Development of diffusion database of rock and buffer materials

Tochigi, Yoshikatsu; Tachi, Yukio  

The database for utilizing the data related to the diffusion coefficient of nuclides in the buffer material and rock was improved on the basis of the existing diffusion database. Renewals of database definition include maintenance of database contents, extension of stored data scope, etc. The database was updated with especially emphasis on introduction of estimated value in data evaluation and description concerning reliability of information. Existing data of domestic rock were updated by implementation of the result of literature survey in accordance with the definition of updated database and new data of domestic bentonite. As the result of data addition, total data count of effective diffusion coefficient is about 450 and that of apparent diffusion coefficient is about 1,350. As an example of practical use of the improved database, the example of evaluation for the plot of a diffusion coefficient of dry density or porosity was discussed.