Experimental study on the blowdown load during the steam generator feedwater line break accident in the evolutionary pressurized water reactor

► We performed tests to obtain thermal-hydraulic parameters during feedwater line break accident. ► To fulfill the break opening time of ∼1 ms, we used double rupture disc assembly. ► Propagation of pressure wave was clearly observed. ► Meaningful dynamic pressure could not be measured in case of quick opening valve use. ► Using MARS code, it was feasibile to simulate the dynamic pressure behavior.