ABSTRACT The pool‐type research reactors require reliable Emergency Core Cooling Systems (ECCS) to ensure safe operation during Loss of Coolant Accidents (LOCA). Computational fluid dynamic (CFD) simulations were performed in this research with the help of ANSYS Fluent to examine the effectiveness of spray‐based ECCS configurations. Three nozzle designs including full cone, fan type and multi‐orifice were analysed based on effectiveness of cooling, distribution of spray and thermal uniformity inside porous reactor core. A systematic parametric study was conducted to establish the optimal number of nozzles and the effect of outlet diameter of nozzle on heat removal capacity. The test results indicated that the best cooling was offered by six full cone nozzles with an outlet diameter of 8 mm, providing a balanced trade‐off between heat removal and hydraulic efficiency. The comparison between the types of nozzles proved that the full cone type was more successful in top‐to‐bottom cooling and reducing local hotspots than both the fan and multi‐orifice nozzles. Additionally, modelling of time‐varying decay heat based on the Way–Wigner equation provided a more realistic prediction of long‐term cooling behaviour compared to constant heat assumptions. Lastly, control measures implemented using User Defined Functions (UDFs) showed that the PID‐driven regulation of spray pressure resulted in smoother and more stable cooling behaviour compared to simple ON‐OFF control. These findings provide useful insights for the design and optimization of spray‐based ECCS in pool‐type research reactors.
Khan et al. (Sun,) studied this question.