Transmission of a Gaseous Radioactive Isotope Through an Adsorber Bed

The time-dependent and steady-state solutions for the transmission of a gaseous radioactive isotope through an adsorber bed are derived. The transmission, defined as the ratio of the outlet concentration to the inlet concentration, depends on three dimensionless quantities, namely, the dispersion number Δ, the product of the radioactive decay constant and the propagation time λtp, and the dimensionless time t/t_p. Based on the mathematical results, criteria are given for the design of adsorber beds for decreasing the concentration of a radioactive contaminant. An example illustrates the possibility of reducing the radioactivity of short-lived xenon isotopes in a carrier gas flowing through adsorber beds; however, consideration must be given to the low efficiency of the adsorber bed resulting from dispersion effects.