An efficient hybrid multi-level CMFD in space and energy for accelerating the high-fidelity neutron transport calculation

•Implemented an efficient hybrid multi-level CMFD in space and energy.•Significantly reduce the computational burden of high-fidelity neutron transport.•1/4 pin-cell-based multi-group gCMFD, and cell-based one group gCMFD.•However, due to the large condition number of this 1/4Cell-MG-gCMFD linear system, it shows a slower convergence and then a new low-order cell-based one group gCMFD is applied to accelerate the 1/4Cell-MG-gCMFD.•And the success of the new hybrid multi-level CMFD is just the implementation of a 1/4 cell based CMFD, while the cell based one group gCMFD is applied to further reduce the computational cost of the 1/4Cell-MG-gCMFD and its contributions to the acceleration will be more obvious in the transient simulations.