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Noseck, U.*; Sch
fer, T.*; Alonso, U.*; Hamamoto, Takafumi*; Havlova, V.*; Hibberd, R.*; Ishidera, Takamitsu; Kitamura, Akira; Klajmon, M.*; Missana, T.*; et al.
Applied Geochemistry, 201, p.106762_1 - 106762_23, 2026/04
Times Cited Count：0 Percentile：0.00(Geochemistry & Geophysics)Thermodynamic benchmark calculations have been performed to better understand the behavior of 
Se(VI), 
Tc(VII), 
U(VI), 
Np(V), 
Am(III), Th(IV) and 
Pu(IV)) in the evolving geochemical conditions of the Long-term In-situ Test (LIT) at the Grimsel Test Site (GTS) and corresponding mock-up experiment. It also aims to identify the status of the geochemical speciation models and databases for these elements. The experiments are simulating the near-field conditions in some radioactive waste repository concept including a bentonite engineered barrier emplaced in crystalline rock and the findings are contributing to the long-term safety assessment of these facilities.
Fukatsu, Yuta; Oguri, Tomomi*; Hamamoto, Takafumi*; Ishida, Keisuke*; Martin, A.*; Tachi, Yukio
Journal of Contaminant Hydrology, 277, p.104865_1 - 104865_12, 2026/02
Times Cited Count：0 Percentile：0.00(Environmental Sciences)Matsubara, Ryuta*; Hamamoto, Takafumi*; Ishidera, Takamitsu
NUMO-TR-24-03, p.65 - 70, 2024/10
no abstracts in English
Onoe, Hironori*; Yoshida, Fumiko*; Hamamoto, Takafumi*; Saegusa, Hiromitsu*; Ishida, Keisuke*; Sawada, Atsushi
NUMO-TR-24-03, p.71 - 75, 2024/10
no abstracts in English
Hamamoto, Takafumi*; Koike, Ayaka*; Ishidera, Takamitsu; Iwata, Hajime; Fukatsu, Yuta; Taneichi, Yayoi
NUMO-TR-24-03, p.85 - 86, 2024/10
no abstracts in English
Koike, Ayaka*; Ishida, Keisuke*; Hamamoto, Takafumi*; Mihara, Morihiro
NUMO-TR-24-01, p.98 - 101, 2024/05
no abstracts in English
Hamamoto, Takafumi*; Ishidera, Takamitsu; Sasamoto, Hiroshi
NUMO-TR-24-01, p.87 - 90, 2024/05
no abstracts in English
Matsubara, Ryuta*; Hamamoto, Takafumi*; Ishidera, Takamitsu
NUMO-TR-24-01, p.91 - 94, 2024/05
no abstracts in English
Hamamoto, Takafumi*; Fukatsu, Yuta
NUMO-TR-24-01, p.95 - 97, 2024/05
no abstracts in English
Hamamoto, Takafumi*; Ishidera, Takamitsu; Tachi, Yukio
NUMO-TR-24-01, p.102 - 103, 2024/05
no abstracts in English
Hamamoto, Takafumi*; Ishida, Keisuke*; Tachi, Yukio
NUMO-TR-22-02, p.62 - 64, 2023/03
no abstracts in English
Hamamoto, Takafumi*; Ishida, Keisuke*; Ishidera, Takamitsu; Tachi, Yukio
NUMO-TR-22-02, p.88 - 89, 2023/03
no abstracts in English
Ichikawa, Nozomi*; Hamamoto, Takafumi*; Ishidera, Takamitsu; Sasamoto, Hiroshi
NUMO-TR-22-02, p.55 - 57, 2023/03
no abstracts in English
Hamamoto, Takafumi*; Ishida, Keisuke*; Ishidera, Takamitsu
NUMO-TR-22-02, p.58 - 61, 2023/03
no abstracts in English
Koike, Ayaka*; Ishida, Keisuke*; Hamamoto, Takafumi*; Mihara, Morihiro
NUMO-TR-22-02, p.74 - 77, 2023/03
no abstracts in English
Hamamoto, Takafumi*; Ishida, Keisuke*; Shibutani, Sanae*; Fujisaki, Kiyoshi*; Tachi, Yukio; Ishiguro, Katsuhiko*; McKinley, I. G.*
Proceedings of 2019 International High-Level Radioactive Waste Management Conference (IHLRWM 2019) (USB Flash Drive), p.77 - 82, 2019/04
Hamamoto, Takafumi*; Matsubara, Ryuta*; Shibutani, Sanae*; Suyama, Tadahiro*; Tachi, Yukio
JAEA-Data/Code 2017-014, 31 Pages, 2018/03
JAEA-Data-Code-2017-014.pdf:2.1MB
JAEA-Data-Code-2017-014-appendix(CD-ROM).zip:0.61MB
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.
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
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.
Saito, Takumi; Hamamoto, Takafumi*; Mizuno, Takashi; Iwatsuki, Teruki; Tanaka, Satoru*
Journal of Analytical Atomic Spectrometry, 30(6), p.1229 - 1236, 2015/06
Times Cited Count：17 Percentile：64.76(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.
Ishidera, Takamitsu; Shibutani, Sanae*; Hamamoto, Takafumi*
no journal, ,
