A Benchmark for Coupled 3D Neutron Kinetics/Thermohydraulics System Codes - Main Steam Header Break in a NPP with VVER-440 Reactor

Recently 3D neutron kinetics core models have been coupled to advanced thermohydraulics system codes. These coupled codes can be used for the analysis of the whole reactor system. In the framework of the international "Atomic Energy Research" (AER) association on VVER Reactor Physics and Reactor Safety, a benchmark for these code systems was defined. The reference reactor is the Russian VVER-440. The response of the reactor core to a main steam header break should be investigated. Solutions were received from the following five organizations: Kurchatov Institute Moscow (Russia), VTT Energy Espoo (Finland), Nuclear Research Institute Rez (Czech Republic), KFKI AEKI Budapest (Hungary) and Forschungszentrum Rossendorf (Germany). The paper presents an overview of the results of the benchmark. A good agreement in the thermohydraulic behaviour can be observed, the main differences between the solutions arise from the use of different nuclear data.