NRC Package Rule Skips Criticality Limits That Govern Fresh HALEU Shipments
A proposed NRC rule to modernize certification of fuel transportation packages was published on July 27, 2026, and its comment period closes August 26 under Docket ID NRC-2025-1667, according to Neutron Bytes.
The proposal addresses radiation dose limits and testing methodology, Neutron Bytes reported, while the fissile-package criticality provisions at 10 CFR 71.55 and 71.59 stay as written, with no amendment, no discussion, and no invitation to comment.
Criticality rather than dose is what governs fresh high-assay low-enriched uranium. Neutron Bytes counts three things an advanced fuel cycle moves: fresh fuel, fresh fueled reactors, and irradiated reactors. Dose governs the irradiated category alone, and that is the only one the rule helps.
The 71.55(g) moderation exception, which permits uranium hexafluoride shippers to assume water stays out of a package, stops at 5 wt% U-235, per Neutron Bytes. Enrichment for HALEU runs between 5 and 20 percent U-235. The exception therefore ends where the HALEU band begins.
On dose, Neutron Bytes reported that the 0.1 mSv/h limit measured 2 meters from the vehicle stays in place. An alternative of 0.5 mSv/h is proposed for a narrow case only: package contents meeting the highway route controlled quantity definition in 49 CFR 173.403, plus advance coordination by the licensee with Federal, State, or local inspection authorities.
Enrichment build-out is already under way. Centrus expects 12 metric tons of annual HALEU capacity from its initial build-out, with first new capacity by 2029, Neutron Bytes reported. Separately, DOE is funding five companies on two-and-three-year schedules to develop and license transport packages.
Those package licensing schedules and the Centrus capacity timeline run alongside criticality provisions for fresh HALEU packages that the proposal leaves unchanged.
Source: neutronbytes.com (opens in a new tab)1 sourcePermalink