The combined electrolysis-catalytic-exchange pilot system was modified to improve the reliability of the unit for continuous operation. An experimental run for 60 consecutive hours using a single catalytic exchange column was made to estimate values of height of a transfer unit and height equivalent to a theoretical plate for the pilot system. The calculated values were in agreement with existing data from a bench-scale system. Further experiments were performed with the cryogenic hydrogen isotope distillation system, this time using H/sub 2/-HT mixtures. A mixture containing approximately 250 Ci/m/sup 3/ of HT in H/sup 2/ was stripped to less than 0.1 Ci/m/sup 3/, while a product of 1100 Ci/m/sup 3/ was recovered. Two experiments were successful in separating gaseous hydrogen containing tritium from tritiated water. Initial tritium concentrations of the water were approximately 1 and 10 Ci/cm/sup 3/. Radiolytic damage tests of a hydrophobic exchange catalyst being used in the development of a process to recover tritium from tritiated waste water are reported. Triplicate samples of cement, cement-plaster (1:1 ratio by weight), and cement-plaster (1:1 ratio by volume) were injected with 386 Ci of tritium, cured for five days, and then impregnated with catalyzed styrene monomer. After polymerization, the samples were …