HTGR thermohydraulic study on steady-state conditions using ANSYS FLUENT

HTGR is a reactor type that uses helium gas as its coolant that has a high operating temperature. Many countries are considering building HTGR because it has higher thermal efficiency compared to PWR or BWR. Many studies have been carried out related to HTGR, one of them is related to thermohydraulic performance. Because the thermohydraulic performance is closely related to its safety, therefore this study will be carried out to determine the temperature distribution on the HTGR core, and the graphite reflector temperature will also be compared to experimental data. The HTGR type which is used as a reference in this research is the HTR-10 which has been built in China. The calculation of temperature distribution on HTGR core was carried out using ANSYS FLUENT code applying a porous medium approach and a 2-dimensional model with axisymmetry. The 2-D was applied to simplify the geometrical model as the HTR-10 core was a cylinder, and consequently, it would also speed up the CFD calculation and reach convergence. From the CFD calculations, the results showed that the core outlet helium gas temperature was 795 °C. As for the temperature measurement in the side reflector, the calculation results at the height of 80 cm produced the least difference compared to the experimental results, which is 4 % (at a radius of 193 cm). And the biggest difference was 22 % (at a radius of 93 cm). As for the height of 170 cm, the least difference with the experimental data was 4,3 % (at a radius of 93 cm) and the greatest one was 12,76 % (at 189 cm). (author)