Prospects for uranium enrichment

The biggest technological barrier to practical laser enrichment of U isotopes is the lack of suitable lasers. The major motivation behind studies of laser-induced photochemical enrichment of uranium is the potential efficiency of the technique. A gaseous-diffusion plant requires ten million times more energy to separate fissionable uranium-235 from the more-common uranium-238 than the theoretical minimum of 60 joules per gram calculated from the entropy of mixing one gram of 235U with 140 g of 238U. The centrifuge process requires only one-tenth the energy needed for gaseous diffusion, but laser techniques promise to be 100 times more efficient than the centrifuge. The laser approach also can provide higher enrichment factors per stage, thereby reducing energy requirements and size of a uranium-enrichment plant. It is noted that laser-induced isotope separation has been shown to be feasible with a variety of conceptually different approaches. The major challenge now is to build lasers with reliability and efficiency adequate to move the emphasis to economic feasibility