Abstract
Blowdown process of helium in HCS of CH-HCSB is theoretically analyzed. The influenced area is divided into three volumes and uniform assumption is adopted for VV and main loop of HCS. Analytical correlations of mass and pressure in VV and HCS are obtained. Validation of the analytical model is done by comparison with the numerical results of 3D CFD code. The effect of flow friction is also analyzed. It is found that the flow friction plays important role in the blowdown process and cannot be omitted. The blowdown process in TBM is simulated and analyzed. The results show that the flow in HCS keeps a high value in 20 seconds after break, which will benefit to the removal of decay heat. The results also show that the shock in vacuum vessel caused by pressure rising is not significant.
