The progress on the 3D whole-core neutronics calculation of PANGU code

•This paper introduces the recent progress on the 3D whole-core neutronics calculation of PANGU code.•Diffusion and SP3 solvers based on nodal Green function method (NGFM) have been developed.•The 3 D Sn solver combined with pCMFD acceleration is developed for reference calculation and pre-homogenization.•Two methods are proposed for treating the strong absorbers in the framework of 3D whole-core diffusion calculation. PANGU code is a modern computer code for the physics analysis of pebble-bed high temperature gas-cooled reactors (HTGRs). This paper presents the recent progress on the development of PANGU’s capability in three-dimensional (3D) whole-core neutronics calculations. Firstly, diffusion and SP3 solvers based on nodal Green function method (NGFM) have been developed for the 3D whole-core calculation. Secondly, the 3D discrete-ordinate (Sn) neutron transport solver with coarse mesh finite difference (CMFD) acceleration has been developed to provide reference solutions, as well as being used for pre-homogenization calculations. Thirdly, two methods have been proposed for treating the strong absorbers in the framework of 3D whole-core diffusion calculations. Finally, the performances of the newly developed methods and solvers are tested by typical numerical cases based on HTR-10.