The drop time of the control rod plays an important role in judging whether a nuclear reactor can be safely shut down in an emergency condition and has become one of the most important parameters for the safety analysis of nuclear power plants. Exact assessment of the drop time is greatly dependent on the forces acting on the control rod. In this research, a three-dimensional numerical simulation of the control rod in a low-temperature heating reactor was established based on 6DOF (6 degrees of freedom) model using dynamic meshing technology, and it was used to analyze the control rod dropping experiment. The behavior of dropping the control rod was obtained, including the velocity, the displacement, and the pressure distribution on the control rod guide tube. The comparison between the simulation and the experiment results indicated that the simulation was capable of simulating the dropping characteristic of the control rod. Some important parameters can be calculated, such as the time of control rod dropping process and the maximum impact force. Based on this, useful information could be provided for the design of control rod driveline structure.

控制杆的下降时间在判断核反应堆是否可以在紧急情况下安全关闭方面起着重要作用，并且已成为核电厂安全分析的最重要参数之一。下降时间的准确评估在很大程度上取决于作用在控制杆上的力。在这项研究中，基于6DOF（6自由度）模型，使用动态啮合技术建立了低温加热反应堆中控制棒的三维数值模拟，并将其用于分析控制棒掉落实验。获得了控制杆掉落的行为，包括速度，位移和控制杆导管上的压力分布。仿真与实验结果比较表明，该仿真能够模拟控制杆的下落特性。可以计算出一些重要的参数，例如控制杆掉落的时间和最大冲击力。基于此，可以为控制杆传动系统结构的设计提供有用的信息。