RADIATION TESTING
❱❱ Naturally occurring radiation materials can become concentrated as a result of industrial processing activity on ores and mining products
T
Establishing the NORM in industrial waste
here is the potential for exposure to radiation from many different sources; x-rays are one example of ionising radiation, with transmissions from the TV and radio an example of lower-frequency non-ionising
radiation. Naturally occurring radioactive materials
(NORMs) are those that are naturally found in the environment, making up around 85 per cent of radiation sources, with radioactive elements such as uranium, thorium and potassium usually present in such materials. Even a single banana naturally contains 15 Becquerel (Bq) – the unit of measurement for radioactivity. This form of measurement is counted by the number of interactions the alpha, beta or gamma radiation has with matter, material or a radiation detection instrument.
NORM IN INDUSTRY In terms of industry, activities like the mining, extraction and production of rare earth elements increase the concentration (and radioactivity) of the substances mined. These are classed as Type 2 NORM industrial activities by the Environmental Permitting Regulations 2010, with any waste arising from these types of activities regulated as radioactive materials or radioactive waste. Oil and gas production is a good example of this.
As the heavy drilling equipment penetrates the earth’s layers the produced waters, scale found inside the pipes and/or sludge from dissolved solids may contain radioactive elements. Then, depending on the type of
Jasper Hattink, laboratory manager for environmental radiochemistry at Socotec explains the need for analysing naturally occurring radioactive materials in process and industrial waste
radiation within these materials – alpha, beta or gamma – equipment used may also become contaminated from the NORM. While alpha rays can be blocked by paper and beta
radiation can be stopped by aluminium, gamma radiation has the strength to penetrate steel plates, concrete or other heavy infrastructure. This is why a decommissioning programme for any industrial installation must identify all structures, equipment, and materials that have been in proximity of the industrial activity (such as drilling) so potential radioactive penetration values can be determined, with a decommissioning regime for each. Soils, water, concrete, metals, oils and solid waste are all likely to contain radioactive elements in the surrounding areas of industrial activity. That is why NORM analysis can support a number
of regulatory obligations, such as characterising NORM for decommissioning of nuclear or other power plants, as well as testing for waste acceptance criteria (WAC) when disposing of unwanted materials or waste.
REGULATIONS Radioactive materials are regulated. As with anything that is potentially harmful to human health, exposure risks must be effectively controlled. For radioactive exposure, employers must take action to restrict the exposure of their employees and other persons who may be affected under Ionising Radiations Regulations 2017 (IRR17). Under IRR17, the threshold for notification and
September 2018 /// Environmental Engineering /// 15
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