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.

► Establishment of a modeling capability to simulate the integral thermal operation of an HTR.
► The focus was on the capability rather than improving the assumptions and correlations.
► All assumptions and correlations applied were taken from previous credible research.
► It was shown that it is possible to establish such a capability using current information.
► With this capability, it is now possible to test updated correlations and determine the integral effect.