137Cs 和 90Sr 在北山花岗岩中吸附和扩散探究

Adsorption and Diffusion of 137Cs and 90Sr in Beishan Granite

关键核素在相关介质中的吸附和扩散参数获取是深地质处置安全评价的重要组成部分。探究了137Cs和90Sr在北山不同地区花岗岩中的吸附和扩散过程,并通过拟合扩散数据给出有效扩散系数。不同地区花岗岩矿物组成基本类似,但是具体比例有所差异。吸附实验结果表明:算井子地区的花岗岩对137Cs和90Sr的吸附性能最强,而新场和沙枣园地区的花岗岩的吸附性能相当。137Cs在新场、算井子和沙枣园地区的有效扩散系数分别为9.0×10^(-14)、9.3×10^(-14)和1.0×10^(-13) m^(2)·s-1,90Sr在新场、算井子和沙枣园地区的有效扩散系数分别为1.2×10^(-13)、5.6×10^(-13)和3.2×10^(-13) m^(2)·s-1,两种核素在3个地区的花岗岩中的有效扩散系数差异不大,表明北山地区花岗岩内部孔隙结构具有一定的一致性。

The acquisition of adsorption and diffusion parameters of key nuclides in the relevant media is an important part of the safety assessment of deep geological disposal.In this paper,the adsorption and diffusion processes of 137Cs and 90Sr in granites from different areas of Beishan were investigated,and the effective diffusion coefficients were obtained by fitting the diffusion data.The mineral composition of granites from different areas is basically similar,but the ratio of the minerals varies.The results of the adsorption experiments showed that the granites in the area of Suanjingzi had the strongest sorption ability for 137Cs and 90Sr,while the granites in the areas of Xinchang and Shazaoyuan had comparable sorption ability.The effective diffusion coefficients of 137Cs in the areas of Xinchang,Suanjingzi and Shazaoyuan were 9.0×10^(-14),9.3×10^(-14) and 1.0×10^(-13) m^(2)·s-1,respectively,and 90Sr of Xinchang,Suanjingzi and Shazaoyuan areas were 1.2×10^(-13),5.6×10^(-13) and 3.2×10^(-13) m^(2)·s-1,respectively.The effective diffusion coefficients of the two nuclides in the granites of the three areas were not significantly different,indicating that the internal pore structure of granites in the Beishan area has some consistency.