The task of long-term structural and mechanical stability of VVER core baffle rings made of new austenitic steel requires reviewing the existing technological process of multi-stage thermo-deformation production technology. Heat treatment at the stage of ingot heating for forging (homogenization) is an essential part of the process. Despite much effort to solve the complex problem of controlling the micro-scale segregation heterogeneity of cast metal, researchers still fail to conduct a system analysis of diffusion processes covering the stages of dendritic crystallization of multicomponent steels under conditions of significant diffusion suppression in the resulting solid phase, as well as the subsequent diffusion homogenization. The need for a solution based on a comprehensive review and dramatic improvement of its methodology is critical. Thus, the paper presents system analysis steps of the first stages of the technological process of VVER-TOI core baffle rings production. If implemented, those steps provide the necessary adequacy of the numerical modeling.