49 CFR § 173.426 - Excepted packages for articles containing natural uranium or thorium.
A manufactured article in which the sole Class 7 (radioactive) material content is natural uranium, unirradiated depleted uranium or natural thorium, and its packaging, are excepted from the requirements in this subchapter for specification packaging, labeling, marking (except for the UN identification number marking requirement described in § 173.422(a)), and if not a hazardous substance or hazardous waste, shipping papers and the requirements of this subpart if:
(b) The outer surface of the uranium or thorium is enclosed in an inactive sheath made of metal or other durable protective material;
(c) The conditions specified in § 173.421 (b), (c) and (d) are met; and
(d) The article is otherwise prepared for shipment as specified in § 173.422.