The prospective for radiological sustainability through the reuse of NORM residues in construction materials

Terrestrial materials contain naturally occurring radionuclides, including U-238, Ra-226, Th-232, and K-40, are important for radiation protection. Such naturally occurring radioactive material (NORM) residues are produced in large quantities and would be of high economic benefit if they were to a certain extent incorporated in mixtures or as additive in building material production, allowing for flexible reuse options depending on the final product in that way reducing potential radiological effects on humans and the environment. Thus, reusing NORM residue products is a cost-effective and environmentally friendly method for reducing potential radiological impacts on humans, preserving natural resources, lowering CO2 emissions, and conserving energy. The European Basic Safety Standards Directive mandates that NORMs must be characterized as a secondary raw material for use in building materials. Regardless of their origin, the radiological behavior and material properties of NORMs as an additive or secondary material are crucial. In general, the primary consideration for achieving radiological sustainability is to recycle or reutilize residue or by-products containing NORMs instead of disposing of them as waste. The focus is on re-utilizing materials in building materials and striving for radiological sustainability. This study therefore examines the potential for reproducing NORM residues based on their properties and the appropriate treatment before reutilization. The evaluation of their radiological indices is valuable for categorizing NORM residues prior to their use in construction materials. These indices provide a better indication of the risk of external exposure compared to the specific activity concentration of U-238, Ra-226, Th-232, and K-40. The study results indicated that incorporating NORM residues into mixtures or using them as additives can decrease the activity concentration and indices in the original residue, allowing for flexible reuse options based on the final product.