ASTEC validation on PANDA SETH

The ASTEC code (jointly developed by IRSN and GRS, i.e. Gesellschaft fur Anlagen- und Reaktorsicherheit mbH) development is aimed to provide an integral code for the simulation of the whole course of severe accidents in Light-Water Reactors. ASTEC is a complex system of codes for reactor safety assessment. In this benchmark, only the CPA (Containment Part of ASTEC) module is used. CPA is a lumped-parameter able to represent a multi-compartments containment. It used the following main elements: zones (compartments), junctions (liquids and atmospherics) and structures. The zones are connected by junctions and contain steam, water and non condensable gases. They exchange heat with structures by different heat transfer regimes: convection, radiation and condensation. In this paper, three selected from the PANDA SETH Benchmark 9, 9bis and 25 are considered to investigate the impact of injection velocity and steam condensation on the plume shape and on gas distribution. Coarse and fine meshes were developed by considering the test facility with the two vessels DW1, DW2, and the interconnection pipe. The obtained numerical results are analyzed and compared to the experiments. The comparison shows the good agreement between experiments and calculations. (author)