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A Guide to Naturally Occurring Radioactive Materials (NORM)

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A Guide to Naturally Occurring Radioactive Materials (NORM) ABOUT NORM SOME NORM NUCLIDES OF SPECIAL INTEREST A Guide to Naturally There are three types of NORM: Occurring Radioactive • Cosmogenic – NORM produced by cosmic rays interacting with the Earth’s Materials (NORM) Beryllium 7 atmosphere; the most important Developed by the 3 7 14 examples are H (tritium), Be, and C. 7Be is being continuously formed in the DHS Secondary Reachback Program • Primordial – Sufficiently long-lived atmosphere by cosmic rays. Jet engines can March 2010 NORM for some to have survived from accumulate enough 7Be to set off before the formation of the Earth; there radiological alarms when being cleaned. are 20 primordial NORM nuclides with As defined by the International Atomic the most important being 40K, 232Th, Energy Agency (IAEA), Naturally 235U, and 238U. Polonium 210 Occurring Radioactive Materials • Daughters – When 232Th, 235U and 238U In the 238U decay chain 210Po is a distant (NORM) include all natural radioactive decay 42 different radioactive nuclides daughter of 226Ra. 210Po gained notoriety in materials where human activities have are formed (see below) with the most the 1960s as a radioactive trace component increased the potential for exposure in important being 222Rn, 226Ra, 228Ra and in cigarette smoke. Heavy use of phosphate comparison with the unaltered natural 228 Ac. fertilizers (which have trace amounts of out here. fold Next situation. If processing has increased 226Ra) can triple the amount of 210Po found the concentrations of radionuclides in a When 232Th, 235U and 238U decay a in tobacco. material then it is Technologically radioactive “daughter” nuclide is formed, Enhanced NORM (TE-NORM). which then decays into a radioactive “granddaughter” and so on until the last Radon 222 First fold out here. fold out First decay is to a stable isotope of lead; this 238 222 sequence is a decay chain. Longer lived In the U decay chain Rn is the daughter 226 222 daughters accumulate in a material that is of Ra. Rn is an inert gas that can undisturbed for a long time. accumulate in the air of confined spaces such as house basements and uranium mines. Long term exposure to high concen- trations of radon can cause lung cancer. Cesium 137 137Cs is not NORM, but rather a long-lived fission product. Atmospheric testing of nuclear weapons and, to a greater extent, the Chernobyl reactor accident spread 137Cs world-wide. It has entered into the soil, and A truckload of clay-based kitty litter contains sufficient from thence into plants and animals. Being quantities of NORM to cause radiation portal alarms. chemically similar to potassium, it is often found in agricultural and wood products Granite often contains small amounts of thorium and wherever the NORM nuclide 40K is found. Joint Analysis Center (JAC) uranium – and all their decay chain daughters like radium. 24-hour Technical Assistance HOTLINE: 877-363-6522 Email : [email protected] Page 2 Page 6 COMMON NORM NUCLIDES NORM IN INDUSTRY NORM IN COMMODITIES Concerns about NORM arise in many NORM is present in many common Uranium 238 and 235 types of industries, such as commodities, and can cause 235U and 238U are primordial nuclide found • Electricity generation, e.g. coal-fired radiation portal alarms when these in low quantities in rocks, minerals, and and geothermal plants are transported in bulk quantities. A soil – at an average of 2-4 parts per million. few examples are below. • Oil and natural gas production Uranium is 40 times more abundant than silver in the Earth’s crust. Both nuclides • Drinking and waste water treatment A single banana contains form a chain of radioactive daughters when • Production and use of fertilizers 450mg of potassium, 0.01% they decay that are comingled with the of which is the NORM 40K. uranium in nature. • Mining, milling, and smelting, e.g. aluminum, copper, gold, silver, titanium, uranium, and zircon Fertilizers with high phos- Radium 226 and 228 phate and potassium content • Construction, e.g. soil movement and can contain a variety of Natural radium is mostly 226Ra, a daughter building materials NORM nuclides including 40K, of 238U, intermingled with trace quantities 238U, 230Th, 226Ra, and 232Th. of 228Ra, a daughter of 232Th. Minute First fold in here. fold in First Raw material processing quantities of radium will be found in An Industrial affects daughter concentra- uranium and thorium deposits, and Example: Oil tions in the 238U and 232Th particularly in uranium ore. Production decay chains. Step 1 – Ground water and Many products sold in Next fold in here.in fold Next oil mingle in under-ground Thorium 232 deposits; water with a high home improvement Like uranium, 232Th is a primordial nuclide chloride content has higher stores contain NORM such solubility, including for as cement, gravel, brick, at the head of a chain of radioactive radium. wallboard, wood, tile, and daughters. It is found in most rocks and Step 2 – Saline, radium bearing water is brought granite counter tops. soils – and is about as abundant as lead to the surface with the oil. and 4 times more abundant than uranium. Step 3 – Water is separated from oil in an apparatus consisting of pumps, pipes, casings, fittings, tanks, etc. Fresh US mushrooms may have measurable amounts Potassium 40 Step 4 – Changes in water temperature and pressure cause chemical changes which result in of 40K, 226Ra, and 228Ra. 40K is a radioactive primordial nuclide minerals being deposited as scale on various constituting a bit more than 0.01% of all apparatus components; the scale is generally carbonate and sulfate minerals, including barite potassium. Potassium is the seventh most which readily traps radium. TE-NORM Example abundant element on the Earth’s crust, Step 5 – Water disposal is by pumping into an Coal contains tiny amounts of NORM, nearly all of and is found in seawater, soils, minerals, injection well, or other means. which stays in the ash when the coal is burned. and in all living plant and animal life. Step 6 – When the separation apparatus is Ash is about 10% the weight of unburned coal, so 40K may be sufficiently concentrated in repaired or decommissioned it can contain the concentration of NORM in power plant waste is some food products and fertilizer to set off hazardous amounts of radium and radium decay ten times that of the plant’s coal fuel. For more products, and must be handled or transported in information on TE-NORM see: radiological alarms in bulk quantities. accordance with government regulations. http://www.epa.gov/rpdweb00/tenorm/index.html Page 3 Page 4 Page 5 .
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