Method to determine forces developed during a time dependent opening of a relief valve discharging a two-phase mixture

Safety relief valve (SRV) operation creates unsteady reaction forces on the discharge piping due to fluid acceleration. It is important to estimate these forces in order to properly design the piping system and pipe motion restraints. Normally an SRV discharges steam or other gaseous substance. However, the SRV piping design of a nuclear power system may be required to withstand reaction forces caused by the discharge of two-phase steam/water mixtures. The method of characteristics is used to solve both the two-phase and gas flow equations in an SRV piping system. Pipe segment forces for a sample SRV system are presented for cases of steam and water discharge. 5 refs