Not that easy to get raw uranium, so there is no "cheap" method. Your best bet is to be scrupulous about the proven methods and prevent any loss of the valuable uranium (which will preclude or minimize any heavy-metal toxic risk). DU would be available only as a byproduct of uranium enrichment. The "green" energy industry has no use for nuclear power, which source completely undermines the argument for the "green" ("renewable") power systems.
Not that easy to get raw uranium, so there is no "cheap" method. Your best bet is to be scrupulous about the proven methods and prevent any loss of the valuable uranium (which will preclude or minimize any heavy-metal toxic risk). DU would be available only as a byproduct of uranium enrichment. The "green" energy industry has no use for nuclear power, which source completely undermines the argument for the "green" ("renewable") power systems.