JOPSS - Search Results

NUMO and JAEA have developed the methodology of post-closure safety assessment for the geological disposal. For this purpose, NUMO and JAEA have conducted a collaborative research project for developing the safety assessment methodology based on international state of the art knowledge. The present report focuses on investigation of sorption and diffusion data reported and their QA evaluation for updating sorption and diffusion database (SDB and DDB) as the collaborative research project between NUMO and JAEA. This report includes sorption and diffusion data for mainly sedimentary rocks and cement materials. As a result, 1,746 sorption data from 19 references and 593 diffusion data from 25 references were extracted and prepared in the datasheet of SDB and DDB.

Journal Articles

Assessment of sorption and diffusion in the rock matrix in the NUMO safety case

Hamamoto, Takafumi*; Shibutani, Sanae*; Ishida, Keisuke*; Fujisaki, Kiyoshi*; Yamada, Motoyuki*; Tachi, Yukio

Proceedings of 6th East Asia Forum on Radwaste Management Conference (EAFORM 2017) (Internet), 6 Pages, 2017/12

http://eaform2017.aesj.or.jp/file/PapersList/Session4/(4A-2)_%20T.Hamamoto(NUMO).pdf

NUMO has developed a generic safety case to demonstrate the feasibility and safety of geological disposal of HLW and TRU in Japan and to provide a basic structure for the safety case which will be applicable to any potential site. In this safety case, the safety assessment was carried out for the repositories tailored to site descriptive models developed for three representative rock groups (plutonic, Neogene sedimentary and Pre-Neogene sedimentary rocks). Radionuclide migration parameters in rocks, i.e. distribution coefficients (Kds) and effective diffusion coefficients (Des), were derived to allow safety analysis for a range of scenarios. In this generic stage, the values of these parameter were given as the statistical values derived from laboratory data for certain rock types. The data were extracted from the latest database, with interpretation based on radionuclide speciation derived from relevant groundwater thermodynamic modelings.

Journal Articles

Comparative study of granitic and sedimentary groundwater colloids by flow-field flow fractionation coupled with ICP-MS

Saito, Takumi; Hamamoto, Takafumi*; Mizuno, Takashi; Iwatsuki, Teruki; Tanaka, Satoru*

Journal of Analytical Atomic Spectrometry, 30(6), p.1229 - 1236, 2015/06

https://doi.org/10.1039/C5JA00088B

Times Cited Count：13 Percentile：58.84(Chemistry, Analytical)

Size distribution and elemental compositions of colloids in granitic and sedimentary deep groundwater was determined by flow field flow fractionation (Fl-FFF) combined with ICP-MS. In the granitic groundwater organic colloids and various inorganic elements were found in limited size ranges (10 nm and 140 nm). The presence of different types of organic colloids was suggested in this groundwater. Most of the inorganic elements exhibited similar size distributions at 10 nm, which were largely overlapped with organic colloids rich in fluorophores. In the sedimentary groundwater small organic and probably inorganic colloids were found at 5 nm together with relatively large inorganic colloids. Organic colloids in this groundwater were homogeneous in terms of their sizes and the compositions of chromohores and fluorophores. The size distribution of inorganic elements depended on their types, indicating the presence of different host colloidal phases for them.

Oral presentation

Corrosion behavior of simulated high-level waste glass in the presence of carbon steel

Goto, Takahiro*; Matsubara, Ryuta*; Hamamoto, Takafumi*; Fujisaki, Kiyoshi*; Mitsui, Seiichiro; Taniguchi, Naoki

no journal, ,

To improve long-term glass corrosion model, immersion tests with specimens of carbon steel and simulated waste glass were conducted at 50 $^{circ}$ C and 80 $^{circ}$ C under nitrogen gas atmosphere for 131 days. Control tests with a specimen of carbon steel or glass under the same conditions were also conducted. After the tests, the element concentration in the solution was analyzed to determine glass corrosion rates. We also analyzed the surface of specimens with XRD and TEM/ED (electron diffraction)/EDX to identify secondary phases. Glass corrosion rates for the tests with specimens of carbon steel and glass were two times larger than those for the control tests with glass specimen. With XRD and TEM/ED/EDX, we determined iron silicates on the surface of both carbon steel and glass. These observations are consistent with the results of geochemical calculation and published studies. The results indicate that glass corrosion could be enhanced by the precipitation of iron silicates.

Oral presentation

Sorption of Zr and Np(IV) on montmorillonite in the presence of carbonate

Ishidera, Takamitsu; Hamamoto, Takafumi*; Okazaki, Mitsuhiro*; Yamada, Yoshihide*; Tomura, Tsutomu*

no journal, ,

no abstracts in English

Oral presentation

Validation of reactive transport model for evolution of cementitious material

Koike, Ayaka*; Ishida, Keisuke*; Hamamoto, Takafumi*; Mihara, Morihiro

no journal, ,

no abstracts in English

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Evaluation of the effects of bentonite colloids

Development of radionuclide release model for safety assessment of TRU waste disposal

Validation of a model for radionuclide transport in rocks with fractures using in-situ test data

Development of the methodology for setting radionuclide migration parameters reflecting site investigations and data acquisition

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

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A Systematic radionuclide migration parameter setting approach for potential siting environments in Japan

Investigation and evaluation of sorption and diffusion data for sedimentary rocks and cementitious materials (Report on NUMO-JAEA collaborative research in FY2016-2017) (Joint research)

Assessment of sorption and diffusion in the rock matrix in the NUMO safety case

Comparative study of granitic and sedimentary groundwater colloids by flow-field flow fractionation coupled with ICP-MS

Corrosion behavior of simulated high-level waste glass in the presence of carbon steel

Sorption of Zr and Np(IV) on montmorillonite in the presence of carbonate

Validation of reactive transport model for evolution of cementitious material