ML25065A177

Final Safety Evaluation Report for CoC No. 1040, Revision 1 to Amendment Nos. 0, 1, and 2 for the HI-STORM Umax

ML25065A177
Person / Time
Site:	HI-STORM 100
Issue date:	03/12/2025
From:	Storage and Transportation Licensing Branch
To:	Holtec
Shared Package
ML25065A166	List: ML25065A167 ML25065A168 ML25065A169 ML25065A170 ML25065A171 ML25065A172 ML25065A173 ML25065A174 ML25065A175 ML25065A176 ML25065A177
References
CAC 001028, EPID L-2023-LLA-0070
Download: ML25065A177 (1)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 FINAL SAFETY EVALUATION REPORT DOCKET NO. 72-1040 HOLTEC INTERNATIONAL HI-STORM UMAX CANISTER STORAGE SYSTEM CERTIFICATE OF COMPLIANCE NO. 1040 REVISION 1 TO AMENDMENT NOS. 0, 1, AND 2

SUMMARY

This safety evaluation report (SER) documents the U.S. Nuclear Regulatory Commission (NRC) staffs review and evaluation of Holtec Internationals (Holtec, the applicant) request to revise Certificate of Compliance (CoC) No. 1040, Amendment Nos. 0, 1, and 2, for the HI-STORM UMAX Canister Storage System.

By letter dated May 5, 2023 (Agencywide Documents Access and Management System

[ADAMS] Accession No. ML23125A237), as supplemented on January 31, 2024 (ML24031A659), March 4, 2024 (ML24072A501), and June 26, 2024 (ML24178A111), the applicant requested that the NRC revise CoC No. 1040 Amendment Nos. 0, 1, and 2 to update the technical specifications (TS) for the radiation protection program and the associated bases information to clearly articulate the basis for the dose rate limits for the closure lids and modify the dose rate limit values and the description of the location of the dose rate measurements.

The intent of this request is to revise Amendment Nos. 0, 1, and 2 to match the previously approved Amendment No. 4 for CoC No.1040 in terms of the dose rate limit values and measurement locations for the closure lids. Holtec submitted the Amendment No. 4 application as a corrective action to address issues identified in a previous NRC inspection, which is discussed in the Shielding Evaluation section of this SER. This revision request is a follow-up corrective action to which Holtec committed to resolve the issue and ensure that the correct dose rate limit values and measurement locations for the closure lids are reflected in all of the approved amendments to CoC No. 1040. Therefore, the staffs review of this revision request focused on whether the changes proposed in this request were consistent with those approved in Amendment No. 4.

The revised CoCs, when codified through rulemaking, will be denoted as Amendment No. 0, Revision 1; Amendment No. 1, Revision 1; and Amendment No. 2, Revision 1 to CoC No. 1040.

The staff's evaluation is based on a review of Holtecs application and whether it meets the applicable requirements of Title 10 of the Code of Federal Regulations (10 CFR) Part 72, Licensing Requirements for the Independent Storage of Spent Nuclear Fuel, High-Level Radioactive Waste, and Reactor-Related Greater Than Class C Waste, for dry storage of spent nuclear fuel. The staffs evaluation focused on modifications to the TS requested in the application, as supported by the submitted revised final safety analysis report (FSAR) and did not reassess previous revisions of the FSAR nor previous amendments to the CoC. In its review, the staff followed the guidance in NUREG-2215, Standard Review Plan for Spent Fuel Dry Storage Systems and Facilities (ML20121A190).

2 The NRC staff determined that not all disciplines described in NUREG-2215 are affected by the requested revision, and therefore, the following SER sections are not needed: Principal Design Criteria, Structural, Thermal, Criticality, Materials, Confinement, Radiation Protection, Operation Procedures and Systems Evaluation, Conduct of Operations, Quality Assurance, and Accident Analysis Evaluation. This revision only requires evaluations on Shielding and Technical Specifications, as described in this SER.

GENERAL DESCRIPTION The objective of this chapter is to review the changes requested to CoC No. 1040 for the HI-STORM UMAX storage system to ensure that the applicant provided an adequate description of the pertinent features of the storage system and the changes requested in the application. The specific changes requested by the applicant are described and evaluated in the following sections of this SER.

SHIELDING EVALUATION The applicant proposed to revise the TS for Amendment Nos. 0, 1, and 2 of the HI-STORM UMAX storage system, CoC No. 1040, along with supporting information in the UMAX FSAR.

The proposed revision is the culmination of efforts to address issues raised during an NRC inspection of Holtec in 2018, the results of which are documented in Inspection Report No.

07201014/2018-201 (ML18306A853), and a 2019 follow-up inspection documented in Inspection Report No. 07201014/2019-201 (ML19228A016). During the 2018 inspection, the NRC noted that the shielding analysis documented in the Holtec UMAX FSAR did not provide a technical basis for the TS dose rate limit values and location of the dose rate measurement for either the Standard lid or the Version B lid. As noted in the inspection reports, the applicants initial efforts and corrective actions to address these issues included the request for Amendment No. 4 to the UMAX CoC. The inspection reports also noted that the applicant committed to revising Amendment Nos. 0, 1, and 2 to include identical changes from Amendment No. 4 after the NRC approved Amendment No. 4. The staffs SER provides documentation of its review and approval of Amendment No. 4 (ML20349A211). Note that there is no currently approved Amendment No. 3 for the UMAX CoC. The purpose of the proposed TS revisions and FSAR changes for Amendment Nos. 0, 1, and 2 of the CoC No. 1040 is to address the NRC inspection findings by revising the TS dose rate limit values and measurement locations along with a supporting FSAR shielding analysis, completing actions needed to address the NRCs inspection findings.

The applicant requested to change the TS dose rate limit in section 5.3.4.a of appendix A of each of the CoC amendments for the vertical ventilated module (VVM) Standard and Version B closure lids. The applicant proposed to change the dose rate limit of the Standard lid to 66 millirem (mrem)/hour (hr) and the Version B lid to 22 mrem/hr. The applicant also proposed changes to the measurement location of the dose rate in section 5.3.8.a of the TS in appendix A of each of the CoC amendments. For the Standard lid, the measurements are to be taken [o]n the side of the closure lid approximately midheight and approximately 90 degrees apart. For the Version B lid, the measurements are to be taken [o]n the side of the closure lid approximately midheight and adjacent to the inlet vent. One measurement per each lid side, rotationally symmetric by approximately 90 degrees. The differences in language for the two lids are necessary due to the differences in the lid shapes and inlet vent designs. The applicant also provided revised FSAR pages that include evaluation information, including dose rates, to support and provide the bases for the revised TS limit values and measurement locations.

3 The proposed changes in this revision request are identical to those changes that were approved by the NRC as part of Amendment No. 4 to the HI-STORM UMAX (ML20349A206, package). Thus, as described in the NRC staffs SER for Amendment No. 4, the proposed dose rate values at the identified measurement locations are the highest calculated dose rate values for the HI-STORM UMAX Standard and Version B lids. The applicants calculation files, submitted with the Amendment No. 4 application, demonstrate that a storage system that meets these limits will also meet the 10 CFR 72.104(a), Criteria for radioactive materials in effluents and direct radiation from an ISFSI [independent spent fuel storage installation] or MRS

[monitored retrievable storage installation], dose rate limits beyond the controlled area boundary, satisfying, in part, the regulations in 10 CFR 72.236(d), Specific requirements for spent fuel storage cask approval and fabrication, which require that the CoC holder ensure that the radiation shielding features of the storage system are sufficient to meet the requirements of 10 CFR 72.104. The requirements in 10 CFR 72.236(d) include all of 10 CFR 72.104. The regulations in 10 CFR 72.104(c) require that operational limits be established for direct radiation levels associated with the ISFSI operations to meet the limits in 10 CFR 72.104(a). Establishing appropriate dose rate limits for the dry storage system provides the NRC staff with reasonable assurance that, in addition to site-specific requirements in 10 CFR 72.212, Conditions of general license issued under § 72.210, 10 CFR 72.104 will also be met.

The NRC staff noted in its SER for Amendment No. 4 that the shielding analyses documented in the FSAR for the HI-STORM UMAX storage system do not have bounding analyses with respect to the source term and rely, in part, on these dose rate measurements to ensure that 10 CFR 72.104 can be met, allowing the NRC staff to make a finding that 10 CFR 72.236(d) has been met. Also discussed in the SER for Amendment No. 4, the staff found that the HI-STORM UMAX satisfies the 10 CFR 72.106, Controlled area of an ISFSI or MRS, accident condition dose limit. Although the analysis did not use a bounding source term for the system in the storage configuration (i.e., the loaded spent fuel canister in the in-ground VVM with the lid in place), the NRC staff found it acceptable based on the large margins between the results from the analysis for the limiting accident for the overpack and the regulatory limit; specifically, there is more than an order of magnitude between the dose rates from this accident and the regulatory limit. The staff identified that the applicants analysis used a bounding source term for the transfer cask accident dose rate analyses. These staff considerations and findings from the Amendment No. 4 review are relevant for this revision request given there are no differences in the UMAX shielding design, contents, and analysis approach between Amendment No. 4 and these proposed revisions to Amendment Nos. 0, 1, and 2.

The review of this revision application identified that there are no changes to the radiation source term used in the analysis or the HI-STORM UMAX shielding design versus those in Amendment No. 4. Therefore, the revised dose rate values and locations applicable to Amendment No. 4 are also applicable and appropriate for Amendment Nos. 0, 1, and 2. Based on this outcome and the considerations and findings described above that apply from the Amendment No. 4 review, the NRC staff finds that the proposed revisions to Amendment Nos.

0, 1, and 2 are acceptable.

TECHNICAL SPECIFICATIONS The applicant proposed updates to the TS for the radiation protection program. The requested changes to the TS are discussed in the Shielding Evaluation section of this SER. The staff finds the changes acceptable based on the staffs findings in the Shielding Evaluation section of this SER.

4 Additionally, the applicant requested an editorial change to the TS 5.3.2 in Amendment Nos. 0, 1, and 2 of the CoC No. 1040, to change the current reference to 10 CFR 72.212(b)(2)(i)(C), as this regulatory citation no longer exists. The applicant requested to update the regulatory citation to 10 CFR 72.212(b)(5)(iii) to reflect the citation currently in the regulations. The staff finds that updating the regulatory citation in the TS to reflect the citation currently in the regulations is an appropriate editorial change and is not pertinent to the safety review conducted for the revision application.

CONCLUSIONS Based on the review of the application, as described above, the NRC staff finds that the proposed TS dose rate limits and locations are consistent with those in the approved HI-STORM UMAX Amendment No. 4. The NRC staff also finds that, with the above noted considerations, the new TS dose rate limit values and measurement locations are acceptable and adequately address the issues raised in Inspection Report Nos. 07201014/2018-201 and 07201014/2019-201. The NRC staff also finds reasonable assurance that, with this revision, the HI-STORM UMAX Amendment Nos. 0, 1, and 2 meet the requirements of 10 CFR 72.236(d).

These requirements include that radiation shielding features must be provided sufficient to meet 10 CFR 72.104 and 10 CFR 72.106, among which are dose limits and operational limits for radiation levels to meet the dose limits in 10 CFR 72.104(a) (see 10 CFR 72.104(c)). Therefore, Revision 1 to Amendment Nos. 0, 1, and 2 of CoC No. 1040 for the HI-STORM UMAX storage system should be approved.

Issued with CoC No. 1040, Revision 1 to Amendment Nos. 0, 1, and 2 on March 12, 2025.