We are pleased to announce the publication of our new paper in the Journal of Nuclear Engineering and Technology.

When designing concrete shielding around the reactor vessel of a nuclear power plant, the specific materials used in the concrete are often not predetermined, and the initial design is typically performed by equipment-side engineers. Only after the available aggregates, cement types, and construction methods are selected is the concrete mix finally determined. Although a feedback system should ideally exist between shielding design and concrete mixture design, the actual process is commonly one-directional.

Several guidelines present example concretes with specified elemental composition ratios. However, when we recalculated these compositions from a concrete engineering perspective, we found that some mixtures contained unrealistically high water contents or were not rationally defined from the standpoint of concrete technology.

In this study, we explored how elemental compositions for shielding design could be determined based on concrete-engineering knowledge. Under the assumption that material selection and construction processes should remain flexible, we examined what “conservatism” should mean in shielding design and proposed a simplified method for determining elemental compositions.

Key parameters include unit water content (both chemically bound and mobile water after long-term operation), aggregate content, and aggregate composition. By simplifying aggregates into either SiO₂-based or CaCO₃-based categories, we propose a method that allows designers to easily and reasonably define elemental compositions for shielding analyses.

Although this research targets a niche field, it provides useful insights for resolving practical misunderstandings and inconsistencies in current design practice. We hope those interested will take a look at the paper. It is available in Open Access.

O. Kontani, O. Sato, S. Sawada, T. Igari, K. Fujikawa, H. Akatsuka, I. Maruyama, Quantitative evaluation of material-dependent elemental composition in ordinary concrete for radiation shielding applications, Nucl. Eng. Technol. 58 (2026) 104004. https://doi.org/10.1016/j.net.2025.104004.