【摘要】 高放废物地质处置环境中存在大量的磷酸盐,势必会影响放射性核素的迁移行为。采用贯穿扩散(through-diffusion)法研究了磷酸盐对Se(Ⅳ)在高庙子膨润土中扩散行为的影响。采用自编扩散参数分析程序获得有效扩散系数(De)约为(0.61~1.3)×10-11 m2/s,岩石容量因子(α)约为0.16~0.58。结果表明:磷酸盐浓度对Se(Ⅳ)的扩散行为影响不明显。酸性条件下,Se(Ⅳ)的有效扩散系数和岩石容量因子均升高。由于Se(Ⅳ)能够吸附在膨润土的表面,使得表观扩散系数(Da)降低。而碱性条件下,岩石容量因子小于总孔隙率,Se(Ⅳ)不吸附在膨润土表面。更多还原

【Abstract】 The abundant phosphate in a high level nuclear waste repository will influence the migration of radionuclides.Thus,the effect of phosphate on the diffusion behavior of Se(Ⅳ)in Gaomiaozi(GMZ)bentonite was investigated by through-diffusion method.The diffusion parameters like effective diffusion coefficient(De)and rock capacity factor(α)were determined by house-made code named Fitting for Diffusion Parameters.The Deandαvalues were about(0.61-1.3)×10-11 m2/s and 0.16-0.58,respectively.It shows that the concentration of phosphate has insignificant effect on Se(Ⅳ)diffusion.Under acidic condition,both of De andαincreased.The apparent diffusion coefficient(Da)value decreased because Se(Ⅳ)could be sorbed on the surface of bentonite.Sinceαwas less than the total porosity,it could not be sorbed on bentonite.更多还原