Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Hayano, Akira; Ishii, Eiichi
Shigen, Sozai Koenshu (Internet), 5(1), 9 Pages, 2018/03
no abstracts in English
Sugita, Yutaka; Yui, Mikazu
JNC TN8450 2001-007, 16 Pages, 2002/02
JNC-TN8450-2001-007.pdf:0.78MB
This report summary the dataset of the relationship between unconfined compressive strength and tensile strength of the rock mass described in supporting report 2; repository design and engineering technology of second progress report (H12 report) on research and development for the geological disposal of HLW in Japan.
Futakuchi, Katsuhito*; Hashimoto, Shuji*; Sakuramoto, Yuji*; ; Kamei, Gento
JNC TN8400 2001-007, 52 Pages, 2001/04
JNC-TN8400-2001-007.pdf:2.34MB
As a natural analogue, the authors investigted a Tertiary argillaceous bed and a Quarternary hypabyssal rock (porphyrite) which intruded into the argillaceous rock, distributed in the Nishikubiki district of Niigata prefecture in Japan. We examined the variation of clay mineral species in the argillaceous rock surrounding the intrusive rock and carried out thermal analyses for the argillaceous rock based on the coolig history of the intrusive rock. The predominant clay mineral varied from montmorillonite to illite through illite/montmorillonite interlayers with approaching to the intrusive rock. The thermal analyses indicated that the temperature descended from 270 to 15 
C during the 7.5
10
years at alocalty of argillaceous rock containing 75% illite in the interlayers. On the assumption that the alteration from montmorillonite to illite was regarded as a first-order reaction, we evaluated the apparent activation energy based on the thermal condition mentioned above; about 103 kJ/mol was obtained for this illitization. This was within the range of values reported previously by laboratory experiments and/or examinations of natural illitizations.
Sato, Haruo
JNC TN8410 2001-003, 40 Pages, 2001/01
JNC-TN8410-2001-003.pdf:1.13MB
A program (TDROCK1.FOR) for simulation and analysis of through-diffusion experiments for a single layer of diffusion media was developed. This program was made by Pro-Fortran language, which was suitable for scientific and technical calculations, and relatively easy explicit difference method was adopted for an analysis. In the analysis, solute concentration in the tracer cell as a function of time that we could not treat to date can be input and the decrease in the solute concentration as a function of time by diffusion from the tracer cell to the measurement cell, the solute concentration distribution in the porewater of diffusion media and the solute concentration in the measurement cell as a function of time can be calculated. In addition, solution volume in both cells and diameter and thickness of the diffusion media are also variable as an input condition. This simulation program could well explain measured result by simulating solute concentration in the measurement cell as a function of time for case which apparent and effective diffusion coefficients were already known. Based on this, the availability and applicability of this program to actual analysis and simulation were confirmed. This report describes the theoretical treatment for the through-diffusion experiments for a single layer of diffusion media, analytical model, an example of source program and the manual.
Ashida, Takashi; ; Sato, Haruo; ; Kitamura, Akira; Kawamura, Kazuhiro
JNC TN8400 99-083, 63 Pages, 1999/11
Studies on the chemical and migration behaviour of radionuclides were carried out in the Quantitative Assessment Radionuclide Migration Experimental Facility (QUALITY)for assuring the relaiability and for improving the propriety of data concerning nuclide migration used in the Second Progress Report for the geoloical disposal of high-level radioactive waste. Five studies for solubility, sorption and diffusion concerning nuclide migration were carried out. The overview of each study and the result is as follows: (1)Study on Effect of Carbonate on Np Solubility. Solubilities of Np(IV) were measured as functions of pH and carbonate concentration under reducing conditions. The obtained data could be well described by considering two hydroxo-carbonate complexes, and those stability constants were estimated and compared with the literature data. Consequently, the data obtained in this study were similar to the literature data. (2)Study on Effect of Carbonate on Np Sorption on Bentonite. Distribution coefficients (Kd) of Np(IV) on smectite were measured as a function of carbonate concentration. The obtained Kd values were approximately constant over the carbonate concentration (total carbon concentration 0.04-0.15M). The results of desorption tests by 1M KCl and HCl at the end of sorption experiments showed two different desorption behaviour; Np(IV) was well removed by HCl for the experiments in low carbonate concentration and by KCl for those in high carbonate concentration. (3)Distribution Coefficient Measurements for Cs, Pb and Cm on Rocks. Distribution Coefficients for Cs, Pb and Cm on Japanese major rocks (basalt, mudstone, sandstone, granodiorite and tuff) were measured as a function of ionic strength. The obtained Kd values were either the same orders or higher compared with data used to both fresh and saline groundwater systems in the Second Progress Report. This indicates that the Kd data used in the Second Progress Report are either proper or conservative. ...
G M N BASTON*; J A BERRY*; M BROWNSWORD*; D J LLETT*; C M LINKLATER*; S W SWANTON*; Tweed, C. J.*
JNC TJ8400 99-078, 72 Pages, 1999/03
A desk study has been carried out to establish the feasibility of measuring the oxidation state of plutonium under near-neutral strongly-reducing conditions. X-ray absorbance spectroscopy appears to be capable of establishing the oxidation state of plutonium sorbed on a suitable substrate. An experimental and modelling investigation has been performed to study the sorption of plutonium onto basalt, mudstone and sandstone under strongly-reducing conditions at three concentrations of carbonate. Appropriate synthetic rock-equilibrated de-ionised water and seawater were used. A model has been developed to describe the sorption of plutonium onto basalt, mudstone and sandstone in de-ionised water and seawater. Predicted R
values are generally in good agreement with the observed experimental measurements. The model is based on sorption of plutonium(III) species and assumes iron oxide is the dominant sorbing phase.
Sato, Haruo
PNC TN8410 97-202, 205 Pages, 1998/01
This thesis summarizes the results investigated in order to establish a basic theory on the predictive method of diffusion coefficients of nuclides in compacted sodium bentonite which is a candidate buffer material and in representative rocks for the geological disposal of radioactive waste by measuring the pore structural factors of the compacted bentonite and rocks such as porosity and tortuosity, measuring diffusion coefficients of nuclides in the bentonite and rocks, acquiring basic data on diffusion and developing diffusion models which can quantitatively predict nuclide migration in long-term. This consists of 7 chapters. Chapter 1 is the introduction, in which conventional studies on nuclide migration in buffer materials and rocks for the geological disposal of radioactive waste carried out to date are reviewed, and those problems are summarized as well as the objectives of this study are described. Besides, the difinition of geological disposal is explained. In Chapter 2, it is described on non-steady state diffusion of HTO, Sr-90, Tc-99, I-129, Cs-137, Np-237, Am-241 and Pu in purified sodium bentonite, Kunipia-F, in which the rate of constituent Na-smectite was raised approximately 100wt%. In-diffusion experiments were carried out in a range of bentonite densities of 200 
2000 kg
m
under ambient aerobic conditions at room temperature (20 23C), and apparent diffusion coefficients (Da) were obtained. The apparent diffusion coefficients decreased with increasing dry density of bentonite. It was quantitatively indicated from diffusion experiments using HTO that these Da values include the effect of geometric retardation such as the tortuosity factor of compacted bentonite. It was experimentally clarified that Da is not affected by diffusion time based on diffusion experiments for different experimental periods using Sr and Cs. Moreover, it was also experimentally clarified that Da is not affected by tracer ...
Shibutani, Tomoki; Yoshikawa, Hideki; Sato, Haruo; Yui, Mikazu; Umeki, Hiroyuki; Ishiguro, Katsuhiko
PNC TN8410 92-163, 51 Pages, 1992/09
None
Tachi, Yukio; Akagi, Yosuke*; Nemoto, Kazuaki; Matsumoto, Kazuhiro; Ishii, Eiichi
no journal, ,
To validate radionuclide migration model in single fractures in sedimentary rocks, the mudstone sample with single fracture from Wakkanai Formation at Horonobe Underground Research Laboratory was investigated. The migration behaviors of deuterated water, iodine and cesium were measured by series of laboratory experiments including batch sorption, through-diffusion and flow-through experiments.
Ono, Hirokazu; Takeda, Masaki; Ishii, Eiichi; Kawate, Satoshi
no journal, ,
It is necessary to clarify the mass transport behavior in a deep underground natural barrier, for improving the reliability of safety assessment of high-level radioactive waste disposal. In situ mass transport experiments are being conducted for fractures and rock matrices at the G.L. -350 m gallery in the Horonobe Underground Research Laboratory (URL). This study reports an overview and preliminary results of in situ diffusion experiments for rock matrices.
Takeda, Masaki; Ishii, Eiichi; Ono, Hirokazu; Kawate, Satoshi
no journal, ,
no abstracts in English
Ito, Tsuyoshi*; Tachi, Yukio; Nemoto, Kazuaki*; Sato, Tomofumi*; Takeda, Masaki; Ono, Hirokazu
no journal, ,
To validate the mass transfer model in sedimentary rocks, in-situ tracer test in rock matrix was conducted at rock matrix at 350 m deep drift in the Horonobe URL. The modeling results were evaluated to be reasonable by comparing in-situ and laboratory data.
Ono, Hirokazu; Takeda, Masaki; Ishii, Eiichi; Tachi, Yukio
no journal, ,
It is necessary to clarify the mass transport behavior in a deep underground natural barrier, for improving the reliability of safety assessment of high-level radioactive waste disposal. This study reports an analysis using data from in situ tracer tests for fractures in mudstone at Horonobe Underground Research Laboratory (URL).
Abe, Takeyasu; Ishii, Eiichi
no journal, ,
Understanding of diagenesis is important for engineering use of underground environments for example industrial and radioactive waste management, CO
storage, and so on. Authors have been developing numerical model of reactive transport in sedimentary rocks. In order to analyse ion exchange reactions during freshening process of fossil seawater in Horonobe mudstones, active fraction model was adopted. Exchangeable cationic composition was simulated under the assumption of static exchange reactions. Our calculation revealed that Na-desorption and Ca-adsorption will occur when exchange parameters of the rocks are assumed to be those of soils. This result is qualitatively consistent with observed depth profile of bulk composition. We try to calculate bulk compositional profiles by coupled modelling between ion exchange reactions and advective-dispersive transport of solutes, and will quantitatively discuss ion exchange parameters inherent in Horonobe mudstones.