Sorption of cesium by graphites as a function of strontium and barium concentration at high temperatures. Progress report, February, 1, 1975--January 31, 1976

Cesium desorption isotherms on H-451 graphite were obtained at 800, 900, 1000, and 1100$sup 0$C. Hysteresis was observed at cesium vapor pressures below 5 x 10$sup -6$ atm on the 1000$sup 0$C isotherm. A cesium background experiment indicated that the sorption tube background contribution is not a major factor in assessing the cesium behavior within the higher vapor pressure range. One strontium desorption experiment was conducted, using H-451 graphite impregnated to 2.28 $mu$moles Sr/g C. Two sorption experiments on strontium impregnated H-451 graphite (approximately 5 and approximately 1 $mu$mole/g) are about to begin. From the preliminary analysis of the kinetic behavior, it is concluded that the lengthy times required for the graphite sample to equilibrate (3 to 12 days) is determined by the diffusion of cesium atoms from graphite pore surfaces into the graphite grains. One sorption sample was radially profiled upon completion of a 1000$sup 0$C sorption experiment, and this profile was analyzed. Concentration- dependent strontium diffusion studies on H-451 graphite have also begun at 1600$sup 0$K, with an initial uniform strontium concentration of 10 $mu$g Sr/g C in the first experiment. Electron microprobe qualitative analyses are being conducted on H-451 graphite samples