UO2燃料燃耗对高放废物管理的影响研究

从乏燃料的不同燃耗引起放射性和化学组成的变化出发，分析乏燃料经后处理后的衰变热、Mo及贵金属含量对玻璃固化工艺和玻璃固化体储存的影响，计算得到了不同燃耗乏燃料制得的高放玻璃的数量。计算结果认为：对于冷却8 a的乏燃料，决定玻璃固化体包容量的不是高放主组分的热功率；对于燃耗小于40 GW?d/tU的乏燃料，决定玻璃固化体包容量的是Mo元素含量；当燃耗大于45 GW?d/tU时，贵金属含量成为决定玻璃固化体包容量的主要因素，同时UO₂燃料燃耗与高放玻璃固化体数量上存在线性关系，燃耗增加会导致高放废物玻璃固化体数量增加。随着燃耗的增加，以Mo含量及贵金属含量计算得到的玻璃固化体数量比以衰变热计算得到的玻璃固化体数量多，因此，高放废物玻璃固化前将Mo及贵金属进行分离有利于减少高放废物玻璃固化体数量。对于UO₂燃料，燃耗加深对于高放废物玻璃固化体暂存时间几乎无影响。

Influence by Burnup of UO2 Fuel on High-level Waste Glass Management

The influence of the heat generation rate and the Mo or noble metal content after nuclear fuel reprocessing on technique of high-level waste glass and waste management was analyzed based on the radioactivity and the chemical component of nuclear fuel changed with burnup of UO₂ fuel, and the numbers of high-level waste glass units were calculated by different burnups of UO₂ fuel. The calculated results indicate that heat generation rate caused by main components is not decisive factor for the waste loading of glass if the spent nuclear fuels are cooled longer than 8 a, Mo content is the decisive factor if the burnup is under 40 GW?d/tU, and the noble metal content is the decisive factor when the burnup is above 45 GW?d/tU. The linear relation exists between the number of glass units and the burnup of spent nuclear fuel, and the number of glass units generated increases with the burnup of spent nuclear fuel. With the increase of the burnup, the number of glass units calculated by Mo content and noble metal content is more than the number calculated by heat generation rate, thus, the number of glass units can decrease with the separation of Mo and noble metal. Increasing the burnup of spent nuclear fuel has barely influence on buffer storage time of high-lever waste glass units.