Thermo-hydro-mechanical near-field repositories

A RESEARCH PROGRAM FOR NUMERICAL EXPERIMENTS ON THE COUPLED THERMO-HYDRO-MECHANICAL AND CHEMICAL PROCESSES IN THE NEAR-FIELD OF A HIGH-LEVEL RADIOACTIVE WASTE REPOSITORY... 

Abstract In the near-field of a high-level radioactive waste (HLW) repository, the coupled thermo -hydro -mechanical and chemical (T-H-M-C) processes will occur. Observation periods by laboratory and in-situ experiments are very short and information by natural analogue studies is very limited, so numerical experiments are the only available approach to predict the near-field long-term evolution. We have initiated a research on the coupled T-H-M-C processes and are trying to carry out numerical experiments on the coupled T-H-M-C processes in order to predict the near-field long-term evolution. This paper presents our current status and future activities on the research for numerical experiments on the coupled T-H-M-C processes. 

In the near-field of a HLW repository, the coupled thermo -hydro -mechanical and chemical (T-H-M-C) processes will occur, involving the interactive processes among radioactive decay heat from the vitrified waste, infiltration of groundwater into bentonite, swelling pressure of bentonite due... 

Our activities on development of the coupled T-H-M-C code and further demonstration analysis are presented by Neyama et al. in GeoProc 2003 conference, entitled Prototype Code Development for Numerical Experiments on the Coupled Thermo-Hydro-Mechanical and Chemical Processes in the Near-field of a High-level Radioactive Waste Repository . The prototype code is based on the coupled T-H-M code, mass transport code and geochemical code which have been well verified and validated through benchmark tests and various experiments, and... 

Japan Nuclear Cycle Development Institute (JNC) has already developed the coupled thermo -hydro and mechanical (T-H-M) model and has initiated a research on the coupled T-H-M-C processes to predict the chemical evolution of buffer material and porewater chemistry, and the chemical effects on other (thermal, hydraulic and mechanical) processes. In this research, numerical experiment system for the coupled T-H-M-C processes is developed in order to predict the longterm evolution of the near-field (engineered barriers and surrounding host rock) for various repository designs and geological environments. 

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