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The EU encourages the use of NORM residues in building materials, subject to dose rate from gamma exposure being below 1 mSv/yr from them. Coal ash and smelting slag are an important constituent of building materials in China. Recycling and NORM NORM results from activities such as burning coal, making and using fertilisers, oil and gas production. In the USA, 858 million tonnes of coal was used in 2013 for electricity production. With an average content of 1.3 ppm uranium and 3.2 ppm thorium, US coal-fired electricity generation in that year gave rise to 1100 tonnes of uranium and 2700 tonnes of thorium in coal ash. In Victoria, Australia, some 65 million tonnes of brown coal is burned annually for electricity production. This contains about 1.6 ppm uranium and 3.0-3.5 ppm thorium, hence about 100 tonnes of uranium and 200 tonnes of thorium is buried in landfill each year in the Latrobe Valley. Gonzalez, A, J., 2011, Radiation Protection, presentation given at the World Nuclear University Event –‘Key Issues in the World Nuclear Industry Today’, Ulaanbaatar, Mongolia.
For example, scrap steel from gas plants may be recycled if it has less than 500,000 Bq/kg (0.5 MBq/kg) radioactivity (the exemption level). This level however is one thousand times higher than the clearance level for recycled material (both steel and concrete) from the nuclear industry! Anything above 500 Bq/kg may not be cleared from regulatory control for recycling.Current IAEA Basic Safety Standards (BSS) clearance levels specify 1 Bq/g for natural radionuclides in the U-238 series in secular equilibrium with progeny, and the same for those in the Th-232 series. IAEA BSS clearance levels for bulk amounts being recycled are: Fe-55 1 MBq/kg, Co-60m 1 MBq/kg, Ni-63 100 kBq/kg, C-14 1 kBq/kg, Cs-137 0.1 kBq/kg, Ra-226 1 kBq/kg. Radon exposure is often an issue in metal mines, and a survey of 25 underground mines in China showed six having radon concentrations of over the control limit of 1000 Bq/m 3. In all the metal mines the annual average effective dose from radon and radon progeny was 7.75 mSv. Mineral sands Why on earth did Norm’s family have to move, anyway? In their old house he’d never tried to pee in anything other than a toilet. And when Norm is in bed, he’s kept awake by his dad snoring like a constipated rhinoceros!
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In 2017 Australia exported 372 million tonnes of coal. With an average of 0.9 ppm uranium and 2.6 ppm thorium, at least 330 tonnes of uranium per year and 970 tonnes of thorium could conceivably be added to published export figures. A survey of 44 Chinese coal mines (40 of which were underground operations) indicated that radon concentrations in 15% of them were above 1000 Bq/m 3. (NORM VII proceedings, IAEA 2015) Oil and gas production Norm knew it was going to be one of those days when he woke up and found himself about to pee in his dad’s wardrobe.
The eleventh hilarious title in the award-winning, laugh-out-loud series, The World of Norm. Perfect for fans of Tom Gates and Diary of a Wimpy Kid. Norm knew it was going to be one of those days when he woke up and nothing happened ... Home alone and the fridge to himself? What could possibly go wrong? Well, apart from the snails. And having to hang his mum's pants out to dry. And the dreaded perfect cousins paying a visit. And worst of all, the entire family going vege-flipping-tarian! But apart from that, what could possibly go wrong? You'd think Norm would know better by now, wouldn't you? ABSO-FLIPPING-LUTELY! With brilliantly funny illustrations throughout from Donough O'Malley. Praise for Jonathan Meres: 'Hilarious stuff from one of my comic heroes!' - Harry Hill 'Jonathan Meres is flipping funny!' - Eddie Izzard About This Edition ISBN: Typically exposure to radon and its progeny accounts for half of an individual’s radiation dose, making it the single largest contributor. This radon comes from the ground, with exposure affected by factors such as local geography, building construction, and lifestyle. Radon levels in the air range from about 4 to 20 Bq/m 3. Indoor radon levels have attracted a lot of interest since the 1970s and in USA they average about 55 Bq/m 3, with an EPA action level of 150 Bq/m3. Levels in Scandinavian homes are about double the US average, and those in Australian homes average one fifth of those in USA. Levels up to 100,000 Bq/m 3 have been measured in US homes. In caves open to the public, levels of up to 25,000 Bq/m 3 have been measured.A Japanese study on 3000 residents living in an area with 60 Bq/m 3 radon near Misasa hot springs showed no health difference. The ICRP recommends keeping workplace radon levels below 300 Bq/m 3, equivalent to about 10 mSv/yr. Rare Earth Elements (REEs) are chemically rather similar to uranium and thorium they are often found in conjunction with these radionuclides. Another NORM issue relates to radon exposure in homes, particularly those built on granitic ground. Occupational health issues include the exposure of flight crew to higher levels of cosmic radiation, the exposure of tour guides to radon in caves, exposure of miners to radon underground, and exposure of workers in the oil & gas and mineral sands industries to elevated radiation levels in the materials they handle. NORM sourcesTreatment with sulfuric acid leads to the production of gypsum (phosphogypsum) which retains about 80% of Ra-226 and 30% of Th-232 and 14% of U-238. This means that uranium and thorium are enhanced to about 150% of the value of the beneficiated ore, making it a significant NORM. This gypsum can either be sold or disposed of. In the USA, the use of phosphogypsum with a radioactivity greater than 370 Bq/kg is banned by the Environmental Protection Authority. Gypsum can either be disposed of in piles or discharged to rivers and the sea. Some leaching from the material is possible. Gypsum wastes can have radioactivity levels up to 1700 Bq/kg. Scales from the sulfuric acid process are formed in the pipes and filtration systems of plants and need to be cleaned or replaced periodically. While much smaller in volume than gypsum, these wastes can be much more radioactive – even over 1MBq/kg. The first four columns represent four of the 14 nuclides in the uranium decay series, the next two represent two of 10 in the thorium series. (For total activity in any coal, assume these are in serial equilibrium, hence multiply U-238 by 14 and Th-232 by 10, then add K-40.)
Tantalum usually occurs with the chemically-similar niobium, often in tantalite and columbite, coltan (columbite + tanatalite), or polychlore (niobium). Tantalum ores, often derived from pegmatites, comprise a wide variety of more than a hundred minerals, some of which contain uranium and/or thorium. Hence the mined ore and concentrate contain both these and their decay products in their crystal lattice. Concentration of the tantalum minerals is generally by gravity methods (as with mineral sands), so the lattice-bound radioisotope impurities if present will report with the concentrate. With increased uranium prices the uranium in ash becomes significant economically. In the 1960s and 1970s, some 1100 tU was recovered from coal ash in the USA.The feasibility depends on grade and the composition of the ash – high acid consumption makes recovery uneconomic. International Atomic Energy Agency, Extent of Environmental Contamination by Naturally Occurring Radioactive Material (NORM) and Technological Options for Mitigation, Technical Reports Series No. 419, STI/DOC/010/419, ISBN: 9201125038 (December 2003) The first hilarious title in the award-winning, laugh-out-loud series, The World of Norm. Perfect for fans of Tom Gates and Diary of a Wimpy Kid. NORM levels are typically expressed in one of two ways: Becquerels per kilogram (or gram) indicates level of radioactivity generally or due to a particular isotope, while parts per million (ppm) indicates the concentration of a specific radioisotope in the material. Terrestrial NORMDecommissioning experts are increasingly concerned about double standards developing in Europe which allow 30 times the dose rate from non-nuclear recycled materials than from those out of the nuclear industry. In respect to actual dose limits, 0.3 to 1.0 mSv/yr individual dose constraint is applied to oil and gas recyclables, and 0.01 mSv/yr for release of materials with the same kind of radiation from the nuclear industry.
The main radionuclide in scrap from the oil and gas industry is radium-226, with a half-life of 1600 years as it decays to radon. Those in nuclear industry scrap are cobalt-60 and caesium-137, with much shorter half-lives. Application of a 0.3 mSv/yr dose limit results in a clearance level for Ra-226 of 500 Bq/kg for oil/gas scrap, compared with 10 Bq/kg for nuclear material. McBride et al., 1977, Radiological Impact of Airborne Effluents of Coal-Fired and Nuclear Power Plants, Oak Ridge National Laboratory, ORNL-5315 International Atomic Energy Agency, Naturally Occurring Radioactive Material (NORM VII): Proceedings of an International Symposium Beijing, China, 22-26 April 2013, STI/PUB/1664, ISBN 9789201040145 (January 2015)Activity concentration guidelines for the use of NORM residues in building construction have been developed using the ACI approach and material has been classified into three categories, depending on whether the dose is below 0.5 mSv/yr (unrestricted use), between 0.5 and 1 mSv/yr (use restricted to roads, bridges, dams or, with dilution, low occupancy buildings) or above 1 mSv/yr (prohibited use). These levels correspond to equivalent activity concentration under 350 Bq/kg (and under 200 Bq/kg Ra-226), 350 to 1350 Bq/kg (200-1000 Bq/kg Ra-226) and over 1350 Bq/kg (1000 for Ra-226) respectively. Eisenbud, M.; and Gesell, T. F. 1997, Environmental Radioactivity from Natural, Industrial & Military Sources, Fourth Edition: From Natural, Industrial and Military Sources, Academic Press (ISBN: 9780122351549)
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