Investigation of Increasing Safety and Reliability of Small Modular Reactors Using Dual-cooled Annular Fuel Element

The use of dual-cooled annular fuel is one of the proposed methods to increase the safety of nuclear reactors. This type of fuel allows the cooling fluid to pass through the internal channel and as a result more heat is removed from the fuel surface. For this purpose, in this study, a dual-cooled annular fuel assembly with 11×11 array in a small modular reactor has been investigated by neutronic and thermal-hydraulic simulations. In the results of neutronic calculations, designed dual-cooled annular fuel assembly were compared with the reference reactor, it was found that these two designs have similar neutronic properties. But in the thermohydraulic results, a significant effect of the use of dual-cooled annular fuel was extracted. The use of this type of fuel reduced the maximum fuel temperature, the pressure drop and increased minimum departure from nucleate boiling ratio.