Tritium waste control: July--September 1978. [Catalytic exchange detritiation; fixation of aqueous tritiated waste in polymer-impregnated concrete; gas generation by self-radiolysis of polymer-impregnated concrete

Abstract

The combined Electrolysis Catalytic Exchange system was modified to allow better control of experimental conditions and to prevent the overflow of water into the air detritation system. A program designed to regenerate the activity of the hydrophobic catalyst was also completed. Slight differences in the release rate of high specific activity tritiated liquid wastes from the drums are now beginning to appear. The three drums with the highest fractional permeation rate had the least amount of tritium when packaged. The fractional permeation rate of the two octane drums appears to have leveled off at about the same rate as the oil and water drums. Tests continued on samples of cement and cement-plaster mixtures which were injected with 386 Ci of tritiated water, cured, and then impregnated with catalyzed styrene monomer. After polymerization, the samples were put into uncontaminated water and the tritium concentration was monitored. No significant differences were noted except in two cases when the polyethylene bottle had been removed, which resulted in 35 to 80 times more tritium being released into the surrounding water. Full scale (cold) waste drum No. 5 was polymerized with excellent results. Pressure increase and gas composition were measured over (1) tritiated water withoutmore » fixation, (2) polymer-impregnated concrete, and (3) nonpolymer concrete. Activities for all samples were 10 Ci/m/sup 3/. Pressure buildup results are essentially the same for concrete made with tritiated distilled water and tritiated waste water. However, the pressure buildup rate is slightly higher for the polymer impregnated concrete than for the nonpolymer concrete. Mass analysis of the cover gas over tritiated water without fixation and over the polymer and nonpolymer concrete samples made with tritiated waste water show that hydrogen represents about 85% of the gas generated.« less