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Savage, D.*; Wilson, J.*; Benbow, S.*; Sasamoto, Hiroshi; Oda, Chie; Walker, C.*; Kawama, Daisuke*; Tachi, Yukio
Applied Clay Science, 195, p.105741_1 - 105741_11, 2020/09
Times Cited Count：2 Percentile：10.08(Chemistry, Physical)Safety functions for the clay buffer in a repository for high-level radioactive waste (HLW) are fulfilled if the presence of montmorillonite with high swelling capacity and low permeability is maintained in the long-term. The transformation of montmorillonite to the non-swelling mineral likely illite is addressed in most safety assessments by using simple semi-empirical kinetic models, but this approach contrasts with more complex reactive-transport simulations. In the present study, reactive-transport simulations are compared with simple semi-empirical kinetic models. Results suggest that reactive-transport simulations err on the side of conservatism, but may produce unrealistic estimates of illitization. This comparison demonstrates that reactive-transport models may be carefully applied to simulate the long-term evolution of near field environment for HLW disposal.
Savage, D.*; Wilson, J.*; Benbow, S.*; Sasamoto, Hiroshi; Oda, Chie; Walker, C.*; Kawama, Daisuke*; Tachi, Yukio
Applied Clay Science, 179, p.105146_1 - 105146_10, 2019/10
Times Cited Count：13 Percentile：62.41(Chemistry, Physical)Natural systems evidence for the effects of temperature and the activity of aqueous silica upon montmorillonite stability was evaluated. Thermodynamic modeling using three different TDBs shows that stability fields for montmorillonite exist from 0 to 140
C, but at low values of silica activity, a stability field for illite replaces that for montmorillonite. Pore fluid chemical and mineralogical data for sediments from ODP sites from offshore Japan show a trend from montmorillonite + amorphous silica stability at temperatures up to 60C to that for illite + quartz at higher temperatures. However, even over very long timescales (
1 Ma), smectite does not transform to illite under thermodynamically-favourable conditions at temperatures less than 80C.
Nagano, Tetsushi; Nakayama, Shinichi
Genshiryoku Bakkuendo Kenkyu, 8(1), p.81 - 88, 2001/09
Japan Atomic Energy Research Institute has studied to predict the long-term migration of radionuclides in geosphere in terms of radioactive waste disposal. The research activity was introduced to junior high and high school students at a seminar of the Mineralogical Society of Japan. The content of the lecture was summarized.
Nagano, Tetsushi; Sato, Tsutomu*; Williams, I. S.*; Zaw, M.*; Payne, T. E.*; Airey, P. L.*; Yanase, Nobuyuki; Isobe, Hiroshi*; Onuki, Toshihiko
Geochemical Journal, 34(5), p.349 - 358, 2000/10
Times Cited Count：4 Percentile：13.58(Geochemistry & Geophysics)no abstracts in English
Nagano, Tetsushi; Sato, Tsutomu*; Yanase, Nobuyuki; Isobe, Hiroshi*; Onuki, Toshihiko; I.S.Williams*; M.Zaw*; T.E.Payne*; P.L.Airey*
JAERI-Research 99-024, 52 Pages, 1999/03
JAERI-Research-99-024.pdf:3.3MB
no abstracts in English
Sekine, Keiichi; Muraoka, Susumu; Bamba, Tsunetaka
JAERI-Review 97-007, 61 Pages, 1997/03
JAERI-Review-97-007.pdf:2.18MB
no abstracts in English
Sekine, Keiichi; Muraoka, Susumu; Bamba, Tsunetaka
JAERI-Review 96-005, 97 Pages, 1996/03
JAERI-Review-96-005.pdf:2.88MB
no abstracts in English
Klein, L.*; Hardie, S.*; McKinley, I.*; Tachi, Yukio; Shibata, Masahiro; Amano, Yuki; Takase, Hiroyasu*
no journal, ,
The uplift / erosion is treated as a special perturbation scenario for the safety assessment of the geological disposal, due to the Japanese tectonic setting, the impact of uplift must be considered as part of "likely" repository evolution. In an initial study, a simple uplift and erosion scenario was assessed with resultant changes in solubility and sorption of key radionuclides. A special challenge here is development of models and associated databases to quantify the impact of rock mechanical, hydrogeological and bio-geochemical changes on radionuclide migration both in the EBS and in the geosphere. There are great uncertainties with any laboratory studies to investigate the processes involved and therefore natural analogues have great potential here. The paper will list and discuss the key safety-relevant processes and potential analogue studies by considering both data mining of existing knowledge bases and also new projects that are specifically focused on this application.
Kikuchi, Ryosuke*; Fujimura, Tatsuya*; Sato, Tsutomu*; Otake, Tsubasa*; Otomo, Yoko*; Goto, Takahiro*; Suzuki, Satoru*; Taniguchi, Naoki; Suzuki, Hiroyuki*
no journal, ,
