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Chijimatsu, Masakazu*; B
rgesson, L.*; Fujita, Tomoo; Hernelind, J.*; Jussila, P.*; Nguyen, T. S.*; Rutqvist, J.*; Jing, L.*
Proceedings of 2nd International Conference on Coupled T-H-M-C Processes in Geo-systems; Fundamentals, Modeling, Experiments and Applications (GeoProc 2006), p.254 - 260, 2006/05
In Task A of DECOVALEX-THMC, five research teams study the influence of THM coupling on the safety of the near-field of a typical geological repository for high-level radioactive waste. In order to refine the analyses, the teams calibrated their models with laboratory experiments, including: swelling pressure tests, water uptake tests, thermally gradient tests, and the CEA mock-up THM experiment. This paper describes the mathematical models used by the teams, and compares the results of their calibration with the experimental data.
Yamamoto, Hajime*; Kunimaru, Takanori; Kurikami, Hiroshi; Shimo, Michito*; Xu, T.*
Proceedings of 2nd International Conference on Coupled T-H-M-C Processes in Geo-systems; Fundamentals, Modeling, Experiments and Applications (GeoProc 2006), p.382 - 387, 2006/05
no abstracts in English
Kurikami, Hiroshi; Kunimaru, Takanori; Yabuuchi, Satoshi; Seno, Shoji; Shimo, Michito*; Kumamoto, So*
Proceedings of 2nd International Conference on Coupled T-H-M-C Processes in Geo-systems; Fundamentals, Modeling, Experiments and Applications (GeoProc 2006), p.584 - 589, 2006/05
no abstracts in English
Fujisaki, Kiyoshi; Suzuki, Hideaki*; Fujita, Tomoo; Ito, Akira*; Oda, Yoshihiro
Proceedings of 2nd International Conference on Coupled T-H-M-C Processes in Geo-systems; Fundamentals, Modeling, Experiments and Applications (GeoProc 2006), p.213 - 219, 2006/05
An important part of the safety assessments of near field in a geological disposal system of high-level radioactive waste consists an assessment of the coupled thermal-hydraulic-mechanical and chemical (THMC) phenomena. In order to validate the newly developed THMC model, the engineered scale experimental studies on the coupled THMC processes by COUPLE equipment have been carried out with a simulated engineered barrier surrounded by a mortar block. In this experiment, temperature at heater and side surface of mortar block was controlled at constant temperature, respectively. And high-pH water reacted with mortar infiltrates into the buffer material. This paper presents the results of measured data by various sensors during the experiment and sampling data of pH and leaching cations in buffer material after the experiment, in COUPLE equipment. And also the results of preliminary simulations on coupled T-H processes and chemical process in the experiment are described.
Uehara, Shinichi*; Kobayashi, Akira*; Chijimatsu, Masakazu*; Onishi, Yuzo*; Fujita, Tomoo
Proceedings of 2nd International Conference on Coupled T-H-M-C Processes in Geo-systems; Fundamentals, Modeling, Experiments and Applications (GeoProc 2006), p.738 - 743, 2006/05
This paper reports the results of calculations about coupled hydro-mechanical process in the domain around excavations at clay rock site at Tournemire, France. We operated the numerical modelling by using a Finite Element Method code named THAMES, on the assumption that swelling pressure is parallel to saturation ratio. The results of modelling indicated that saturation ratio changes seasonally at the domain within several tens cm from tunnel wall. This extension is similar to that of damage zone observed in the tunnel at Tournemire site in 1881, which supports the idea that the saturation-desaturation cycles has decreased the rock strength and caused damage zone extension. The modelling results also suggested that the consideration of swelling pressure could affect evolution of stress state abruptly.
Nguyen, T. S.*; Brgesson, L.*; Chijimatsu, Masakazu*; Fujita, Tomoo; Hernelind, J.*; Jussila, P.*; Rutqvist, J.*; Jing, L.*
Proceedings of 2nd International Conference on Coupled T-H-M-C Processes in Geo-systems; Fundamentals, Modeling, Experiments and Applications (GeoProc 2006), p.141 - 149, 2006/05
In order to demonstrate the feasibility of geological disposal of spent CANDU fuel in Canada, a safety assessment was performed for a hypothetical repository in the Canadian Shield. The assessment shows that such repository would meet international criteria for dose rate; however, uncertainties in the assumed evolution of the repository were identified. Such uncertainties could be resolved by the consideration of coupled Thermal-Hydro-Mechanical-Chemical (THMC) processes. In Task A of the DECOVALEX-THMC project, THM models will be refined and used to perform near-field simulations of the evolution of the repository in order to address the above uncertainties. This paper presents the definition and rationale of Task A and the preliminary results.
Kobayashi, Akira*; Yamamoto, Kiyohito*; Aoyama, Shigeyasu*; Chijimatsu, Masakazu*; Fujita, Tomoo
Proceedings of 2nd International Conference on Coupled T-H-M-C Processes in Geo-systems; Fundamentals, Modeling, Experiments and Applications (GeoProc 2006), p.281 - 286, 2006/05
To investigate the effect of the chemical degradation on the mechanical behavior, the rock samples preserved in the 10 % salt water and distilled water for 90 days are subjected to the unconfined compression test. The rock samples were obtained from 
sp HRL in Sweden. The damage parameters were identified from the unconfined compression tests for two types of rock samples. Beforehand, the characteristics of the effect of each damage parameter on the mechanical behavior were investigated by numerical simulation. By investigating the change in the damage parameters of the chemically degraded rock, the effect of the chemical degradation was tried to infer through the results of parametric study. Moreover, the 3-D finite element simulation was carried out to examine the effect of change in the damage parameters due to chemical effect in detail.
Fujita, Tomoo; Fujisaki, Kiyoshi; Suzuki, Hideaki*; Kawakami, Susumu; Yui, Mikazu; Chijimatsu, Masakazu*; Neyama, Atsushi*; Ishihara, Yoshinao*; Hishiya, Tomoyuki*
Proceedings of 2nd International Conference on Coupled T-H-M-C Processes in Geo-systems; Fundamentals, Modeling, Experiments and Applications (GeoProc 2006), p.416 - 421, 2006/00
We have initiated a research on the coupled Thermo-Hydro-Mechanical-Chemical (THMC) processes and are trying to carry out numerical experiments on the coupled THMC processes in order to predict the near-field long-term evolution. This paper describes the modified THMC model to add on the function of de-gases and gases diffusion, accumulation and dilution phenomena for mass transport analysis, and of ionic exchange, surface reaction and kinetic reaction for geochemical analysis. And also the results of demonstration study with THMC code are shown.