A multiphase thermo-hydro-mechanical model for concrete at high temperatures-Finite element implementation and validation under LOCA load

The aim of this paper is to study the thermo-hydraulic behavior of concrete subjected to severe loading conditions, such as those typical of nuclear waste storage structures and pressurized water reactors (PWR's) vessels in accidental conditions. The paper presents a coupled thermo-hydro-mechanical (THM) model for the description of concrete at high temperatures. The model is characterized by the presence of a deformable solid matrix (linearly elastic) filled with three fluid phases (liquid water, vapour water and dry air) and has been implemented in a finite element code freely available for research purposes (CAST3M) developed by the French research center for nuclear energy (CEA). The code has been validated by means of some case tests and has been finally applied for the prediction of the thermo-hydraulic conditions in a concrete slab submitted to a loss-of-coolant accident (LOCA) load.