A dataset of higher-order modes results obtained by the hybrid two-step method

Based on the higher-order modes diffusion calculation code HARMONY, we developed a new higher-order modes calculation code HARMONY2.0 using the MC-deterministic hybrid two-step strategy. In the HARMONY2.0, the mesh homogenized multigroup constants are obtained by OpenMC in the first step, then higher-order modes are calculated with the mesh homogenized core diffusion model using Implicitly Restarted Arnoldi Method. In addition, to improve the calculation efficiency in particularly large higher-order modes, event-driven parallelization / domain decomposition methods are embedded in the HARMONY2.0 code to accelerate the inner iteration of λ/α mode by using OpenMP.

Furthermore, the higher-order modes of the complex geometric models, such as Hoogenboom and ATR reactor for λ mode and MUSE-4 experiment facility for prompt α mode, are computed in diffusion theory.