Benchmarking of the multigroup, fine mesh, SP₃ methods in parcs with the VENUS-2 MOX critical experiments

A multigroup, pin-by-pin, transport capability has been added to the U.S. NRC neutron kinetics code PARCS for the purpose of analyzing MOX fueled cores. The focus of the work reported here is the benchmarking of the new PARCS methods using the VENUS-2 critical experiments. Both the two- and three-dimensional versions of the benchmark were analyzed with PARCS using group constants generated with the HELIOS lattice physics code. The 2-D VENUS-2 benchmark was performed with a specified axial buckling and PARCS results are compared to a full core transport solution generated with HELIOS. The 3-D VENUS-2 benchmark is still a “blind” benchmark and assembly and axial power distributions from PARCS results are reported. The PARCS core calculation was performed using a fine mesh SP₃ kernel with 2 and 8 energy groups with cell homogenized cross sections. A conventional 2 group nodal calculation with pin power reconstruction was performed using PARCS ANM kernel in order to compare the new methods in PARCS with conventional core analysis methods. A preliminary analysis was also performed using SPH factors to account for errors introduced by pin cell homogenization.