Naturally occurring radioactive material

Radionuclides of natural origin contained in or released from process materials may pose a risk to workers, public or the environment. These radioactive elements in minerals and ores originally found in the environment are commonly known as NORM – naturally occurring radioactive material. Some NORM materials require radiation control and regulation.

The activity concentrations of the radionuclides in rocks and soil found in the nature are generally low. Certain minerals, including some that are commercially exploited, contain uranium, thorium or potassium at elevated concentrations.

During the extraction of minerals from the Earth’s crust and their physical or chemical processing, the radionuclides may become unevenly distributed between the various materials arising from the process. These human activities can significantly increase the concentration of NORM radionuclides around us. NORM associated with these industrial activities can exist in many forms — it can be ore, process feedstock, intermediate product, end product, by-product or process residue. It can in a solid, a liquid or a gas form.

The processes most often associated with processing of NORM  with elevated concentrations of radioactive materials include mining and milling of metalliferous and non-metallic ores, production of coal, oil and gas, extraction and purification of water, generation of geothermal energy, and production of industrial minerals, including phosphate, clay and building materials. The type and amount of radioactive materials varies considerably from one industrial process to another.

Both, public and workers might be exposed to ionizing radiation at levels which require regulation and control. Regulatory bodies need to address existing uncertainties in worker and public dose assessment and determine the nature and extent of control of these materials. Many of these industry sectors have not been regulated in the past and therefore face several challenges in establishing control over NORM. The International Basic Safety Standards (GSR Part 3) has established requirements for NORM industries which can be used for this purpose.