((a)) Whoever willfully, with intent to endanger the safety of any person on board or anyone who he believes will board the same, or with a reckless disregard for the safety of human life, damages, disables, destroys, tampers with, or places or causes to be placed any explosive or other destructive substance in, upon, or in proximity to, any motor vehicle which is used, operated, or employed in interstate or foreign commerce, or its cargo or material used or intended to be used in connection with its operation; or

((b)) Whoever is convicted of a violation of subsection (a) involving a motor vehicle that, at the time the violation occurred, carried high-level radioactive waste (as that term is defined in section 2(12) of the Nuclear Waste Policy Act of 1982 ()) or spent nuclear fuel (as that term is defined in section 2(23) of the Nuclear Waste Policy Act of 1982 ()), shall be fined under this title and imprisoned for any term of years not less than 30, or for life.