[en] The purpose of the workshop was to provide a forum for numerical analysts and experimentalists to exchange information in the field of NRS-related activities relevant to CFD validation, with the objective of providing input to WGAMA CFD experts to create a practical, state-of-the-art, web-based assessment matrix on the use of CFD for NRS applications. The workshop included single-phase and multiphase CFD applications as well as new experimental techniques, including the following: Single-phase and two-phase CFD simulations with an emphasis on validation were sought in areas such as boiling flows, free-surface flows, direct contact condensation, and turbulent mixing. These should relate to NRS-relevant issues such as pressurized thermal shock, critical heat flux, pool heat exchangers, boron dilution, hydrogen distribution, and thermal striping. The use of systematic error quantification and Best Practice Guidelines (BPGs) was encouraged. Experiments providing data suitable for CFD validation-specifically in the area of NRS-including local measurement devices such as multi-sensor optical or electrical probes, Laser Doppler Velocimetry (LDV), hot-film/wire anemometry, Particle Image Velocimetry (PIV), Laser-Induced Fluorescence (LIF), and other innovative techniques. There were over 200 registered participants at the CFD4NRS-3 workshop. The program consisted of about 75 technical papers. Of these, 57 were oral presentations and 19 were posters. An additional 20 posters related to the OECD/NEA-sponsored CFD benchmark exercise on thermal fatigue in a T-Junction were presented. In addition, five keynote lectures were given by distinguished experts. This is about a 30 pc increase with respect to the previous XCFD4NRS workshop held in Grenoble in 2008, and a 70 pc increase compared to the first CFD4NRS workshop held in Garching in 2006. This confirms that there is a real and growing need for such workshops. The papers presented in the conference tackled different topics related to nuclear reactor safety issues. The conference consisted of 14 technical sessions. Among the topics included were containment, advanced reactors, multiphase flows, flow in a rod bundle, fire analysis, flows in dry casks, thermal analysis, mixing flows and pressurized thermal shock (PTS). About 1/3 of the papers were concerned with two-phase flow issues and the rest were devoted to single-phase CFD validation. South Korea is a candidate to host a follow-up meeting scheduled in 2012, organized by KAERI. KAERI also volunteered to sponsor and organize the second OECD/NEA CFD benchmark exercise. In the closure meeting after the panel session discussion, the representative from the Paul Scherrer Institut (PSI) proposed to host a future workshop scheduled for 2014, and to organize and sponsor the third OECD/NEA benchmark exercise based on a stratification experiment in the PANDA facility at PSI. The great majority of participants were interested in attending a follow-up workshop within two years. Comments were made during the panel session on the content of CFD4NRS-3. Two of the comments are that experiments can provide insight into the physics, and that CFD is now an accepted analysis tool, though it is very important to follow BPGs. There was a consensus on the need to maintain the high quality of the papers. The promotion of international benchmarking exercises for CFD was strongly encouraged. Another comment suggested that such workshops should be a forum to discuss novel approaches, but that one must also keep in mind that the end users are people from the nuclear safety community. The CFD4NRS, XCFD4NRS and CFD4NRS-3 workshops have proved to be very valuable means to assess the status of CFD code capabilities and validation, to exchange experiences in CFD code applications, and to monitor future progress