放射性核素从废物体中向外释放行为初步研究

以去离子水为初始释放环境，考察了1年释放周期内，两类典型低、中水平放射性废物固化体在被水完全浸泡情景下，3种关键核素⁶⁰Co、¹³⁷Cs、⁹⁰Sr的向外释放行为。使用平均有效扩散系数作为表征参数。多个样品的测试结果表明：3种核素向外释放表现出规律性的趋势，即¹³⁷Cs最快，⁶⁰Co最慢， ⁹⁰Sr相比居中。对于不同的核素，起始活度对释放行为的影响是不同的。借助SEM探讨了废物体微观结构对核素释放的影响。

Study on Release Behavior of Radionuclides From Waste Forms

The release behavior of three radioactive nuclides (⁶⁰Co, ¹³⁷Cs, ⁹⁰Sr) in two types of low and intermediated level radioactive solidified waste forms were studied. The release scenario is that waste forms are totally immersed by deionized water about one year. Average effective diffusivity was used as parameter to defined release behavior. The analysis results of several samples show that the release of ¹³⁷Cs is fastest, ⁶⁰Co is slowest, and ⁹⁰Sr is middle. The total activity of radioactive nuclides in waste form has different effect on the release of different nuclides. The effect of microstructure of waste form on release of nuclides was studied based on the SEM photomicrographs.