Thermal cracking can pose a threat to a mass concrete structure increasing concerns over their serviceability and performance. This is the key issue surrounding engineered barriers in the nuclear industry, because the primary objective of such structures is to isolate radioactive hazards from the human environment. The present study focuses thermal stress analyses of a silo in a radioactive waste repository considering construction conditions (i.e., the temperature of the concrete and air and the boundary conditions of the structures). In addition, cracking risk is discussed according to the construction conditions based on the numerical analysis results. In the analysis results, it was found that the magnitude of the thermal stress in the silo varied according to the construction conditions. The temperature difference between the ambient and concrete, the ambient temperature, and the magnitude of external constraint were critical factors that influenced thermal stress in the silo. (C) 2017 Elsevier B.V. All rights reserved.