Effect of room temperature differences on safety-related reinforced concrete floors and walls in the reactor building of OL 2 NPP

The results suggests that thermal stresses can induce tensile stresses that exceed those induced by the mechanical stresses in the reactor building even with temperature differences of 20 °C. However, the crack widths evaluated are smaller than a recommended value of 0.3 mm with the current temperature distribution with a maximum temperature of some 40 °C. The results also suggest that the integrity of the reactor building is not critically impaired in normal operational conditions between 20 and 65 °C. However, attention should be given to situations where thermal and mechanical stresses simultaneously induce tension to a structural piece.

Furthermore, the study also includes a literature review on the temperature dependence of the thermal and mechanical properties of concrete. In the studied temperature range, the thermal properties showed no significant temperature dependence. As for the mechanical properties, compressive stress and strain as well as the modulus of elasticity showed considerable temperature dependence, although some models suggested negligible dependence.