The authors propose and compare three methods—filter burnup, single energy burnup, and burnup extremum analysis—to build a high-resolution neutronics model for the production of 238Pu in high-flux reactors. The filter burnup and single energy burnup methods achieve a spectrum resolution of up to ~1 eV, allowing the construction of importance and yield curves over the full energy range. The burnup extremum analysis method combines these curves to consider the influence of irradiation time on production efficiency, resulting in extreme curves. These curves, which quantify the transmutation rate of nuclei in each energy region, are physically significant due to their similar distributions. The high-resolution neutronics model established based on these curves demonstrates universality and feasibility, guiding neutron spectrum optimization and improving 238Pu yield by up to 18.81%. The model reveals the law of nuclear transmutation in all energy regions with high spectrum resolution, providing theoretical support for high-flux reactor design and irradiation production of 238Pu.The authors propose and compare three methods—filter burnup, single energy burnup, and burnup extremum analysis—to build a high-resolution neutronics model for the production of 238Pu in high-flux reactors. The filter burnup and single energy burnup methods achieve a spectrum resolution of up to ~1 eV, allowing the construction of importance and yield curves over the full energy range. The burnup extremum analysis method combines these curves to consider the influence of irradiation time on production efficiency, resulting in extreme curves. These curves, which quantify the transmutation rate of nuclei in each energy region, are physically significant due to their similar distributions. The high-resolution neutronics model established based on these curves demonstrates universality and feasibility, guiding neutron spectrum optimization and improving 238Pu yield by up to 18.81%. The model reveals the law of nuclear transmutation in all energy regions with high spectrum resolution, providing theoretical support for high-flux reactor design and irradiation production of 238Pu.