Naturally occurring radioactive materials (NORM) in energy production sectors: exposure, effective doses and regulatory challenges

The oil and gas industry, coal mining, and coal-fired power plants, as well as geothermal energy plants, have been investigated in the past with respect to various aspects of naturally occurring radioactive materials (NORM). However, existing assessments are usually highly specific and often inconclusive due to differing perspectives, and an overview of NORM issues across these energy sectors is still missing. The European data collected within the international RadoNorm project, and presented in this paper, have made it possible to identify common denominators related to the primordial source of radiation risk in these industrial sectors. Depending on the technological processes, radionuclides of natural origin (e.g.,^226,228Ra, ²²⁸Th,²²²Rn,²¹⁰Pb,²¹⁰Po, from ²³⁸U and ²³²Th decay chains) were found in a range of materials, such as scales, sludges, produced water, and liquid and gaseous discharges. Both radionuclides and materials may follow different pathways, leading to radiation exposure doses in various exposure scenarios for workers, the public, and the environment. The novelty of this paper lies in the comparative qualitative and quantitative evaluation of radiation protection aspects across the entire sequence of energy generating processes, which includes the sourcing of raw materials, NORM generating processes, their fate and potential risks to humans and the environment, as well as a comparison of management, regulatory control, and existing challenges. The presented findings will support future international harmonization of decision-making processes during industrial operations, decommissioning activities or at legacy sites, which are often encountered in these energy generation sectors. Moreover, this information will be particularly valuable for countries worldwide that are still in the initial phase of NORM inventory characterization and/or legislation development.