On the stability of the Discrete Generalized Multigroup method
Author(s)Gibson, Nathan A.; Forget, Benoit; Gibson, Nathan Andrew; Forget, Benoit Robert Yves
MetadataShow full item record
This paper investigates the stability of the recondensation procedure of the Discrete Generalized Multigroup method and proposes alternatives to improve stability of the original formulation. Instabilities are shown to happen when employing a simple Picard fixed point iteration and an ill-informed group mapping scheme. This work presents a mapping procedure that improves stability of the original method for fine group calculations. Additionally, a relaxation scheme, Krasnoselskij iteration, is introduced to the fixed point iteration to further improve the stability characteristics and remove the need for fine group flux updates. Both improvements are applied on heterogeneous problems using the SHEM361 and the NG2042 group structures. The results indicate improved stability from a well-informed group mapping and demonstrate the possibility of eliminating the need for fine group flux updates.
DepartmentMassachusetts Institute of Technology. Department of Nuclear Science and Engineering
Annals of Nuclear Energy
Gibson, Nathan A., and Forget, Benoit. “On the Stability of the Discrete Generalized Multigroup Method.” Annals of Nuclear Energy 65 (March 2014): 421–432. © 2013 Elsevier Ltd
Author's final manuscript