How long until fusion power

In tokamaks and RFP devices, the current flowing through the plasma also serves to heat it to a temperature of about 10 million degrees Celsius.

Beyond that, additional heating systems are needed to achieve the temperatures necessary for fusion. In stellarators, these heating systems have to supply all the energy needed. The tokamak toroidalnya kamera ee magnetnaya katushka — torus-shaped magnetic chamber was designed in by Soviet physicists Andrei Sakharov and Igor Tamm.

Tokamaks operate within limited parameters outside which sudden losses of energy confinement disruptions can occur, causing major thermal and mechanical stresses to the structure and walls. Nevertheless, it is considered the most promising design, and research is continuing on various tokamaks around the world. Research is also being carried out on several types of stellarator. Lyman Spitzer devised and began work on the first fusion device — a stellarator — at the Princeton Plasma Physics Laboratory in Due to the difficulty in confining plasmas, stellarators fell out of favour until computer modelling techniques allowed accurate geometries to be calculated.

Because stellarators have no toroidal plasma current, plasma stability is increased compared with tokamaks. Since the burning plasma can be more easily controlled and monitored, stellerators have an intrinsic potential for steady-state, continuous operation. The disadvantage is that, due to their more complex shape, stellarators are much more complex than tokamaks to design and build. RFP devices differ from tokamaks mainly in the spatial distribution of the toroidal magnetic field, which changes sign at the edge of the plasma.

The RFX machine in Padua, Italy is used to study the physical problems arising from the spontaneous reorganisation of the magnetic field, which is an intrinsic feature of this configuration. In inertial confinement fusion, which is a newer line of research, laser or ion beams are focused very precisely onto the surface of a target, which is a pellet of D-T fuel, a few millimetres in diameter. This heats the outer layer of the material, which explodes outwards generating an inward-moving compression front or implosion that compresses and heats the inner layers of material.

The core of the fuel may be compressed to one thousand times its liquid density, resulting in conditions where fusion can occur. The energy released then would heat the surrounding fuel, which may also undergo fusion leading to a chain reaction known as ignition as the reaction spreads outwards through the fuel. The time required for these reactions to occur is limited by the inertia of the fuel hence the name , but is less than a microsecond.

So far, most inertial confinement work has involved lasers. Recent work at Osaka University's Institute of Laser Engineering in Japan suggests that ignition may be achieved at lower temperature with a second very intense laser pulse guided through a millimetre-high gold cone into the compressed fuel, and timed to coincide with the peak compression.

This technique, known as 'fast ignition', means that fuel compression is separated from hot spot generation with ignition, making the process more practical. In the UK First Light Fusion based near Oxford is researching inertial fusion energy IFE with a focus on power driver technology using an asymmetric implosion approach. As well as power generation, the company envisages material processing and chemical manufacturing applications. It focuses powerful laser beams into a small target in a few billionths of a second, delivering more than 2 MJ of ultraviolet energy and TW of peak power.

A completely different concept, the 'Z-pinch' or 'zeta pinch' , uses a strong electrical current in a plasma to generate X-rays, which compress a tiny D-T fuel cylinder. Magnetized target fusion MTF , also referred to as magneto-inertial fusion MIF , is a pulsed approach to fusion that combines the compressional heating of inertial confinement fusion with the magnetically reduced thermal transport and magnetically enhanced alpha heating of magnetic confinement fusion.

A range of MTF systems are currently being experimented with, and commonly use a magnetic field to confine a plasma with compressional heating provided by laser, electromagnetic or mechanical liner implosion.

As a result of this combined approach, shorter plasma confinement times are required than for magnetic confinement from ns to 1 ms, depending on the MIF approach , reducing the requirement to stabilize the plasma for long periods. Conversely, compression can be achieved over timescales longer than those typical for inertial confinement, making it possible to achieve compression through mechanical, magnetic, chemical, or relatively low-powered laser drivers.

Due to the reduced demands on confinement time and compression velocities, MTF has been pursued as a lower-cost and simpler approach to investigating these challenges than conventional fusion projects.

Fusion can also be combined with fission in what is referred to as hybrid nuclear fusion where the blanket surrounding the core is a subcritical fission reactor. The fusion reaction acts as a source of neutrons for the surrounding blanket, where these neutrons are captured, resulting in fission reactions taking place.

These fission reactions would also produce more neutrons, thereby assisting further fission reactions in the blanket. The concept of hybrid fusion can be compared with an accelerator-driven system ADS , where an accelerator is the source of neutrons for the blanket assembly, rather than nuclear fusion reactions see page on Accelerator-driven Nuclear Energy.

The blanket of a hybrid fusion system can therefore contain the same fuel as an ADS — for example, the abundant element thorium or the long-lived heavy isotopes present in used nuclear fuel from a conventional reactor could be used as fuel.

The blanket containing fission fuel in a hybrid fusion system would not require the development of new materials capable of withstanding constant neutron bombardment, whereas such materials would be needed in the blanket of a 'conventional' fusion system. A further advantage of a hybrid system is that the fusion part would not need to produce as many neutrons as a non-hybrid fusion reactor would in order to generate more power than is consumed — so a commercial-scale fusion reactor in a hybrid system does not need to be as large as a fusion-only reactor.

A long-standing quip about fusion points out that, since the s, commercial deployment of fusion power has always been about 40 years away. While there is some truth in this, many breakthroughs have been made, particularly in recent years, and there are a number of major projects under development that may bring research to the point where fusion power can be commercialised.

Much research has also been carried out on stellarators. It is being used to study the best magnetic configuration for plasma confinement. At the Garching site of the Max Planck Institute for Plasma Physics in Germany, research carried out at the Wendelstein 7-AS between and is being progressed at the Wendelstein 7-X, which was built over 19 years at Max Planck Institute's Greifswald site and started up at the end of In the USA, at Princeton Plasma Physics Laboratory, where the first stellarators were built in , construction on the NCSX stellerator was abandoned in due to cost overruns and lack of funding 2.

There have also been significant developments in research into inertial fusion energy IFE. Both are designed to deliver, in a few billionths of a second, nearly two million joules of light energy to targets measuring a few millimeters in size. Between and , the initial designs were drawn up for an International Thermonuclear Experimental Reactor ITER, which also means 'a path' or 'journey' in Latin with the aim of proving that fusion could produce useful energy.

The four parties agreed in to collaborate further on engineering design activities for ITER. Canada and Kazakhstan are also involved through Euratom and Russia, respectively. The envisaged energy gain is unlikely to be enough for a power plant, but it should demonstrate feasibility. In , the USA rejoined the project and China also announced it would join. The deal involved major concessions to Japan, which had put forward Rokkasho as a preferred site.

India became the seventh member of the ITER consortium at the end of The total cost of the MW ITER comprises about half for the ten-year construction and half for 20 years of operation. Site preparation works at Cadarache commenced in January First concrete for the buildings was poured in December Experiments were due to begin in , when hydrogen will be used to avoid activating the magnets, but this is now expected in The first D-T plasma is not expected until ITER is large because confinement time increases with the cube of machine size.

The vacuum vessel will be 19 m across and 11 m high, and weigh more than tonnes. The goal of ITER is to operate with a plasma thermal output of MW for at least seconds continuously with less than 50 MW of plasma heating power input.

No electricity will be generated at ITER. It is focused on the divertor structure to remove helium, testing the durability of tungsten materials used. A 2 GW Demonstration Power Plant, known as Demo, is expected to demonstrate large-scale production of electrical power on a continual basis.

The conceptual design of Demo was expected to be completed by , with construction beginning around and the first phase of operation commencing from It has since been delayed, with construction now planned for after JET is the largest tokamak operating in the world today. JET produced its first plasma in , and became the first experiment to produce controlled fusion power in November , albeit with high input of electricity.

Up to 16 MW of fusion power for one second and 5 MW sustained has been achieved in D-T plasmas using the device, from 24 MW of power injected into its heating system, and many experiments are conducted to study different heating schemes and other techniques.

JET has been very successful in operating remote handling techniques in a radioactive environment to modify the interior of the device and has shown that the remote handling maintenance of fusion devices is realistic. It has been significantly upgraded in recent years to test ITER plasma physics and engineering systems. Further enhancements are planned at JET with a view to exceeding its fusion power record in future D-T experiments.

MAST Upgrade is focused on designing a plasma exhaust system or divertor that would be able withstand the intense power loads created in commercial-sized fusion reactors. It achieved first plasma in October The technical objectives of STEP are: to deliver predictable net electricity greater than MW; to exploit fusion energy beyond electricity production; to ensure tritium self-sufficiency; to qualify materials and components under appropriate fusion conditions of neutron flux; and to develop a viable path to affordable life-cycle costs.

STEP is scheduled for completion in Tokamak Energy in the UK is a private company developing a spherical tokamak, and hopes to commercialize this by The company grew out of Culham laboratory, home to JET, and its technology revolves around high temperature superconducting HTS magnets, which allow for relatively low-power and small-size devices, but high performance and potentially widespread commercial deployment.

It produced plasma temperatures of 15 million degrees Celsius in and after the commissioning of further magnetic coils. Chief executive of Tokamak Energy David Kingham said: "The ST40 is designed to achieve million degrees C and get within a factor of ten of energy break-even conditions. The funds will contribute to core development work on high temperature superconducting HTS magnets and plasma exhaust system divertor technologies.

The divertor must handle high levels of heat and particle bombardment while removing impurities and waste from the system. It aims to have a prototype delivering electricity to the grid by It is a pilot device for ITER, and involves much international collaboration.

The tokamak with 1. Its first stage of development to was to prove baseline operation technologies and achieved plasma pulses of up to 20 seconds. For the second phase of development , KSTAR was upgraded to study long pulses of up to seconds in H mode — the s target was in — and embark upon high-performance AT mode.

It achieved 70 seconds in high-performance plasma operation in late , a world record. This is a steep pressure gradient in the core of the plasmas due to the enhanced core plasma confinement. Phase 4 will test DEMO-related prior arts. The device does not have tritium handling capabilities, so will not use D-T fuel. According to the PPPL, it would generate "some 1 billion watts of power for several weeks on end", a much greater output than ITER's goal of producing million watts for seconds by the late s.

K-DEMO is expected to have a 6. About KRW billion of that spending has already been funded. The heat from a fusion reactor would generate steam. This steam would then drive a turbine and electrical generator, the same way most electricity is produced nowadays.

In contrast, renewable energy sources such as solar and wind "are not accommodated well by the current design of electric grids.

The researchers ultimately hope SPARC-inspired fusion power plants would generate between to 1, megawatts of electricity. SPARC would only produce heat, not electricity. Join our Space Forums to keep talking space on the latest missions, night sky and more!

And if you have a news tip, correction or comment, let us know at: community space. Your physics questions answered — Photos: Inside the world's top physics labs. Charles Q. See all comments Scientists have been saying that for decades. Clark Kent said:. Not only trite but very silly. We first achieved sustained fusion in JET around Getting power over unity is only a matter of time and work now and should be achieved by ITER.. Fusion for space propulsion is a quite different problem to power generation.

On the positive. Rockets generally only run in short pulses. If longer accelerations are needed multiple pulses can be chained together. On the negative. Though that claim is technically true, did the audience of non-physicists know he was referring to directly injected energy and thermal power? Or did they assume he was talking about overall electrical power? So obviously, fusion has hurt itself in how the capital Q has been interpreted in the community or in public.

Henderson said a commercial fusion reactor would need a Q-physics of about 40, four times the Q of ITER, to generate sufficient power to be viable. The number represents an incredible leap forward in fusion, but a leap nearly 50 years and an unknown sum of money in the making, if things go according to plan — a plan over which there seems to be much confusion. Michel Claessens was the communications director for ITER for about five years and wrote a book about the project, in which he spoke bluntly about Q.

So I had the impression that we were mixing the two arguments. He said the organization does not believe there is any public misunderstanding of the Q ratio, nor does it believe its representation of Q was vague or incorrect.

Coblentz said that ITER has made efforts in the past to reach out to publications and journalists when it felt the Q ratio was misrepresented, and that despite simplifications made by congressional representatives during hearings, ITER is confident lawmakers correctly understand the goals of the project. In the meantime, Steven Krivit has reached out to the organizations who had published the Q ratio without an explanation of what it meant. Go on an adventure into unexpected corners of the health and science world each week with award-winning host Maiken Scott.

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Those latter ingredients, he added, can be harder to come by. But Krivit is skeptical. What did all that mean for ITER, and its claim to be able to produce 10 times the power it used? Subscribe to The Pulse Stories about the people and places at the heart of health and science. Ways to Listen. Will ITER actually produce 10 times more energy than it consumes?