Holtec HI-STORM UMAX Amendment 5 Approved B1 B2 Canister Designs

Proposed Rule

List of Approved Spent Fuel Storage Casks: Holtec International HI-STORM UMAX Canister Storage System, Certificate of Compliance No. 1040, Amendment No. 5

A Proposed Rule by the Nuclear Regulatory Commission on 04/02/2026

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• Public Inspection Published Document: 2026-06374 (91 FR 16588) Document Headings ###### Nuclear Regulatory Commission

1. 10 CFR Part 72
2. [NRC-2026-0562]
3. RIN 3150-AL66

AGENCY:

Nuclear Regulatory Commission.

ACTION:

Proposed rule.

SUMMARY:

The U.S. Nuclear Regulatory Commission (NRC) is proposing to amend its spent fuel storage regulations by revising the Holtec International HI-STORM UMAX Canister Storage System listing within the “List of approved spent fuel storage casks” to include Amendment No. 5 to Certificate of Compliance No. 1040. Amendment No. 5 revises the certificate of compliance to include two new versions of the HI-STORM UMAX design (Version B1 and B2).

DATES:

Submit comments by May 4, 2026. Comments received after this date will be considered if it is practical to do so, but the NRC is able to ensure consideration of only comments received on or before this date.

ADDRESSES:

Submit your comments, identified by Docket ID NRC-2026-0562, at https://www.regulations.gov. If your material cannot be submitted using https://www.regulations.gov, call or email the individual listed in the FOR FURTHER INFORMATION CONTACT section of this document for alternate instructions.

Do not include any personally identifiable information (such as name, address, or other contact information) or confidential business information that you do not want publicly disclosed. All comments are public records; they are publicly displayed exactly as received, and will not be deleted, modified, or redacted. Comments may be submitted anonymously.

Follow the search instructions on https://www.regulations.gov to view public comments.

You can read a plain language description of this proposed rule at https://www.regulations.gov/​docket/ ( printed page 16589) NRC-2026-0562. For additional direction on obtaining information and submitting comments, see “Obtaining Information and Submitting Comments” in the SUPPLEMENTARY INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT:

Amy McKenna, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; email: Amy McKenna@nrc.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Obtaining Information and Submitting Comments

II. Rulemaking Procedure

III. Background

IV. Plain Writing

V. Regulatory Planning and Review

VI. Availability of Documents

I. Obtaining Information and Submitting Comments

A. Obtaining Information

Please refer to Docket ID NRC-2026-0562 when contacting the NRC about the availability of information for this action. You may obtain publicly available information related to this action by any of the following methods:

• Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2026-0562. Address questions about NRC dockets to Helen Chang, telephone: 301-415-3228, email: Helen.Chang@nrc.gov. For technical questions contact the individual listed in the FOR FURTHER INFORMATION CONTACT section of this document.
• NRC's Agencywide Documents Access and Management System (ADAMS): You may obtain publicly available documents online in the ADAMS Public Documents collection at https://www.nrc.gov/​reading-rm/​adams.html. To begin the search, select “Begin ADAMS Public Search.” For problems with ADAMS, please contact the NRC's Public Document Room (PDR) 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.
• NRC's 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, Monday through Friday, except Federal holidays.

B. Submitting Comments

The NRC encourages electronic comment submission through the Federal rulemaking website (https://www.regulations.gov). Please include Docket ID NRC-2026-0562 in your comment submission.

The NRC cautions you not to include identifying or contact information that you do not want to be publicly disclosed in your comment submission. The NRC will post all comment submissions at https://www.regulations.gov as well as enter the comment submissions into ADAMS. The NRC does not routinely edit comment submissions to remove identifying or contact information.

If you are requesting or aggregating comments from other persons for submission to the NRC, then you should inform those persons not to include identifying or contact information that they do not want to be publicly disclosed in their comment submission. Your request should state that the NRC does not routinely edit comment submissions to remove such information before making the comment submissions available to the public or entering the comment into ADAMS.

II. Rulemaking Procedure

Because the NRC considers this action to be non-controversial, the NRC is publishing this proposed rule concurrently with a direct final rule in the Rules and Regulations section of this issue of the Federal Register. The direct final rule will become effective on June 16, 2026. However, if the NRC receives any significant adverse comment by May 4, 2026, then the NRC will publish a document that withdraws the direct final rule. If the direct final rule is withdrawn, the NRC will address the comments in a subsequent final rule. In general, absent significant modifications to the proposed revisions requiring republication, the NRC will not initiate a second comment period on this action in the event the direct final rule is withdrawn.

A significant adverse comment is a comment where the commenter explains why the rule would be inappropriate, including challenges to the rule's underlying premise or approach, or would be ineffective or unacceptable without a change. A comment is adverse and significant if:

(1) The comment opposes the rule and provides a reason sufficient to require a substantive response in a notice-and-comment process. For example, a substantive response is required when:

(a) The comment causes the NRC to reevaluate (or reconsider) its position or conduct additional analysis;

(b) The comment raises an issue serious enough to warrant a substantive response to clarify or complete the record; or

(c) The comment raises a relevant issue that was not previously addressed or considered by the NRC.

(2) The comment proposes a change or an addition to the rule, and it is apparent that the rule would be ineffective or unacceptable without incorporation of the change or addition.

(3) The comment causes the NRC to make a change (other than editorial) to the rule, certificate of compliance, or technical specifications.

For a more detailed discussion of the proposed rule changes and associated analyses, see the direct final rule published in the Rules and Regulations section of this issue of the Federal Register.

III. Background

Section 218(a) of the Nuclear Waste Policy Act of 1982, as amended, requires that “[t]he Secretary [of the Department of Energy] shall establish a demonstration program, in cooperation with the private sector, for the dry storage of spent nuclear fuel at civilian nuclear power reactor sites, with the objective of establishing one or more technologies that the [Nuclear Regulatory] Commission may, by rule, approve for use at the sites of civilian nuclear power reactors without, to the maximum extent practicable, the need for additional site-specific approvals by the Commission.” Section 133 of the Nuclear Waste Policy Act states, in part, that “[t]he Commission shall, by rule, establish procedures for the licensing of any technology approved by the Commission under Section 219(a) [sic: 218(a)] for use at the site of any civilian nuclear power reactor.”

To implement this mandate, the Commission approved dry storage of spent nuclear fuel in NRC-approved casks under a general license by publishing a final rule that added a new subpart K in part 72 of title 10 of the Code of Federal Regulations (10 CFR) entitled “General License for Storage of Spent Fuel at Power Reactor Sites” (55 FR 29181; July 18, 1990). This rule also established a new subpart L in 10 CFR part 72 entitled “Approval of Spent Fuel Storage Casks,” which contains procedures and criteria for obtaining NRC approval of spent fuel storage cask designs. The NRC subsequently issued a final rule on March 6, 2015 (80 FR 12073), as corrected (80 FR 15679; March 25, 2015), that approved the Holtec International HI-STORM UMAX Canister Storage System design and added it to the list of NRC-approved ( printed page 16590) cask designs in § 72.214 as Certificate of Compliance No. 1040.

IV. Plain Writing

The Plain Writing Act of 2010 (Pub. L. 111-274) requires Federal agencies to write documents in a clear, concise, and well-organized manner. The NRC has written this document to be consistent with the Plain Writing Act as well as the Presidential Memorandum, “Plain Language in Government Writing,” published June 10, 1998 (63 FR 31885). The NRC requests comment on this proposed rule with respect to clarity and effectiveness of the language used.

V. Regulatory Planning and Review

Executive Order (E.O.) 12866

Executive Order (E.O.) 12866, as amended by E.O. 14215, provides that the Office of Information and Regulatory Affairs (OIRA) will determine whether a regulatory action is significant as defined by E.O. 12866 and will review significant regulatory actions. OIRA determined that this proposed rule is not a significant regulatory action under E.O. 12866.

VI. Availability of Documents

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

| Document | ADAMS

                            accession No./web link/ **Federal Register** citation |

| --- | --- |
| Proposed Certificate of Compliance and Technical Specifications Documents | |
| User Need Memo for Amendment No. 5 of the Certificate of Compliance No. 1040 for the Holtec HI-STORM UMAX Storage System | ML26013A271 |
| Proposed CoC No. 1040, Amendment No. 5 | ML26013A272 |
| Proposed Technical Specifications for CoC No. 1040, Amendment No. 5, Appendix A | ML26013A273 |
| Proposed Technical Specifications for CoC No. 1040, Amendment No. 5, Appendix B | ML26013A274 |
| Preliminary Safety Evaluation Report for CoC No. 1040, Amendment No. 5 | ML26013A275 |
The NRC may post materials related to this document, including public comments, on the Federal rulemaking website at https://www.regulations.gov under Docket ID NRC-2026-0562. In addition, the Federal rulemaking website allows members of the public to receive alerts when changes or additions occur in a docket folder. To subscribe: (1) navigate to the docket folder (NRC-2026-0562); (2) click the “Subscribe” link; and (3) enter an email address and click on the “Subscribe” link.

Dated: March 20, 2026.

For the Nuclear Regulatory Commission.

Michael King,

Executive Director for Operations.

[FR Doc. 2026-06374 Filed 4-1-26; 8:45 am]

BILLING CODE 7590-01-P

Published Document: 2026-06374 (91 FR 16588)