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168 Sentences With "fusion reaction"

How to use fusion reaction in a sentence? Find typical usage patterns (collocations)/phrases/context for "fusion reaction" and check conjugation/comparative form for "fusion reaction". Mastering all the usages of "fusion reaction" from sentence examples published by news publications.

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That's the same fusion reaction that powers our own sun.
A nuclear fusion reaction can bake apart liquid metal, but the stuff rapidly reforms.
Free-floating hydrogen atoms are compressed in an electromagnetic field until they create a fusion reaction.
It uses the energy from a primary nuclear fission to set off a subsequent fusion reaction.
This is a far cry from engineering breakeven, and even further from net positive energy fusion reaction.
The second milestone is what Cuneo called "engineering breakeven," which is when a fusion reactor can be scaled to the point that the amount of energy produced by the fusion reaction is the same as the amount of energy required by the entire facility to make that fusion reaction happen.
Eventually, the extra mass the dwarf has accreted triggers a runaway fusion reaction in its core, resulting in a huge detonation.
The result of compressing energy and time to this degree is a fusion reaction and a lot of x-ray energy.
Thermonuclear weapons typically use a fission explosion to create a fusion reaction, which is far more powerful than a fission reaction.
But another team found that a fusion reaction could exist between a pair of quarks to produce this particle, and others, releasing energy.
Here's why: In order to combine the small atoms and start a fusion reaction, such a bomb needs a large amount of energy.
So far, the National Ignition Facility in California is the only research lab in the world to have demonstrated a fusion reaction that achieved scientific breakeven.
A few research institutions and projects have been able to achieve a fusion reaction, but maintaining it and getting more power out than was put in has been elusive.
It's still unclear whether the new design will have an advantage in producing a workable fusion reaction, but the W7-X represents a major step forward in researching that question.
The first is known as scientific breakeven, which is when there is the same amount of energy released in a fusion reaction as there is in the plasma that created it.
This process of fusion releases even more energy per unit of mass than fission does, and the energy released from the fusion reaction also feeds back into the fission reaction, increasing its output.
While it gets its bang from the fusion reaction, it takes a lot of heat to get the process started -- to get the atoms to smash together and start a nuclear chain reaction.
Last year, for example, researchers at MIT increased the efficiency of a fusion reaction by an order of magnitude after adding small amounts of helium-3 to a fuel cell containing hydrogen and deuterium.
A successful two-stage hydrogen bomb, which uses atomic fission to trigger a larger nuclear fusion reaction, can be between several hundred and several thousand times more powerful than the test North Korea conducted.
This results in less energy waste and easier containment since protons are charged particles , which makes it easier to directly harvest energy from the fusion reaction by manipulating the protons with electric and magnetic fields.
The Nomad 7 Plus promises consistent 7 watt, 1.4 amp charging, thanks to a power regulator that helps smooth out the inconsistencies that come when you're charging with a nuclear fusion reaction 100 million miles away.
A thermonuclear bomb (also known as a hydrogen bomb) is a more advanced and powerful design, where a fission bomb ignites a second stage of fissionable material to induce a fusion reaction, resulting in a much larger explosion.
They spent 20 minutes discussing how much time, money and technology separated humanity from a sustainable fusion reaction — that is, how to produce clean energy by mimicking the sun's power — before Mr. Chase thought to ask the man his name.
The energy released during this fusion reaction will heat the liquid metal surrounding the plasma, and this heated liquid metal will be used to produce steam that turns turbines to generate electricity, just like in a normal nuclear fission power plant today.
Tri Alpha's design is based on colliding beam fusion, which basically means that the particles meant to undergo fusion are sent on a crash course in a particle accelerator at the ridiculously high speeds that will cause a fusion reaction to happen.
If this approach to creating fusion were to be used to create a fusion power plant, the shots that currently only occur once per day would not only have to occur in rapid succession around the clock, but the energy produced by the fusion reaction would have to be harvested and distributed.
All nuclear power plants use fission. No man-made fusion reaction has resulted in a viable source of electricity.
These more massive nuclei can not undergo an energy-producing fusion reaction that can sustain the hydrostatic equilibrium of a star.
According to the timeline deduced by the Gundam Officials, in UC 0071, Zeon researchers created the Minovsky ultracompact fusion reactor. Instead of the conventional magnetic field, this improved version of the Minovsky-Ionesco reactor used an I-field to confine and compress the reactor fuel, triggering a fusion reaction. The Minovsky particles produced as a byproduct of the helium-3 fusion reaction were recycled to keep that reaction going. The Minovsky particles that form the I-field lattice also helped catalyze the fusion reaction, in a process similar to the muon-catalyzed fusion investigated by real-world scientists during the 1950s.
The fusion reaction rate increases rapidly with temperature until it maximizes and then gradually drops off. The D–T rate peaks at a lower temperature (about 70 keV, or 800 million kelvins) and at a higher value than other reactions commonly considered for fusion energy. D–T (deuterium–tritium) fusion is the fusion reaction that produces the most energetic neutrons, with 14.1 MeV of kinetic energy and traveling at 17% of the speed of light. D–T fusion is also the easiest fusion reaction to ignite, reaching near-peak rates even when the deuterium and tritium nuclei have only a thousandth as much kinetic energy as the 14.1 MeV that will be produced.
Bootstrapping in inertial confinement fusion refers to the alpha particles produced in the fusion reaction providing further heating to the plasma. This heating leads to ignition and an overall energy gain.
This is many times more than what was needed to overcome the energy barrier. The fusion reaction rate increases rapidly with temperature until it maximizes and then gradually drops off. The DT rate peaks at a lower temperature (about 70 keV, or 800 million kelvin) and at a higher value than other reactions commonly considered for fusion energy. The reaction cross section (σ) is a measure of the probability of a fusion reaction as a function of the relative velocity of the two reactant nuclei.
A simplified summary of the above explanation is: # An implosion assembly type of fission bomb explodes. This is the primary stage. If a small amount of deuterium/tritium gas is placed inside the primary's core, it will be compressed during the explosion and a nuclear fusion reaction will occur; the released neutrons from this fusion reaction will induce further fission in the 239Pu or 235U used in the primary stage. The use of fusion fuel to enhance the efficiency of a fission reaction is called boosting.
This process becomes dominant at a temperature of about 17 million K, which is slightly higher than the core temperature of the Sun, but is less efficient than the Sun's proton-proton chain reaction fusion reaction. The CNO cycle is highly temperature sensitive, which results in a convection zone about the core that evenly distributes the 'ash' from the fusion reaction within the core region. The overlying atmosphere is in radiative equilibrium. This is in contrast to the Sun, which has a radiation zone centered on the core with an overlying convection zone.
The ARC design has several major departures from traditional tokamak-style reactors. The changes occur in the design of the reactor components, whilst making use of the same D–T (deuterium - tritium) fusion reaction as current-generation fusion devices.
Since these reactions involve the reactants and products of the primary fusion reaction, it would be difficult to further lower the neutron production by a significant fraction. A clever magnetic confinement scheme could in principle suppress the first reaction by extracting the alphas as soon as they are created, but then their energy would not be available to keep the plasma hot. The second reaction could in principle be suppressed relative to the desired fusion by removing the high energy tail of the ion distribution, but this would probably be prohibited by the power required to prevent the distribution from thermalizing. In addition to neutrons, large quantities of hard X-rays would be produced by bremsstrahlung, and 4, 12, and 16 MeV gamma rays will be produced by the fusion reaction :11B + p → 12C + γ + 16.0 MeV with a branching probability relative to the primary fusion reaction of about 10−4.
This force can take one of three forms: gravitation in stars, magnetic forces in magnetic confinement fusion reactors, or inertial as the fusion reaction may occur before the plasma starts to expand, so the plasma's inertia is keeping the material together.
Lithium-6–deuterium fusion reaction: an aneutronic fusion reaction, with energy released carried by alpha particles, not neutrons. Aneutronic fusion is any form of fusion power in which very little of the energy released is carried by neutrons. While the lowest-threshold nuclear fusion reactions release up to 80% of their energy in the form of neutrons, aneutronic reactions release energy in the form of charged particles, typically protons or alpha particles. Successful aneutronic fusion would greatly reduce problems associated with neutron radiation such as damaging ionizing radiation, neutron activation, and requirements for biological shielding, remote handling and safety.
After the project was effectively ended, the former project manager established a company which is called NSD-Fusion. To date, the highest neutron flux achieved by a fusor-like device has been 3 × 1011 neutrons per second with the deuterium-deuterium fusion reaction.
The D-T fusion reaction (between deuterium and tritium) has been investigated as a possible energy source, as it is currently the only fusion reaction with sufficient energy output for feasible implementation. In this scenario, enriched lithium-6 would be required to generate the necessary quantities of tritium. The abundance of lithium-6 is a potential limiting factor in this scenario, though other sources of lithium (such as seawater) may also be usable. Lithium-6 is one of only three stable isotopes with a spin of 1, the others being deuterium and nitrogen-14, and has the smallest nonzero nuclear electric quadrupole moment of any stable nucleus.
Considering the idea of the fission bomb theoretically settled—at least until more experimental data was available—the 1942 Berkeley conference then turned in a different direction. Edward Teller pushed for discussion of a more powerful bomb: the "super", now usually referred to as a "hydrogen bomb", which would use the explosive force of a detonating fission bomb to ignite a nuclear fusion reaction in deuterium and tritium.. Teller proposed scheme after scheme, but Bethe refused each one. The fusion idea was put aside to concentrate on producing fission bombs. Teller also raised the speculative possibility that an atomic bomb might "ignite" the atmosphere because of a hypothetical fusion reaction of nitrogen nuclei.
When they first fall into the center of the fusor, the ions will all have the same energy, but the velocity distribution will rapidly approach a Maxwell–Boltzmann distribution. This would occur through simple Coulomb collisions in a matter of milliseconds, but beam-beam instabilities will occur orders of magnitude faster still. In comparison, any given ion will require a few minutes before undergoing a fusion reaction, so that the monoenergetic picture of the fusor, at least for power production, is not appropriate. One consequence of the thermalization is that some of the ions will gain enough energy to leave the potential well, taking their energy with them, without having undergone a fusion reaction.
Greenpeace falsely claimed that nuclear fusion is unsafe and produces waste like nuclear fission. However, nuclear fusion does not produce nuclear waste nor is there a meltdown risk because the conditions required to sustain nuclear fusion mean that if there is a containment breach, the fusion reaction would simply halt.
The largest nuclear device ever tested by the U.S. (Castle Bravo) yielded because of an unexpectedly high involvement of lithium-7 in the fusion reaction; the preliminary prediction for the yield was from . The largest weapons deployed by the Soviet Union were also around (e.g., the SS-18 Mod. 3 warhead).
Helium-3 is also produced via beta decay of tritium, which in turn can be produced from deuterium, lithium, or boron. Even if a self- sustaining fusion reaction cannot be produced, it might be possible to use fusion to boost the efficiency of another propulsion system, such as a VASIMR engine.
In February 2005 the documentary series Horizon commissioned two leading sonoluminescence researchers, Seth Putterman, Seth Putterman personal page. and Kenneth S. Suslick, to reproduce Taleyarkhan's work. Using similar acoustic parameters, deuterated acetone, similar bubble nucleation, and a much more sophisticated neutron detection device, the researchers could find no evidence of a fusion reaction.
All current thermonuclear weapons use a fission bomb as a first stage to create the high temperatures and pressures necessary to start a fusion reaction between deuterium and tritium in a second stage. For many years, nuclear weapon designers have researched whether it is possible to create high enough temperatures and pressures inside a confined space to ignite a fusion reaction, without using fission. Pure fusion weapons offer the possibility of generating arbitrarily small nuclear yields because no critical mass of fissile fuel need be assembled for detonation, as with a conventional fission primary needed to spark a fusion explosion. There is also the advantage of reduced collateral damage stemming from fallout because these weapons would not create the highly radioactive byproducts associated with fission-type weapons.
Rihe Liu et al. optimized the 3’-puromycin oligonucleotide spacer. They reported that dA25 in combination with a Spacer 9 (Glen Research), and dAdCdCP at the 5’ terminus worked the best for the fusion reaction. They found that linkers longer than 40 nucleotides and shorter than 16 nucleotides showed greatly reduced efficiency of fusion formation.
The laser- generated proton beam produces a tenfold increase of boron fusion because protons and boron nuclei collide directly. Earlier methods used a solid boron target, "protected" by its electrons, which reduced the fusion rate. Experiments suggest a petawatt-scale laser pulse could launch an ‘avalanche’ fusion reaction. This possibility, however, remains highly controversial.
The hot fusion reaction using a uranium target was first reported at Dubna in 2000: : + → + x (x = 3, 4, 5, 6). They observed decays from 260Rf and 259Rf, and later for 259Rf. In 2006, as part of their program on the study of uranium targets in hot fusion reactions, the team at LBNL also observed 261Rf.
They were able to confirm both the decay data and cross sections for the fusion reaction. A 2016 experiment at RIKEN aimed at studying the 48Ca+248Cm reaction seemingly detected one atom that may be assigned to 294Lv alpha decaying to 290Fl and 286Cn, which underwent spontaneous fission; however, the first alpha from the livermorium nuclide produced was missed.
For fusion to occur the ions must be at a temperature of at least 4 keV (kiloelectronvolts), or about 45 million kelvins. The second easiest reaction is fusing deuterium with itself. Because this gas is cheaper, it is the fuel commonly used by amateurs. The ease of doing a fusion reaction is measured by its cross section.
In order to initiate a sustained fusion reaction, it is usually necessary to use many methods to heat the plasma. Neutral Beam Injection (NBI) involves injecting a high energy beam of neutral atoms, typically hydrogen or deuterium, into the core of the plasma. These energetic atoms transfer their energy to the plasma, raising the overall temperature. The neutral atoms injected don't remain neutral.
Gruen used ultra- sensitive ion measurement techniques for his research on nuclear fusion reactors. Plasma cloud containment remains a fundamental hurdle in fusion research. Dr. Gruen developed an approach of coating the cloud containment vessel walls with a self-removing copper/lithium compound. This enables the plasma cloud to remain contained longer, a key step toward eventually enabling a fusion reaction to occur.
The first human-made, large-scale fusion reaction was the test of the hydrogen bomb, Ivy Mike, in 1952. As part of the PACER project, it was once proposed to use hydrogen bombs as a source of power by detonating them in caverns and then generating electricity from the heat produced, but such a power station is unlikely ever to be constructed.
If the temperature gets high enough, nuclear fusion will ignite and form a protostar. The protostar is 'born' when it begins to emit enough radiative energy to balance out its gravity and halt gravitational collapse. Typically, a cloud of material remains a substantial distance from the star before the fusion reaction ignites. This remnant cloud is the protostar's protoplanetary disk, where planets may form.
Deuterium fusion, also called deuterium burning, is a nuclear fusion reaction that occurs in stars and some substellar objects, in which a deuterium nucleus and a proton combine to form a helium-3 nucleus. It occurs as the second stage of the proton–proton chain reaction, in which a deuterium nucleus formed from two protons fuses with another proton, but can also proceed from primordial deuterium.
Once Artsimovich was asked when the first thermonuclear reactor would start its work. He replied: "When mankind needs it, maybe a short time before that." Under his guidance a thermonuclear fusion reaction was produced in the laboratory for the first time. From 1963 to 1973 he was the vice-chairman of the Soviet Pugwash Committee and the chairman of the National Committee of Soviet Physicists.
There is an even higher-yield D– fusion reaction, though the breakeven point of D– is higher than that of most other fusion reactions; together with the scarcity of , this makes it implausible as a practical power source until at least D–T and D–D fusion reactions have been performed on a commercial scale. Commercial nuclear fusion is not yet an accomplished technology.
The fuel capsule wall is synthesized using light elements ( like plastic, beryllium, or high density carbon, i.e. diamond) . The outer portion of fuel capsule explodes outward when ablated by the x-rays produced by the hohlraum wall upon irradiation by lasers. Due to Newton's third law, the inner portion the fuel capsule implodes, causing the D-T fuel to be supercompressed activating fusion reaction.
The inherent danger of a conventional fission reactor is any situation leading to a positive feedback, runaway, chain reaction such as occurred during the Chernobyl disaster. In a hybrid configuration the fission and fusion reactions are decoupled, i.e. while the fusion neutron output drives the fission, the fission output has no effect whatsoever on the fusion reaction, completely eliminating any chance of a positive feedback loop.
When one of the scientists examining him says he heard Sartorius had died, the other replies: "From being crushed? Hardly. Everything human in Sartorius was consumed by fire long ago. We believe his powers manifested a fusion reaction that completely sublimated his central nervous system -- creating functional facsimiles of his heart, his lungs, his kidneys -- all working in concert to produce a near-endless supply of energy". Detective Comics #825.
Ultrasound when applied in specific configurations can produce short bursts of light in an exotic phenomenon known as sonoluminescence. This phenomenon is being investigated partly because of the possibility of bubble fusion (a nuclear fusion reaction hypothesized to occur during sonoluminescence). Ultrasound is used when characterizing particulates through the technique of ultrasound attenuation spectroscopy or by observing electroacoustic phenomena or by transcranial pulsed ultrasound. Audio can be propagated by modulated ultrasound.
There is evidence that the Tsar Bomba had several third stages rather than a single very large one. The initial three-stage design (coded A620EN, not tested) was capable of yielding approximately through fast fission, 3,000 times the size of the Hiroshima and Nagasaki bombs, but it was thought that it would have caused too much nuclear fallout and the aircraft delivering the bomb would not have had enough time to escape the explosion. To limit the amount of fallout, the third stage and possibly the second stage had a lead tamper instead of a uranium-238 fusion tamper (which greatly amplifies the fusion reaction by fissioning uranium atoms with fast neutrons from the fusion reaction). This eliminated fast fission by the fusion-stage neutrons so that approximately 97% of the total yield resulted from thermonuclear fusion alone (as such, it was one of the "cleanest" nuclear bombs ever created, generating a very low amount of fallout relative to its yield).
With considerable overlap between the two devices, the prompt radiation effects of a pure fusion weapon would similarly be much higher than that of a pure- fission device: approximately twice the initial radiation output of current standard fission-fusion-based weapons. In common with all neutron bombs that must presently derive a small percentage of trigger energy from fission, in any given yield a 100% pure fusion bomb would likewise generate a more diminutive atmospheric blast wave than a pure-fission bomb. The latter fission device has a higher kinetic energy-ratio per unit of reaction energy released, which is most notable in the comparison with the D-T fusion reaction. A larger percentage of the energy from a D-T fusion reaction, is inherently put into uncharged neutron generation as opposed to charged particles, such as the alpha particle of the D-T reaction, the primary species, that is most responsible for the coulomb explosion/fireball.
Plasma Rifles and Cannons - The main field energy weapon, capable of taking out powered armor. The plasma rifles utilize a magazine containing lithium-deuteride pellets and a power source to feed the laser compressors that initiate the fusion reaction that drives the weapon. Chameleon Suits - The standard issue marine uniform that allows the wearer to fade into the background. The suits also offer limited ballistic protection and can be configured for work in vacuum environments.
Plasma Rifles and Cannons - The main field energy weapon, capable of taking out powered armor. The plasma rifles utilize a magazine containing lithium- deuteride pellets and a power source to feed the laser compressors that initiate the fusion reaction that drives the weapon. Chameleon Suits - The standard issue marine uniform that allows the wearer to fade into the background. The suits also offer limited ballistic protection and can be configured for work in vacuum environments.
Phoenix Nuclear Labs developed a proprietary gas target neutron generator technology and has designed and built a number of particle accelerator-related technologies. It has the technology to produce 3×1011 neutrons per second with the deuterium-deuterium fusion reaction. This can be sustained for a 24-hour period. Their spin-off company, SHINE Medical Technologies plans to open a facility for the mass production of Mo-99, an isotope used for medical care.
The first cold fusion reaction to produce copernicium was performed by GSI in 1996, who reported the detection of two decay chains of copernicium-277. : + → + In a review of the data in 2000, the first decay chain was retracted. In a repeat of the reaction in 2000 they were able to synthesize a further atom. They attempted to measure the 1n excitation function in 2002 but suffered from a failure of the zinc-70 beam.
Teller proposed scheme after scheme, but Bethe rejected each one. The fusion idea was set aside to concentrate on producing fission bombs. Teller also raised the speculative possibility that an atomic bomb might "ignite" the atmosphere because of a hypothetical fusion reaction of nitrogen nuclei, but Bethe calculated that this could not happen, and a report co-authored with Teller showed that "no self-propagating chain of nuclear reactions is likely to be started".
Technical results presented on the T4 experiment in 2015 showed a cold, partially ionized plasma with the following parameters: peak electron temperature of 20 electron volts, electron density, less than 1% ionization fraction and of input power. No confinement or fusion reaction rates were presented. McGuire presented two theoretical reactor concepts in 2015. One was an ideal configuration weighing 200 metric tons with 1 meter of cryogenic radiation shielding and 15 tesla magnets.
Left to right: formation of bubble; slow expansion; quick and sudden contraction; purported fusion event. Bubble fusion is the non-technical name for a nuclear fusion reaction hypothesized to occur inside extraordinarily large collapsing gas bubbles created in a liquid during acoustic cavitation. The more technical name is sonofusion. The term was coined in 2002 with the release of a report by Rusi Taleyarkhan and collaborators that claimed to have observed evidence of sonofusion.
The A.D. Sakharov group constructed the first tokamaks, the most successful being the T-3 and its larger version T-4. T-4 was tested in 1968 in Novosibirsk, producing the world's first quasistationary fusion reaction.:90 When this was first announced, the international community was highly skeptical. A British team was invited to see T-3, however, and after measuring it in depth they released their results that confirmed the Soviet claims.
Type Ia supernovae, caused by a runaway nuclear fusion reaction in a white dwarf star, are thought to account for roughly one-third of all supernovae. There are currently seven neutrino detector members of SNEWS: Borexino, Daya Bay, KamLAND, HALO, IceCube, LVD, and Super-Kamiokande. SNEWS began operation prior to 2004, with three members (Super-Kamiokande, LVD, and SNO). The Sudbury Neutrino Observatory is no longer active as it is being upgraded to its successor program SNO+.
The most common reference to gravitational compression is stellar evolution. The Sun and other main-sequence stars are produced by the initial gravitational collapse of a molecular cloud. Assuming the mass of the material is large enough, gravitational compression reduces the size of the core, increasing its temperature until hydrogen fusion can begin. This hydrogen-to-helium fusion reaction releases energy that balances the inward gravitational pressure and the star becomes stable for millions of years.
No further gravitational compression occurs until the hydrogen is nearly used up, reducing the thermal pressure of the fusion reaction. At the end of the Sun's life, gravitational compression will turn it into a white dwarf. At the other end of the scale are massive stars. These stars burn their fuel very quickly, ending their lives as supernovae, after which further gravitational compression will produce either a neutron star or a black hole from the remnants.
Fusion ignition is the point at which a nuclear fusion reaction becomes self- sustaining. This occurs when the energy being given off by the fusion reactions heats the fuel mass more rapidly than various loss mechanisms cool it. At this point, the external energy needed to heat the fuel to fusion temperatures is no longer needed. As the rate of fusion varies with temperature, the point of ignition for any given machine is typically expressed as a temperature.
The synthesis of rutherfordium was first attempted in 1964 by the team at Dubna using the hot fusion reaction of neon-22 projectiles with plutonium-242 targets: : + → + 3 or 5 . The first study produced evidence for a spontaneous fission with a 0.3 second half-life and another one at 8 seconds. While the former observation was eventually retracted, the latter eventually became associated with the 259Rf isotope."Discovery of the transneptunium elements", IUPAC/IUPAP Technical Report, Pure Appl. Chem.
One of Farnsworth's most significant contributions at ITT was the PPI Projector, an enhancement on the iconic "circular sweep" radar display, which allowed safe air traffic control from the ground. This system developed in the 1950s was the forerunner of today's air traffic control systems. In addition to his electronics research, ITT management agreed to nominally fund Farnsworth's nuclear fusion research. He and staff members invented and refined a series of fusion reaction tubes called "fusors".
A graphic depiction of a nuclear fusion reaction. Two nuclei fuse into one, emitting a neutron. Reactions that created new elements to this moment were similar, with the only possible difference that several singular neutrons sometimes were released, or none at all. A superheavy atomic nucleus is created in a nuclear reaction that combines two other nuclei of unequal size into one; roughly, the more unequal the two nuclei in terms of mass, the greater the possibility that the two react.
Cross-section of part of the planned ITER fusion reaction vessel. The vacuum vessel is the central part of the ITER machine: a double walled steel container in which the plasma is contained by means of magnetic fields. The ITER vacuum vessel will be twice as large and 16 times as heavy as any previously manufactured fusion vessel: each of the nine torus-shaped sectors will weigh between 390 and 430 tonnes.ITER Vacuum Vessel Assembly – Call for Expression of Interest. ITER.
In 2008, Wilson achieved nuclear fusion using an inertial electrostatic confinement (IEC) device, which was a variation of the fusor, invented by Philo T. Farnsworth in 1964. He used the flux of neutrons from a deuterium-deuterium fusion reaction to conduct nuclear experiments, and studied novel fusion fuels inside the IEC device. In March 2012, Wilson spoke at a TED conference regarding the building of his fusion reactor. Along with the IEC reactors, Wilson has conducted fusion research using dense plasma focus devices.
Theory predicts, however, that the hydrogen isotope deuterium fuses with hydrogen-1, creating helium-3. The heat from this fusion reaction tends to inflate the protostar, and thereby helps determine the size of the youngest observed pre- main-sequence stars. The energy generated from ordinary stars comes from the nuclear fusion occurring at their centers. Protostars also generate energy, but it comes from the radiation liberated at the shocks on its surface and on the surface of its surrounding disk.
When fuel is injected into a fusion reactor, powerful "rogue" waves might be created that can cause it to escape confinement. These waves can reduce the efficiency or even stop the fusion reaction. Mathematical models can determine the likelihood of a rogue wave and to calculate the exact angle of a counter- wave to cancel it out. Magnetic islands are anomalies where magnetic field lines separate from the rest of the field and form a tube, allowing fuel to escape.
The physicists at Aldermaston had plenty of ideas about how to follow up Grapple X. Possibilities were discussed in September 1957. One was to tinker with the width of the shells in the Dick to find an optimal configuration. If they were too thick, they would slow the neutrons generated by the fusion reaction; if they were too thin, they would give rise to Taylor instability. Another was to do away with the shells entirely and use a mixture of uranium-235, uranium-238 and deuterium.
Bead Rifles and Cannons - Projectile weapons that fire five- millimeter steel-coated, glass- or tungsten-cored beads "accelerated to phenomenal speeds" via electromagnetic lining in the weapon's barrel. Plasma Rifles and Cannons - The main field energy weapon, capable of taking out powered armor. The plasma rifles utilize a magazine containing lithium- deuteride pellets and a power source to feed the laser compressors that initiate the fusion reaction that drives the weapon. Chameleon Suits - The standard issue marine uniform that allows the wearer to fade into the background.
Lithium deuteride was the fusion fuel of choice in early versions of the hydrogen bomb. When bombarded by neutrons, both 6Li and 7Li produce tritium — this reaction, which was not fully understood when hydrogen bombs were first tested, was responsible for the runaway yield of the Castle Bravo nuclear test. Tritium fuses with deuterium in a fusion reaction that is relatively easy to achieve. Although details remain secret, lithium-6 deuteride apparently still plays a role in modern nuclear weapons as a fusion material.
In 1977, the team at Oak Ridge repeated the experiment and were able to confirm the discovery by the identification of K X-rays from the daughter lawrencium. ;254Es(13C,xn)267−xDb In 1988, scientists as the Lawrence Livermore National Laboratory (LLNL) used the asymmetric hot fusion reaction with an einsteinium-254 target to search for the new nuclides 264Db and 263Db. Due to the low sensitivity of the experiment caused by the small Es-254 target, they were unable to detect any evaporation residues (ER).
One of the biggest problems in fusion research is to keep the hot fuel from hitting the walls of the container. If this is allowed to happen, the fuel cannot be kept hot enough for the fusion reaction to occur. Farnsworth reasoned that he could build an electrostatic plasma confinement system in which the "wall" fields of the reactor were electrons or ions being held in place by the multipactor. Fuel could then be injected through the wall, and once inside it would be unable to escape.
T-4 was tested in 1968 in Novosibirsk, conducting the first quasistationary thermonuclear fusion reaction ever.Great Soviet Encyclopedia, 3rd edition, entry on "Токамак", available online here In the 1980s Kurchatov Institute employees and computer engineers played a very important role in establishing computer culture through participating in the development of the DEMOS operating system. It led to the spread of the internet in Russia and contributed to the dissolution of the Soviet Union. Until 1991, the Ministry of Atomic Energy oversaw the Kurchatov Institute's administration.
For a core primarily composed of oxygen, neon and magnesium, the collapsing white dwarf is likely to form a neutron star. In this case, only a fraction of star's mass will be ejected as a result. If the core is instead made of carbon-oxygen, however, increasing pressure and temperature will initiate carbon fusion in the center prior to attainment of the Chandrasekhar limit. The dramatic result is a runaway nuclear fusion reaction that consumes a substantial fraction of the star within a short time.
A city on Mars named Port Lowell is also mentioned by Clarke in his 1955 short story "Refugee" and The Lost Worlds of 2001. The transformation of Phobos into a second sun has similarities to what is done to Jupiter in Clarke's novel 2010: Odyssey Two. In that case, alien technology triggers a fusion reaction in the planet, which is largely hydrogen. In the case of Phobos - tiny and mostly rock - Clarke proposes an imaginary "meson resonance reaction"Chapter fifteen that has recently been discovered.
Nuclear fusion occurs when the nuclei of two atoms approach closely enough for the nuclear force to pull them together into a single larger nucleus. The strong force is opposed by the electrostatic force created by the positive charge of the nuclei's protons, pushing the nuclei apart. The amount of energy that is needed to overcome this repulsion is known as the Coulomb barrier. The amount of energy released by the fusion reaction when it occurs may be greater or less than the Coulomb barrier.
Initially the Valkyrie's engine would work by using small quantities of antimatter to initiate an extremely energetic fusion reaction. A magnetic coil captures the exhaust products of this reaction, expelling them with an exhaust velocity of 12-20% the speed of light (35,000-60,000 km/s). As the spacecraft approaches 20% the speed of light, more antimatter is fed into the engines until it switches over to pure matter-antimatter annihilation. It will use this mode to accelerate the remainder of the way to .
Traditional staged thermonuclear weapons consist of two parts, a fission "primary" and a fusion/fission "secondary". The energy released by the primary when it explodes is used to (indirectly) compress the secondary and start a fusion reaction within it. Conventional explosives are far too weak to provide the level of compression needed. The primary is generally built as small as possible, due to the fact that the energy released by the secondary is much larger, and thus building a larger primary is generally inefficient.
The fusion reaction of stars is strongly dependent upon temperature. For proton-proton reactions such as found in Earth's sun, the reaction rate scales with the fourth power of temperature (T4). For other reactions such as the CNO cycle, the proportionality can be as high as T20. Thus, increasing the temperature of the star even a small amount (for example by using reflective solar sails), would create a large increase in power output, resulting in a much higher equilibrium temperature, and therefore luminosity, of the star.
Consequently, the deuterium-tritium fuel cycle requires the breeding of tritium from lithium using one of the following reactions: : + → + : + → + + The reactant neutron is supplied by the D-T fusion reaction shown above, and the one that has the greatest yield of energy. The reaction with 6Li is exothermic, providing a small energy gain for the reactor. The reaction with 7Li is endothermic but does not consume the neutron. At least some neutron multiplication reactions are required to replace the neutrons lost to absorption by other elements.
Quantum tunneling is essential for nuclear fusion in stars. The temperature in stars' cores is generally insufficient to allow atomic nuclei to overcome the Coulomb barrier and achieve Thermonuclear fusion. Quantum tunneling increases the probability of penetrating this barrier. Though this probability is still low, the extremely large number of nuclei in the core of a star is sufficient to sustain a steady fusion reaction for millions, billions, or even trillions of years – a precondition for the evolution of life in insolation habitable zones.
In 1954, Chen worked at the Princeton Plasma Physics Laboratory (PPPL), where he worked initially with the Model B1 Stellarator, a device used to confine hot plasma with magnetic fields in order to sustain a controlled nuclear fusion reaction. With the B1 Stellarator, Chen was the first to show that electrons could be trapped by a magnetic field for millions of traverses. Chen remained at PPPL until 1969. In 1969, Chen became a professor of electrical engineering at the University of California, Los Angeles.
This is a hybrid approach in which antiprotons are used to catalyze a fission/fusion reaction or to "spike" the propulsion of a fusion rocket or any similar applications. The antiproton-driven Inertial confinement fusion (ICF) Rocket concept uses pellets for the D-T reaction. The pellet consists of a hemisphere of fissionable material such as U235 with a hole through which a pulse of antiprotons and positrons is injected. It is surrounded by a hemisphere of fusion fuel, for example deuterium-tritium, or lithium deuteride.
F. Winterberg, Z. f. Naturforsch. 19a, 231 (1964) And in 1968, he proposed to use intense electron and ion beams, generated by Marx generators, for the same purpose.F. Winterberg, Phys. Rev. 174, 212 (1968) The advantage of this proposal is that the generation of charged particle beams is not only less expensive than the generation of laser beams but also can entrap the charged fusion reaction products due to the strong self-magnetic beam field, drastically reducing the compression requirements for beam ignited cylindrical targets.
In September 2007, the BBC News reported that there was speculation about the possibility of using positronium annihilation to drive a very powerful gamma ray laser. Dr. David Cassidy of the University of California, Riverside proposed that a single such laser could be used to ignite a nuclear fusion reaction, replacing the banks of hundreds of lasers currently employed in inertial confinement fusion experiments. Space-based X-ray lasers pumped by a nuclear explosion have also been proposed as antimissile weapons. Such devices would be one-shot weapons.
Chemists at the Los Alamos Laboratory developed methods of purifying uranium and plutonium, the latter a metal that only existed in microscopic quantities when Project Y began. Its metallurgists found that plutonium had unexpected properties, but were nonetheless able to cast it into metal spheres. The laboratory built the Water Boiler, an aqueous homogeneous reactor that was the third reactor in the world to become operational. It also researched the Super, a hydrogen bomb that would use a fission bomb to ignite a nuclear fusion reaction in deuterium and tritium.
Physics professor and director of the UK's national Fusion laboratory Steven Cowley called for more data, pointing out that the current thinking in fusion research is that "bigger is better". According to Cowley, experience building other fusion reactors suggests that when machine size is doubled one achieves 8 times improvement in heat confinement, that is how much of the extremely high temperatures needed for the fusion reaction can be contained without eg. heating the cooled superconducting magnets too much. Saying so Cowley questions the suggested small size of a working machine.
In March 2006, Nature published a special report that called into question the validity of the results of the Purdue experiments. The report quotes Brian Naranjo of the University of California, Los Angeles to the effect that neutron energy spectrum reported in the 2006 paper by Taleyarkhan, et al. was statistically inconsistent with neutrons produced by the proposed fusion reaction and instead highly consistent with neutrons produced by the radioactive decay of Californium 252, an isotope commonly used as a laboratory neutron source . The response of Taleyarkhan et al.
The lab was the co-discoverer of new superheavy elements 113, 114, 115, 116, 117, and 118. The chemical element with atomic number 116 was given the name livermorium, after the laboratory, in 2012. LLNL is the location of the world's highest-energy laser, the National Ignition Facility (NIF), a project designed to create the first sustained, controlled nuclear fusion reaction, which would generate fusion power, a potential energy source. Livermore is also the California site of Sandia National Laboratories, which is managed and operated by a subsidiary of Honeywell International.
Most modern nuclear weapons utilize 238U as a "tamper" material (see nuclear weapon design). A tamper which surrounds a fissile core works to reflect neutrons and to add inertia to the compression of the 239Pu charge. As such, it increases the efficiency of the weapon and reduces the critical mass required. In the case of a thermonuclear weapon, 238U can be used to encase the fusion fuel, the high flux of very energetic neutrons from the resulting fusion reaction causes 238U nuclei to split and adds more energy to the "yield" of the weapon.
In the distant future, the advancement of science has exceeded humanity's ability to control it. During a subatomic experiment, an accident causes an uncontrollable fusion reaction, utterly destroying the surface of the planet Earth. One year later, Earth has been classified as "condemned" by the ruling imperial theocracy, meaning that it is now legal for anyone to salvage anything left on the planet. Mercenaries from all over come to raid the dead planet, forced to battle not only each other, but the robot sentinels that the government has left behind.
The pressure waves would converge to become a spherical shockwave at the center of the sphere. This approach created excessively strong magnetic fields, which caused instabilities in the liquid metal wall. As of October 2017, the approach was to use slower pistons and compression time of for lower peak energy densities. In addition to its role in compressing the plasma, the use of a liquid metal liner shields the power plant structure from neutrons released by the deuterium-tritium fusion reaction, overcoming the problem of structural damage to plasma-facing materials.
In all of these machines, the density of the particles in the plasma is very low, often described as a "poor vacuum". This limits its approach to the triple product along the temperature and time axis. This requires magnetic fields on the order of tens of Teslas, currents in the megaampere, and confinement times on the order of tens of seconds."Conditions for a fusion reaction" , JET Generating currents of this magnitude is relatively simple, and a number of devices from large banks of capacitors to homopolar generators have been used.
Plasma Physics Group Leader Dr. Siegfried Glenzer said they've shown they can maintain the precise fuel layers needed in the lab, but not yet within the laser system. As of January 2010, the NIF could run as high as 1.8 megajoules. Glenzer said that experiments with slightly larger hohlraums containing fusion-ready fuel pellets would begin before May 2010, slowly ramping up to 1.2 megajoules—enough for ignition according to calculations. But first the target chamber needed to be equipped with shields to block neutrons that a fusion reaction would produce.
In these devices, the energy released by the fission explosion is used to compress and heat fusion fuel, starting a fusion reaction. Fusion releases neutrons. These neutrons hit the surrounding fission fuel, causing the atoms to split apart much faster than normal fission processes—almost instantly by comparison. This increases the effectiveness of bombs: normal fission weapons blow themselves apart before all their fuel is used; fusion/fission weapons do not have this practical upper limit. In 1949 an expatriate German, Ronald Richter, proposed the Huemul Project in Argentina, announcing positive results in 1951.
In these systems, the power output is enhanced by the fission events, and power is extracted using systems like those in conventional fission reactors. Designs that use other fuels, notably the p-B reaction, release much more of their energy in the form of charged particles. In these cases, alternate power extraction systems based on the movement of these charges are possible. Direct energy conversion was developed at Lawrence Livermore National Laboratory (LLNL) in the 1980s as a method to maintain a voltage using the fusion reaction products.
Stars like the Sun are powered by the fusion of four protons into a helium nucleus, two positrons, and two neutrinos. The uncontrolled fusion of hydrogen into helium is known as thermonuclear runaway. A frontier in current research at various institutions, for example the Joint European Torus (JET) and ITER, is the development of an economically viable method of using energy from a controlled fusion reaction. Nuclear fusion is the origin of the energy (including in the form of light and other electromagnetic radiation) produced by the core of all stars including our own Sun.
In May 2010, North Korea's state newspaper, Rodong Sinmun, announced in an article that North Korea had successfully carried out a nuclear fusion reaction. The aforementioned article, referring to the alleged test as "a great event that demonstrated the rapidly developing cutting-edge science and technology of the DPRK", also made mention of efforts by North Korean scientists to develop "safe and environment-friendly new energy", and made no mention of plans to use fusion technology in its nuclear weapons program."North Korea claims nuclear fusion success". AFP via The Australian.
Temperature is a measure of the average kinetic energy of particles, so by heating the material it will gain energy. After reaching sufficient temperature, given by the Lawson criterion, the energy of accidental collisions within the plasma is high enough to overcome the Coulomb barrier and the particles may fuse together. In a deuterium–tritium fusion reaction, for example, the energy necessary to overcome the Coulomb barrier is 0.1 MeV. Converting between energy and temperature shows that the 0.1 MeV barrier would be overcome at a temperature in excess of 1.2 billion kelvins.
This reaction produces tritium and helium-4, and another slow neutron. Li-6 can react with high or low energy neutrons, including those released by the Li-7 reaction. This means that a single fusion reaction can produce several tritiums, which is a requirement if the reactor is going to make up for natural decay and losses in the fusion processes. When the lithium blanket is replaced, or supplanted, by fission fuel in the hybrid design, neutrons that do react with the fissile material are no longer available for tritium breeding.
Radioactive rubidium beams can be produced since 2015 at CERN's HIE-ISOLDE apparatus with sufficient intensity to consider the production of element 120 in the reaction of rubidium beams with a bismuth-209 target in a cold fusion reaction. In particular, the use of 95Rb would allow the neutron shell at N = 184 to be reached. The laboratories at RIKEN in Japan and at the JINR in Russia are best suited to these experiments as they are the only ones in the world where long beam times are accessible for reactions with such low predicted cross sections.
Before the first successful synthesis of hassium in 1981 by the GSI team, the synthesis of bohrium was first attempted in 1976 by scientists at the Joint Institute for Nuclear Research at Dubna using this cold fusion reaction. They detected two spontaneous fission activities, one with a half-life of 1–2 ms and one with a half-life of 5 s. Based on the results of other cold fusion reactions, they concluded that they were due to 261Bh and 257Db respectively. However, later evidence gave a much lower SF branching for 261Bh reducing confidence in this assignment.
The combination of reduced weight in relation to yield and immunity to radiation has ensured that most modern nuclear weapons are fusion-boosted. The fusion reaction rate typically becomes significant at 20 to 30 megakelvins. This temperature is reached at very low efficiencies, when less than 1% of the fissile material has fissioned (corresponding to a yield in the range of hundreds of tons of TNT). Since implosion weapons can be designed that will achieve yields in this range even if neutrons are present at the moment of criticality, fusion boosting allows the manufacture of efficient weapons that are immune to predetonation.
Figure 7: Plot of the cross section of different fusion reactions. Nuclear fusion refers to nuclear reactions that combine lighter nuclei to become heavier nuclei. All chemical elements can be fused; for elements with fewer protons than iron, this process changes mass into energy that can potentially be captured to provide fusion power. The probability of a fusion reaction occurring is controlled by the cross section of the fuel,"Development of the indirect drive approach to inertial confinement fusion and the target physics basis for ignition and gain" John Lindl, Physics of Plasma, 1995 which is in turn a function of its temperature.
It has been proposed that energy may be extracted from polywells using heat capture or, in the case of aneutronic fusion like D-3He or p-11B, direct energy conversion, though that scheme faces challenges. The energetic alpha particles (up to a few MeV) generated by the aneutronic fusion reaction would exit the MaGrid through the six axial cusps as cones (spread ion beams). Direct conversion collectors inside the vacuum chamber would convert the alpha particles' kinetic energy to a high-voltage direct current. The alpha particles must slow down before they contact the collector plates to realize high conversion efficiency.
Natural uranium nails, lined to the top of their head with copper, attached the radiation case to the ballistic case. The nails were bolted in vertical arrays in a double-shear configuration to better distribute the shear loads. This method of attaching the radiation case to the ballistic case was first used successfully in the Ivy Mike device. The radiation case had a parabolic end, which housed the COBRA primary that was employed to create the conditions needed to start the fusion reaction, and its other end was a cylinder, as also seen in Bravo's declassified film.
Unlike Daedalus, which used an open-cycle fusion engine, Longshot would use a long-lived nuclear fission reactor for power. Initially generating 300 kilowatts, the reactor would power a number of lasers in the engine that would be used to ignite inertial confinement fusion similar to that in Daedalus. The main design difference is that Daedalus also relied on the fusion reaction to power the ship, whereas in the Longshot design the internal reactor would provide this power. The reactor would also be used to power a laser for communications back to Earth, with a maximum power of 250 kW.
Andrei Yegorovich Durnovtsev (; 14 January 1923 - 24 October 1976) was a pilot of the Soviet Air Force. He dropped the Tsar Bomba on 30 October 1961 at Cape Sukhoi Nos, from Mityushikha Bay, north of Matochkin Strait. The tests were monitored by a government commission headed by Marshal of the Soviet Union Kirill Moskalenko. He flew a specially modified Tu-95V which utilized special white paint to reflect the enormous amount of heat radiation given off by the Tsar Bomba's fusion reaction; the release plane was accompanied by a Tu-16 observer plane that took air samples and filmed the test.
Along with Stanislaw Ulam, he calculated that not only would the amount of tritium needed for Teller's model of a thermonuclear weapon be prohibitive, but a fusion reaction could still not be assured to propagate even with this large quantity of tritium. Fermi was among the scientists who testified on Oppenheimer's behalf at the Oppenheimer security hearing in 1954 that resulted in denial of Oppenheimer's security clearance. In his later years, Fermi continued teaching at the University of Chicago. His PhD students in the postwar period included Owen Chamberlain, Geoffrey Chew, Jerome Friedman, Marvin Goldberger, Tsung-Dao Lee, Arthur Rosenfeld and Sam Treiman.
In order to ensure that a proton has a chance to collide with a boron, it has to travel past a number of boron atoms. The rate of collisions is: where is the nuclear cross section between a proton and boron, is the density of boron, and is the average distance the proton travels through the boron before undergoing a fusion reaction. For p-B11, is 0.9 x 10−24 cm−2, is 2.535 g/cm3, and thus ~ 8 cm. However, travelling through the block causes the proton to ionize the boron atoms it passes, which slows the proton.
A third confinement principle is to apply a rapid pulse of energy to a large part of the surface of a pellet of fusion fuel, causing it to simultaneously "implode" and heat to very high pressure and temperature. If the fuel is dense enough and hot enough, the fusion reaction rate will be high enough to burn a significant fraction of the fuel before it has dissipated. To achieve these extreme conditions, the initially cold fuel must be explosively compressed. Inertial confinement is used in the hydrogen bomb, where the driver is x-rays created by a fission bomb.
The 3He-D reaction has been studied as an alternative fusion plasma because it is the fuel with the lowest energy threshold for aneutronic fusion reaction. The proton-lithium-6, helium-3-lithium, and helium-3-helium-3 reaction rates are not particularly high in a thermal plasma. When treated as a chain, however, they offer the possibility of enhanced reactivity due to a non-thermal distribution. The product 3He from the Proton-lithium-6 reaction could participate in the second reaction before thermalizing, and the product p from helium-3-lithium could participate in the former before thermalizing.
The deuterium-tritium fusion reaction generates mono-energetic neutrons with an energy of 14.1 MeV. In fusion power plants, neutrons will be present at fluxes in the order of 1018 m−2s−1 and will interact with the material structures of the reactor by which their spectrum will be broadened and softened. A fusion relevant neutron source is an indispensable step towards the successful development of fusion energy. Safe design, construction and licensing of a fusion power facility by the corresponding Nuclear Regulatory agency will require data on the plasma- facing materials degradation under neutron irradiation during the life-time of a fusion reactor.
Some of the world's most powerful and complex arrangements of multiple lasers and optical amplifiers are used to produce extremely high intensity pulses of light of extremely short duration, e.g. laboratory for laser energetics, National Ignition Facility, GEKKO XII, Nike laser, Laser Mégajoule, HiPER. These pulses are arranged such that they impact pellets of tritium-deuterium simultaneously from all directions, hoping that the squeezing effect of the impacts will induce atomic fusion in the pellets. This technique, known as "inertial confinement fusion", so far has not been able to achieve "breakeven", that is, so far the fusion reaction generates less power than is used to power the lasers, but research continues.
In an implosion-type nuclear weapon design, a sphere of plutonium, uranium, or other fissile material is imploded by a spherical arrangement of explosive charges. This decreases the material's volume and thus increases its density by a factor of two to three, causing it to reach critical mass and create a nuclear explosion. In some forms of thermonuclear weapons, the energy from this explosion is then used to implode a capsule of fusion fuel before igniting it, causing a fusion reaction (see Teller–Ulam design). In general, the use of radiation to implode something, as in a hydrogen bomb or in laser driven inertial confinement fusion, is known as radiation implosion.
As a member of Oak Ridge's Nuclear Materials Processing Group, she is part of the research and development staff, working with "super heavy" transuranic isotopes that are produced mainly by nuclear transmutation. She is also a member of the Medical, Industrial and Research Isotopes Group, where she researches elements such as actinium, lanthanum, europium, and samarium. Phelps was involved in the discovery of the second-heaviest known element, tennessine (element 117). She was part of a three-month process to purify 22 mg of berkelium-249, which was shipped to the Joint Institute for Nuclear Research and combined with calcium-48 in a fusion reaction to create tennessine.
In the subsequent expansion the plasma energy and the fusion energy carried by trapped alpha particles is directly recovered, making the mechanical cycle self-sustaining. The LINUS reactor can thus be regarded as a fusion engine, except that there is no shaft output: all the energy appears as heat. The liquid metal acts as both a compression mechanism and heat transfer mechanism, allowing the energy from the fusion reaction to be captured as heat. LINUS researchers anticipated that the liner could also be used to breed tritium fuel for the power plant, and would protect the machine from high-energy neutrons by acting as a regenerative first wall.
The natural product of the fusion reaction is a small amount of helium, which is completely harmless to life. Of more concern is tritium, which, like other isotopes of hydrogen, is difficult to retain completely. During normal operation, some amount of tritium will be continually released. Although tritium is volatile and biologically active, the health risk posed by a release is much lower than that of most radioactive contaminants, because of tritium's short half-life (12.32 years) and very low decay energy (~14.95 keV), and because it does not bioaccumulate (instead being cycled out of the body as water, with a biological half-life of 7 to 14 days).
In the Teller-Ulam design, which accounts for all multi-megaton yield hydrogen bombs, this is accomplished by placing a fission bomb and fusion fuel (tritium, deuterium, or lithium deuteride) in proximity within a special, radiation-reflecting container. When the fission bomb is detonated, gamma rays and X-rays emitted first compress the fusion fuel, then heat it to thermonuclear temperatures. The ensuing fusion reaction creates enormous numbers of high-speed neutrons, which can then induce fission in materials not normally prone to it, such as depleted uranium. Each of these components is known as a "stage", with the fission bomb as the "primary" and the fusion capsule as the "secondary".
In 1997, scientists at the Joint European Torus (JET) facilities in the UK produced 16 megawatts of fusion power. Scientists can now exercise a measure of control over plasma turbulence and resultant energy leakage, long considered an unavoidable and intractable feature of plasmas. There is increased optimism that the plasma pressure above which the plasma disassembles can now be made large enough to sustain a fusion reaction rate acceptable for a power plant. Electromagnetic waves can be injected and steered to manipulate the paths of plasma particles and then to produce the large electrical currents necessary to produce the magnetic fields to confine the plasma.
The technical problem was figuring out a way to get a fusion reaction to initiate and propagate, which required temperatures attainable only with a fission bomb. The hydrodynamic calculations involved were daunting, and ENIAC was used to run a computer simulation of the Super in December 1945 and January 1946. The Polish mathematician Stanislaw Ulam, his wife Francoise Ulam, who performed the calculations, and their collaborator, Cornelius Everett, worked on the Super design through 1949. There was no push from the military for the weapon, because the AEC regarded it as too secret to inform either its own Military Liaison Committee or the Armed Forces Special Weapons Project about it.
A Piece of the Sun: The Quest for Fusion EnergyHIGH PERFORMANCE EXPERIMENTS IN JT-60U REVERSED SHEAR DISCHARGES A self-sustaining nuclear fusion reaction would need a value of Q that is greater than 5. In 2005, ferritic steel (ferromagnet) tiles were installed in the vacuum vessel to correct the magnetic field structure and hence reduce the loss of fast ions.ferromagnet diagrams On May 9, 2006, the JAEA announced that the JT-60 had achieved a 28.6 second plasma duration time. The JAEA used new parts in the JT-60, having improved its capability to hold the plasma in its powerful toroidal magnetic field.
Nuclei are positively charged, and thus repel each other due to the electrostatic force. Overcoming this repulsion costs a considerable amount of energy, which is known as the Coulomb barrier or fusion barrier energy. Generally, less energy will be needed to cause lighter nuclei to fuse, as they have less charge and thus a lower barrier energy, and when they do fuse, more energy will be released. As the mass of the nuclei increase, there is a point where the reaction no longer gives off net energy—the energy needed to overcome the energy barrier is greater than the energy released in the resulting fusion reaction.
Theoretical astrophysicist Ethan Siegel and nuclear physicist Peter Thieberger have pointed out that the claims for the E-Cat are incompatible with the fundamentals of nuclear physics.Ethan Siegel, 2011-12-05, The Physics of why the E-Cat's Cold Fusion Claims Collapse Jennifer Ouellette, Could starships use cold fusion propulsion? // HowStuffWorks, () In particular, the Coulomb barrier for the claimed fusion reaction is so high that it is insurmountable anywhere in the known universe, including the interior of stars. The reaction also would create gamma radiation that would have penetrated the few inches of shielding apparently provided by the E-Cat, inducing acute radiation syndrome in persons in the vicinity of the purported demonstrations.
No single-stage U.S. version was tested, but the Union shot of Operation Castle, April 26, 1954, was a two- stage thermonuclear device code-named Alarm Clock. Its yield, at Bikini, was 6.9 megatons. Because the Soviet Sloika test used dry lithium-6 deuteride eight months before the first U.S. test to use it (Castle Bravo, March 1, 1954), it was sometimes claimed that the USSR won the H-bomb race, even though the United States tested and developed the first hydrogen bomb: the Ivy Mike H-bomb test. The 1952 U.S. Ivy Mike test used cryogenically cooled liquid deuterium as the fusion fuel in the secondary, and employed the D-D fusion reaction.
The Soviet team had been working on the RDS-6T concept, but it also proved to be a dead end. In 1954, Sakharov worked on a third concept, a two-stage thermonuclear bomb. The third idea used the radiation wave of a fission bomb, not simply heat and compression, to ignite the fusion reaction, and paralleled the discovery made by Ulam and Teller. Unlike the RDS-6S boosted bomb, which placed the fusion fuel inside the primary A-bomb trigger, the thermonuclear super placed the fusion fuel in a secondary structure a small distance from the A-bomb trigger, where it was compressed and ignited by the A-bomb's x-ray radiation.
In the later, the neutrons given off by the fusion reactions are used to cause fission reactions in a surrounding blanket of uranium or other nuclear fuel, and those fission events are responsible for most of the energy release. In both cases, conventional steam turbine systems are used to extract the heat and produce electricity. Construction on NIF completed in 2009 and it began a lengthy series of run-up tests to bring it to full power. Through 2011 and into 2012, NIF ran the "national ignition campaign" to reach the point at which the fusion reaction becomes self-sustaining, a key goal that is a basic requirement of any practical IFE system.
For every volt that an ion of ±1 charge is accelerated across it gains 1 electronvolt in energy, similar to heating a material by 11,604 kelvins in temperature . After being accelerated by 15 kV a singly-charged ion has a kinetic energy of 15 keV, similar to the average kinetic energy at a temperature of approximately 174 megakelvins, a typical magnetic confinement fusion plasma temperature. Because most of the ions fall into the wires of the cage, fusors suffer from high conduction losses. On a bench top, these losses can be at least five orders of magnitude higher than the energy released from the fusion reaction, even when the fusor is in star mode.
If they were too thick, they would slow the neutrons generated by the fusion reaction; if they were too thin, they would give rise to Taylor instability. Another was to do away with the shells entirely and use a mixture of uranium-235, uranium-238 and deuterium. Ken Allen had an idea, which Sam Curran supported, of a three-layer Dick that used lithium deuteride that was less enriched in lithium-6 (and therefore had more lithium-7), but more of it, reducing the amount of uranium-235 in the centre of the core. This proposal was the one adopted in October, and it became known as "Dickens" because it used Ken's Dick.
A cobalt bomb could be made by placing a quantity of ordinary cobalt metal (59Co) around a thermonuclear bomb. When the bomb explodes, the neutrons produced by the fusion reaction in the secondary stage of the thermonuclear bomb's explosion would transmute the cobalt to the radioactive cobalt-60, which would be vaporized by the explosion. The cobalt would then condense and fall back to Earth with the dust and debris from the explosion, contaminating the ground. The deposited cobalt-60 would have a half-life of 5.27 years, decaying into 60Ni and emitting two gamma rays with energies of 1.17 and 1.33 MeV, hence the overall nuclear equation of the reaction is: \+ n → → + e− \+ gamma rays.
The craft was to be powered by nuclear fusion, using laser beams to produce pulses of nuclear energy in a generator in the centre of the craft, at a rate of over 1000 Hz to prevent resonance, which could damage the vehicle. The pulses of energy would then have been transferred out of a nozzle into a series of radial electrodes running along the underside of the craft, which would have converted the energy into electricity that would then pass into a ring of powerful electromagnets (the patent describes using superconductors if possible). These magnets would accelerate subatomic particles emitted by the fusion reaction, providing lift and thrust. This general design was used in several fusion rocket studies.
The fusion process alone currently does not achieve sufficient gain (power output over power input) to be viable as a power source. By using the excess neutrons from the fusion reaction to in turn cause a high-yield fission reaction (close to 100%) in the surrounding subcritical fissionable blanket, the net yield from the hybrid fusion–fission process can provide a targeted gain of 100 to 300 times the input energy (an increase by a factor of three or four over fusion alone). Even allowing for high inefficiencies on the input side (i.e. low laser efficiency in ICF and Bremsstrahlung losses in Tokamak designs), this can still yield sufficient heat output for economical electric power generation.
Hybrid nuclear fusion–fission (hybrid nuclear power) is a proposed means of generating power by use of a combination of nuclear fusion and fission processes. The basic idea is to use high-energy fast neutrons from a fusion reactor to trigger fission in nonfissile fuels like U-238 or Th-232. Each neutron can trigger several fission events, multiplying the energy released by each fusion reaction hundreds of times, but there is no self-sustaining chain reaction from fission. This would not only make fusion designs more economical in power terms, but also be able to burn fuels that were not suitable for use in conventional fission plants, even their nuclear waste.
Beyond the inner wall of the containment vessel one of several test blanket modules will be placed. These are designed to slow and absorb neutrons in a reliable and efficient manner, limiting damage to the rest of the structure, and breeding tritium for fuel from lithium-bearing ceramic pebbles contained within the blanket module following the following reactions: : + → + : + → + + where the reactant neutron is supplied by the D-T fusion reaction. Energy absorbed from the fast neutrons is extracted and passed into the primary coolant. This heat energy would then be used to power an electricity-generating turbine in a real power station; in ITER this generating system is not of scientific interest, so instead the heat will be extracted and disposed of.
In his 1995 book Dark Sun: The Making of the Hydrogen Bomb, author Richard Rhodes describes in detail the internal components of the "Ivy Mike" Sausage device, based on information obtained from extensive interviews with the scientists and engineers who assembled it. According to Rhodes, the actual mechanism for the compression of the secondary was a combination of the radiation pressure, foam plasma pressure, and tamper- pusher ablation theories described above; the radiation from the primary heated the polyethylene foam lining the casing to a plasma, which then re- radiated radiation into the secondary's pusher, causing its surface to ablate and driving it inwards, compressing the secondary, igniting the sparkplug, and causing the fusion reaction. The general applicability of this principle is unclear.
The 54-m3 detector tank was filled with 101 tons of gallium trichloride-hydrochloric acid solution, which contained 30.3 tons of gallium. The gallium in this solution acted as the target for a neutrino-induced nuclear reaction, which transmuted it into germanium through the following reaction: : νe \+ 71Ga → 71Ge + e−. The threshold for neutrino detection by this reaction is very low (233.2 keV), and this is also the reason why gallium was chosen: other reactions (as with chlorine-37) have higher thresholds and are thus unable to detect low-energy neutrinos. In fact, the low energy threshold makes the reaction with gallium suitable to the detection of neutrinos emitted in the initial proton fusion reaction of the proton-proton chain reaction, which have a maximum energy of 420 keV.
The simplest was shooting a "cylindrical plug" into a sphere of "active material" with a "tamper"—dense material that would focus neutrons inward and keep the reacting mass together to increase its efficiency. They also explored designs involving spheroids, a primitive form of "implosion" suggested by Richard C. Tolman, and the possibility of autocatalytic methods, which would increase the efficiency of the bomb as it exploded. Considering the idea of the fission bomb theoretically settled—at least until more experimental data was available—the Berkeley conference then turned in a different direction. Edward Teller pushed for discussion of a more powerful bomb: the "Super", usually referred to today as a "hydrogen bomb", which would use the explosive force of a detonating fission bomb to ignite a nuclear fusion reaction between deuterium and tritium.
The breeding blanket (also known as a fusion blanket, lithium blanket or simply blanket), is a key part of many proposed fusion reactor designs. It serves several purposes; one is to act as a cooling mechanism, absorbing the energy from the neutrons produced within the plasma by the nuclear fusion reaction between deuterium and tritium (D-T), another is to "breed" further tritium fuel, that would otherwise be difficult to obtain in sufficient quantities, through the reaction of neutrons with lithium in the blanket. The breeder blanket further serves as shielding, preventing the high-energy neutrons from escaping to the area outside the reactor and protecting the more radiation-susceptible portions, like the superconducting magnets, from damage. Of these three duties, it is only the breeding portion that cannot be replaced by other means.
On January 28, 2010, the facility published a paper reporting the delivery of a 669 kJ pulse to a gold hohlraum, setting new records for power delivery by a laser, and leading to analysis suggesting that suspected interference by generated plasma would not be a problem in igniting a fusion reaction. Due to the size of the test hohlraums, laser/plasma interactions produced plasma-optics gratings, acting like tiny prisms, which produced symmetric X-ray drive on the capsule inside the hohlraum. After gradually altering the wavelength of the laser, scientists were able to compress a spherical capsule evenly and heat it up to 3.3 million kelvins (285 eV). The capsule contained cryogenically cooled gas, acting as a substitute for the deuterium and tritium fuel capsules that will be used later on.
Rather, the increased temperature accelerates the rate of the fusion reaction, in a runaway process that feeds on itself. The thermonuclear flame consumes much of the white dwarf in a few seconds, causing a Type Ia supernova explosion that obliterates the star. In another possible mechanism for Type Ia supernovae, the double-degenerate model, two carbon–oxygen white dwarfs in a binary system merge, creating an object with mass greater than the Chandrasekhar limit in which carbon fusion is then ignited. Observations have failed to note signs of accretion leading up to Type Ia supernovae, and this is now thought to be because the star is first loaded up to above the Chandrasekhar limit while also being spun up to a very high rate by the same process.
In 2008, the team at RIKEN conducted the analogous reaction with a lead-206 target for the first time: : + → + They were able to identify 8 atoms of the new isotope 263Hs.Mendeleev Symposium. Morita In 2008, the team at the Lawrence Berkeley National Laboratory (LBNL) studied the analogous reaction with iron-56 projectiles for the first time: : + → + They were able to produce and identify 6 atoms of the new isotope 263Hs. A few months later, the RIKEN team also published their results on the same reaction. Further attempts to synthesise nuclei of hassium were performed the team at Dubna in 1983 using the cold fusion reaction between a bismuth-209 target and manganese-55 projectiles: : + → + x (x = 1 or 2) They were able to detect a spontaneous fission activity assigned to 255Rf, a product of the 263Hs decay chain.
Due to its physical size and use of cryogenic liquid deuterium, it was not suitable for use as a deliverable weapon, but the Castle Bravo test on 1 March 1954 used a much smaller device with solid lithium deuteride. Boosted by the nuclear fusion reaction in lithium-7, the yield of was more than twice what had been expected, and indeed was the largest detonation the Americans would ever carry out. This resulted in widespread radioactive fallout that affected 236 Marshall Islanders, 28 Americans, and the 23 crewmen of a Japanese fishing boat, the Daigo Fukuryū Maru (Lucky Dragon No. 5). Meanwhile, the Soviet Union tested Joe 4, a boosted fission weapon with a yield of on 12 August 1953. This was followed by Joe 19, a true two-stage thermonuclear weapon on 20 November 1954.
Thomson passed his concepts on to Stan Cousins and Alan Ware, who assembled a linear pinch device using old radar equipment, and started operations in 1947. Follow-on experiments used large banks of capacitors to store energy that was quickly dumped into the plasma through a solenoid wrapped around a short tube. These experiments demonstrated a number of dynamic instabilities that caused the plasma to break up and hit the walls of the tube long before it was compressed or heated enough to reach the required fusion conditions. After a short time in Chicago, Tuck was hired by Los Alamos to work on the "Super" project (the hydrogen bomb), where he was put on the task of calculating the nuclear cross section of the deuterium-tritium fusion reaction. This work continued to pique his interest in fusion power, and he spent some time through 1951 considering the problem.
The nucleus can also be modified through bombardment by high energy subatomic particles or photons. If this modifies the number of protons in a nucleus, the atom changes to a different chemical element. If the mass of the nucleus following a fusion reaction is less than the sum of the masses of the separate particles, then the difference between these two values can be emitted as a type of usable energy (such as a gamma ray, or the kinetic energy of a beta particle), as described by Albert Einstein's mass-energy equivalence formula, E=mc^2, where m is the mass loss and c is the speed of light. This deficit is part of the binding energy of the new nucleus, and it is the non-recoverable loss of the energy that causes the fused particles to remain together in a state that requires this energy to separate.
Francium can be synthesized by a fusion reaction when a gold-197 target is bombarded with a beam of oxygen-18 atoms from a linear accelerator in a process originally developed at the physics department of the State University of New York at Stony Brook in 1995. Depending on the energy of the oxygen beam, the reaction can yield francium isotopes with masses of 209, 210, and 211. :197Au + 18O → 209Fr + 6 n :197Au + 18O → 210Fr + 5 n :197Au + 18O → 211Fr + 4 n alt=A complex experimental setup featuring a horizontal glass tube placed between two copper coils. The francium atoms leave the gold target as ions, which are neutralized by collision with yttrium and then isolated in a magneto-optical trap (MOT) in a gaseous unconsolidated state. Although the atoms only remain in the trap for about 30 seconds before escaping or undergoing nuclear decay, the process supplies a continual stream of fresh atoms.
Firstly, its hydrogen isotope fuels are relatively abundant – one of the necessary isotopes, deuterium, can be extracted from seawater, while the other fuel, tritium, would be bred from a lithium blanket using neutrons produced in the fusion reaction itself."Fusion fuels". ITER. Retrieved 24 October 2011. Furthermore, a fusion reactor would produce virtually no CO2 or atmospheric pollutants, and its radioactive waste products would mostly be very short-lived compared to those produced by conventional nuclear reactors (fission reactors). On 21 November 2006, the seven participants formally agreed to fund the creation of a nuclear fusion reactor. The program is anticipated to last for 30 years – 10 for construction, and 20 of operation. ITER was originally expected to cost approximately €5 billion, but the rising price of raw materials and changes to the initial design have seen that amount almost triple to €13 billion. The reactor is expected to take 10 years to build with completion originally scheduled for 2019, but construction has continued into 2020.
At this time studies were also startedPRO AIR 2/13759 E18B that ultimately led to a decision in 1954 to develop a thermonuclear weapon, and the design studies were split into two tracks because the British at that time had not yet discovered the Teller-Ulam technique necessary to initiate fusion. One track led to an intermediate design, the so-called Type A thermonuclear design, similar to the 'Alarm Clock' and layer cake hybrid designs of other nuclear powers; although these designs are now regarded as large boosted fission weapons, and no longer regarded as thermonuclear weapons that derive a very large part of their energy from a fusion reaction, designated by the British as Type B, but as hybrids. The British hybrid weapon was known as Green Bamboo, weighed approx 4,500 lb (2,045 kg) and its spherical shape measured approx 45 inches diameter with a 72-point implosion system.PRO. AVIA 65/1193 E10A.
Szilárd's ideas for nuclear reactors using neutron-mediated nuclear chain reactions in light elements proved unworkable. Inspiration for a new type of reactor using uranium came from the discovery by Lise Meitner, Fritz Strassmann and Otto Hahn in 1938 that bombardment of uranium with neutrons (provided by an alpha-on-beryllium fusion reaction, a "neutron howitzer") produced a barium residue, which they reasoned was created by the fissioning of the uranium nuclei. Subsequent studies in early 1939 (one of them by Szilárd and Fermi) revealed that several neutrons were also released during the fissioning, making available the opportunity for the nuclear chain reaction that Szilárd had envisioned six years previously. On 2 August 1939 Albert Einstein signed a letter to President Franklin D. Roosevelt (written by Szilárd) suggesting that the discovery of uranium's fission could lead to the development of "extremely powerful bombs of a new type", giving impetus to the study of reactors and fission.
The surrounding blanket can be a fissile material (enriched uranium or plutonium) or a fertile material (capable of conversion to a fissionable material by neutron bombardment) such as thorium, depleted uranium or spent nuclear fuel. Such subcritical reactors (which also include particle accelerator-driven neutron spallation systems) offer the only currently-known means of active disposal (versus storage) of spent nuclear fuel without reprocessing. Fission by- products produced by the operation of commercial light water nuclear reactors (LWRs) are long-lived and highly radioactive, but they can be consumed using the excess neutrons in the fusion reaction along with the fissionable components in the blanket, essentially destroying them by nuclear transmutation and producing a waste product which is far safer and less of a risk for nuclear proliferation. The waste would contain significantly reduced concentrations of long-lived, weapons-usable actinides per gigawatt-year of electric energy produced compared to the waste from a LWR.
In 1942, Teller was invited to be part of Robert Oppenheimer's summer planning seminar, at the University of California, Berkeley for the origins of the Manhattan Project, the Allied effort to develop the first nuclear weapons. A few weeks earlier, Teller had been meeting with his friend and colleague Enrico Fermi about the prospects of atomic warfare, and Fermi had nonchalantly suggested that perhaps a weapon based on nuclear fission could be used to set off an even larger nuclear fusion reaction. Even though he initially explained to Fermi why he thought the idea would not work, Teller was fascinated by the possibility and was quickly bored with the idea of "just" an atomic bomb even though this was not yet anywhere near completion. At the Berkeley session, Teller diverted discussion from the fission weapon to the possibility of a fusion weapon—what he called the "Super", an early concept of what was later to be known as a hydrogen bomb.
Despite the many millions of dollars spent by the U.S. between 1952 and 1992 to produce a pure fusion weapon, no measurable success was ever achieved. In 1998, the U.S. Department of Energy (DOE) released a restricted data declassification decision stating that even if the DOE made a substantial investment in the past to develop a pure fusion weapon, "the U.S. is not known to have and is not developing a pure fusion weapon and no credible design for a pure fusion weapon resulted from the DOE investment". The power densities needed to ignite a fusion reaction still seem attainable only with the aid of a fission explosion, or with large apparatus such as powerful lasers like those at the National Ignition Facility, the Sandia Z-pinch machine, or various magnetic tokamaks. Regardless of any claimed advantages of pure fusion weapons, building those weapons does not appear to be feasible using currently available technologies and many have expressed concern that pure fusion weapons research and development would subvert the intent of the Nuclear Non-Proliferation Treaty and the Comprehensive Test Ban Treaty.

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