离子辐照导致硼硅酸盐玻璃浸出性能的变化北大核心CSCD

在高放射性废物深地质处置过程中,放射性核素衰变引起的强辐射场会导致玻璃固化体浸出性能的变化。本工作利用15 MeV Si离子辐照模拟深地质处置强辐射场,采用MCC-1静态浸泡法在pH=9.0的KOH溶液中对硼硅酸盐玻璃分别浸泡1、3、7、14、28 d,结合电感耦合等离子体发射光谱仪、拉曼光谱仪以及扫描电镜研究了辐照前后玻璃样品的浸出行为。结果表明:随着浸出时间推移,玻璃表面会不断地腐蚀脱落;辐照后玻璃样品的浸出率明显高于未辐照玻璃样品的,蚀变层结构与元素组成无明显差异,但厚度明显增大;形成的蚀变层中Na元素和B元素基本耗尽;蚀变层中SiO_(2)网络体结构溶解,生成大量的Si—OH键及硼硅酸盐结构,并出现四配位B单元向三配位B单元的转变。

Ion Irradiation Induced Leaching Property Changes of Borosilicate Glass

In the process of deep geological disposal of high-level radioactive waste, the strong radiation field caused by the decay of radionuclides can lead to the leaching property changes of the waste glass. In this work, the 15 MeV Si ion irradiation was used to simulate the strong radiation field of deep geological disposal. The samples were immersed for 1, 3, 7, 14, and 28 days in KOH solution with pH=9.0 by using the MCC-1 method, respectively. The leaching behavior of the borosilicate glass before and after irradiation was studied by inductively coupled plasma emission spectrometer, Raman spectrometer and scanning electron microscope. It is observed that the leached glass surfaces occur constantly corrode and fall off with the increase of leaching time. The leaching rate of the irradiated glass samples is significantly higher than that of the unirradiated glass samples. Although it is observed that the thickness of altered layer is increased after irradiation, there are no significant difference in the structure and element composition of the altered layer between the unirradiated glass and the irradiated glass. The sodium and boron elements in the formed altered layer are basically depleted. The SiO₂ network structure in the altered layer is dissolved, a large number of Si—OH bonds and borosilicate structures are created, and the transformation from four-coordinated boron units to three-coordinated boron units is also observed.