Applications of Nuclear Power | Science & Technology for UPSC CSE PDF Download

The Many Uses of Nuclear Technology

• The first power station to produce electricity by using heat from the splitting of uranium atoms began operating in the 1950s. Today most people are aware of the important contribution nuclear energy makes in providing a significant proportion of the world's low-carbon electricity.
• The applications of nuclear technology outside of civil electricity production in power plants are less well-known.
• Radioisotopes, nuclear power process heat and non-stationary power reactors have essential uses across multiple sectors, including consumer products, food and agriculture, industry, medicine and scientific research, transport, and water resources and the environment.

Radioisotopes

• Isotopes are variants of a given chemical element that have nuclei with the same number of protons, but different numbers of neutrons. Some isotopes are referred to as 'stable' as they are unchanging over time. Others are 'unstable' or radioactive since their nuclei change over time through the loss of alpha and beta particles. The attributes of naturally decaying atoms, known as ‘radioisotopes’, give such atoms several applications across many aspects of modern day life.
• The first practical application of a radioisotope was made by a Hungarian man named George de Hevesy in 1911. At the time de Hevesy was a young student working in Manchester, studying naturally radioactive materials. Not having much money he lived in modest accommodation and ate his meals with his landlady. He began to suspect that some of the meals that appeared regularly might be made from leftovers from the preceding days or even weeks, but he could never be sure. To try and confirm his suspicions de Hevesy put a small amount of radioactive material into the remains of a meal. Several days later, when the same dish was served again, he used a simple radiation detection instrument – a gold leaf electroscope – to check if the food was radioactive. It was, and de Hevesy's suspicions were confirmed.
• History has forgotten the landlady, but George de Hevesy went on to win the Nobel prize in 1943 and the Atoms for Peace award in 1959. His was the first use of radioactive tracers – now routine in environmental science.

Supply of Radioisotopes

The main isotope suppliers are Mallinckrodt Pharmaceuticals (Ireland), MDS Nordion (Canada), IRE (Europe), NTP (South Africa), Isotop-NIIAR (Russia), and ANSTO (Australia).
Most medical radioisotopes made in nuclear reactors are sourced from relatively few research reactors, including:

• HFR at Petten in Netherlands (supplied via IRE and Mallinckrodt).
• BR-2 at Mol in Belgium (supplied via IRE and Mallinckrodt).
• Maria in Poland (supplied via Mallinckrodt).
• Orphee at Saclay in France (supplied via IRE).
• FRJ-2/FRM-2 at Julich in Germany (supplied via IRE).
• LWR-15 at Rez in Czech Republic.
• HFETR at Chengdu in China.
• Safari in South Africa (supplied from NTP).
• OPAL in Australia (supplied from ANSTO to domestic market, exports from 2016).
• ETRR-2 in Egypt (forthcoming: supplied to domestic market).
• Dimitrovgrad in Russia (Isotop-NIIAR).

Of fission radioisotopes, the vast majority of demand is for of Mo-99 (for Tc-99m), and the world market is some $550 million per year. About 40% of it is supplied by MDS Nordion, 25% from Mallinckrodt (formerly Covidien), 17% from IRE, and 10% from NTP. Over half of the Mo-99 has been made in two reactors: NRU in Canada (30-40% but ceased production in October 2016) and HFR in the Netherlands (30%). The rest is from BR-2 in Belgium (10%), Maria in Poland (5%), Safari-1 in South Africa (10-15%), Opal in Australia (increasing to 20% from mid-2016), and until the end of 2015, Osiris in France (5%). Output from each varies due to maintenance schedules.

Russia is keen to increase its share of world supply, and in 2012 some 66% of its radioisotope production was exported. For I-131, 75% is from IRE, 25% from NTP.

World demand for Mo-99 was 23,000 six-day TBq/yr* in 2012, but has apparently dropped back to about 19,500 since. Mo-99 is mostly produced by fission of U-235 targets in a nuclear research reactor, much of this (75% in 2016) using high-enriched uranium (HEU) targets. The targets are then processed to separate the Mo-99 and also to recover I-131. OPAL, Safari, and increasingly other reactors such as Maria use low-enriched uranium (LEU) targets, which adds about 20% to production costs. However, in medical imaging, the cost of Mo-99 itself is small relative to hospital costs. Mo-99 can also be made by bombarding Mo-98 with neutrons in a reactor. However, this activation Mo-99 has relatively low specific activity, with a maximum of 74 GBq/g (depending on the neutron flux available in the reactor), compared with 185 TBq/g or more for conventional fission-produced Mo-99.

* 23,000 six-day TBq is on the basis of activity at six days from production reference point, i.e. (given a 66-hour half-life) 22% of around 104,000 TBq. This is still about two days from the end of irradiation, so some 170,000 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.

Agriculture

• See also information paper on Radioisotopes in Food & Agriculture. The Food and Agriculture Organization (FAO) of the United Nations (UN) estimates that about 795 million people (one in nine) were suffering from chronic undernourishment in 2014-16. 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. The FAO works with the IAEA on programs to improve food sustainability assisted by nuclear and related biotechnologies.

Plant Mutation Breeding

• 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

• Fertilisers are expensive and if not properly used can damage the environment. It is important that as much used fertilizer as possible is “fixed” in the plant matter and that a minimum is lost to the environment. 
• 'Labelling' fertilizers with a particular isotope (e.g. nitrogen-15) provides a means of ascertaining how much has been taken up by the plants, allowing for better management of fertilizer use.

Insect Control

• Estimates of crop losses to insects vary, but are usually significant. Despite the widespread use of insecticides, losses are likely to be of the order of 10% globally, and often notably higher in developing countries. 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. 
• Radiation is used to control insect populations via the Sterile Insect Technique (SIT). 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. The International Plant Protection Convention recognises the benefits of SIT, and categorises the insects as beneficial organisms. 
• SIT was first developed in the USA and has been used successfully for more than 60 years. 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). Three UN organizations – the IAEA, the FAO, the World Health Organization (WHO) – with the governments concerned, are promoting new SIT programs in many countries.

Consumer Products

• 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. Smoke detectors, watches & clocks, and non-stick materials, among others, all utilise the natural properties of radioisotopes in their design. 
• One of the most common uses of radioisotopes today is in household smoke detectors. These contain a small amount of americium-241 which is a decay product of plutonium-241 originating in nuclear reactors. The Am-241 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.

Food

See also information paper on Radioisotopes in Food & Agriculture.

Food Irradiation

• Some 25-30% of food harvested is lost as a result of spoilage before it can be consumed. 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.

Industry

See also information paper on Radioisotopes in Industry.

Industrial Tracers

• 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.

Inspection and Instrumentation

• 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.

Carbon Dating

• Analysing the relative abundance of particular naturally-occurring radioisotopes is of vital importance in determining the age of rocks and other materials that are of interest to geologists, anthropologists, hydrologists, and archaeologists, among others.

Desalination

• See also information paper on Nuclear Desalination. Potable water is a major priority in sustainable development. Where it cannot be obtained from streams and aquifers, desalination of seawater, mineralised groundwater, or urban waste water is required. Most desalination today uses fossil fuels and thus contributes to increased levels of greenhouse gases. 
• The feasibility of integrated nuclear desalination plants has been proven with over 150 reactor-years of experience, chiefly in Kazakhstan, India, and Japan. Large-scale deployment of nuclear desalination on a commercial basis with reactors built primarily for that purpose will depend on economic factors.

Medicine

• See also information paper on Radioisotopes in Medicine. Many people are aware of the wide use of radiation and radioisotopes in medicine particularly for diagnosis (identification) and therapy (treatment) of various medical conditions. 
• In developed countries about one person in 50 uses diagnostic nuclear medicine each year, and the frequency of therapy with radioisotopes is about one-tenth of this.

Diagnosis

• Diagnostic techniques in nuclear medicine use radiopharmaceuticals (or radiotracers) which emit gamma rays from within the body. These tracers are generally short-lived isotopes linked to chemical compounds which permit specific physiological processes to be scrutinised.
• Dependent on the type of examination, radiotracers are either injected into the body, swallowed, or inhaled in gaseous form. The emissions from the radiotracers are detected by the imaging device, which provides pictures and molecular information. The superimposition of nuclear medicine images with computed tomography (CT) or magnetic resonance imaging (MRI) scans can provide comprehensive views to physicians to aid diagnosis.
• An advantage of nuclear over X-ray techniques is that both bone and soft tissue can be imaged very successfully.
• The most widely used diagnostic radioisotope is technetium-99m, with a half-life of six hours, and which gives the patient a very low radiation dose. Such isotopes are ideal for tracing many bodily processes with the minimum of discomfort for the patient. They are widely used to indicate tumours and to study the heart, lungs, liver, kidneys, blood circulation and volume, and bone structure.

Therapy

• Nuclear medicine is also used for therapeutic purposes. Most commonly, radioactive iodine (I-131) is used in small amounts to treat cancer and other conditions affecting the thyroid gland.
• The uses of radioisotopes in therapy are comparatively few, but important. Cancerous growths are sensitive to damage by radiation, which may be external (using a gamma beam from a cobalt-60 source), or internal (using a small gamma or beta radiation source). Short-range radiotherapy is known as brachytherapy, and this is becoming the main means of treatment. Many therapeutic procedures are palliative, usually to relieve pain.
• A new field is targeted alpha therapy (TAT), especially for the control of dispersed cancers. The short range of very energetic alpha emissions in tissue means that a large fraction of that radiative energy goes into the targeted cancer cells once a carrier, such as a monoclonal antibody, has taken the alpha-emitting radionuclide to exactly the right places.

Sterilisation

• Hospitals use gamma radiation to sterilise medical products and supplies such as syringes, gloves, clothing, and instruments that would otherwise be damaged by heat sterilisation.
• Many medical products today are sterilised by gamma rays from a cobalt-60 source, a technique which generally is much cheaper and more effective than steam heat sterilisation. The disposable syringe is an example of a product sterilised by gamma rays. Because it is a 'cold' process, radiation can be used to sterilise a range of heat-sensitive items such as powders, ointments, and solutions, as well as biological preparations such as bone, nerve, skin, etc, used in tissue grafts.
• The benefit to humanity of sterilisation by radiation is tremendous. It is safer and cheaper because it can be done after the item is packaged. The sterile shelf life of the item is then practically indefinite provided the package is not broken open. Apart from syringes, medical products sterilised by radiation include cotton wool, burn dressings, surgical gloves, heart valves, bandages, plastic and rubber sheets, and surgical instruments.

Insect Control

• In addition to agricultural pest control (see Agriculture section above), SIT has found important applications in the fight against disease-carrying insects. 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. 
• Following its outbreak, impacted countries requested urgent support from the IAEA to help develop the established technique to suppress populations of disease-carrying mosquitoes. The IAEA responded by providing expert guidance, extensive training, and by facilitating the transfer of gamma cell irradiators to Brazil.

Sterile Insect Technique

Transport

Nuclear-Powered Ships

• Nuclear power is particularly suitable for vessels which need to be at sea for long periods without refuelling, or for powerful submarine propulsion. The majority of the approximately 140 ships powered by small nuclear reactors are submarines, but they range from icebreakers to aircraft carriers. See also information paper on Nuclear-Powered Ships.

Nuclear Reactors for Space

• Radioisotope thermal generators (RTGs) are used in space missions. The heat generated by the decay of a radioactive source, often plutionium-238, is used to generate electricity. The Voyager space probes, the Cassini mission to Saturn, the Galileo mission to Jupiter, and the New Horizons mission to Pluto are all powered by RTGs. 
• The Spirit and Opportunity Mars rovers have used a mix of solar panels for electricity and RTGs for heat. The latest Mars rover, Curiosity, is much bigger and uses RTGs for heat and electricity as solar panels would not be able to supply enough electricity. See also information paper on Nuclear Reactors for Space.

Hydrogen, Electricity and Cars

• In the future, electricity or heat from nuclear power plants could be used to make hydrogen. Hydrogen can be used in fuel cells to power cars, or can be burned to provide heat in place of gas without producing emissions that would cause climate change. See also information paper on Transport and the Hydrogen Economy.

Water resources and the Environment

See also information paper on Radioisotopes in Water Resources and the Environment.

Environmental Tracers

• Radioisotopes play an important role in detecting and analysing pollutants. Nuclear techniques have been applied to a range of pollution problems including smog formation, sulphur dioxide contamination of the atmosphere, sewage dispersal from ocean outfalls, and oil spills.

Water Resources

• Adequate potable water is essential for life. Yet in many parts of the world fresh water has always been scarce and in others it is becoming so.
• Isotope hydrology techniques enable accurate tracing and measurement of the extent of underground water resources. Such techniques provide important analytical tools in the management and conservation of existing supplies of water and in the identification of new sources. They provide answers to questions about origin, age, and distribution of groundwater, as well as the interconnections between ground and surface water, and aquifer recharge systems. 
• The results permit planning and sustainable management of these water resources. For surface waters they can give information about leakages through dams and irrigation channels, the dynamics of lakes and reservoirs, flow rates, river discharges, and sedimentation rates. Neutron probes can measure soil moisture very accurately, enabling better management of land affected by salinity, particularly in respect to irrigation.

Conservation

The Rhisotope Project is investigating the use of radioisotopes in the prevention of rhino poaching. The University of Witwatersrand in collaboration with the Australian Nuclear Science and Technology Organisation (Ansto), Colorado State University, Rosatom and the Nuclear Energy Corporation of South Africa (Necsa), is examining the possibility of injecting trace amounts of stable isotopes into the horns of rhinos, to disincentivize poaching and to increase the chances of identifying and arresting smugglers. At the launch of the project in May 2021, Rosatom said: "With over 10,000 radiation detection devices installed at various ports of entry across the globe, experts are confident that this project will make the transportation of horn incredibly difficult and will substantially increase the likelihood of identifying and arresting smugglers."