Double porosity model to describe both permeability change and dissolution processes

Mechanical Engineering Journal

Yuichi NIIBORI¹  Taiji CHIDA¹  Hideo USUI¹ 

[1]Department of Quantum Science and Energy Engineering, Tohoku University

关键词: geological disposal;    radioactive waste;    cement materials;    groundwater;    permeability;    dissolution;    diffusion;    porosity;   

DOI  :  10.1299/mej.15-00210

来源: DOAJ

【 摘 要 】

Cement is a practical material for constructing the geological disposal system of radioactive wastes. The dynamic behavior of both permeability change and dissolution process caused by a high pH groundwater was explained using a double porosity model assuming that each packed particle consists of the sphere-shaped aggregation of smaller particles. This model assumes two kinds of porosities between the particle clusters and between the particles, where the former porosity change mainly controls the permeability change of the bed, and the latter porosity change controls the diffusion of OH- ions inducing the dissolution of silica. The fundamental equations consist of a diffusion equation of spherical coordinates of OH- ions including the first-order reaction term and some equations describing the size changes of both the particles and the particle clusters with time. The change of over-all permeability of the packed bed is evaluated by Kozeny-Carman equation and the calculated radii of particle clusters. The calculated result well describes the experimental result of both permeability change and dissolution processes.

【 授权许可】

Unknown