Improvement of the model for surface process of tritium release from lithium oxide

Among the various tritium transport processes in lithium ceramics, the impo rtance and the detailed mechanism of surface reactions remain to be elucida ted. The dynamic adsorption and desorption model for tritium desorption fro m lithium ceramics, especially Li2O was constructed. From the experimental results, it was considered that both H-2 and H2O are dissociatively adsorbe d on Li2O and generate OH- on the surface. In the first model developed in 1994, it was assumed that either the dissociative adsorption of H-2 or H2O on Li2O generates two OH- on the surface. However, recent calculation resul ts show that the generation of one OH- and one H- is more stable than that of two OH- s by the dissociative adsorption of H-2 Therefore, assumption of H-2 adsorption and desorption in the first model is improved and the triti um release behavior from Li2O surface is evaluated again by using the impro ved model. The tritium residence time on the Li2O surface is calculated usi ng the improved model, and the results are compared with the experimental r esults. The calculation results using the improved model agree well with th e experimental results than those using the first model. (C) 2000 Elsevier Science B.V. All rights reserved.