乏燃料棒中关键核素径向分布特点及对废包壳测量准确度影响  

Characteristics of Radial Distribution of Key Nuclides in Spent Fuel Rod and Effect on Measurement Accuracy of Leached Hull

作　　者：柏磊[1] 王仲奇[1] 刘晓琳[1] 何丽霞[1] 夏兆东[1] 吕牛[1] BAI Lei;WANG Zhongqi;LIU Xiaolin;HE Lixia;XIA Zhaodong;LYU Niu(China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《原子能科学技术》2020年第5期888-894,共7页Atomic Energy Science and Technology

摘　　要：废包壳是水法乏燃料后处理工艺首端高放固态废物的主要来源,通常采用非破坏性测量方法进行整体测量并分析其中残余的U、Pu等感兴趣关键核素的量,传统方法中多引用组件的平均燃耗作为分析计算的输入参数。但根据反应堆运行经验,乏燃料组件和乏燃料棒中燃烧生成的核素及残余U的浓度呈非均匀空间分布状态,这一特性增大了废包壳非破坏性测量分析结果的不确定度。本文采用模拟计算的方法重建乏燃料棒中感兴趣关键核素的径向分布特征,数据表明废包壳中感兴趣核素的质量浓度比与采用燃料棒平均燃耗计算的结果相差可达100%,由此建立了采用非均匀分布特性修正废包壳中感兴趣核素浓度测量分析方法。Leached hull is the most important high-level radioactive solid waste in spent fuel PUREX process.Non-destructive assay technique and instruments are widely used for uranium and plutonium and other nuclides content analysis in leached hull.Average burnup of spent fuel assembly is quoted as initial parameter in traditional algorithm.According to reactor operation experience,spent fuel assembly burnup and fission product in spent fuel rods are inhomogeneity.So it contributes uncertainty to non-destructive analysis results of leached hull.Based on simulated reconstruction techniques,the key nuclides distribution along radius of spent fuel rods was got.The results show that the key nuclides concentration deviation between leached hull and fuel rod can be up to 100%.Several correction factors were added to establish fitting curves for correcting inhomogeneity affects.

关 键 词：非破坏性分析 乏燃料 关键核素 非均匀分布 

分 类 号：TL24[核科学技术—核燃料循环与材料]