Calculation analysis on the natural circulation characteristics of a new pressurized water reactor

A mathematical model was developed for predicting the steady-state natural circulation characteristics of a new type of pressurized water reactor (PWR) based on the one-dimensional mass, momentum and energy conservation equations. The detailed geometry characteristics of the PWR as well as the flow patterns and heat transfer conditions were considered in the model. With numerically solving the mathematical model, a theoretical investigation was performed on the steady-state natural circulation characteristics of the PWR. The preliminary calculation analysis shows that natural circulation mass flow rate is proportional to the exponential function of the power, and the value of the exponent is related to working conditions of the steam generator in secondary side. In addition, the higher elevation difference between the core and the steam generator is favorable to the heat removal capacity of the natural circulation.