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Jo, Mayumi*; Ono, Makoto*; Nakayama, Masashi; Asano, Hidekazu*; Ishii, Tomoko*
Geological Society Special Publications, 482, 16 Pages, 2018/09
Times Cited Count：2 Percentile：12.53(Geology)Sasamoto, Hiroshi; Ishii, Tomoko*; Sato, Hisao*; Sazarashi, Masami
JAEA-Research 2010-030, 64 Pages, 2010/09
JAEA-Research-2010-030.pdf:15.41MB
It is necessary to evaluate the alteration behavior of buffer material by interactions of overpack (iron) and buffer (bentonite) materials for geological disposal of high level radioactive waste. In the present study, laboratory experiments were carried out for the better understanding of phenomena caused by iron-bentonite (smectite) interactions. Before conducting the experiments, literature survey was performed to summarize the existing knowledge about iron-bentonite interactions and to identify the dominant factors affecting the alteration behavior. As the results of experiment, experimental conditions caused remarkable alteration, secondary minerals suggested as alteration product, different behavior of alteration between batch and compacted systems etc. were revealed.
Hama, Katsuhiro; Kunimaru, Takanori; Kurikami, Hiroshi; Sasamoto, Hiroshi; Takahashi, Yasuhiro*; Haginuma, Masashi*; Ishii, Tomoko*; Matsuo, Yuji*
JAEA-Research 2006-070, 93 Pages, 2006/09
JAEA-Research-2006-070.pdf:23.48MBJAEA-Research-2006-070(errata).pdf:0.08MB
Japan Atomic Energy Agency and Institute of Research and Innovation have started collaborative study in order to enhance the reliability of technology for the geological disposal of High-level Radioactive Waste (HLW) since 2005 fiscal year. In this collaborative study, the analysis has carried out to estimate long-term evolution of groundwater chemistry and groundwater flow. The study items and results are summarized in this report. (1) Groundwater Chemistry. The following items have been carried out: 1. Multivariate analysis. 2. Estimation of distribution of groundwater chemistry. 3. Construction of geochemical model. (2) Groundwater Flow: 1. Construction of geological model. 2. Construction of hydrogeological model. 3. Groundwater flow analysis. The modeling work will be continued in 2006 fiscal year. The applicability of the modeling methodology will also be evaluated.
Sasamoto, Hiroshi; Sazarashi, Masami; Ishii, Tomoko*; Sato, Hisao*; Kato, Hiroyasu*
no journal, ,
To investigate bentonite-iron interaction under high temperature condition, alteration experiments considering several factors (smectite composition, solution chemistry, iron-bentonite ratio) which were believed to affect on bentonite alteration were conducted with different experimental conditions. As the results, it was suggested that the factors considered in this study could also significantly affect on bentonite alteration in addition to temperature condition.
Sasamoto, Hiroshi; Sazarashi, Masami; Ishii, Tomoko*; Sato, Hisao*; Kato, Hiroyasu*
no journal, ,
To investigate bentonite-iron interaction under high temperature condition, alteration experiments considering several factors (smectite composition, solution chemistry, iron-bentonite ratio) which were believed to affect on bentonite alteration were conducted with different experimental conditions. As the results, it was suggested that the factors considered in this study could also significantly affect on bentonite alteration in addition to temperature condition.
Sasamoto, Hiroshi; Sazarashi, Masami; Ishii, Tomoko*; Kato, Hiroyasu*; Sugiyama, Kazutoshi*
no journal, ,
Regarding to alteration of bentonite coexisting with iron material, laboratory experiments with different temperature and iron-bentonite (I/B) ratio and literature surveys for bentonite alteration in the natural system were conducted. As the results, the conditions which promote the alteration of smectite significantly were estimated approximately. Additionally, the important alteration products necessary for evaluation of smectite alteration were summarized by literature surveys. Such information will be useful for evaluation of smectite alteration considering the conditions of time and duration interested.
-Lactamase TOHO-1 determined by combined high-resolution neutron and X-ray crystallographyKurihara, Kazuo; Sunami, Tomoko; Yamada, Mitsugu; Nitanai, Yasushi*; Okazaki, Nobuo; Adachi, Motoyasu; Tamada, Taro; Shimamura, Tatsuro*; Miyano, Masashi*; Ishii, Yoshikazu*; et al.
no journal, ,
To help resolve questions regarding the catalytic activity of -lactamase, the crystal structure of an unliganded form of the -lactamase Toho-1 with double mutation R274N/R276N (Toho-1/NN) has been determined by the use of high-resolution neutron and X-ray diffraction data. A large single crystal of Toho-1/NN with a dimension of 2.6 
2.5 1.3 mm
was used to collect 100 K neutron diffraction data to 1.5 
resolution and X-ray diffraction data to 1.4 resolution. The structural model of Toho-1/NN was refined to an R-factor of 19.7% using a program PHENIX. The structure showed that Glu166, a catalytic residue of Toho-1, was protonated even at pH 7 nonetheless for the close location to the positively charged side chain amino group (-NH3
) of Lys73. It is also found that there is a hydration water network bridging between the protonated Glu166 and the oxyanion hole comprising two main chain nitrogen atoms of Ser70 and Ser237. The neutron structure analysis also revealed the clear configuration of the proposed catalytic water molecule bridging Glu166 and Ser70. These observations are important to understand the catalytic action of -lactamase Toho-1.
Terashima, Motoki; Saito, Takumi; Ishii, Tomoko*; Akagi, Yosuke*; Tachi, Yukio
no journal, ,
no abstracts in English
Ishidera, Takamitsu; Tachi, Yukio; Ashida, Takashi; Ishii, Tomoko*; Akagi, Yosuke*; Takeda, Chizuko*
no journal, ,
no abstracts in English
Ono, Makoto*; Motoshima, Takayuki*; Shirase, Mitsuyasu*; Yokoyama, Satoshi*; Jo, Mayumi*; Ishii, Tomoko*; Nakayama, Masashi; Ono, Hirokazu
no journal, ,
To understand phenomenon of buffer material erosion in the vertical disposal concept, in situ tests on engineering scale have been carried out at Horonobe URL. As results of water injection with flow rate control, when water flowed in a continuous large flow rate, buffer materials did not swell enough to stop the water flow and the water flow path was confirmed to be formed by aggregated into a single pipe. Further, it was suggested that water pressure of the injection side contributes to the erosion of buffer materials.
Atsumi, Hiroyuki*; Masumoto, Kazuhiko*; Ishii, Tomoko*; Jo, Mayumi*; Nakayama, Masashi; Ono, Hirokazu
no journal, ,
In the vertical disposal concept of high level radioactive waste, it is important to evaluate influence of the groundwater inflow into the disposal pits against performance of buffer material as an artificial barrier because the inflow might cause the erosion of buffer material. The target of this study was to estimate the inflow control technique (e.g. grouting) around the disposal pits using numerical analysis. The model for the simulation should be a discrete fracture network model when the groundwater mainly flows along the fractures in the rock mass, therefore, the discrete fracture network model was selected to estimate the inflow control technique in this study. The results of numerical flow analysis showed that the effectiveness of grouting for the disposal pits and the impact of grouting for the other disposal pits or surrounding disposal tunnel could be evaluated quantitatively.
Terashima, Motoki; Saito, Takumi*; Ishii, Tomoko*; Ito, Miki*; Akagi, Yosuke*; Tachi, Yukio
no journal, ,
no abstracts in English
Jo, Mayumi*; Iwatani, Takafumi*; Kawakubo, Masahiro*; Ishii, Tomoko*; Ono, Makoto*; Nakayama, Masashi
no journal, ,
For the purpose of "maintaining the soundness of the artificial barrier", we are studying "restraints on the outflow of the buffer material". We conducted an experiment of a scale of 30 cm to 1 m in an actual underground environment and confirmed the occurrence of the buffer material outflow under water inflow conditions. The experiment in this study was undertaken in order to acquire the necessary data for considering a method to control the outflow of the buffer material.
Shirase, Mitsuyasu*; Ishii, Tomoko*; Kobayashi, Ichizo*; Jo, Mayumi*; Ono, Makoto*; Nakayama, Masashi
no journal, ,
A candidate emplacement concept of the engineered barrier system (EBS) for geological disposal in Japan is vertical emplacement option, which has a certain gap is between the wall of the disposal hole and the buffer material. This gap is considered to be filled with the swollen buffer material (self-sealing function) when the underground water is infiltrated to the buffer material. However, some underground water flow conditions such as a pipe-shaped water channel induce erosion of the buffer material, which causes lowering of the function of the EBS. Therefore, RWMC (Radioactive Waste Management Funding and Research Center) studies engineering countermeasures against piping and erosion. RWMC used an intentional water supply system to test the pre-hydration of bentonite buffers.
