Fusion reactors have been getting a lot of press recently because they offer some major advantages over other power sources. They will use abundant sources of fuel, they will not leak radiation above normal background levels and they will produce less radioactive waste than current fission reactors.
Nobody has put the technology into practice yet, but working reactors aren't actually that far off. Fusion reactors are now in experimental stages at several laboratories in the United States and around the world.
Fusion power is power generated by nuclear fusion processes. In fusion reactions two light atomic nuclei fuse together to form a heavier nucleus (in contrast with fission power). In doing so they release a comparatively large amount of energy arising from the binding energy due to the strong nuclear force which is manifested as an increase in temperature of the reactants. Fusion power is a primary area of research in plasma physics.
The term is commonly used to refer to potential commercial production of net usable power from a fusion source, similar to the usage of the term "steam power." The leading designs for controlled fusion research use magnetic (tokamak design) or inertial (laser) confinement of a plasma, with heat from the fusion reactions used to operate a steam turbine which in turn drives electrical generators, similar to the process used in fossil fuel and nuclear fission power stations.
Fusion power is believed to have significant safety advantages over current power stations based on nuclear fission. Fusion only takes place under very limited and controlled circumstances (by comparison fission, including catastrophic failure, only requires that there is sufficient fuel within a small enough space). For this reason, a failure of precise control or cessation of fueling quickly shuts down fusion power reactions. There is no possibility of runaway heat build-up or large-scale release of radioactivity, little or no atmospheric pollution, the power source comprises light elements in small quantities which are easily obtained and largely harmless to life, the waste products are short-lived in terms of radioactivity, and there is little overlap with nuclear weapons technology.
Fusion powered electricity generation was initially believed to be readily achievable, as fission power had been. However the extreme requirements for continuous reactions and plasma containment led to projections being extended by several decades, and more than 60 years after the first attempts, commercial power production is still believed to be unlikely before 2050.[1]
As of July 2010[update], the largest experiment by means of magnetic confinement has been the Joint European Torus (JET). In 1997, JET produced a peak of 16.1 megawatts (21,600 hp) of fusion power (65% of input power), with fusion power of over 10 MW (13,000 hp) sustained for over 0.5 sec. In June 2005, its successor, ITER, was announced by the seven parties involved in the project - the United States, China, the European Union (EU), India, Japan, the Russian Federation, and South Korea.[2] ITER is designed to produce ten times more fusion power than the power put into the plasma over many minutes; for example 50 MW of input power to produce 500 MW of output power. ITER is currently under construction in Cadarache, France. DEMO is intended as the next generation of research from ITER, and to be the first reactor demonstrating sustained net energy-producing fusion on a commercial scale. It has been proposed to begin construction of DEMO in 2024.
Inertial (laser) confinement, which was for a time seen as more difficult or infeasible, has generally seen less development effort than magnetic approaches. However this approach made a comeback following further innovations, and is being developed at both the United States National Ignition Facility as well as the planned European Union High Power laser Energy Research (HiPER) facility. As of 2010 heating to 3.3 million Kelvin was achieved[3] and in October 2010 the first integrated ignition test was announced to have been completed successfully with the 192-beam laser system firing over a million joules of ultraviolet laser energy into a capsule filled with hydrogen fuel. Fusion ignition tests are to follow.[4]
Nobody has put the technology into practice yet, but working reactors aren't actually that far off. Fusion reactors are now in experimental stages at several laboratories in the United States and around the world.
Nuclear FusionIf light nuclei are forced together, they will fuse with a yield of energy because the mass of the combination will be less than the sum of the masses of the individual nuclei. If the combined nuclear mass is less than that of iron at the peak of the binding energy curve, then the nuclear particles will be more tightly bound than they were in the lighter nuclei, and that decrease in mass comes off in the form of energy according to the Einstein relationship. For elements heavier than iron, fission will yield energy.For potential nuclear energy sources for the Earth, the deuterium-tritium fusion reaction contained by some kind of magnetic confinement seems the most likely path. However, for the fueling of the stars, other fusion reactions will dominate.
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Deuterium-Tritium Fusion
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Fusion power is power generated by nuclear fusion processes. In fusion reactions two light atomic nuclei fuse together to form a heavier nucleus (in contrast with fission power). In doing so they release a comparatively large amount of energy arising from the binding energy due to the strong nuclear force which is manifested as an increase in temperature of the reactants. Fusion power is a primary area of research in plasma physics.
The term is commonly used to refer to potential commercial production of net usable power from a fusion source, similar to the usage of the term "steam power." The leading designs for controlled fusion research use magnetic (tokamak design) or inertial (laser) confinement of a plasma, with heat from the fusion reactions used to operate a steam turbine which in turn drives electrical generators, similar to the process used in fossil fuel and nuclear fission power stations.
Fusion power is believed to have significant safety advantages over current power stations based on nuclear fission. Fusion only takes place under very limited and controlled circumstances (by comparison fission, including catastrophic failure, only requires that there is sufficient fuel within a small enough space). For this reason, a failure of precise control or cessation of fueling quickly shuts down fusion power reactions. There is no possibility of runaway heat build-up or large-scale release of radioactivity, little or no atmospheric pollution, the power source comprises light elements in small quantities which are easily obtained and largely harmless to life, the waste products are short-lived in terms of radioactivity, and there is little overlap with nuclear weapons technology.
Fusion powered electricity generation was initially believed to be readily achievable, as fission power had been. However the extreme requirements for continuous reactions and plasma containment led to projections being extended by several decades, and more than 60 years after the first attempts, commercial power production is still believed to be unlikely before 2050.[1]
As of July 2010[update], the largest experiment by means of magnetic confinement has been the Joint European Torus (JET). In 1997, JET produced a peak of 16.1 megawatts (21,600 hp) of fusion power (65% of input power), with fusion power of over 10 MW (13,000 hp) sustained for over 0.5 sec. In June 2005, its successor, ITER, was announced by the seven parties involved in the project - the United States, China, the European Union (EU), India, Japan, the Russian Federation, and South Korea.[2] ITER is designed to produce ten times more fusion power than the power put into the plasma over many minutes; for example 50 MW of input power to produce 500 MW of output power. ITER is currently under construction in Cadarache, France. DEMO is intended as the next generation of research from ITER, and to be the first reactor demonstrating sustained net energy-producing fusion on a commercial scale. It has been proposed to begin construction of DEMO in 2024.
Inertial (laser) confinement, which was for a time seen as more difficult or infeasible, has generally seen less development effort than magnetic approaches. However this approach made a comeback following further innovations, and is being developed at both the United States National Ignition Facility as well as the planned European Union High Power laser Energy Research (HiPER) facility. As of 2010 heating to 3.3 million Kelvin was achieved[3] and in October 2010 the first integrated ignition test was announced to have been completed successfully with the 192-beam laser system firing over a million joules of ultraviolet laser energy into a capsule filled with hydrogen fuel. Fusion ignition tests are to follow.[4]
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