Experimental research about performance deterioration of engineered barrier in radioactive waste disposal facility

本研究的目的是探讨1)化学变化，如Ca(OH)2和C-S-H的Ca/Si比的降低；2)物理变化，如累积孔隙体积和阈孔的增加；3)电处理评价孔隙率浸出引起的扩散系数变化的可行性。研究结果为进一步认识电浸改矿及电浸改矿的可行性提供了重要数据。特别是，获得了以下使用电气处理的项目。1)证实了C-S-H中Ca(OH)2和Ca/Si比值的降低。2)累积孔隙体积和孔隙比增大。可以说，电处理对于评价胶凝材料因浸出而发生的蚀变是有用的。3)电处理得到的孔隙比与扩散系数的关系与前人的模型相似。因此，这一结果表明了电处理在浸出蚀变中的适用性。

The purposes of this research were to investigate 1) the chemical alteration, such as decrease of Ca(OH)2 and Ca/Si ratio of C-S-H, 2) the phyisical alteration, such as increase of cumulative pore volume and threshold pore and 3) the feasivility of the electrical treatment for evaluation of diffusion coefficient alteration due to leaching with void ratio. As the results of this study, the important data were obtained for underestanding the leaching alteration by electrical treatment and indicating the feasivility. Espacially, the following items for using electrical treatment were obtained. 1) Decrease of Ca(OH)2 and Ca/Si ratio of C-S-H were confirmed. 2) Cumulative pore volume and pore ratio were increased. It can be said that the electrical treatment is useful for evaluating the alteration of cementitious material due to leaching. 3) The relationship between void ratio and diffusion coefficient which was obtained by electrical treatment was similar to the modeled one in previous studies. Therefore, this result were showing the applicability of the electrical treatment for leaching alteration.