KIT Multi-scale thermal–hydraulic coupling methods for improved simulation of nuclear power plants

Abstract

In a Nuclear Power Plant (NPP), the Thermal-Hydraulic (TH) phenomena take place at different scales in the core and the primary and secondary circuits. Thus different TH codes have been developed to describe the phenomena at the macro- and meso- scale (system, sub-channel, porous media codes). Besides, the use of general-purpose CFD codes for the analysis of specific local problems is rapidly increasing. To take full advantage of the code's strength, the multi-scale TH approach which couple those codes together is becoming a trend in recent years. At Karlsruhe Institute of Technology (KIT), those multi-scale TH approaches involve the system, sub-channel, and CFD codes: 1) the system code TRACE and the sub-channel code SubChanFlow (SCF) were coupled to improve the prediction of the core thermal hydraulics; 2) the system code TRACE and the open-source CFD code TrioCFD were also coupled to improve the prediction of the TH phenomena inside the Reactor Pressure Vessel (RPV). Those works are based on an Interface for Code Coupling (ICoCo) either with or without the SALOME platform. The current investigations demonstrate the potential of multi-scale TH coupling approaches for improved safety-related analysis of the NPP behavior under accidental conditions. In the future, the focus of KIT work is on multiscale coupling based on domain decomposition using both ICoCo and user define functions of commercial CFD codes.