Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

The paper gives an overview about the tasks defined in the framework of the X2 benchmark, firstly proposed at the 19th symposium of the AER in 2009. The X2 benchmark was proposed for further validation and verification of the reactor physics code systems for VVER-1000 reactors with TVSA fuel assemblies. The X2 benchmark comprises all stages of reactor core calculations starting with the fuel assembly data preparation. Therefore X2 benchmark specifies the FA and core characteristics as well as the core loading patterns of four consecutive cycles for a Ukraine VVER-1000 reactor core. A set of operational data for comparisons with steady state reactor core calculations and transient neutron kinetics calculations were provided. The benchmark is useful for validating and verifying the whole system of codes and data libraries for reactor physics calculations including fuel assembly modelling, fuel assembly data preparation and reactor core modelling. Reviewed results of the tasks 1 and 2 for X2 benchmark steady state calculations were presented at the AER symposia. In the framework of several projects supported by the German BMU5) the 3D neutron kinetic code DYN3D and the coupling of DYN3d with thermo-hydraulics system codes were validated and verified on the basis of the data provided in the framework of the X2 benchmark. In preparing results for the X2 benchmark several organisations have been participated: IBBS, HZDR, SSTC, TÜV SÜD. On that basis TÜV SÜD has been provided the analysis and formulation of the specific X2 benchmark tasks. As continuation of the work on the X2 benchmark the tasks were extended with task 3 including data of the 3D calculations results and pin-by-pin distributions for selected fuel assemblies as well as task 4 providing data for 3D neutron kinetic calculations of reactor transients. The paper presents the current state of the X2 benchmark and discusses new results as continuation of the work started with the X2 benchmark proposal in 2009.