Study of severe accident natural gas circulation with the CDF code TRIO_U.
H. Mutelle, U. Bieder, Technical meeting on use of CFD codes for safety analysis of reactor systems, including containment, 11-14 /11 2002, Pise (Italy).
This paper reports the preliminary studies carried out with the CFD code Trio_U to study the natural gas circulation that can establish in the primary circuit of a pressurized water reactor during a high-pressure severe accident scenario. Two types of 3D simulations have been performed on one loop using a LES approach. In the first type of calculations, the gas flow in the hot leg has been investigated with a simplified representation of the reactor vessel and the Steam Generator (SG) tubes. Structured and unstructured meshing has been tested on the full-scale geometry with and without radiative heat transfer modelling between walls and gas. The second type of calculations deals with the gas circulation in the SG. The first results show a good agreement with the available experimental data and provide some confidence in the Trio_U code to simulate complex natural flows.
This work has been done with the collaboration of the CEA.