Abstract
Most of the materials found on the Earth’s surface, such as iron ores and all other materials entering the integrated steel-making process, contain measurable amounts of natural radioactivity mainly due to the presence of uranium-238 (238U), thorium-232 (232Th) and their respective daughter decay products. Some materials after being processed can present a relatively high concentration of natural radionuclides. These materials are defined as Naturally Occurring Radioactive Materials (NORM). Since 2010, in the United Kingdom, industries producing NORM are subject to a new permitting regime. The current regime is named Environmental Permitting Regulations 2010 (EPR 2010), recently amended and replaced by EPR2016 and is directly derived from the European Directive EURATOM 1996, itself reviewed in 2013 and replaces the previous exemption limits defined in the previous regime Radioactive Substances Act 1993 (RSA93). As a result, the steel industry is now potentially producing materials above the new exemption levels to dispose of and therefore has a new environmental duty to accurately determine the radioactivity content of a wide range of iron- and steel-making materials used on site within the processes and/or sold off to third parties. In the steel industry, the main isotopes of concern are polonium-210 (210Po) and lead-210 (210Pb), which concentrate in the waste off-gas dusts from the iron ore sintering and blast furnaces processes, and radium-226 (226Ra) which can be found in slag materials from the blast furnace process. NORM can also result in potential exposure of the workforce to radioactive substances, mainly in workplaces where NORM are handled, stockpiled or processed. The UK steel industry has a duty of care to protect the workers and assess the potential occupational exposure to natural radioactivity in its workplaces in accordance with the Ionising Radiations Regulations 1999 (IRR99), recently replaced by IRR17 since 1st January 2018.