CATHARE-3: A first computation of a 3-inch break Loss-Of-Coolant Accident using both Cartesian and cylindrical 3D-meshes modeling of a PWR vessel
Abstract
CATHARE-3 is the new version of the French thermal-hydraulic code for safety analysis of nuclear
reactors. It is developed in the framework of the NEPTUNE project launched by the CEA, EDF, AREVANP and IRSN in 2001. CATHARE-3 V2.0 was delivered by December 2016.
The paper will focus on a particular test-case, showing the new abilities of CATHARE-3. The PWR vessel
has been described using seven 3D-modules, with a Cartesian coordinate meshing for the core (with one
cell per assembly in a horizontal section) and cylindrical coordinate meshing for the other vessel
components (downcomer, upper and lower plena …). Using this modeling, a 2,800s simulation of a 3-inchbreak Loss-Of-Coolant Accident (LOCA) in one of the PWR cold legs has been run and compared to results
with a CATHARE-2 and CATHARE-3 “classical” modeling for the vessel (with only cylindrical grids).
This computation has been made possible by the development of non-conformal junctions between
Cartesian coordinates and cylindrical coordinates. A similar computation is not possible with CATHARE2 because non-conformal junctions are not available. Many analytical verification test-cases of the nonconformal junctions have also been made, checking the mass-flow and energy-flow conservation at the
non-conformal junctions on various configurations. These test-cases, showing that an improvement for
momentum equations is needed, are also presented in the paper.
This 3D-vessel modeling also shows the abilities of CATHARE-3 to manage a large number of 3D-cells
(about 7000 instead of less than 1000 for a typical CATHARE-2 3D-vessel modeling) thanks to the new
numerical methods available in CATHARE-3.
This computation demonstrates the potential of CATHARE-3, which should reach the status of an industrial
tool available for safety studies in 2019.
Origin : Files produced by the author(s)
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