Research on pin-by-pin calculation method of rectangular mesh based on quasi-diffusion theory

• Published in: Annals of nuclear energy Vol. 205; p. 110584
• Main Authors: Zhuang, Kun, Wang, Yongzhan, Yan, Jiangtao, Zou, Hang, Deng, Lina, Wang, Yingzhen, Wang, Sipeng, Zhang, Qian, Zhang, Jinchao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.09.2024
• Subjects: Eddington factor; MOC; Nodal expansion method; Pin-by-pin; Quasi-diffusion; MOC; Quasi-diffusion; Nodal expansion method; Eddington factor; Pin-by-pin
• ISSN: 0306-4549; 1873-2100
• DOI: 10.1016/j.anucene.2024.110584

•A pin-by-pin method of rectangular mesh based on quasi-diffusion theory was developed.•A MOC-based deterministic code ALPHA was developed to generate the Eddington factor.•This pin-by-pin method has similar accuracy as P3 and similar efficiency as diffusion calculation. With the development of nuclear energy techniques, pin-by-pin calculation using the SP3 method based on pin cell homogenization attracts researchers. This study proposed a pin-by-pin calculation method of rectangular mesh based on quasi-diffusion (QD) theory. The QD equation and boundary condition were derived from a transport equation similar to the P1 equation derivation. The Eddington factor was treated as a few-group homogenized parameter and calculated based on a deterministic code ALPHA. The numerical method of QD equation was developed based on nodal expansion method of nonlinear iteration. Some benchmarks were used to verify the Eddington factor and the numerical method of QD. 4 colorset models with different neutron anisotropy levels were analyzed by pin-by-pin-QD method. Pin-by-pin-QD can reduce keff error by about 600 pcm and agree better with reference results. Additionally, it has better accuracy and similar efficiency as diffusion calculation and is suitable for problems with strong anisotropy.