A one-dimensional model for multi-group equivalence parameters in subgroup method. (15th September 2022)

• Record Type: Journal Article
• Authors: He, Qingming; Yi, Siyu; Liu, Zhouyu; Wu, Hongchun; Cao, Liangzhi
• Is Part Of: Annals of nuclear energy. Volume 175(2022)
• Publication Date: 2022-09-15
• Subjects: Multi-group equivalence -- Resonance self-shielding calculation -- Subgroup method -- Generalized equivalence theory -- Discontinuity factor; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 621.4805
• DOI: 10.1016/j.anucene.2022.109208
• Languages: English
• ISSNs: 0306-4549

Abstract

Highlights: A one-dimensional model for computing partial current discontinuity factor (PCDF) in subgroup method; The multi-group equivalence effect can be captured in an acceptable precision by the PCDF based on 1D model; There is negligible increase in computational time brought by the model. Abstract: In the previous study, a non-iterative equivalence method is proposed, which guarantees that the reaction rates calculated by subgroup method in self-shielding calculation are preserved in subgroup-collapsed one-group calculation. This method shows advantage in efficiency over the Super-Homogenization (SPH) method. However, one-group fixed-source calculations are still needed for obtaining multi-group (MG) equivalence parameters. In this paper, a one-dimensional model is employed for obtaining the MG equivalence parameters in subgroup method. Based on the one-dimensional model, the one-group fixed-source calculation is simplified to one-angle tracking sweeping, which is time-saving. The numerical results show that the reaction rates can be preserved with the MG equivalence parameters obtained based on the one-dimensional model for pin cell problems. For fuel assembly problems, the k inf is improved by 140 pcm ∼ 187 pcm with negligible increase in computational time.