Sketch-n/athlet steady-state and dynamic coupling scheme verification on kalinin-3 benchmark results

The paper describes the multi-physics coupling scheme between the SKETCH-N nodal neutronics code and the best-estimate thermohydraulic code ATHLET v3.2. Some first results are discussed. Various possible options of coupling have been considered. A scheme is selected and applied for data exchange between the codes based on MPI library. The verification and validation were performed using the transient of the Kalinin-3 international Benchmark. The simulation results show good agreement with experimental data and calculations performed by the participants of the benchmark. Parallel to the coupling scheme development, a visualization system to process the results is being created. The steady-state analysis is carried out using both simple and complex thermohydraulic models. The calculations of the transient "Switch off of one MCP (Main Coolant Pump) at nominal power" is performed applying a more elaborate thermohydraulic model taking into account inter-channel mass transfer.