Abstract
The paper presents a methodology for modeling the dynamics of volumetric fuel distribution based on the coupling of thermal-hydraulic and neutronic calculations. An algorithm was developed for the automated conversion of CFD simulation results into an MCNP computational model. The methodology makes it possible to account for changes in geometry, phase composition, and spatial distribution of fuel and structural materials during fuel degradation and melting processes. To achieve this, software was developed for processing thermal-hydraulic calculation data, generating computational lattices of various types, implementing an angular duplication algorithm, and automatically creating input files for neutronic calculations. Unlike the conventional approach, which relies on the development of a set of separate neutronic models corresponding to fixed stages of fuel degradation, the proposed methodology enables power distribution calculations for any state of the experimental device obtained from thermal-hydraulic simulations. Verification of the developed neutronic model of the test facility containing fuel within the reactor model of the IGR reactor was performed. The obtained results can be used for computational support of experiments investigating nuclear fuel degradation and melting processes, as well as for the development of coupled thermal-hydraulic and neutronic modeling methodologies for reactor research applications.