Calculation of the thermohydraulic parameters of a core comprised of unjacketed fuel assemblies

A computer program for calculating the thermohydraulic parameters of a core with jacketless fuel assemblies as a single mass of fuel elements is developed on the basis of the Kedr program for the channelwise computation. The Kedr-A program algorithm employs the principle of decomposition (partition) to the computed region of the core (1/12th part). The computational space is divided into a definite number of subregions – symmetry elements with repeatable geometric structure of the lattice of fuel elements and other structural components of the core. The thermohydraulic parameters of the cells in each section of the core are calculated iteratively over the symmetry elements of the jacket-less fuel assemblies of 1/12th part of the core of a nuclear reactor with water coolant. The symmetry elements are interrelated by the conditions at the boundaries connecting theses regions. The computational algorithm is checked by comparing with experimental data on the mixing of the coolant obtained on a technological stand consisting seven jacketless fuel assemblies.