DRAGON and CORD-2 nuclear calculation of the NPP Krško fuel assembly

The geometry of the reactor core is usually too complex to be solved in one step. Therefore, a solution for the whole core in 3-D geometry is sought in several steps, where some kind of homogenization procedure of neutron few-group cross sections is applied. Usually, assembly-homogenized effective two-group cross sections are determined, which are suitable for solving the diffusion equation for the whole core by a coarse mesh nodal methods. In this paper DRAGON 4 and CORD-2 codes are used for the calculation of NPP Krško 16 × 16 fuel assemblies without and with IFBA rods. DRAGON code was selected, since it can use the same cross-section library as the WIMS-D5 code employed in the CORD-2 system. Different results arise therefore solely from the different models used in the calculations. The heterogeneous depletion calculation was performed up to burnup of 60,000 MWd/tU. Results of both codes are compared for the infinite multiplication factor, fast to thermal spectral ratio and pin power distributions.