Development of JAEA sorption database (JAEA-SDB); Update of sorption/QA data in FY2024

Sugiura, Yuki  ; Suyama, Tadahiro*; Ishidera, Takamitsu 

The sorption of radionuclides (RNs) on buffer materials (bentonites), rocks, and cementitious materials is a key process in the safe geological disposal of radioactive waste because it can retard the migration of RNs in these materials. Therefore, the RN sorption process should be fully understood and a database of reliable data and mechanistic/predictive models should be developed to allow the use of reliable parameters under various geochemical conditions relevant to performance assessment (PA). Thus, the Japan Atomic Energy Agency (JAEA) has developed a database of sorption parameters on bentonites, rocks, and cementitious materials. This sorption database (SDB) was first developed to be a basis for the H12 PA for high-level radioactive waste disposal and was made available online. JAEA continuously improves and updates the SDB based on potential future needs of data, especially focusing on assuring the desired quality level and testing the usefulness of the databases in setting PA-related sorption parameters. This report focuses on updating the sorption database (JAEA-SDB) as a basis for an integrated approach to setting a PA-related distribution coefficient (K) and developing mechanistic sorption models. Moreover, this report includes an overview of the database structure and contents. The K data and their quality assurance (QA) results were updated based on the literature collected with wide ranges. K data (7,670 entries) from 73 references were included in this update, bringing the total number of K values in the JAEA-SDB to more than 86,000. In addition, QA evaluation and classification were performed to the K data already recorded in the JAEA-SDB for which QA evaluation had not been performed. By incorporating the most recent K data and assigning QA levels to all K data, the reliability of the JAEA-SDB as fundamental information for setting K parameters in future PA was improved.