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

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

JAEA-Data/Code 2025-004, 48 Pages, 2025/11

JAEA-Data-Code-2025-004.pdf:1.34MB

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.

None

Matsubara, Ryuta*; Ishidera, Takamitsu; Eguchi, Ayano

NUMO-TR-25-03, p.83 - 88, 2025/10

no abstracts in English

None

Matsubara, Ryuta*; Hamamoto, Takafumi*; Ishidera, Takamitsu

NUMO-TR-24-03, p.65 - 70, 2024/10

https://www.numo.or.jp/technology/technical_report/pdf/NUMO-TR-24-03.pdf

no abstracts in English

Trivalent lanthanide sorption onto illite in the presence of carbonate; A Study combining thermodynamic sorption modeling, time-resolved laser fluorescence spectroscopy, and parallel factor analysis

Sugiura, Yuki; Ishidera, Takamitsu; Aoyagi, Noboru; Mei, H.; Saito, Takumi*; Tachi, Yukio

Applied Clay Science, 258, p.107476_1 - 107476_10, 2024/09

https://doi.org/10.1016/j.clay.2024.107476

Evaluation of the effects of bentonite colloids

Matsubara, Ryuta*; Hamamoto, Takafumi*; Ishidera, Takamitsu

NUMO-TR-24-01, p.91 - 94, 2024/05

no abstracts in English

Long-term alteration behavior of buffer material by the interaction with overpack and cement

Hamamoto, Takafumi*; Ishidera, Takamitsu; Sasamoto, Hiroshi

NUMO-TR-24-01, p.87 - 90, 2024/05

no abstracts in English

Sorption of Sn and Nb on montmorillonite at neutral to alkaline pH

Ishidera, Takamitsu; Okazaki, Mitsuhiro*; Yamada, Yoshihide*; Tomura, Tsutomu*; Shibutani, Sanae*

Journal of Nuclear Science and Technology, 60(5), p.536 - 546, 2023/05

https://doi.org/10.1080/00223131.2022.2125453

The distribution coefficient () value of radionuclides is an important parameter in the radionuclide migration analysis in the safety assessment of the geological disposal of high-level radioactive waste. The values must be extensively evaluated especially under conditions where they might be decreased to improve the reliability of safety assessment. In this study, the pH dependence of the values for Sn and Nb on montmorillonite was evaluated using batch sorption experiments at neutral to alkaline pH, which might be caused by the leaching of cementitious materials and the corrosion of carbon steel. The values were determined in the range 8 pH 12 by the experiments and were found to decrease with increasing pH. A model calculation using a thermodynamic sorption model was conducted on the measured pH dependence of the values. Two different sorption sites were required to describe the pH dependence of the values of Sn in the model calculation, whereas one sorption site was considered predominant in the sorption of Nb.

None

Hamamoto, Takafumi*; Ishida, Keisuke*; Ishidera, Takamitsu; Tachi, Yukio

NUMO-TR-22-02, p.88 - 89, 2023/03

https://www.numo.or.jp/technology/technical_report/NUMO-TR-22-02.pdf

no abstracts in English

Effects of buried environment on corrosion of iron artifacts excavated from Heijo Palace Site; Examination of the chloride salt accumulation inside of an iron artifact in soil

Yanagida, Akinobu*; Ura, Yoko*; Mitsui, Seiichiro; Ishidera, Takamitsu; Kawakita, Ryohei

Nara Bunkazai Kenkyujo Soritsu 70-Shunen Kinen Rombunshu; Bunkazai Ronso 5, p.843 - 856, 2023/03

To investigate chloride salt accumulation inside an iron artifact in soil, non-destructive analysis of three iron artifacts excavated from the Heijo Palace Site was conducted using elemental mapping by X-ray fluorescence analysis, micro-X-ray diffraction analysis, and X-ray computed tomography. Furthermore, the buried environments of the artifacts were presumed based on the previous reports of the environmental investigation at the Heijo Palace site. The results revealed the iron artifact's corrosion behavior was different individually- (1) the iron artifact that was presumed buried under oxidation environments had a goethite/magnetite corrosion layer and contained akageneite inside the corrosion layer. (2) the metal of the other iron artifacts buried under the oxidation environment had eluted absolutely and the artifacts had a rust layer formed by only goethite. (3) the other artifact buried in reduction environments had a rust layer composed of siderite. Accumulation of chloride salts inside an iron artifact was observed only in (1). Because each Cl concentration measured in underground water observation holes at the Heijo Palace Site showed almost the same level concentrations, it was presumed that the accumulation of chloride salts depended on the environmental factor except for Cl concentration. Based on these results, there was a possibility that the occurrence of local corrosion attributed to the separation of anodic and cathodic regions through the formation of the goethite/magnetite rust layer caused chloride salts accumulation inside an iron artifact.

Diffusion of acetic acid, butyric acid, and butanol in compacted montmorillonite

Ishidera, Takamitsu

Journal of Radioanalytical and Nuclear Chemistry, 330(1), p.149 - 158, 2021/10

https://doi.org/10.1007/s10967-021-07953-z