%0 Conference Paper %F Oral %T Improved PWR LOCA simulations through refined core 3D simulations - An advanced 3D modelling and the associated METERO validation program %+ Service de Thermo-hydraulique et de Mécanique des Fluides (STMF) %A Bestion, Dominique %A Fillion, Philippe %A Préa, Raphaël %A Bernard-Michel, Gilles %< avec comité de lecture %B NUTHOS-12 - 12th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety %C Qingdao, China %8 2018-10-14 %D 2018 %K Two-phase flow %K Pressure Vessel %K 3D in porous medium %K Validation experiment %Z Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph]Conference papers %X System thermalhydraulic codes have 3D models initially devoted to the prediction of large scale 3D effects during LBLOCAS, which were validated on the 2D-3D experimental program performed in UPTF, SCTF and CCTF facilities. 3D core simulations using one mesh per assembly may become a standard practice in near future and a local refinement of the highest power assemblies with sub-channel analysis becomes also possible. Looking at much finer multi-dimensional physical processes may provide a better accuracy of predictions but also requires more detailed and precise 3D models with a new specific validation. A detailed PIRT identifies all local flow processes to be considered at such a finer scale. Some of these processes may be neglected depending on the sub-component (core, lower plenum, annular downcomer, upper plenum) and depending on the physical situation encountered in accidental transients. An experimental program using the METERO test facility focuses on SLB, IBLOCA and SBLOCA situations in a PWR core to develop models and to validate them in a separateeffect way. Adiabatic water tests and air-water tests will provide information for the development and validation of turbulent diffusion and dispersion of heat and momentum due to time and space averaging, void dispersion, 3D wall friction and interfacial friction forces in non-isotropic media particularly in presence of non axial flows in a core. %G English %2 https://cea.hal.science/cea-04084545/document %2 https://cea.hal.science/cea-04084545/file/METERO-Nuthos12_post.pdf %L cea-04084545 %U https://cea.hal.science/cea-04084545 %~ CEA %~ DEN %~ CEA-UPSAY %~ UNIV-PARIS-SACLAY %~ CEA-UPSAY-SACLAY %~ DEN-SACLAY