The U.S. fusion-specific regulatory framework (Federal Register 91(38), February 26, 2026) regulates fusion machines under the byproduct-materials regime — a risk-informed path built for what fusion actually is, and one that fits MetroVolt unusually well.
Fission licensing exists because of criticality, meltdown decay heat, and bulk actinide inventories; fusion has none of the three, and now the rulebook says so. Under the framework, the licensing conversation centers on the actual source terms: tritium inventory, activation products, and effluents.
That is where MetroVolt's fuel choice compounds: sub-kilogram site tritium (a design rule), ~25× lower structural activation than a D-T comparator, a low-level-waste decommissioning pathway, and a 5.25% neutron budget shrinking the shielding and dose analysis the application must carry. The series maps each source term to its deposited analysis.
Regulatory schedule is a first-order cost driver for any first-of-a-kind plant. A byproduct-materials path, entered with the smallest source terms in the fusion field and an auditable analysis behind each one, is a licensing story measured in years — not the decade-class sagas that priced fission out of new builds.
| Framework | Federal Register 91(38), 26 Feb 2026 |
| Regime | byproduct materials (risk-informed) |
| MetroVolt source terms | <1 kg T · ~25× lower activation · LLW path |
| Neutron budget entering analysis | 5.25% |
| Basis | each source term → deposited analysis |