Code of Federal Regulations Title 10. Energy 10 CFR Pt. 110, App. M—Categorization of Nuclear Material

1. Plutonium ¹

Unirradiated ²

2 kg or more

Less than 2 kg but more than 500 g

500 g or less but more than 15 g.

2. Uranium-235 (²³⁵U)

Unirradiated ²:

—Uranium enriched to 20 percent ²³⁵U or more

5 kg or more

Less than 5 kg but more than 1 kg

1 kg or less but more than 15 g.

—Uranium enriched to 10 percent ²³⁵U but less than 20 percent ²³⁵U

10 kg or more

Less than 10 kg but more than 1 kg.

—Uranium enriched above natural, but less than 10 percent ²³⁵U

10 kg or more.

3. Uranium-233 (²³³U)

Unirradiated ²

2 kg or more

Less than 2 kg but more than 500 g

500 g or less but more than 15 g.

4. Irradiated Fuel (The categorization of irradiated fuel in the table is based on international transport considerations. The State may assign a different category for domestic use, storage and transport taking all relevant factors into account).

Depleted or natural uranium, thorium or low enriched fuel (less than 10 percent fissile content) ⁴⁵