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In nuclear fuel manufacturing, dry conversion is a key step used to produce UO₂ powder from crystalline UF₆ for subsequent pellet fabrication. The properties of the final material are highly sensitive to operating conditions, which makes a thorough understanding of the process crucial for maintaining both safety and supply reliability. These processes involve materials that are challenging to handle and require high-temperature operation. In this context, numerical modeling and simulation provide valuable support for process analysis and optimization. The dry conversion step is a continuous chemical sequence combining a reactor and a furnace. Once treated in the reactor, the powder is transferred into a heated tubular furnace where it is transported along its length. During this stage, UO₂F₂ is gradually converted into UO₂ through successive gas–solid reactions, involving both exothermic and endothermic mechanisms, with gases flowing in counter-current to the powder. The furnace has been modelled using COMSOL Multiphysics®. A one-dimensional approach is employed to model the thermochemistry along the furnace, enabling the determination of reaction locations, temperature profiles within the equipment, and the composition of the produced powder. To precise this model and evaluate the level of temperature heterogeneity on transversal section, a two-dimensional-thermal model is developed in different cut planes along the furnace. Then, the grains dynamics is modelled in a two-dimensional approach to estimate the proportion of powder above and in the powder likely to react with the gas. A user interface has been developed to enable easy adjustment of operating conditions. COMSOL ServerTM provides remote access to the model over a secure HTTPS connection. These models provide a deeper understanding of the chemical reactions occurring within the furnace, the temperature field, and how the furnace rotation impacts powder distribution. Sensitivity studies on operating conditions can be conducted using the user interface to optimize parameters and ther eby enhance the quality, efficiency and productivity of the process.