Nuclear energy is playing a vital role in the life of every man, woman, and child in the. United States today. In the years ahead it will affect increasingly all the. The atoms. The fission process and the reaction chain. Basic principles of nuclear reactors. Genesis of nuclear reactor technology. A nuclear reactor: how. The purpose of a nuclear power plant is not to produce or release “Nuclear Power.” The purpose of It should not be surprising, then, that a nuclear power plant.
|Language:||English, Arabic, Dutch|
|ePub File Size:||21.33 MB|
|PDF File Size:||16.65 MB|
|Distribution:||Free* [*Sign up for free]|
when the fossil fuel (coal, natural gas or oil) is burned that drives the turbine in a conventional thermal power plant. In a nuclear power plant, it is the heat. HOW DOES A. NUCLEAR POWER PLANT. WORK? O n t a r i o. P o w e r. G e n e r a t i o n. PU. TT. ING OU. R. E. NE. RG. Y. TO. G. O. O. D. U. S. E. How nuclear power plants generate electricity. .. Capacity and generation of U.S. nuclear power plants. .. pdf.
The condenser is a heat exchanger which is connected to a secondary side such as a river or a cooling tower. The water is then pumped back into the steam generator and the cycle begins again.
Nuclear Energy from Fission
The water-steam cycle corresponds to the Rankine cycle. The nuclear reactor is the heart of the station. In its central part, the reactor's core produces heat due to nuclear fission. With this heat, a coolant is heated as it is pumped through the reactor and thereby removes the energy from the reactor.
Heat from nuclear fission is used to raise steam, which runs through turbines , which in turn powers the electrical generators. Nuclear reactors usually rely on uranium to fuel the chain reaction. Uranium is a very heavy metal that is abundant on Earth and is found in sea water as well as most rocks.
Naturally occurring uranium is found in two different isotopes: Isotopes are atoms of the same element with a different number of neutrons. Thus, U has neutrons and U has neutrons. Different isotopes have different behaviours. For instance, U is fissile which means that it is easily split and gives off a lot of energy making it ideal for nuclear energy.
On the other hand, U does not have that property despite it being the same element. Different isotopes also have different half-lives. A half-life is the amount of time it takes for half of a sample of a radioactive element to decay.
U has a longer half-life than U, so it takes longer to decay over time. This also means that U is less radioactive than U Since nuclear fission creates radioactivity, the reactor core is surrounded by a protective shield. This containment absorbs radiation and prevents radioactive material from being released into the environment.
In addition, many reactors are equipped with a dome of concrete to protect the reactor against both internal casualties and external impacts. The purpose of the steam turbine is to convert the heat contained in steam into mechanical energy.
The engine house with the steam turbine is usually structurally separated from the main reactor building. It is so aligned to prevent debris from the destruction of a turbine in operation from flying towards the reactor.
In the case of a pressurized water reactor, the steam turbine is separated from the nuclear system. To detect a leak in the steam generator and thus the passage of radioactive water at an early stage, an activity meter is mounted to track the outlet steam of the steam generator.
In contrast, boiling water reactors pass radioactive water through the steam turbine, so the turbine is kept as part of the radiologically controlled area of the nuclear power station. The generator converts mechanical power supplied by the turbine into electrical power. Low-pole AC synchronous generators of high rated power are used. A cooling system removes heat from the reactor core and transports it to another area of the station, where the thermal energy can be harnessed to produce electricity or to do other useful work.
Typically the hot coolant is used as a heat source for a boiler , and the pressurized steam from that drives one or more steam turbine driven electrical generators.
In the event of an emergency, safety valves can be used to prevent pipes from bursting or the reactor from exploding. The valves are designed so that they can derive all of the supplied flow rates with little increase in pressure. In the case of the BWR, the steam is directed into the suppression chamber and condenses there. The chambers on a heat exchanger are connected to the intermediate cooling circuit.
The main condenser is a large cross-flow tube-and-shell heat exchanger that takes wet vapor, a mixture of liquid water and steam at saturation conditions, from the turbine-generator exhaust and condenses it back into sub-cooled liquid water so it can be pumped back to the reactor by the condensate and feedwater pumps. The cooling water typically come from a natural body of water such as a river or lake.
Palo Verde Nuclear Generating Station , located in the desert about 60 miles west of Phoenix, Arizona, is the only nuclear facility that does not use a natural body of water for cooling, instead it uses treated sewage from the greater Phoenix metropolitan area.
The water coming from the cooling body of water is either pumped back to the water source at a warmer temperature or returns to a cooling tower where it either cools for more uses or evaporates into water vapor that rises out the top of the tower. The water level in the steam generator and the nuclear reactor is controlled using the feedwater system. The feedwater pump has the task of taking the water from the condensate system, increasing the pressure and forcing it into either the steam generators in the case of a pressurized water reactor or directly into the reactor for boiling water reactors.
Continuous power supply to the reactor is critical to ensure safe operation.
Most nuclear stations require at least two distinct sources of offsite power for redundancy. These are usually provided by multiple transformers that are sufficiently separated and can receive power from multiple transmission lines.
In addition, in some nuclear stations, the turbine generator can power the station's loads while the station is online, without requiring external power. This is achieved via station service transformers which tap power from the generator output before they reach the step-up transformer. This is in addition to station service transformers that receive offsite power directly from the switch yard.
Even with the redundancy of two power sources, total loss of offsite power is still possible. For this reason, nuclear power stations are also equipped with emergency generators. In the United States and Canada, workers except for management, professional such as engineers and security personnel are likely to be members of either the International Brotherhood of Electrical Workers IBEW or the Utility Workers Union of America UWUA , or one of the various trades and labor unions representing Machinist, laborers, boilermakers, millwrights, ironworkers etc.
The economics of new nuclear power stations is a controversial subject, and multibillion-dollar investments ride on the choice of an energy source. Nuclear power stations typically have high capital costs, but low direct fuel costs, with the costs of fuel extraction, processing, use and spent fuel storage internalized costs.
Therefore, comparison with other power generation methods is strongly dependent on assumptions about construction timescales and capital financing for nuclear stations.
Cost estimates take into account station decommissioning and nuclear waste storage or recycling costs in the United States due to the Price Anderson Act. However, up to now, there has not been any actual bulk recycling of waste from a NPP, and on-site temporary storage is still being used at almost all plant sites due to waste repository construction problems. Only Finland has stable repository plans, therefore from a worldwide perspective, long-term waste storage costs are uncertain.
On the other hand, construction, or capital cost aside, measures to mitigate global warming such as a carbon tax or carbon emissions trading , increasingly favor the economics of nuclear power. In Eastern Europe, a number of long-established projects are struggling to find finance, notably Belene in Bulgaria and the additional reactors at Cernavoda in Romania, and some potential backers have pulled out.
Analysis of the economics of nuclear power must take into account who bears the risks of future uncertainties. To date all operating nuclear power stations were developed by state-owned or regulated utility monopolies  where many of the risks associated with construction costs, operating performance, fuel price, and other factors were borne by consumers rather than suppliers. Many countries have now liberalized the electricity market where these risks and the risk of cheaper competitors emerging before capital costs are recovered, are borne by station suppliers and operators rather than consumers, which leads to a significantly different evaluation of the economics of new nuclear power stations.
Following the Fukushima I nuclear accidents , costs are likely to go up for currently operating and new nuclear power stations, due to increased requirements for on-site spent fuel management and elevated design basis threats.
In his book, Normal accidents , Charles Perrow says that multiple and unexpected failures are built into society's complex and tightly-coupled nuclear reactor systems. Such accidents are unavoidable and cannot be designed around. This leads to on average one serious accident happening every eight years worldwide. Modern nuclear reactor designs have had numerous safety improvements since the first-generation nuclear reactors. A nuclear power plant cannot explode like a nuclear weapon because the fuel for uranium reactors is not enriched enough, and nuclear weapons require precision explosives to force fuel into a small enough volume to go supercritical.
Most reactors require continuous temperature control to prevent a core meltdown , which has occurred on a few occasions through accident or natural disaster, releasing radiation and making the surrounding area uninhabitable.
Plants must be defended against theft of nuclear material for example to make a dirty bomb and attack by enemy military which has occurred  planes or missiles, or planes hijacked by terrorists. The nuclear power debate is about the controversy     which has surrounded the deployment and use of nuclear fission reactors to generate electricity from nuclear fuel for civilian purposes.
The debate about nuclear power peaked during the s and s, when it "reached an intensity unprecedented in the history of technology controversies", in some countries.
Components of a nuclear reactor
Proponents argue that nuclear power is a sustainable energy source which reduces carbon emissions and can increase energy security if its use supplants a dependence on imported fuels.
Proponents also believe that nuclear power is the only viable course to achieve energy independence for most Western countries. They emphasize that the risks of storing waste are small and can be further reduced by using the latest technology in newer reactors, and the operational safety record in the Western world is excellent when compared to the other major kinds of power plants.
Opponents say that nuclear power poses many threats to people and the environment, and that costs do not justify benefits. Threats include health risks and environmental damage from uranium mining , processing and transport, the risk of nuclear weapons proliferation or sabotage, and the unsolved problem of radioactive nuclear waste.
The hot water modifies the environmental conditions for marine flora and fauna. They also contend that reactors themselves are enormously complex machines where many things can and do go wrong, and there have been many serious nuclear accidents. Actual construction costs often exceed estimates, and spent fuel management costs do not have a clear time limit. Nuclear reprocessing technology was developed to chemically separate and recover fissionable plutonium from irradiated nuclear fuel.
Originally reprocessing was used solely to extract plutonium for producing nuclear weapons. With the commercialization of nuclear power , the reprocessed plutonium was recycled back into MOX nuclear fuel for thermal reactors. Finally, the breeder reactor can employ not only the recycled plutonium and uranium in spent fuel, but all the actinides , closing the nuclear fuel cycle and potentially multiplying the energy extracted from natural uranium by more than 60 times. Nuclear reprocessing reduces the volume of high-level waste, but by itself does not reduce radioactivity or heat generation and therefore does not eliminate the need for a geological waste repository.
Reprocessing has been politically controversial because of the potential to contribute to nuclear proliferation , the potential vulnerability to nuclear terrorism , the political challenges of repository siting a problem that applies equally to direct disposal of spent fuel , and because of its high cost compared to the once-through fuel cycle.
The Vienna Convention on Civil Liability for Nuclear Damage puts in place an international framework for nuclear liability. In the U. Under the Energy policy of the United Kingdom through its Nuclear Installations Act , liability is governed for nuclear damage for which a UK nuclear licensee is responsible.
Between ten and thirty years afterwards, the Government meets this obligation. Nuclear decommissioning is the dismantling of a nuclear power station and decontamination of the site to a state no longer requiring protection from radiation for the general public.
The main difference from the dismantling of other power stations is the presence of radioactive material that requires special precautions to remove and safely relocate to a waste repository. Decommissioning involves many administrative and technical actions.
It includes all clean-up of radioactivity and progressive demolition of the station. Once a facility is decommissioned, there should no longer be any danger of a radioactive accident or to any persons visiting it.
Nuclear power plant
After a facility has been completely decommissioned it is released from regulatory control, and the licensee of the station no longer has responsibility for its nuclear safety. The Chernobyl disaster occurred in April , it is considered the worst nuclear accident in history.
An experiment was being carried out on one of the reactors in the plant. The purpose of the experiment was to find out the reactor's safety in the event of the failure of the main electricity supply to the plant. Right after the experiment began there was a steam explosion which exposed the reactor's graphite moderator to air, which caused it to ignite.
The resulting fire sent highly radioactive plumes of smoke into the atmosphere for about ten days.
The radioactive plume spread over large areas of Europe. Approximately , people were evacuated from the kilometers squared exclusion zone. The accident caused 31 direct deaths from the explosion and radiation poisoning, and several more deaths in the population exposed to high radiation doses. The nuclear industry says that new technology and oversight have made nuclear station much safer, but 57 small accidents have occurred since the Chernobyl disaster in until Two thirds of these mishaps occurred in the US.
According to Benjamin Sovacool , an interdisciplinary team from MIT in estimated that given the expected growth of nuclear power from — , at least four serious nuclear accidents would be expected in that period.
Nuclear stations are used primarily for base load because of economic considerations. The fuel cost of operations for a nuclear station is smaller than the fuel cost for operation of coal or gas plants.
Since most of the cost of nuclear power plant is capital cost, there is almost no cost saving by running it at less than full capacity. Nuclear power plants are routinely used in load following mode on a large scale in France, although "it is generally accepted that this is not an ideal economic situation for nuclear stations.
A new generation of designs for nuclear power stations, known as the Generation IV reactors , are the subject of active research.
Passively safe stations such as the ESBWR are available to be built  and other reactors that are designed to be nearly fool-proof are being pursued.
The reactor was originally scheduled to go online in , but has been repeatedly delayed,   and as of September has been pushed back to The Taishan reactors were scheduled to go online in and ,  first criticality was achieved at Taishan Unit 1 in As of March [update] , there are seven nuclear power stations under construction in India , and five in China.
In November Gulf Power stated that by the end of it hopes to finish downloading off acres of land north of Pensacola, Florida in order to build a possible nuclear power station. In Russia launched a floating nuclear power station. By , Southeast Asia nations plan to have a total of 29 nuclear power stations: Indonesia will have 4 nuclear power stations, Malaysia 4, Thailand 5 and Vietnam 16 from nothing at all in In China had 32  nuclear reactors under construction, the highest number in the world.
Expansion at two nuclear power stations in the United States, Vogtle and V. Summer Nuclear Power Station , located in Georgia and South Carolina, respectively, were scheduled to be completed between and The construction of the two South Carolina reactors have been abandoned due to cost overruns and the bankruptcy of Westinghouse Electric Company who designed and was building the reactors in March . The two new Vogtle reactors, and the two new reactors at Virgil C.
Summer Nuclear Station, represented the first nuclear power construction projects in the United States since the Three Mile Island nuclear accident in Several countries have begun thorium-based nuclear power programs. Thorium is four times more abundant in the earth's crust than uranium. Even if very large uranium resources are available, especially uranium diluted in seawater, for long-term sustainability, breeders will still be essential.
It is crucial to use life-cycle analyses of different electricity production systems to be able to compare efficiency. For fission energy, resource use and radioactive emissions from mining to repositories have to be considered. For example, it is important to look carefully into the health issues that are related to the mining of uranium.
Nuclear energy from fission rates favorably in such life-cycle analyses. The Generation IV systems will need much less fuel, thus minimizing environmental impact during the life cycle.
Part of the downturn of the nuclear energy industry in previous decades was probably due to the more competitively priced coal-produced electricity. Obviously, for the expansion of nuclear energy, new plants will have to be economically competitive, without compromising safety and reliability.
As has been briefly mentioned above, Generation IV reactors with breeder technology will use nuclear fuel much more efficiently and will also be able to use spent fuel from existing reactors , thus minimizing the waste and drastically shortening the required storage time for the final waste. Breeder systems will increase the available energy from natural uranium by a factor 60— Among the different plans for the new generation of reactors are the subcritical thorium-based nuclear systems driven by accelerators that could have advantages over uranium-based systems.
Thorium-based systems might be able to produce energy for several thousands of years with known thorium resources.In contrast, boiling water reactors pass radioactive water through the steam turbine, so the turbine is kept as part of the radiologically controlled area of the nuclear power station. The principles for using nuclear power to produce electricity are the same for most types of reactor.
British Journal of Political Science. The water level in the steam generator and the nuclear reactor is controlled using the feedwater system. However, up to now, there has not been any actual bulk recycling of waste from a NPP, and on-site temporary storage is still being used at almost all plant sites due to waste repository construction problems.
- ENGLISH VERBS LIST WITH HINDI MEANING PDF
- ARTEMIS FOWL THE TIME PARADOX PDF
- ANIME PAPERCRAFT PDF
- LA SIGNORINA JULIE PDF DOWNLOAD
- TEMPERAMENTOS TRANSFORMADOS PDF
- NOOK BOOK WITHOUT WIFI
- 70-462 ADMINISTERING MICROSOFT SQL SERVER 2012 DATABASES PDF
- FINGER PHONICS BIG BOOK
- LEARN ENGLISH IN 30 DAYS BOOK PDF
- TELEMECANIQUE XVA-LC3 PDF
- SAMANNAPHALA SUTTA DOWNLOAD
- URDU NOVELS PDF FILES
- MENS FITNESS ULTIMATE WORKOUT PLAN PDF
- HANDBOOK OF CANCER CHEMOTHERAPY PDF