Study on Operation Ranges and Discharge Performance of Steam Injector System

Steam Injector (SI) is a passive pump activated by steam and water, and it does not require any external power supplies or rotating machineries. Moreover, SI has high ability as a heat exchanger by undergoing direct contact condensation mechanism. From these characteristics, SI has a capability to be applied as a passive safety system in the nuclear power plant. In the present study, experiments targeting the operating range and pump performance were carried out to obtain SI’s detailed characteristics under following supply conditions; inlet steam pressure was 0.02 ∼ 0.81MPaG, inlet water flow rate was 0.21 ∼ 0.80 kg/s. In the former experiment, operating range was investigated by changing inlet conditions, and the influence of steam inlet pressure and water inlet flow rates on SI operating range was tested. In the latter experiment, pump performance of SI was evaluated by investigating the maximum discharge pressure in each inlet condition by using back pressure valve. From the results of experiments, it was confirmed the operating range of SI was limited by supplied steam pressure and supplied water flow rate, and some clear trends were found in the operation boundary map. In addition, SI could discharge water at least 1.2 times higher than inlet steam pressure under above-mentioned conditions, which verified SI’s capability to be applied for the nuclear power plant as a core cooling system. And furthermore, existing 1D analysis model’s predictive capability was tested based on these experimental results.