JAEA-Research-2010-034.pdf:16.23MB - JAEAの研究開発成果 ...

JAEA-Research 2010-034
Development of Numerical Model on the Coupled Thermo-Hydro-Mechanical-Chemical Process
for the Assessment Methodology of Chemical Effects in the Buffer Material
Makoto KIMURA *1 ,Masami SAZARASHI ※1 , Tomoo FUJITA, Shigeo NAKAMA
and Hideaki SUZUKI ※2
Geological Isolation Research Unit
Geological Isolation Research and Development Directorate
Japan Atomic Energy Agency
Tokai-mura, Naka-gun, Ibaraki-ken
(Received August 2, 2010)
Numerical model which is mainly paid attention on chemical effects in the buffer material has been
developed, for the purpose of quantification of the early complex evolution on the coupled
thermo-hydro-mechanical-chemical processes in the near-field of a HLW repository. In this paper,
governing equations are described, considering heat flow, fluid flow, mass transport and a variety of
chemical reactions such as mineral dissolution/precipitation, gas dissolution/exsolution, ion-exchange and
surface complexation. And also limitations are described.
Through the comparison analysis against another coupled model, TOUGHREACT which has been
developed in the Lawrence Berkeley National Laboratory, propriety of our coupled modeling and
uncertainties between models are shown. And also designed laboratory tests for the salt
accumulation/precipitation are presented. As the result of verification analysis against experimental salt
concentration data, the almost distribution of saturation, temperature and concentration of aqueous species
and minerals in the buffer material agree. This result suggests chemical effects such as salt
accumulation/precipitation is able to simulate using our numerical model. Moreover, using the geological
environment data based on the existing investigation in the Horonobe Underground Research Laboratory
Project, simulation on chemical changes in the near-field involving the radioactive decay heat arising from
the vitrified waste and infiltration of ground water into the buffer material is also presented.
Keywords: Pore-water Chemistry, Bentonite, Salt Accumulation/Precipitation, Unsaturated-saturated
Condition, Coupled Numerical Modeling
This activity was funded with the project “Assessment Methodology Development of Chemical Effects
on Geological Disposal System” of the Ministry of Economy, Trade and Industry (METI).
※1 Special Topic Researcher
※2 Collaborating Engineer
*1 Hazama Corporation(former Special Topic Engineer)
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