The Theory and Parameter Identification for the Graphite Block Collision Model

The graphite core, as the crucial component of a gas-cooled reactor, may trigger collision due to the gap between components under seismic loads, to affect the safety of the reactor. Studying its collision dynamic characteristics is of great significance for the safety assessment of nuclear engineering. For seismic analysis of nuclear equipment, the whole system is often simplified (such as the modal superposition method) to carry out efficient dynamic calculations, so it is necessary to find a linearized core collision behavior analysis model. The classical L-N collision modeling, the Kelvin collision modeling, and the modeling theory analysis of the linear simplified model were carried out based on the collision behaviors of graphite blocks. Then, the effects of model parameters on its collision behaviors were discussed, and an iterative recognition algorithm for model parameters was proposed. Finally, a dedicated collision test system for graphite blocks was established. The collision responses under various initial velocities were measured, to enable the statistical analysis of collision characteristics, the parameter identification for the collision model, and the validation of the linear equivalent model. This study can provide an important reference for the seismic analysis model for nuclear equipment containing graphite cores and other collision components.