持续裂变链引发的零维蒙特卡罗模拟

Simulation of Persistent Fission Chain Initiation With Zero-Dimension Monte-Carlo Method

采用基于点动力学模型的零维蒙特卡罗方法,模拟计算了自发裂变中子引发条件下,超瞬发临界5c/的GodivaⅠ快中子脉冲堆内持续裂变链引发时刻概率的分布。结果表明,零维模拟程序与基于Geant4toolkit的三维直接模拟程序的计算结果一致,并与实验结果符合较好。另外,采用零维蒙特卡罗模拟方法,模拟计算了外中子源引发条件下快中子脉冲堆反应性动态加入过程中持续裂变链的引发概率。结果表明,零维方法用于反应性动态加入情形的模拟计算,其结果是合理可信的。可见,在研究快中子脉冲堆的动力学行为时,采用点动力学近似是合理的。

Using a zero-dimension Monte-Carlo method based on point kinetics, burst initiation time for Godiva I assembly in the presence of weak neutron source, whose reactivity was 5 above prompt criticality, was calculated. The initiation time of the simulation is consistent with the results of Monte-Carlo simulation and experiment. The initiation probability of dynamic reactivity addition case with zero-dimension Monte- Carlo method was calculated. Calculation result is consistent with that of the determin- istic prediction. All results show that it is reasonable to study kinetics behavior for fast burst reactor using point kinetics.