The present invention pertains generally to isotope separation and more particularly to non-laser separation of deuterium and tritium from hydrogen.
Isotope separation is becoming increasingly important as new uses are discovered for the less common isotopes and as the amount of nuclear wastes increases. Of particular interest is the separation of hydrogen isotopes. It is of great interest both from an enrichment point of view (heavy water production) and from a purification point of view (tritium removal from nuclear wastes). For proposed processes of separating deuterium, the main concern involves decreasing overall energy costs to the point where the new process becomes competitive with the current processes and eliminating the need for substances which are corrosive or toxic (such as H.sub.2 S in the G.S. process) or expensive (such as catalysts in any of the other exchange processes). The concentration and removal of tritium from nuclear fuel cycle waste streams places stringent demands on proposed processes due to the problems associated with manipulation of radioactive materials. Such processes must have simple, small, and maintenance free equipment, have a large separation factor .beta., and remove tritium from the processed material rather than the light isotope, protium.
Recently a new technique for separating isotopes has been developed, which avoided many of the difficulties associated with currently used techniques, e.g. deadly and corrosive gases, scarce reactants, and high energy requirements. The technique utilizes a glow discharge to enhance the rates of isotopically selective chemical reactions at low temperatures. Without a glow discharge, the reaction would be too slow at the very low temperature necessary to obtain substantial isotope effects. Isotope separation is due to the dramatic increase of kinetic and equilibrium isotope effects. The translational temperature provides the enrichment conditions and the glow discharge provides the reaction rate for the enrichment process.
Basic to this method is the discovery of a reaction which produces reactive species whose net effect is a segregation of isotopes. Further, the energy requirements for the production of these species must be such that the process is self-sustaining or nearly so. Unfortunately, few reactions have these characteristics.
The published work in this area shows that reactions selected so far have a number of drawbacks. Basov and his colleagues reacted oxygen with nitrogen in order to separate nitrogen -15 from nitrogen -14. Their work was reported in Basov et al. Isotope Separation in Chemical Reactions Occurring under Thermodynamic Nonequilibrium Conditions. In JETP Lett. 19(6): p. 190-1, Mar. 20, 1974, and is Basov et al. Kinetics of Nonequilibrium Chemical Reactions and Separation of Isotopes. In Sov. Phys - Jetp 41(6): p. 1017-9, 1976. The reported yields have not been duplicated and the hypothesized mechanism has not been confirmed. Clark and Manuccia reacted hydrogen with nitrogen in order to separate hydrogen isotopes. This method has become the subject of U.S. Pat. No. 4,036,720. The disadvantages of this process is that the lightest isotope, protium, is withdrawn from the gases being processed and a condensation of the product occurs at the walls of the reactor which reduces the throughput and the energy efficiency of the process.