So-called NORM residues are a special form of radioactive waste that is generated in industrial processes. NORM stands for naturally occurring radioactive material . The radioactive substances that accumulate unintentionally come primarily from the decay series of primordial radionuclides ( uranium- 238, uranium-235 and thorium- 232), which means that it is naturally occurring material.
NORM residues arise, for example, during drinking water treatment (see → Natural and anthropogenic contamination of fossil water ), the extraction and treatment of crude oil and natural gas, and geothermal energy . If the radioactive substances are enriched through technological processes, one also speaks of TENORM ( technologically enhanced naturally occurring radioactive material ). It is characteristic here that the special properties of the radioactive material in connection with their occurrence were not specifically exploited.