Towards molecular laser separation of uranium isotopes
G.N. Makarov† Institute of Spectroscopy, Russian Academy of Sciences, ul. Fizicheskaya 5, Troitsk, Moscow, 108840, Russian Federation
About half a century ago, active research began on the use of lasers for the separation of isotopes, including uranium isotopes. In a number of highly developed countries, projects on laser separation of uranium isotopes were initiated. However, in the late 1990s, these projects were closed. At the same time, research on laser separation of uranium isotopes is being carried out in a number of countries at the present time. Research today is mainly focused on the development of low energy methods. A review of the results of studies on molecular laser isotope separation (MLIS) of uranium is presented. MLIS methods, including low-energy methods, as well as the physicochemical processes underlying them, are considered. The infrared and ultraviolet absorption spectra of UF6 molecules, which form the basis of uranium MLIS methods, are presented and discussed. Lasers that have been developed and used to excite and dissociate UF6 molecules are briefly described. The results of studies on laser dissociation of UF6 molecules using different excitation schemes and laser separation of uranium isotopes are presented and analyzed. Applications of low-energy MLIS methods, including SILEX technology, for the separation of uranium isotopes are considered. In the context of molecular laser separation of uranium isotopes using low-energy methods, the recently obtained results on the separation of isotopes in SF6 and CF3Br molecules, which are close analogs of UF6 molecules in a number of spectroscopic properties, are presented and analyzed. Approaches that can be a promising alternative to low-energy MLIS methods are discussed. Data on the efficiency of some laser methods and their comparison with each other are given. A brief historical excursion into research on laser separation of uranium isotopes is given.