Evaluation of Blast Wave Effects on Reactor Coolant System

When a high energy line pipe break (HELB) occurs, the reactor coolant system (RCS) is affected by several dynamic effects. The effects of jet impingement, thrust, subcompartment pressurization, nozzle loads, and blowdown load in the reactor internals (RI) are generally known and have been evaluated so far. The RCS BLPB analyses for APR1400 had been performed for the break cases considering the dynamic effects except blast wave due to the HELB. Responses from the enveloped values of all break cases were used for the RCS design. In this study, the blast wave effects on the RCS due to the main steam nozzle break for APR1400 are evaluated. The forces and moments and response spectra induced by blast wave loads at the RCS main components are included in this evaluation. The structural analysis was performed to evaluate the blast wave effect on the RCS. The analysis results show that blast wave loads affect the responses in main steam nozzle break case. The supports and nozzle loads of the RCS and the response spectra of the SG are increased. However, the supports and nozzle loads are enveloped by other break cases and only high frequency regions of the response spectra are affected.