The Use of CFD in the Design of PBMR Test Facilities

The Pebble Bed Modular Reactor (PBMR) is currently in an advanced stage of the design. Computational Fluid Dynamics (CFD) is used extensively in the thermo-hydraulic design of the reactor unit. For the first time the thermohydraulic design of a nuclear reactor will be based on CFD technology. The verification and validation of applied design codes is of utmost importance for the design and the safety case of the plant. Current inputs into the model are based on data and correlations from the original German developers of the technology. The recent advances made in computational power and CFD technology make it worthwhile to include more detail in the CFD analyses and to strive for better accuracy in predictions. More detailed fundamental data is therefore required to make use of this capability. PBMR is at the moment in the process of developing a number of test facilities to confirm the data being used in the design and also to extend the current knowledge. These test facilities are state of the art and in some aspects first of a kind dealing with a large range of thermal, pressure and flow requirements. CFD plays a fundamental role in the design of this equipment. The purpose of this paper is therefore to show the importance of CFD in this part of the process. (author)