Numerical simulation of water hammer characteristics for integral reactor primary circuit

Based on the method of characteristic line, a set of closed mathematic expressions with reasonable boundary conditions of the nuclear reactor primary circuit has been established. WAHAP program has been developed, and numerical calculation is carried out on the check valve-induced water hammer phenomena in a four pumps paralleled feedwater system during the alternating startup process of parallel pumps. In this paper, we found that the valve disc stroke the valve seat at two different periods and there were two kinds of pressure vibration existed.