Eun Hyeonjin, Lee Seungwoo, Lee Jinyoung, Jeong Mi-Seon, Iqbal Sajid, Yun Jong-Il
Department of Nuclear and Quantum Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
Eco-technology Research Team, Hyundai Engineering & Construction, 75 Yulgok-ro, Jongno-gu, Seoul, 03058, Republic of Korea.
J Environ Radioact. 2024 Sep;278:107501. doi: 10.1016/j.jenvrad.2024.107501. Epub 2024 Jul 19.
Crystalline rock is used as the host rock for the disposal of high-level radioactive waste. Two cationic elements (Cs(I) and Ni(II)) and three anionic elements (Se(IV/VI), Mo(VI), and U(VI)) were selected to comprehensively evaluate the sorption behaviors of these radionuclides on crystalline granite and biotite gneiss. The anionic elements showed weak sorption (log K (L·kg) < 1) and little competition effect, while the cationic elements (log K (L·kg) = 2-3) showed clear competition (18-98% in K values) even at low concentrations. Analysis by pseudo-second-order kinetics showed that Cs(I) sorbed at similar rates on both rocks (20% faster on biotite gneiss), but Ni(II) sorbed 190% faster on biotite gneiss than on granite. That is why the retardation factors for Cs(I) and Ni(II) were reversed in the biotite gneiss column compared to their distribution coefficients. Therefore, the sorption kinetics cannot be neglected in groundwater systems with high flow rates. In the desorption column test, the retardation followed the order of the distribution coefficient. The desorption column test revealed that the distribution coefficient determines the strength of sorption on crystalline rocks.
结晶岩被用作高放废物处置的主岩。选择了两种阳离子元素（铯（I）和镍（II））以及三种阴离子元素（硒（IV/VI）、钼（VI）和铀（VI））来综合评估这些放射性核素在结晶花岗岩和黑云母片麻岩上的吸附行为。阴离子元素表现出较弱的吸附（log K（L·kg）<1）且竞争效应较小，而阳离子元素（log K（L·kg）=2 - 3）即使在低浓度下也表现出明显的竞争（K值相差18 - 98%）。准二级动力学分析表明，铯（I）在两种岩石上的吸附速率相似（在黑云母片麻岩上快20%），但镍（II）在黑云母片麻岩上的吸附速度比在花岗岩上快190%。这就是为什么在黑云母片麻岩柱中，铯（I）和镍（II）的阻滞因子与其分配系数相比发生了反转。因此，在高流速的地下水系统中，吸附动力学不能被忽略。在解吸柱试验中，阻滞作用遵循分配系数的顺序。解吸柱试验表明，分配系数决定了在结晶岩上的吸附强度。
