermore, the removed spent fuel would need to be placed in the spent fuel pool, where it would remain until it could be loaded into an approved storage cask. SNC has rescheduled its 2024 loading campaign to April 2025, and further delay in the loading of this spent fuel into other casks could affect SNC's ability to effectively manage the spent fuel pool capacity and reactor fuel offloading. Not allowing the planned future loading campaign could affect SNC's ability to manage pool capacity, reactor fuel offloading, and refueling. It could also pose challenges to spent fuel heat removal and impact the availability of the specialized resources and equipment needed to support competing fuel loading and operational activities at Hatch, including spent fuel pool clean-up and refueling outages. SNC has ordered an additional five MPC-68M canisters for the planned loading starting in April 2025, that comply with CoC No. 1014, Amendment No. 11. However, due to factors outside of SNC's control, delivery of the compliant canisters is not guaranteed for the April 2025 loading.

The NRC has determined that the no-action alternative would result in undue potential human health and safety impacts that could be avoided by proceeding with the proposed exemption, especially given that the staff has concluded in NRC's Safety Determination Memorandum, issued with respect to the enforcement action against Holtec regarding these violations, that fuel can be stored safely in the MPC-68M-CBS canisters.

Agencies Consulted

The NRC provided the Georgia Division of Natural Resources (DNR) and Georgia Emergency Management and Homeland Security Administration (GEMA) a copy of this draft EA for review by an email dated August 28, 2024. On September 25, 2024, Georgia DNR and GEMA provided its concurrence by email.

III. Finding of No Significant Impact

The environmental impacts of the proposed action have been reviewed in accordance with the requirements in 10 CFR part 51, which implement NEPA. Based upon the foregoing environmental assessment, the NRC finds that the proposed action of granting the exemption from the regulations in 10 CFR 72.212(a)(2), 72.212(b)(3), 72.212(b)(5)(i), 72.212(b)(11), and 72.214, which require the licensee to comply with the terms, conditions, and specifications of the CoC, in this case limited to the past and specific future loading of baskets with the CBS variant design, would not significantly impact the quality of the human environment. Accordingly, the NRC has determined that a FONSI is appropriate, and an environmental impact statement is not warranted.

IV. Availability of Documents

The documents identified in the following table are available to interested persons through ADAMS, as indicated.