Preliminary development of a multi-physics coupled fuel performance code for annular fuel analysis under normal conditions

Benefitted from its dual-cooled structure, annular fuel may enhance fuel performance against conventional solid fuel. To aid the potential deployment of annular fuel, fuel performance analysis can be beneficial. In this study, leveraging the open-source Multiphysics Object-Oriented Simulation Environment (MOOSE), a finite element method (FEM) based fuel performance code, have been preliminarily developed for annular fuel, where governing equations for both fuel and coolant are solved in a fully coupled manner. Afterward, assessments of the developed codes were conducted through selected cases to improve the confidence of code predictions. Then, a comprehensive analysis of annular fuel and its fuel performance comparison against solid fuel were completed. Meanwhile, the uncertainty of fuel relocation on fuel performance was investigated. The results suggest that the (1) predictions by the developed code are reasonable, (2) fuel rod temperature & fission gas release can be notably reduced even under elevated rod power (~1.2x solid fuel power) when annular fuel is employed, (3) the uncertainty of fuel relocation plays a vital role for fuel heat split between internal and external coolant channels which should be considered to evaluate its thermal-hydraulic performance.