The Kinetics That Govern the Release of Tritium From Neutron-Irradiated Lithium Oxide

• Published in: Journal of nuclear materials 1988-02, Vol.151 (3), p.281-292
• Main Author: Bertone, P C
• Format: Article
• Language: English
• ISSN: 0022-3115

A kinetic model is presented that describes the release of tritium from a neutron-irradiated lithium oxide crystal. According to the model, the release is (1) controlled by diffusion of T through the crystal when ak/D > 10; (2) controlled by the desorption of tritiated water from the crystal when ak/D < 1; and (3) controlled by a combination of these processes when 1 < ak/D < 10, where a is a characteristic crystal size, k is the governing desorption rate constant, and D is the governing diffusion coefficient. This model explains the lack of agreement among prior studies because it predicts both diffusion-controlled and desorption-controlled kinetics. As an initial test of this model, preliminary release experiments in the desorption-controlled region were performed. As expected, the observed release was consistent with a desorption-controlled theory. In addition, k was found to be 6.5 x 10 exp 2 e exp --(119 kJ/mol)/RT cm/s. 15 ref.--AA