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History has forgotten the landlady, but George de Hevesy went on to win the Nobel prize in and the Atoms for Peace award in His was the first use of radioactive tracers — now routine in environmental science. Most medical radioisotopes made in nuclear reactors are sourced from relatively few research reactors, including:.
Output from each varies due to maintenance schedules. The targets are then processed to separate the Mo and also to recover I However, in medical imaging, the cost of Mo itself is small relative to hospital costs. Mo can also be made by bombarding Mo with neutrons in a reactor.
This is still about two days from the end of irradiation, so some , TBq must be made in the reactor to allow for cooling, processing, and decay en route to the users.
See also information paper on Research Reactors. Radioisotopes and radiation used in food and agriculture are helping to reduce these figures.
As well as directly improving food production, agriculture needs to be sustainable over the longer term. Plant mutation breeding is the process of exposing the seeds or cuttings of a given plant to radiation, such as gamma rays, to cause mutations. The irradiated material is then cultivated to generate a plantlet. Plantlets are selected and multiplied if they show desired traits.
A process of marker-assisted selection or molecular-marker assisted breeding is used to identify desirable traits based on genes. The use of radiation essentially enhances the natural process of spontaneous genetic mutation, significantly shortening the time it takes. Countries that have utilised plant mutation breeding have frequently realised great socio-economic benefits.
In Bangladesh , new varieties of rice produced through mutation breeding have increased crops three-fold in the last few decades. During a period of rapid population growth, the use of nuclear techniques has enabled Bangladesh and large parts of Asia in general, to achieve food security and improved nutrition.
Fertilisers are expensive and if not properly used can damage the environment. Estimates of crop losses to insects vary, but are usually significant.
One approach to reducing insect depradation in agriculture is to use genetically-modified crops, so that much less insecticide is needed. Another approach is to disable the insects. SIT involves rearing large populations of insects that are sterilised through irradiation gamma or X-rays , and introducing them into natural populations.
The sterile insects remain sexually competitive, but cannot produce offspring. The SIT technique is environmentally-friendly, and has proved an effective means of pest management even where mass application of pesticides had failed. At present, SIT is applied across six continents. Since its introduction, SIT has successfully controlled the populations of a number of high profile insects, including mosquitoes, moths, screwworm, tsetse fly, and various fruit flies Mediterranean fruit fly, Mexican fruit fly, oriental fruit fly, and melon fly.
The most recent high-profile application of SIT has been in the fight against the deadly Zika virus in Brazil and the broader Latin America and Caribbean region see also Insect control within the section on Medicine below.
See also information paper on Radioisotopes in Consumer Products. The function of many common consumer products is dependent on the use of small amounts of radioactive material. One of the most common uses of radioisotopes today is in household smoke detectors. These contain a small amount of americium which is a decay product of plutonium originating in nuclear reactors.
The Am emits alpha particles which ionise the air and allow a current between two electrodes. If smoke enters the detector it absorbs the alpha particles and interrupts the current, setting off the alarm. This problem is particularly prevalent in hot, humid countries. Food irradiation is the process of exposing foodstuffs to gamma rays to kill bacteria that can cause food-borne disease, and to increase shelf life.
In all parts of the world there is growing use of irradiation technology to preserve food. More than 60 countries worldwide have introduced regulations allowing the use of irradiation for food products. In addition to inhibiting spoilage, irradiation can delay ripening of fruits and vegetables to give them greater shelf life, and it also helps to control pests.
Its ability to control pests and reduce required quarantine periods has been the principal factor behind many countries adopting food irradiation practices. See also information paper on Radioisotopes in Industry. Radioisotopes are used by manufacturers as tracers to monitor fluid flow and filtration, detect leaks, and gauge engine wear and corrosion of process equipment.
Small concentrations of short-lived isotopes can be detected whilst no residues remain in the environment. By adding small amounts of radioactive substances to materials used in various processes it is possible to study the mixing and flow rates of a wide range of materials, including liquids, powders and gases, and to locate leaks.
Radioactive materials are used to inspect metal parts and the integrity of welds across a range of industries. For example, new oil and gas pipeline systems are checked by placing the radioactive source inside the pipe and the film outside the welds.
Gauges containing radioactive usually gamma sources are in wide use in all industries where levels of gases, liquids, and solids must be checked. They measure the amount of radiation from a source which has been absorbed in materials. These gauges are most useful where heat, pressure, or corrosive substances, such as molten glass or molten metal, make it impossible or difficult to use direct contact gauges.
The ability to use radioisotopes to accurately measure thickness is widely utilised in the production of sheet materials, including metal, textiles, paper, plastics, and others. Density gauges are used where automatic control of a liquid, powder, or solid is important, for example in detergent manufacture. They can be used to identify trace chemicals in materials such as paint, glass, tape, gunpowder, lead, and poisons.
Finally, farmers can use radioisotopes to control insects that destroy crops as an alternative to chemical pesticides. In this procedure, male insect pests are rendered infertile. Pest populations are then drastically reduced and, in some cases, eliminated. When food is irradiated, harmful organisms are destroyed without cooking or altering the nutritional properties of the food.
It also makes chemical additives and refrigeration unnecessary, and requires less energy than other food preservation methods. Click above and get connected! OK, the second one is pretty easy.
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