The practical application NH₃/H₂ co-firing technology is being considered to reduce CO₂ emissions towards the realization of a decarbonized society. However， NOx production during NH3 combustion is a concern and as such， the development of prediction techniques is required. In this study， a reactor network model was constructed using the chemical reaction analysis software ANSYS CHEMKIN 2023 R1. The resulting NO concentration was found to vary non-linearly under different mixing ratio of NH₃ and H₂.