What is nuclear energy and Definition
Nuclear energy is the energy in the nucleus of an atom. Atoms are the smallest particles that can break a material. At the core of each atom there are two types of particles (neutrons and protons) that are held together. Nuclear energy is the energy that holds neutrons and protons.Nuclear energy can be used to produce electricity. This energy can be obtained in two ways: nuclear fusion and nuclear fission. In nuclear fusion, energy is released when atoms are combined or fused together to form a larger atom. The sun produces energy like this. In nuclear fission, atoms are split into smaller atoms, releasing energy. Actually, nuclear power plants can only use nuclear fission to produce electricity.
When one of these two physical reactions (nuclear fission or nuclear fusion) success, atoms experiment a slight loss of mass. This mass lost generates a big amount of heat energy, explained by Albert Einstein with his famous equation E = mc2.
Although the production of electricity is the most common utility there are many other uses of nuclear energy in other sectors, such as medical, environmental or wartime (atomic bomb).
Components of a nuclear reactor
- There are several components common to most types of reactors:
Fuel. Uranium is the basic fuel. Usually pellets of uranium oxide (UO2) are arranged in tubes to form fuel rods. The rods are arranged into fuel assemblies in the reactor core.*
- In a new reactor with new fuel a neutron source is needed to get the reaction going. Usually this is beryllium mixed with polonium, radium or other alpha-emitter. Alpha particles from the decay cause a release of neutrons from the beryllium as it turns to carbon-12. Restarting a reactor with some used fuel may not require this, as there may be enough neutrons to achieve criticality when control rods are removed.
Moderator. Material in the core which slows down the neutrons released from fission so that they cause more fission. It is usually water, but may be heavy water or graphite.
Control rods. These are made with neutron-absorbing material such as cadmium, hafnium or boron, and are inserted or withdrawn from the core to control the rate of reaction, or to halt it.* In some PWR reactors, special control rods are used to enable the core to sustain a low level of power efficiently. (Secondary control systems involve other neutron absorbers, usually boron in the coolant – its concentration can be adjusted over time as the fuel burns up.)
- In fission, most of the neutrons are released promptly, but some are delayed. These are crucial in enabling a chain reacting system (or reactor) to be controllable and to be able to be held precisely critical.
Coolant. A fluid circulating through the core so as to transfer the heat from it. In light water reactors the water moderator functions also as primary coolant. Except in BWRs, there is secondary coolant circuit where the water becomes steam. (See also later section on primary coolant characteristics)
Pressure vessel or pressure tubes. Usually a robust steel vessel containing the reactor core and moderator/coolant, but it may be a series of tubes holding the fuel and conveying the coolant through the surrounding moderator.
Steam generator. Part of the cooling system of pressurised water reactors (PWR & PHWR) where the high-pressure primary coolant bringing heat from the reactor is used to make steam for the turbine, in a secondary circuit. Essentially a heat exchanger like a motor car radiator*. Reactors have up to six ‘loops’, each with a steam generator. Since 1980 over 110 PWR reactors have had their steam generators replaced after 20-30 years service, 57 of these in USA.
- These are large heat exchangers for transferring heat from one fluid to another – here from high-pressure primary circuit in PWR to secondary circuit where water turns to steam. Each structure weighs up to 800 tonnes and contains from 300 to 16,000 tubes about 2 cm diameter for the primary coolant, which is radioactive due to nitrogen-16 (N-16, formed by neutron bombardment of oxygen, with half-life of 7 seconds). The secondary water must flow through the support structures for the tubes. The whole thing needs to be designed so that the tubes don’t vibrate and fret, operated so that deposits do not build up to impede the flow, and maintained chemically to avoid corrosion. Tubes which fail and leak are plugged, and surplus capacity is designed to allow for this. Leaks can be detected by monitoring N-16 levels in the steam as it leaves the steam generator.
- Containment The structure around the reactor and associated steam generators which is designed to protect it from outside intrusion and to protect those outside from the effects of radiation in case of any serious malfunction inside. It is typically a metre-thick concrete and steel structure.
What are the uses Nuclear Energy?
Military applications, nuclear weapons
A gun is a tool used to attack or defend. Nuclear weapons are those weapons that use nuclear technology. Depending on the role that has the nuclear weapon technology in the two types of nuclear weapons are distinguished: those that use nuclear energy to explode, as in the case of the atomic bomb, and those using nuclear technology for propulsion. In this second category are included cruisers, aircraft carriers, submarines …
Industrial uses of nuclear technology
Nuclear technology has a great importance in the industrial sector. It’s mainly used in development and process improvement to the measurement, automation and quality control.
It is used as a prerequisite for the full automation of high speed production lines, and it’s applied to the investigation of processes, mixing, maintenance and wear and corrosion study of plant and machinery.
Nuclear technology is also used in making plastics and sterilization of single-use products.
Medical uses of nuclear technology
Every third patient who visit a hospital in an industrialized country receives the benefits of any type of nuclear medicine procedure. Radiopharmaceuticals, and radiation therapy techniques for the treatment of malignant tumors, teletherapy for cancer treatment or radiation biology to sterilize medical products are used.
Agricultural uses of nuclear technology
The application of isotopes in agriculture has led to increased agricultural production in less developed countries.
Nuclear technology is useful in controlling insect pests, the best use of water resources, improved crop varieties or in the establishment of the conditions to optimize the efficiency of fertilizers and water .
Uses of nuclear technology to food
As food, nuclear techniques play an important role in food preservation.The application of the isotopes can significantly increase the preservation of food. Currently, over 35 countries permit irradiation of certain foods.
Environmental uses of nuclear technology
The application of isotopes to determine the exact amounts of polluting substances and places in which they occur and their causes. Furthermore, the treatment beam electrons reduces the environmental and health consequences of large-scale employment of fossil fuels, and has a better contribution compared with other techniques, solving problems such as the “greenhouse effect” and acid rain.
Other uses of nuclear technology
Nuclear technology is used as dating, which applies the properties of carbon-14 fixation to bone, wood and organic waste, determining chronological age, and applications in geophysics and geochemistry, which exploit the existence of naturally occurring radioactive materials fixing dates of rock, coal an oil deposits.
We found other applications of nuclear technology in disciplines such as hydrology, mining or the space industry.
Advantages of Nuclear Energy
Despite potential drawbacks and the controversy that surrounds it, nuclear energy does have a few advantages over some other methods of energy production.
Less uranium is needed to produce the same amount of energy as coal or oil, which lowers the cost of producing the same amount of energy. Uranium is also less expensive to procure and transport, which further lowers the cost.
When a nuclear power plant is functioning properly, it can run uninterrupted for up to 540 days. This results in fewer brownouts or other power interruptions. The running of the plant is also not contingent of weather or foreign suppliers, which makes it more stable than other forms of energy.
No Greenhouse Gases
While nuclear energy does have some emissions, the plant itself does not give off greenhouse gasses. Studies have shown that what life-cycle emissions that the plants do give off are on par with renewable energy sources such as wind power. This lack of greenhouse gases can be very attractive to some consumers.
Uranium is used in the process of fission because it’s a naturally unstable element. This means that special precautions must be taken during the mining, transporting and storing of the uranium, as well as the storing of any waste product to prevent it from giving off harmful levels of radiation.
Nuclear fission chambers are cooled by water. This water is then turned into steam, which is used to power the turbines. When the water cools enough to change back into liquid form, it is pumped outside into nearby wetlands. While measures are taken to ensure that no radiation is being pumped into the environment, other heavy metals and pollutants can make their way out of the chamber. The immense heat given off by this water can also be damaging to eco systems located nearby the reactor.
When the uranium has finished splitting, the resulting radioactive byproducts need to be removed. While recycling efforts of this waste product have been undertaken in recent years, the storage of the byproduct could lead to contamination through leaks or containment failures.
Nuclear reactors are built with several safety systems designed to contain the radiation given off in the fission process. When these safety systems are properly installed and maintained, they function adequately. When they are not maintained, have structural flaws or were improperly installed, a nuclear reactor could release harmful amounts of radiation into the environment during the process of regular use. If a containment field were to rupture suddenly, the resulting leak of radiation could be catastrophic.
There have been several nuclear reactors that have failed and been shutdown that are still in existence. These abandoned reactors are taking up valuable land space, could be contaminating the areas surrounding them, yet are often too unstable to be removed.
Disadvantages of Nuclear Energy
1) Radioactive minerals are unevenly distributed around the world and are found in limited quantities.
2) Supply of high quality uranium, one of the raw material, will last only for few decades.
3) Nuclear waste from nuclear power plant creates thermal(heat) pollution which may damage the environment.
4) A large amount of nuclear waste is also created and disposal of this waste is a major problem.
5) The danger of accidental discharge of radio activity also exists.
6) Starting a nuclear plant requires huge capital investment and advanced technology.
7) Nuclear plants are opposed on moral grounds, by many groups, because of their close linkage with development of nuclear weapons.
8) There are number of restrictions on the export or import of nuclear technology,fuels etc.
9) Nuclear power stations are always at the risk from terrorist attack.
10) Aftermaths of Chernobyl cannot be forgotten easily.
11) Safety issues associated with nuclear power are hard to be overlooked.
12) Proliferation of nuclear technology increases the risk of nuclear war too.
13) The waste produced remains ‘active’ over many years and disposing it safely is a an issue which needs to be addressed properly.
14) Nuclear power is not a renewable source of energy. Uranium is a metal that is mined from the ground in much the same way as coal is mined. It is a scarce metal and the supply of uranium will one day run out making all the nuclear power plants obsolete.
Nuclear power—good or bad?
There are plenty of people who support our use of nuclear power, and at least as many who oppose it. Supporters say it’s a less environmentally destructive way of producing electrical energy because, overall, it releases fewer greenhouse emissions (less carbon dioxide gas) than burning fuels such as coal, oil, and natural gas. But opponents are concerned about the dangerous, long-lasting waste that nuclear power stations make, the way nuclear-energy byproducts help people build nuclear bombs, and the risk of catastrophic nuclear accidents.
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