Fine-mesh homogenization and anisotropic SP₃ calculation for PWR cores with plate-type fuel and strong absorbers

SP₃ based pin-by-pin calculation has been proven to be efficient in improving the accuracy of PWR cores with a strong heterogeneity. In this work, it is renamed “fine-mesh transport calculation scheme” when applied to research reactors with plate-type fuel. However, despite that the introduction of strong absorbers has greatly enhanced the angular heterogeneity of the problem, the fine-mesh homogenization for isotropic SP3 calculation still cannot accurately capture the features. This work introduces a series of strategies aimed at enhancing the anisotropic effect for simulating plate-type fuel cores with strong absorbers. These strategies are based on the anisotropic SP3 equations, which are derived from high-order scattering. In addition, an adaptive generation method for the group constants is introduced to further optimize the process. To validate the effectiveness of these strategies, a series of tests, including those employing MTR and JRR-3M, are conducted, demonstrating the significant improvement brought about by the proposed methodology. To conclude, the method introduced in this paper facilitates the two-step method for calculating the reactors with a strong heterogeneity.