The design and safety analysis of advanced fuel materials and innovative Gen-IV reactor concepts, with their distinct physical and engineering requirements compared to conventional reactors, has often been the main drive behind the development of modern multi-physics, high-fidelity computational tools. Two examples of such tools are GeN-Foam for core analysis and OFFBEAT for fuel behavior, both based on the OpenFOAM C++ library. Until recently, code structural limitations prevented the direct coupling of these codes. Additionally, coupling these tools presents challenges due to the multi-scale nature of the problems involved. This study presents a first successful attempt at establishing such a coupling routine between GeN-Foam and OFFBEAT. It briefly outlines the necessary software modifications for integrating the two libraries and then explores two methodologies: a surface coupling method, which exchanges information through boundary conditions between adjacent domains, and an interpolation-based approach using Radial Basis Functions (RBFs) to map data between domains of different scales. The performance of the latter approach is evaluated by simulating the ORNL 19-pin experiment. The simulation demonstrates the potential of the approach for the codes coupling, though challenges remain in handling physical scales and interpolation accuracy. The initial results are promising, and future work is planned aimed at refining and validating the coupling techniques for broader application in Gen-IV reactor safety analysis.