In the design of a geological disposal facility for radioactive waste, it is essential to predict the long-term performance of the engineered barrier system. This is our motivation to develop a Finite Element code known as MACBECE. In this research, we modified the code to evaluate the mechanical behavior of the engineered barrier system after the closure of the repository. The heat generation of the waste and the reflooding process were considered. These were made possible by incorporating an elasto-plastic constitutive model for unsaturated soils and a coupling with external thermal-hydraulic analysis. The code was validated against the in-situ experiment for full-scale engineered barrier system performance experiment at Horonobe Underground Research Laboratory. The observed data were well reproduced with slight difference that may be caused by a limitation of two-dimensional analysis.