Overview of the TrioCFD code: Main features, VetV procedures and typical applications to nuclear engineering

International audience; The main objective of the present paper is to give an overview of the actual state of the Trio_U project. Trio_U is a CFD code developed for about 20 years in the Nuclear Energy Division of CEA. The code is designed to treat efficiently various physical problems, such as turbulent flows, fluid/solid coupling, multiphase flows or flows in porous media. The domains of application are mainly related to the nuclear industry, in particular to the interaction of turbulent flow with the solid structures of nuclear reactors, that Trio_U is able to handle successfully thanks to its massive parallelism. The Trio_U project integrates a major procedure of Verification and Validation (VetV). Numerous verification tests are performed to avoid unintentional modifications and assure a proper implementation of the numerical methods, models and options. Non-regression tests are automatically launched and provide an evaluation of the differencesbetween the development version and the latest released version. The validation is the other part of procedure. Its purpose is to carry out reference calculations on a large range of physical problems and compare their results to analytical, experimental or literature results. It leads to the definition of compromises between accuracy, robustness and restitution time and guarantees that the requirement of a correct quality of results is met. Some typical examples of recent qualification studies in nuclear domain are presented here. Most of them correspond to international experimental or industrial facilities and combine various complex physical phenomena.