Quantitative evaluation of material-dependent elemental composition in ordinary concrete for radiation shielding applications

Determining the elemental composition of ordinary concrete for radiation shielding calculations is challenging, as existing guidelines often present differing compositions and typically lack essential information such as constituent materials, mix proportions, and environmental conditions (e.g., heating or drying histories). Consequently, it is difficult to verify whether a given elemental composition accurately reflects the actual concrete used in shielding structures. This study emphasizes the importance of establishing a clear relationship between the elemental composition used in shielding calculations and ordinary concrete properties. Ensuring this correspondence is essential for the validity and appropriateness of shielding design. In nuclear power plant design, shielding calculations are sometimes required prior to finalizing the concrete mix design. For such cases, we propose elemental compositions in which all aggregate oxides are substituted with silicon dioxide to model silica aggregate-based concrete. This approach ensures conservative results when precise mixture data are unavailable. We also propose a methodology that allows for flexible input of the elemental composition of concrete, accounting for water mass and concrete density. This makes it possible to incorporate known parameters and account for the designer's intended level of conservatism. The proposed approach contributes to the development of more reliable and adaptable shielding design practices.