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• Development of the depletion/activation functionalities in NECP-MCX. • Coupling analysis of particle-transport/depletion/activation/source-term for CFETR. • The activation of Be should not be ignored for the depletion analysis of CFETR. As a bridge between ITER and Chinese DEMO, the design of Chinese Fusion Engineering Test Reactor (CFETR) is being carried out. The tritium breeding ratio (TBR) and the ShutDown-Dose-Rate (SDDR) are two significant neutronics parameters for CFETR and other fusion reactors. However, in the previous researches, the variation of the TBR with time was analyzed without consideration of the activation of beryllium. In the analysis of the SDDR, conventional methods assumes that the neutron spectra are not changed in the whole operation duration. To analyze the TBR and the SDDR with higher precision, the functionalities of the particle-transport/depletion/activation/source-term coupling analysis have been developed based on NECP-MCX, which is a Monte-Carlo-Deterministic particle-transport code developed by the Nuclear Engineering Computational Physics (NECP) Lab at Xi'an Jiaotong University. The transmutation solver NECP-Erica, developed also by the NECP Lab, is coupled with NECP-MCX internally. The integrated analysis code, which inherits the name NECP-MCX, is verified by several fusion-related experimental benchmarks. The verification results show the reliability of NECP-MCX. After the verification, the particle-transport/depletion/activation/source-term coupling analysis of CFETR is performed with NECP-MCX. Numerical results show that ignorance of the activation of beryllium overestimates the TBR of CFETR by 1.42% after an operation time of 16 years with a capability factor of 0.5. In the analysis of the SDDR, the ignorance of spectrum variation brings ∼2.0% discrepancy in the activity and decay heat of the structure materials. [ABSTRACT FROM AUTHOR]

To solve the deep-penetration problem in the Monte-Carlo simulation, the classic consistent adjoint driven importance sampling (CADIS) and forward-weighted CADIS (FW-CADIS) hybrid MC-deterministic method is adopted and enhanced in this paper. An automatic hybrid MC-deterministic code, NECP-MCX, is newly developed. NECP-MCX embeds the discrete-ordinate code NECP-Hydra to automatically perform the forward and adjoint neutron-transport calculations and set up the importance parameters for the MC simulation. In massive parallel calculation for large shielding problems, huge amounts of memory are required to save detailed weight-window information. To mitigate the memory limitation, a mesh-coarsening algorithm is developed based on the contributon theory. It can be applied in the traditional Cartesian-mesh and the nested-mesh structure. NECP-MCX was applied to the VENUS-3 benchmark. The results show that NECP-MCX with the enhanced hybrid method is effective in variance reduction and memory saving for the simulation of large and complicated shielding problems on parallel computer resources. [ABSTRACT FROM AUTHOR]