[en] In order to obtain the fundamental data of concretes, which are used in the construction of storage facilities of HLW, the effects of γ-ray irradiation on the characteristics were evaluated. This work followed the research carried out in 1981 -- '82 fiscal year. Evaluations of irradiation effects on the characteristics with total dose of -- 2 x 10¹⁰R and the effects of environmental factors such as moisture and temperature under irradiation field -- 1 x 10⁵R/hr estimated in the storage facilities were emphasiged. No effects of irradiation corresponding total γ-dose estimated for the storage facilities were identified at room temperature, and neither effects of irradiation on corrosion of steel in concrete moistured by ground water seepage. However, the compressive strength decreased by heating at 160 ⁰C. (author)