ML25346A277

Enclosure - Request for Additional Information for the Review of Certificate of Compliance No. 9294, Revision 11, Model No. New Powder Container

ML25346A277
Person / Time
Site:	07109294
Issue date:	12/18/2025
From:	Storage and Transportation Licensing Branch
To:	Schichlein L Global Nuclear Fuel
Shared Package
ML25346A275	List: ML25346A276 ML25346A277
References
CAC 001029, EPID L-2025-LLA-0079
Download: ML25346A277 (0)

Text

Enclosure Request for Additional Information Certificate of Compliance No. 9294 Docket No. 71-9294 Revision No. 11 Model No. New Powder Container (NPC)

This request for additional information (RAI) identifies information needed by the U.S. Nuclear Regulatory Commission (NRC) staff (the staff) in connection with its review of the application.

The staff used NUREG-2216, Standard Review Plan for Transportation Packages for Spent Fuel and Radioactive Material: Final Report, (NUREG-2216) in its review of the application.

The RAI describes information needed by the staff to complete its review of the application and to determine whether the applicant has demonstrated compliance with the regulatory requirements of 10 CFR Part 71.

CRITICALITY SAFETY EVALUATION RAI-Cr-1 Provide a supplement to the criticality safety evaluation Revision 11 for the Model No. NPC package assuming that all ICCAs are being fully flooded and explain how the evaluation demonstrates compliance with 10 CFR 71.55(b). Include this information in the application.

In Section 6.1 of NEDE-33881P, Revision 8, of the NPC Safety Analysis Report (SAR), it is stated:

Water exclusion from all but two of the [Inner Containment Canister Assemblies] ICCAs is required for this package design. Each container arrays under optimal moderation conditions. The most reactive configuration of the ICCAs for the packages was identified.

The criticality analysis included in the report follows this approach. However, NRC staff (the staff) identified a potential regulatory concern with this methodology.

Specifically, this approach may not align with the requirements of 10 CFR 71.55(b), which states the following:

Except as provided in paragraph (c) or (g) of this section, a package used for the shipment of fissile material must be so designed and constructed and its contents so limited that it would be subcritical if water were to leak into the containment system, or liquid contents were to leak out of the containment system so that, under the following conditions, maximum reactivity of the fissile material would be attained:

(1)

The most reactive credible configuration consistent with the chemical and physical form of the material;

2 (2)

Moderation by water to the most reactive credible extent; and (3)

Close full reflection of the containment system by water on all sides, or such greater reflection of the containment system as may additionally be provided by the surrounding material of the packaging.

The most reactive credible extent of moderation would involve all ICCAs being fully flooded, not just two. This interpretation is consistent with current regulatory expectations and with the methodology used in the previous revision of the SAR for this package.

To assess the potential safety implications, staff conducted preliminary calculations using the input files provided by the licensee as a starting template.

These calculations indicate that, under conditions where all ICCAs are fully flooded and loaded with 8 weight percent (wt.%) uranium 235 (U-235), using the Heterogeneous Optimal Particle Size Fuel model, there is a potential to exceed the Upper Subcritical Limit (USL) and a keff of 0.95 for a single package.

The staff requests that the applicant reviews this issue and provide clarification or revised analysis demonstrating compliance with 10 CFR 71.55(b).