Effective multi-group cross section calculation method for FCM fuel based on improved disadvantage factor method. (February 2022)

• Record Type: Journal Article
• Authors: Yi, Siyu; Liu, Zhouyu; He, Qingming; Zu, Tiejun; Cao, Liangzhi; Wu, Hongchun; Liu, Guoming; Zhang, Liying
• Is Part Of: Annals of nuclear energy. Volume 166(2022)
• Publication Date: 2022-02
• Subjects: FCM fuel -- Effective multi-group cross section -- Double heterogeneity -- Equivalent homogenization; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 621.4805
• DOI: 10.1016/j.anucene.2021.108676
• Languages: English
• ISSNs: 0306-4549

Abstract

Highlights: A new Dancoff based equivalent model is proposed. Multi-group disadvantage factor is obtained by solving an eigenvalue problem. The numerical results show good performance of the developed method. Abstract: Fully Ceramic Micro-encapsulated (FCM) fuel is an important candidate for the accident tolerant fuel (ATF). Compared with traditional fuel, the double heterogeneity of FCM fuel makes the effective multi-group cross section calculation more challenging. In this paper, an improved disadvantage factor method is proposed to deal with the self-shielding effect of FCM fuel in the resonance energy range and non-resonance energy range, to achieve the equivalent homogenization of the FCM fuel. A new equivalent particle–matrix model was constructed by using the particle Dancoff factor to overcome the problem that the traditional volume-weight equivalent model could not consider the macro heterogeneity between fuel rods. Based on the new one-dimensional equivalent sphere model, the ultrafine group slowing down equation is solved to obtain the ultrafine group disadvantage factor in the resonance energy region. In the non-resonance energy region, the multi-group disadvantage factors of the fast group and thermal group are obtained by using the eigenvalue calculation in the new equivalent particle–matrix model. The proposed method has been implemented in the high fidelity neutronics program NECP-X and tested with a set of cases. The results show its good agreement with the Monte Carlo reference for both the reactivity and self-shielding cross sections.