Abstract
The need to understand and characterize the effects of neutron irradiation on concrete has become urgentbecause of the possible extension of service life of many nuclear power generating stations. Currentknowledge is primarily based on a collection of data obtained in test reactors. These data are inher-ently difficult to interpret because materials and testing conditions are inconsistent. A micromechanicalapproach based on the Hashin composite sphere model is presented to derive a first-order separationof the effects of radiation on cement paste and aggregate, and, also, on their interaction. Although thescarcity of available data limits the validation of the model, it appears that, without negating a possiblegamma-ray induced effect, the neutron-induced damage and swelling of aggregate plays a predominantrole on the overall concrete expansion and the damage of the cement paste. The radiation-induced volu-metric expansion (RIVE) effects can also be aided by temperature elevation and shrinkage in the cementpaste.
