An integral CFD approach for the thermal simulation of the PBMR Reactor Unit

A CFD method was developed to conduct integral thermal reactor analysis for the complete Reactor Unit of the Pebble Bed Modular Reactor (Pty) Ltd (PBMR). The requirement was however also to include very detailed aspects such as leakage and bypass flow paths through the reflector blocks and sleeves. The aim was therefore to investigate the influence of leakage and bypass flow on the thermal performance of the Reactor Unit in an integral fashion.The focus of this paper is to discuss the methodology that was developed. The discussion will firstly highlight all the required inputs, elaborate briefly on the underlying theory and how this was implemented into the CFD modeling capability. Results will be discussed briefly, but the focus is on the methodology.