Diffusion of Tc-99 in granite: A small scale laboratory simulation experiment

摘要

The diffusion of Tc-99 in granite was investigated with small-sized diffusion cells, composed of a radioactive source solution cell and a sampling cell. Water in the two cells was kept at the same level. I ml aliquots were taken from the sampling cells daily during the first 50 days, then at intervals of several days, and measured via liquid scintillation counting. The experimental results indicate that the diffusion of Tc-99 and H-3 in granite follows the one-dimensional diffusion equation when diffusion time is long enough (> 100 days). The calculated average diffusion coefficient of Tc-99 (1.4 x 10(-12) m(2)/s) is about one half of that of H-3 (3.2 x 10(-12) in m(2)/s). [References: 12]