Experiments of critical heat flux for helical finned rod under rolling conditions using R-134a.

The research and development efforts are underway to utilize nuclear power across various fields with the aim of carbon neutrality. As part of these efforts, floating nuclear power plants have been proposed. These systems require a compact reactor design due to spatial and weight constraints. Therefore, there is potential for the use of helical-shaped fuel, which offers various advantages in designing high-power-density reactors. However, the effect of non-circular fuel shapes on Critical Heat Flux (CHF) under ocean conditions is not well understood. In this study, the CHF on a helical finned rod heater was experimentally examined under rolling conditions. The experimental results showed that the CHF during rolling conditions varied compared to vertical and inclined CHF. The local wall temperature behavior leading rolling CHF was analyzed for each CHF regime. Commonly, significant heat transfer degradation was observed when reaching the maximum roll angle. As a result, it was found that rolling CHF was decreased compared to inclined CHF due to the influence of tangential force, and the degree of decrease was greater with shorter periods. The CHF database and insights gained from this research can contribute to the design of a nuclear reactor using helical-shaped fuel under ocean conditions. [ABSTRACT FROM AUTHOR]