Southern Nuclear Operating Company; Edwin I. Hatch Nuclear Plant Units 1 and 2; Independent Spent Fuel Storage Installation; Exemption

SUPPLEMENTARY INFORMATION:

The text of the exemption is attached.

Attachment—Exemption

NUCLEAR REGULATORY COMMISSION

Docket Nos. 72-36, 50-321, and 50-366

Southern Nuclear Operating Company; Edwin I. Hatch Nuclear Plant Units 1 and 2; Independent Spent Fuel Storage Installation

I. Background

Southern Nuclear Operating Company (SNC) is the holder of Renewed Facility Operating License Nos. DPR-57 and NPF-5, which authorize operation of the Edwin I. Hatch Nuclear Plant (Hatch), Units 1 and 2 in Baxley, Georgia, pursuant to part 50 of title 10 of the Code of Federal Regulations (10 CFR), “Domestic Licensing of Production and Utilization Facilities.” The licenses provide, among other things, that the facility is subject to all rules, regulations, and orders of the U.S. Nuclear Regulatory Commission (NRC) now or hereafter in effect.

Consistent with 10 CFR part 72, subpart K, “General License for Storage of Spent Fuel at Power Reactor Sites,” a general license is issued for the storage of spent fuel in an independent spent fuel storage installation (ISFSI) at power reactor sites to persons authorized to possess or operate nuclear power reactors under 10 CFR part 50. SNC is authorized to operate nuclear power reactors under 10 CFR part 50 and holds a 10 CFR part 72 general license for storage of spent fuel at the Hatch ISFSI. Under the terms of the general license, SNC stores spent fuel at its Hatch ISFSI using the HI-STORM 100 Cask System in accordance with Certificate of Compliance (CoC) No. 1014, Amendment No. 11.

II. Request/Action

By a letter dated June 25, 2024 (Agencywide Documents Access and Management System [ADAMS] Accession No. ML24177A217), as supplemented on July 26, 2024 (ML24208A172), SNC requested an exemption 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 that require Hatch to comply with the terms, conditions, and specifications of CoC No. 1014, Amendment No. 11 (ML23328A045). If approved, SNC's exemption request would accordingly allow Hatch to maintain three loaded and to load five multi-purpose canisters (MPCs) with an unapproved, variant basket design with continuous basket shims (CBS) ( i.e., MPC-68M-CBS) in the HI-STORM 100 Cask System, and thus, to maintain and load the systems in a storage condition where the terms, conditions, and specifications in CoC No. 1014, Amendment No. 11 are not met.

SNC currently uses the HI-STORM 100 Cask System under CoC No. 1014, Amendment No. 11, for dry storage of spent nuclear fuel in MPC-68M at the Hatch ISFSI. 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 performed a non-mechanistic tip-over analysis with favorable results and implemented the CBS variant design under the provisions of 10 CFR 72.48, “Changes, tests, and experiments,” 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 is not the type of change allowed without a CoC amendment. For this reason, the NRC issued three Severity Level IV violations to Holtec (ML24016A190).

Prior to the issuance of the violation, SNC had loaded three MPC-68M-CBS in the HI-STORM 100 Cask System, which are safely in storage at the Hatch ISFSI. SNC's loading campaign for the Hatch ISFSI include loading five MPC-68M-CBS in the HI-STORM 100 Cask System beginning in April 2025. While Holtec was required to submit a CoC amendment to the NRC to seek approval of the CBS variant design, such a process will not be completed in time to inform decisions for this loading campaign. Therefore, SNC submitted this exemption request to allow for the continued storage of the three already loaded MPC-68-CBS, and future loading of five MPC-68M-CBS beginning in April 2025 at the Hatch ISFSI. This exemption is limited to the use of MPC-68M-CBS in the HI-STORM 100 Cask System only for the three already loaded canisters and the planned loading of five specific new canisters using the MPC-68M-CBS variant basket design.

III. Discussion

Pursuant to 10 CFR 72.7, “Specific exemptions,” the Commission may, upon application by any interested person or upon its own initiative, grant such exemptions from the requirements of the regulations of 10 CFR part 72 as it determines are authorized by law and will not endanger life or property or the common defense and security and are otherwise in the public interest.

A. The Exemption is Authorized by Law

This exemption would allow SNC to maintain three loaded and to load five MPC-68M-CBS in the HI-STORM 100 Cask System at its Hatch ISFSI in a storage condition where the terms, conditions, and specifications in CoC No. 1014, Amendment No. 11, are not met. SNC is requesting an exemption from the provisions in 10 CFR part 72 that require the licensee to comply with the terms, conditions, and specifications of the CoC for the approved cask model it uses. Section 72.7 allows the NRC to grant exemptions from the requirements of 10 CFR part 72. This authority to grant exemptions is consistent with the Atomic Energy Act of 1954, as amended, and is not otherwise inconsistent with NRC's regulations or other applicable laws. Additionally, no other law prohibits the activities that would be authorized by the exemption. Therefore, the NRC concludes that there is no statutory prohibition on the issuance of the requested exemption, and the NRC is authorized to grant the exemption by law.

B. The Exemption Will Not Endanger Life or Property or the Common Defense and Security

This exemption would allow SNC to maintain three loaded and to load five 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 CoC No. 1014, Amendment No. 11, are not met. In support of its exemption request, SNC asserts that issuance of the exemption would not endanger life or property because the administrative controls the applicant has in place prevent a tip-over or handling event, and that the containment boundary would be maintained in such an event. SNC relies, in part, on the approach in the NRC's Safety Determination Memorandum (ML24018A085). The NRC issued this Safety Determination Memorandum to address whether, with respect to the enforcement action against Holtec regarding this violation, there was any need to take an immediate action for the cask systems that were already loaded with non-compliant basket designs. The Safety Determination Memorandum documents a risk-informed approach concluding that, during the design basis event of a non-mechanistic tip-over, the fuel in the basket in the MPC-68M-CBS remains in a subcritical condition.

SNC also provided site-specific technical information, including information explaining why the use of the approach in the NRC's Safety Determination Memorandum is appropriate for determining the safe use of the CBS variant baskets at the Hatch ISFSI. Specifically, SNC described that the analysis of the tip-over design basis event that is relied upon in the NRC's Safety Determination Memorandum, which demonstrates that the MPC confinement barrier is maintained, is documented in the updated final safety analysis report (UFSAR) for the HI-STORM 100 Cask System CoC No. 1014, Amendment No. 11 that is used at the Hatch site. SNC also described its administrative controls for handling of the HI-STORM 100 Cask System at the Hatch ISFSI to prevent a tip-over or handling event. Those controls include operational procedures that demonstrate lift height restrictions and that the system is handled with a single failure proof device, which comply with CoC No. 1014, Amendment No. 11, Appendix A.

Additionally, SNC provided specific information from Hatch's 72.212 Evaluation Report, Revision 27, indicating that during the design basis event of a non-mechanistic tip-over, Hatch's ISFSI would meet the requirements in 10 CFR 72.104, “Criteria for radioactive materials in effluents and direct radiation from an ISFSI or MRS,” and 72.106, “Controlled area of an ISFSI or MRS.” Specifically, SNC described that, in the highly unlikely event of a tip-over, any potential fuel damage from a non-mechanistic tip-over event would be localized, the confinement barrier would be maintained, and the shielding material would remain intact. SNC concluded that compliance with 72.104 and 72.106 is not impacted by approving this exemption request.

The NRC staff reviewed the information provided by SNC and concludes that issuance of the exemption would not endanger life or property because the administrative controls that SNC has in place at the Hatch ISFSI sufficiently minimize the possibility of a tip-over or handling event, and that the containment boundary would be maintained in such an event. The staff confirmed that these administrative controls are documented in the technical specifications and UFSAR for the HI-STORM 100 Cask System CoC No. 1014, Amendment No. 11, that is used at the Hatch site. In addition, the staff confirmed that the information provided by SNC regarding Hatch's 72.212 Evaluation Report, Revision 27, demonstrates that the consequences of normal and accident conditions would be within the regulatory limits of the 10 CFR 72.104 and 10 CFR 72.106. The staff also determined that the requested exemption is not related to any aspect of the physical security or defense of the Hatch ISFSI; therefore, granting the exemption would not result in any potential impacts to common defense and security.

For these reasons, the NRC staff has determined that under the requested exemption, the storage system will continue to meet the safety requirements of 10 CFR part 72 and the offsite dose limits of 10 CFR part 20 and, therefore, will not endanger life or property or the common defense and security.

C. The Exemption is Otherwise in the Public Interest

The proposed exemption would allow the three already loaded MPC-68M-CBS in the HI-STORM 100 Cask System to remain in storage at the Hatch ISFSI, and allow SNC to load five MPC-68M-CBS in the HI-STORM 100 Cask System beginning in April 2025 at the Hatch ISFSI, even though the CBS variant basket design is not part of the approved CoC No. 1014, Amendment No. 11. According to SNC, the exemption is in the public interest because being unable to load fuel into dry storage in the future loading campaign would impact SNC's ability to offload fuel from the Hatch reactor units, consequently impacting continued safe reactor operation.

SNC rescheduled its 2024 loading campaign to 2025 and stated that further delaying the future loading campaign would impact its ability to effectively manage the margin to capacity in the Hatch Units 1 and 2 spent fuel pools. The low spent fuel pool capacity would make it difficult to refuel and present potential risks to fuel handling operations. In addition, a crowded spent fuel pool would challenge the decay heat removal demand of the pool and increase the likelihood of a loss of fuel pool cooling event and a fuel handling accident. Furthermore, Hatch planned the cask loading campaign years in advance based on availability of the specialized resources and equipment. These specialty resources support competing activities and priorities, including spent fuel pool clean-up and refueling outages. Therefore, the available windows to complete cask loading campaigns are limited, and any delays would have a cascading impact on other scheduled specialized activities. SNC also stated that leaving the three loaded CBS canisters is in the public interest because it eliminates the risks associated with dispositioning spent fuel, including increased radiation dose to workers and affecting SNC's ability to manage the spent fuel pool capacity. 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. It would put the 2025 campaign and Hatch's capability for full core offloading of both reactors at risk.

For the reasons described by SNC in the exemption request, the NRC agrees that it is in the public interest to grant the exemption. If the exemption is not granted, in order to comply with the CoC, SNC would have to unload MPC-68M-CBS from the HI-STORM 100 Cask System at the Hatch ISFSI and reload into the older design MPC-68M to restore compliance with the terms, conditions, and specifications of the CoC. This would subject onsite personnel to additional radiation exposures and increase the risk of a possible fuel handling accident. Furthermore, the removed spent fuel would need to be placed in the spent fuel pool until it can be loaded into another storage cask or remain in the spent fuel pool if it is not permitted to be loaded into CBS casks for the future loadings. As described by SNC, this scenario would affect SNC ability to effectively manage the spent pool capacity and reactor fuel offloading at Hatch. In addition, the rescheduling of the specialized resources for the future loading campaign would impact the operations of Hatch.

Therefore, the staff concludes that approving the exemption is in the public interest.

Environmental Consideration

The NRC staff also considered whether there would be any significant environmental impacts associated with the exemption. For this proposed action, the NRC staff performed an environmental assessment pursuant to 10 CFR 51.30. The environmental assessment concluded that the proposed action would not significantly impact the quality of the human environment. The NRC staff concluded that the proposed action would not result in any changes in the types or amounts of any radiological or non-radiological effluents that may be released offsite, and there would be no significant increase in occupational or public radiation exposure because of the proposed action. The environmental assessment and the finding of no significant impact was published on October 11, 2024 (89 FR 82645).

IV. Conclusion

Based on these considerations, the NRC has determined that, pursuant to 10 CFR 72.7, the exemption is authorized by law, will not endanger life or property or the common defense and security, and is otherwise in the public interest. Therefore, the NRC grants SNC an exemption from the requirements of §§ 72.212(a)(2), 72.212(b)(3), 72.212(b)(5)(i), 72.212(b)(11), and 72.214 with respect to the ongoing storage of three MPC-68M-CBS in the HI-STORM 100 Cask System and a future loading in the HI-STORM 100 Cask System of five new MPC-68M-CBS beginning in April 2025.

This exemption is effective upon issuance.

Dated: October 11, 2024.

For the Nuclear Regulatory Commission.

Yoira Diaz-Sanabria,

Chief, Storage and Transportation Licensing Branch, Division of Fuel Management, Office of Nuclear Material Safety, and Safeguards.

[FR Doc. 2024-24917 Filed 10-24-24; 8:45 am]

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