Review of research on flow instabilities in natural circulation boiling systems

Safety concerns of nuclear reactors have attracted the attention of researchers on flow instabilities in natural circulation boiling loops. This paper presents the state of the art in this area by reviewing a number of contributions. A large number of experimental and numerical investigations have been conducted to study and understand the conditions for inception of flow instabilities, parametric effects on instabilities, and the system behaviour under such conditions. Work done on instabilities due to channel thermal hydraulics as well as neutronics thermal hydraulics coupling has been reviewed. Different methods of analysis used by researchers and results obtained by them have been discussed. Various mathematical models and numerical techniques adopted for developing computer codes have also been discussed. The findings reported in the investigations made in the past three decades have been summarized to present the state of the art of the understanding of flow instabilities in natural circulation boiling systems.