铍组件堆内长期服役后的尺寸测量

Size measurements of beryllium assemblies after long term service

铍是核反应堆内的重要反射层材料,其辐照后的尺寸变化对反应堆的安全性具有重要的影响。为获得铍组件堆内长期服役后的尺寸变化,以对其堆内的服役性能评价提供基础数据,设计并加工了一套高放样品远程转运平台,使用三坐标测量机完成了绵阳SPRR-300堆内铍组件的尺寸变化测量实验。实验测量结果表明,SPRR-300堆的铍组件在服役29 a后,在最高中子通量高达6.78×10^(21)cm^(-2).的辐照环境下,铍组件外形尺寸总体上保持良好,截面有微量的收缩变形,最大形变约0.13 mm,这表明在长期中子辐照环境下,辐照蠕变是导致铍组件尺寸变化的主要原因。

Beryllium is an important material as neutron reflection layers in nuclear reactors. The size change of beryllium after long term neutron irradiation has a great influence on the reactor safety. To obtain the size change of beryllium assemblies after long-time irradiation for the assessment of service performance, a set of special tools were designed and manufactured. The size change of post-irradiation beryllium assemblies was examined on a three coordinate measuring machine. The measurement results indicate that beryllium assemblies of the SPRR-300 reactor have excellent stability after 29 a irradiation, even under the maximum neutron fluence of 6.78×10^(21)cm^(-2). The section dimension has little change in local part of beryllium assemblies and the largest change is about 0.13 mm, which indicates that irradiation creep is the main reason for the dimension change of beryllium assemblies during the longtime service.