放射性废物固化体抗浸出性快速测定方法探讨

Discussion on Method for Accelerated Leach Test of Radioactive Waste Form

固化体的抗浸出性是放射性废物安全管理的一重要参数。目前,国内采用国标GB7023—86中的标准浸出试验方法测试固化体的抗浸出性,试验周期长。并且,国标GB14569.1—93仅对核素第42d的浸出率作了规定。这一规定不能很好反映不同固化基材、不同配方固化体间抗浸出性的差异。美国国家标准ANSI/ANS-16.1—2003采用快速浸出试验方法,并用浸出因子来表征核素的抗浸出性。本工作参照美国标准对试验结果的处理方法,对以往获得的真实或模拟放射性废物水泥固化体的浸出试验数据进行重新计算。计算结果表明,当核素累积浸出百分数小于20%时,核素的浸出率与浸出因子间存在一定的换算关系。据此,可考虑建立快速浸出试验方法和新的试验结果表述式,以较全面地判定放射性废物固化体的抗浸出性能。

The measurement of the leach resistance of waste forms is important in waste management. The used method for leach test is the published national standard method （GB 7023--86） in China. However, some lack in the standard method need to be modified. The period of test is too long, and only the leaching rate on the 42nd day of cemented waste is required in GB 14569.1--93. And the leaching rate of nuclides on the 42nd day is used to evaluate the leach resistance of waste form, which cannot roundly reflect the difference of waste form. The accelerated leach method was adopted and the leachability index of nuclides was used to evaluate the leach resistance of waste form in American standard ANSI/ANS-16.1. The data from the leach test during the several past years were calculated newly referring to ANSI/ANS-16.1. It is found that the leachability index of nuclides can be educed from the leaching rate when the cumulative fraction leached is less than 0.20, and it is possible to establish a test method with a short-term test procedure and use the leachability index to evaluate the leach resistance of waste form.