The Practical and Physical Aspect of Uranium Isotope Separation with Lasers

Today, the most actively pursued uranium laser isotope separation methods work with uranium vapor, organic uranium compounds, or uranium hexafluoride. The atomic vapor process has reached the highest development level, but its commercial realization is facing severe obstacles due to the aggressivity of the uranium vapor and the low working pressure. For a commercial separation plant, UF₆ would be the most attractive process gas. A promising approach to overcome the problems caused by the small UF₆ isotope shift seems to be the use of two infrared wavelengths in the 16- and 9-μm range. Currently, only the CO₂ laser pumped CF₄ laser and the stimulated rotational Raman scattering of CO₂ laser radiation in para-hydrogen are able to provide the energies required for the selective 16-μm excitation, with the Raman method offering better prospects with regard to scalability and frequency tuning. The state-of-the-art of both of these lasers is not advanced enough for a commercial separation plant, where a narrowing of the complex UF₆ spectrum by means of a supersonic beam is probably indispensable. Their development level, however, is sufficient to carry through the experiments necessary to clarify the still unanswered questions, i.e., to what extent and with what yield the absorption differences of the two isotopic UF₆ species can be transformed into a selective dissociation.