A radiation-shielding attenuation structure and method of forming the attenuation structure, wherein the attenuation structure is made by additively manufacturing a concrete material that includes one or more attenuation dopants configured to enhance the radiation shielding of the concrete material. The one or more attenuation dopants may be configured in the concrete material to attenuate one or more types of radiation, such as electromagnetic radiation, gamma radiation, X-ray radiation, or neutron radiation. The attenuation structure formed by the concrete material may be additively manufactured on-site according to a model that has already been pre-certified for safe or secure use, thereby providing a repeatable and reproducible process that can reduce lead times and fabrication costs. The attenuation structure may be easily modified during the additive manufacturing process to have different concrete mixtures with different attenuation characteristics, which increases the tailorability and flexibility in design of the attenuation structure.