The Code DYN3DR for Steady-State and Transient Analyses of Light Water Reactor Cores with Rectangular Geometry

The code DYN3D/M2 was developed for steady-state and transient analysis of reactor cores with hexagonal fuel assemblies. The new version DYN3DR contains a method for neutron kinetics solving the two group neutron diffusion equation by a nodal method for cartesian geometry. The thermal-hydraulic model FLOCAL simulating the two phase flow of coolant and the fuel rod hehaviour is used in the two versions. The fundamentals of the neutron kinetics are described. The accuracy of the code is demonstated by comparisons with the results of rod ejection benchmarks for PWR with rectangular fuel assemblies. The developed algorithm of neutron kinetics are suitable for using parallel processing. The speedup of neutronic calculation is demonstrated for a steady state solution of diffusion equation.