A system CFD model of the heat transfer in a prismatic block of a VHTR

Abstract

The conduction heat transfer through the prismatic blocks containing the fuel elements in a Very High Temperature Reactor (VHTR) is of crucial importance for the proper operation of the reactor under normal operating conditions and upset conditions. This paper discusses a system computational fluid dynamics (CFD) model that simulates the heat transfer and fluid flow in a single-channel fuel module of a prismatic block in a representative manner. The model consists of a collection of one-dimensional solid conduction heat transfer, convection heat transfer and pipe elements that are arranged in such a manner to represent the heat transfer and fluid flow in the single-channel fuel module using a network approach. The current model represents one sixth of a single-channel fuel module. The validity of the model was investigated by comparing the temperature distribution in the single-channel fuel module for various scenarios with the corresponding values obtained using a detailed CFD model of the single-channel fuel module. This model requires much less computational resources than the detail CFD and unit cell based models and can form the basis of an integrated model for the entire core