Neutronics benchmark analysis of the tests performed at China Experimental Fast Reactor (CEFR)

As part of Coordinated Research Project (CRP) under the supervision of the International Atomic Energy Agency (IAEA), a neutronic benchmark analysis of the China Experimental Fast Reactor (CEFR), a sodium-cooled fast reactor with a thermal power of 65 MW and a fuel enrichment of 64.4 wt.% U-235, was performed using ENDF/B-VII.1 nuclear data library. First, a critical core configuration model was constructed and verified in OpenMC v0.14.0 and Serpent v2.2.1, then the model was converted into a depletion model in hot full power conditions. The depletion behaviour is analysed and a comparison between the two codes is made. It is found that the effect of unresolved resonance probability table sampling and the predictor-corrector is small. Subsequently, the variance reduction capabilities of Serpent v2.2.1 are analysed by simulation of the neutron flux in detectors up to 7.5 m from the core centre, which proved to be useful and fast. Finally, the neutron spectra were determined in assemblies (2)2) and (è-5) at the fuel mid-plane.