Experiments at the Mixing Test Facility Rocom for Benchmarking of Cfd-codes

For the validation of Computational Fluid Dynamics (CFD) codes experimental data on fluid flow parameters with high resolution in time and space are needed. ROCOM (Rossendorf Coolant Mixing Model) is a test facility for the investigation of coolant mixing in the primary circuit of pressurized water reactors. This facility describes the primary circuit of a German KONVOI type reactor. All important details of the reactor pressure vessel are modelled in a linear scale of 1:5. The facility is characterized by flexible possibilities of operation in a wide variety of flow regimes and boundary conditions. The flow path of the coolant from the cold legs through the downcomer until the inlet into the core is equipped with high resolution measurement technique. Especially, wire mesh sensors in the downcomer of the vessel with a mesh of 64 x 32 measurement positions and in the core inlet plane with one measurement position for the entry into each fuel assembly allow to carry out high-level CFD code validation. Two different types of experiments at the ROCOM test facility are proposed to be used for this purpose. The first proposal concerns the transport of a slug of hot, under-borated condensate, which has formed in the cold leg after a small break LOCA, towards the reactor core with natural circulation flow rate. The propagation of the emergency core cooling water in the test facility under natural circulation or even stagnant flow conditions should be investigated in the second experiment. The measured data can contribute significantly to the validation of the CFD-codes.