Numerical analysis of passive safety injection driven by natural circulation in floating nuclear power plant

Abstract

The traditional energy supply paradigm has been difficult to meet the demands of ocean resources development. As a combination of small nuclear reactors and offshore platforms, the floating nuclear power plant(FNPP) can be well used in offshore energy supply. Considering passive safety injection of FNPP will be deeply affected by the ocean environment, the present study brings a CFD customization model to assess the injection process. The additional inertial force is implanted into the momentum equation to simulate motion conditions. The combination of coordinate transformation and grid traversal is used to output critical parameters. Therefore, it can be seen the overall evolution process and the local flow characteristics of natural circulation intuitively apart from quantitative analysis, making up for the deficiency of the previous analysis code. Results suggested the injection process can be divided into several stages. Affected by ocean conditions, the flow rate in FNPP will decrease with periodic fluctuation after a linear increase, so the safety injection can be completed in 180 s under static conditions while needing more than 240 s under rolling. However, although additional acceleration weakens the driving force of natural circulation, liquid sloshing and disturbed flow will make the reactor core cool more effectively.