Isotopic Enrichment of Plasma Exhausts from Controlled Thermonuclear Reactors by Cryogenic Distillation

Isotopic enrichment of the spent fuels from deuterium-tritium (D-T)-burning tokamak-type power reactors is an essential processing step in the reactor fuel cycle. Analysis of cryogenic distillation as a method for accomplishing this enrichment was carried out using computer methods to simulate the required multicomponent separation of the six isotopomeric forms of molecular hydrogen. The application of matrix inversion techniques (as opposed to iterative methods) resulted in rapid convergence even for simultaneous analyses of multicolumn configurations having a wide range of input and output conditions. Two distinctly different fuel cycle scenarios were studied:

1. 90% cold fuel injection at a T/D ratio of accompanied by neutral beam injection of deuterons (D°) comprising the remaining 10% of the delivered fuel
2. total fueling by injection of equal atomic fractions of neutral tritons (T°) and neutral deuterons (D°).

A cascade design with four to six columns (containing ∼200 total theoretical stages) and one equilibrator (in the top section of the cascade) can adequately meet the enrichment requirements for case 1. The case 2 requirements can be met with five columns and two equilibrators. In general, it was found that separation of the isotopomeric species of hydrogen can be carried out to any degree of purity by judicious selection of (a) the design and operating parameters and (b) the number of distillation columns, appropriately interspersed with chemical equilibrators.