启明星1#次临界装置热中子能谱区裂变率分布测量

启明星1#是我国专门为开展加速器驱动次临界系统研究而建立的国际上第1个具有快-热耦合结构的次临界反应堆实验装置。采用MCNP程序对堆芯裂变率分布进行指导性计算,并参考计算结果布置探测片,用固体核径迹探测器测量了堆芯热区裂变率分布。测量结果显示:堆芯有反射层一端的裂变率比无反射层一端的高;轴向加装反射层末端的裂变率明显增大。测量结果对确定热区的裂变功率提供了数据。

Fission Rate Distribution Measurement of Thermal Neutron Spectrum Zone in Venus 1# Sub-critical Assembly

Venus 1# assembly, which is established for ADS (accelerator driven sub-critical system) research in China, is the first sub-critical assembly consisting of both fast and thermal neutron spectra zones internationally. Fission rate of the assembly was calculated with MCNP code. The calculated result was referenced to determine the positions of detectors in fuel elements. Meanwhile, the measuring principle for fission rate by solid-state nuclear track detector was introduced, and the measuring results were also given. The measurement results show that the axial fission rate at the end close to the reflector is higher than that at the end without reflector, and the effect of reflector increases fission rate. The results provide important data for determining the fission power of thermal neutron spectrum zone.