Research on the Influence on Neutronic Characteristics of Fine Nuclide Density in EBR-II Core based on LoongSARAX

The Experimental Breeder Reactor II (EBR-II) is a famous benchmark for sodium-cooled fast reactors (SFR), with a complicated spatial distribution of nuclide density. Therefore, simplification to the spatial distribution of nuclide density was adopted in many studies on EBR-II benchmark calculation.

[Purpose] This study aims to contrast the difference between the results of the fine model and the simplified model, evaluating the rationality of the simplification. [Methods] In this study, both the fine model and the simplified one were built using LoongSARAX, a neutronic numerical program for fast reactors developed by Xi’an Jiao Tong University. Some approximations were adopted in the models: one-dimensional homogenization was adopted for the half-worth driver assembly to handle its complex radial geometry and the super-assembly method was used in the cross-section generation of poison elements.