Effects of geometry homogenization on the HTR-10 criticality calculations

This study performs an investigation of geometry homogenization simulation using MCNP5 v1.51 and SCALE6 on the HTR-10 criticality calculations and focusing on the impact of geometry homogenization on keff and neutron spectrum. The data libraries employed in this work are both continuous ENDF/B-VI respectively in MCNP5 and SCALE6. Six models, which are Model 1 – heterogeneous model, Model 2 – TRISO coating and graphite matrix homogenized model, Model 3 – TRISO homogenized model, Model 4 – fuel zone of fuel ball homogenized model, Model 5 – fuel ball homogenized model, and Model 6 – core homogenized model, are performed correspondingly by using MCNP5 and SCALE6 on the homogeneous effect analysis in HTR-10. The results revealed that the differences of keff between MCNP5 and SCALE6 are all less than 300 pcm. The small differences of keff, neutron spectra, and also the consistent discrepancies of neutron spectra between each homogenized model (Model 2–6) and Model 1 show the good agreement of MCNP5 with SCALE6 in the geometry homogenization.