Thermo-fluid investigation on a double-side-cooled annular fuel for the prismatic very high temperature gas-cooled reactor

One of the key issues in the development of the very high temperature gas-cooled reactor (VHTR) is an undesirably high temperature of the nuclear fuels. An increased reactor coolant outlet temperature directly drives an increase of the nuclear fuel temperature. Therefore, a special measure has to be taken to overcome the issue of a fuel temperature in the VHTR. In this paper, a double-side-cooled annular fuel concept for a prismatic type reactor is proposed to solve the fuel temperature issue. A detailed thermo-fluid analysis using a computational fluid dynamics (CFD) code was carried out to investigate the thermo-fluid performances of the proposed fuel design. The CFD results show that the proposed design has superior thermo-fluid characteristics to the existing prismatic fuel assembly designs.