ZPPR-21 critical benchmark analyses with ENDF/B-V and -VII data

The six benchmark problems for the ZPPR-21 critical experiments phases A through F were analyzed using the ENDF/B-V2 and ENDF/B-VII.0 data. For reference calculations, Monte Carlo simulations were performed using the VIM code with the continuous energy cross sections. For deterministic calculations, composition and region dependent multi-group cross sections were generated using the ETOE2-2/MC2-2/SDX code system and core calculations were performed with the TWODANT discrete ordinate transport code. Based on sensitivity studies, deterministic core calculations were carried out with 230 energy groups, ∼1 cm spatial mesh size, S24 angular approximation, and P5 anisotropic scattering order Comparisons showed that the core multiplication factor determined with TWODANT agreed well with the VIM Monte Carlo solution within 0.20 %Δk for the ENDF/B-V2 data and 0.27 %Δk for the ENDF/B-VII.0 data. Detailed comparisons of reaction rates were also made between VIM and TWODANT solutions. The results showed that the multigroup cross sections generated with MC2-2 accurately reproduced the isotopic reaction rates of VIM calculations. (authors)