Discussion on the standardization of concrete composite for radiation shielding design I - Concept of standard concrete for radiation shielding

Concrete is widely used as radiation shield in nuclear reactors and irradiation facilities, because of its flexibility and sufficient supply. However, there are few discussions on the content of the shielding concrete composition, and very old data (which have uncertain information regarding material properties beside of elemental data) are still used in the shielding calculation. So, we organized "Radiation Shielding Material Standardization Working Group under Atomic Energy Society of Japan (AESJ) in order to proceed the standardization of shielding concrete. In this paper, the concept of standard concrete for radiation shield is proposed based on the building material aspects, such as mixture proportion, ratio of water to cement, cement hydration and so on. Furthermore, a few candidates of the standard concrete are listed from various data for raw materials of concrete (aggregate and cement). Based on the above trial introduction of the standard concrete, some sensitivity analyses were conducted for simple cylindrical geometry with proton beam incidence on an iron target. The investigation indicated that the proposed trail standard data located intermediate positions among other concrete data and water contents in the concrete were dominant for the dose attenuation.