Modelling of Thermal and Energy Systems Research Group

OpenHyCOmb. Development and validation of CFD combustion models of H2 and CO. Application to severe accident scenarios (Desarrollo y validación de modelos CFD de combustión de H2 and CO. Aplicación a escenarios de accidente severo) (2024-2026).

This project with reference SUBV-5/2023 has been financed by the Nuclear Safety Council (CSN) within the framework of the Resolution of June 1, 2023 of the Presidency of the Nuclear Safety Council, which calls for subsidies for the implementation of R&D&i projects related to the functions of the Agency.

Its objective is to contribute to developing and validating 3D CFD models for turbulent combustion of H2 and CO under conditions of non-homogeneous concentration that can be applied to representative scenarios in the containment of a PWR reactor under conditions of a severe accident with atmospheres of H2, H2O, air and CO to help assess risks and improve GGAS. This main objective is intended to be developed through 4 specific objectives:

• Selection, implementation and validation of CFD models of turbulence and combustion of H2 and CO that can be applicable to safety scenarios. To do this, different selected models will be compared against experimental data carried out at various scales and geometries and whose results are available to the CSN (for example, OECD/NEA-THEMIS and/or ENACEFF-2). It is proposed to test in this project U-RANS models (Unsteady Reynolds Averaged Navier Stokes equations) with turbulence models k-w SST and k-w SST SAS coupled with combustion models for non-homogeneous combustion conditions of H2 and CO type EDC or PaSR with reduced chemical scheme.

• Development of a simplified 3D model and a mesh to be used in CFD of the containment of a PWR-KWU by using CAD and the SALOME mesher.

• Realization of applications to a PWR plant with dry containment of H2 combustion with and without CO of rapid evolution scenarios with local accumulation of H2 and CO from a severe accident. A small LOCA will be analyzed during the moments identified as relevant (homogeneous or stratified atmospheres and combustions initiated by the recombiners) in compartments and/or complete containment.

• Analysis of results and obtaining relevant conclusions and recommendations.