Sys1 wrote:Moreover, millions of years is very fast at geologic scale. That's why either we are extremely rare in the universe, either it's simply impossible to create a sustainable civilisation.
Oxford-based energy generation and inertial confinement fusion research organisation, First Light Fusion is investing £3.6 million to build a pulsed power machine to advance the company’s work exploring fusion. The device, labelled Machine 3, is under construction and on track to be commissioned by the end of 2018. It will be the only pulsed power machine of its scale in the world dedicated to researching fusion energy. Once complete, it will be capable of discharging up to 200,000 volts and in excess of 14 million ampere within two microseconds. The Machine will use around 3km of high voltage cables and another 10km of diagnostic cables. Machine 3 will be used to further research First Light Fusion’s technology as the company seeks to achieve first fusion. The next step in the technological development will be to achieve ‘gain’, whereby the amount of
onlooker wrote:We have been hearing about Fusion since at least WWII, and it's always we are at the cusp. Never mind it appears to be too complicated, cost prohibited and an EROEI loser
onlooker wrote:We have been hearing about Fusion since at least WWII, and it's always we are at the cusp. Never mind it appears to be too complicated, cost prohibited and an EROEI loser
Although its potential to generate electricity at a commercial scale is several decades away, nuclear fusion can become a promising option to replace fossil fuels as the world's primary energy source and could have an important role to play in addressing climate change, participants agreed at an IAEA General Conference side event focused on the status of fusion energy research, with major players in attendance.
Despite the potential benefits to society from fusion, such as the abundance and accessibility of fuel, the carbon free footprint and the absence of high-level radioactive waste, its science remains one of the most challenging areas of experimental physics today: controlling thermonuclear fusion for energy production is a complex and challenging undertaking.
Moderating the discussion, Meera Venkatesh, Director of IAEA Division of Physical and Chemical Sciences, highlighted the difficulties facing fusion technology to make commercially-viable fusion power a reality. She pointed out that finding the right materials to construct the fusion reactor, and developing the mechanism that will be used to extract the enormous energy/heat that is emitted, are among the major tasks ahead. “The realization of fusion power reactors would be a landmark achievement, taking nuclear science and technology to a higher level,” she said.
ITER: Proving fusion technology on Earth
One major step toward reaching this goal is the ITER project, a 35-nation collaboration to design, build and operate an experimental reactor to achieve and sustain a fusion reaction for a short period of time. ITER will be the world’s largest tokamak, a donut-shaped configuration for the containment of the plasma, which is where the reaction — at temperatures hotter than the Sun — will take place.
ITER Director-General, Bernard Bigot, highlighted the extensive progress in manufacturing and construction, which is now more than 50% completed, with the first experiments scheduled by 2025.
“When we prove that fusion is a viable energy source, it will eventually replace burning fossil fuels, which are non-renewable and non-sustainable. Our mission is to provide a new option which is safe, sustainable and economically competitive. Fusion will be complementary with wind, solar and other renewable energies,” he said.
ITER is expected to produce about 500 megawatts of fusion power by the late 2030s, and will enable scientists to observe for the first time a burning plasma, the state when the energy produced by the fusion reaction is almost or completely sufficient to maintain the temperature of the plasma, so that the external heating can be strongly reduced or switched off altogether. Studying the fusion science and technology at ITER’s scale will enable optimization of the plants that follow while leading discoveries in plasma science and technology.
Wendelstein 7-X: A new twist
These efforts are complemented by the world’s largest stellarator — Wendelstein 7-X (W7-X) at Max Planck Institute for Plasma Physics (IPP) in Germany — an alternative to the tokamak as the reactor layout. It is a twisted racetrack-shaped configuration, which is inherently stable and able to operate the plasma in a steady state for greater lengths of time than the tokamak, but it is technically harder to design.
Although W7-X will not produce energy, its designers hope to prove that stellarators are also suitable for application in power plants and to demonstrate their capability to operate continuously. Such continuous mode will be essential for commercial operation of a fusion reactor.
Sibylle Günter, Scientific Director of IPP, highlighted the most recent results from the first high-performance plasma operation of W7-X, which has recently achieved the highest stellarator fusion triple product: the density, confinement time and plasma temperature used by researchers to measure the performance of a fusion plasma.
“This is an excellent value for a device of this size, and it makes us optimistic for our further work. In the future, we expect to run the machine for a longer time,” she said.
The fusion triple product has seen an increase of a factor of 100,000 in the last fifty years of fusion experimentation; another factor of five is needed to arrive at the level of performance required for a power plant. Some of the improvements in this product were the result of experimental fusion reactors becoming larger. Plasma takes longer to diffuse from the centre to the walls in a bigger reactor, and this extends the confinement time.
Günter added: “Size matters in terms of heat insulation. Based on our experience, I believe that ITER will perform even better than planned today.”
Let there be light
While large scale experiments such as ITER and W7-X continue, nearly two dozen start-ups are working on a variety of devices, fuels, and approaches, using new technologies. These start-ups are backed by venture capital funding.
Mila Aung-Thwin, director of the award-winning documentary about the quest for fusion energy, Let There Be Light, which was shown at the event, emphasized that in addition to public investments into fusion research, there is an increase in the number of new players working in the area of nuclear fusion. As an example, the movie shows fusion start-ups in Canada and the USA.
“It’s great that there are more private entities supporting innovation. Perhaps we are at the level of technology now where start-ups can compete with national labs and agencies, as they seem to be in space travel,” he said.
Bigot added: “These companies are trying to develop alternative options to ITER. Their investors want to make fusion a reality, and this demonstrates trust in fusion as a promising energy supply for the world in the middle and long term.”
Fusion Energy at the IAEA
The IAEA has been supporting the research and development work towards future nuclear fusion energy since the beginning, in the 1950s. The IAEA played an important role in the set-up of ITER, and continues to act as a central hub among Member States developing programme plans and initiating new R&D activities leading to various concepts of a demonstration fusion power plant (DEMO) through its DEMO Programme Workshop.
The IAEA is cooperating with the ITER Organization based on the IAEA-ITER Cooperation Agreement, and is playing an important bridging function between the 35 ITER members and the other IAEA Member States through its periodic series of Fusion Energy Conferences, Workshops and Technical Meetings, Coordinated Research Projects, and publishing the leading scientific journal in the field, Nuclear Fusion.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Tanada wrote:In large part this arose because D*D was the first successful Hydrogen Bomb reaction material and all current Hydrogen Bombs are D*T designs based on using Lithium metal as the precursor to Tritium.
diemos wrote:Tanada wrote:In large part this arose because D*D was the first successful Hydrogen Bomb reaction material and all current Hydrogen Bombs are D*T designs based on using Lithium metal as the precursor to Tritium.
You have cause and effect reversed. DT is chosen because it has the highest cross section for interaction at the lowest temperatures. It doesn't occur in the sun because there is no tritium there.
http://www.kayelaby.npl.co.uk/atomic_an ... _7_4b.html
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Tanada wrote:First off the P*D reaction does not appear on the graph you posted despite the fact that it is prevalent in the entire spectrum of dwarf class stars from brown dwarves right up through A stellar class objects.
lpetrich wrote:There is a certain problem with the first step in the proton-proton process. It involves the weak interaction.
Two protons by themselves cannot be bound. That's because they are the same flavor of elementary particle and thus cannot occupy the same quantum state. Likewise for neutrons. But a proton and a neutron are different flavors, and they can be bound, though not by much.
So to make deuterium from protium, two protons have to collide close enough to touch, and when they do so, one of them has to turn into a neutron by positive beta decay. Though one may object that the Sun is very bright by ordinary standards, it is also very large by ordinary standards, and the two effects cancel out. The Sun's energy generation per unit volume in its core is about 1/4 human resting metabolism (Nuclear fusion - Wikipedia).
So we are stuck with fusion reactions that conserve nucleon flavor. This means the likes of D + D, D + T, and D + He3.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
diemos wrote:Tanada wrote:First off the P*D reaction does not appear on the graph you posted despite the fact that it is prevalent in the entire spectrum of dwarf class stars from brown dwarves right up through A stellar class objects.
It does not appear on that plot because it is too small.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Tanada wrote:If that were true it should be exceedingly easy for you to find a reference showing the reaction cross section for Protium*Deuterium fusion being exceedingly small.
Any reference from any physics oriented publication will do, not a random blog please.
Ready, set, go: Scientists evaluate novel technique for firing up fusion-reaction fuel
To capture and control on Earth the fusion reactions that drive the sun and stars, researchers must first turn room-temperature gas into the hot, charged plasma that fuels the reactions. At the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL), scientists have conducted an analysis that confirms the effectiveness of a novel, non-standard way for starting up plasma in future compact fusion facilities.
The innovative technique, known as "transient coaxial helical injection (CHI)," eliminates the central magnet, or solenoid, that launches the plasma inside tokamaks, the most widely used fusion facilities. Such elimination could facilitate constant, or steady state, fusion reactions and also free up valuable space in the center of compact spherical tokamaks, whose cored-apple shape has less room inside than conventional doughnut-shaped tokamaks that are more common.
Providing advantages
The freed-up space could provide advantages: It could be used to strengthen the magnetic field that confines the plasma and thereby improve its performance. Elimination of the solenoid could also simplify the design of compact tokamaks.
Fusion reactions fuse light elements in the form of plasma -- the hot, charged state of matter composed of free electrons and atomic nuclei that occurs naturally throughout the universe -- and thereby generate energy. Scientists are seeking to replicate fusion on Earth for a virtually inexhaustible supply of safe and clean power to generate electricity.
Solenoids run down the center of a tokamak and induce current in the uncharged gas that researchers inject into the facility. The current strips electrons from the atoms in the gas, turning it into a charged plasma -- a process called "ionization," or plasma breakdown. The current also creates a magnetic field that combines with the field produced by magnets that surround the tokamak to bottle up and control the plasma, enabling heating heating to produce fusion reactions.
Eliminating the solenoid
By contrast, the transient CHI process reported in Physics of Plasmas produces the crucial electric current with electrodes placed near the bottom or top of the tokamak, eliminating the space-eating solenoid. "What we primarily focused on was the beginning stage of forming the plasma," said physicist Kenneth Hammond of the Max Planck Institute of Plasma Physics, the lead author of the paper who did research on CHI as a Columbia University graduate student at PPPL and is joining the laboratory this summer. "This helped paint a fuller picture of how CHI discharges work."
Transient CHI -- so-called because the electrodes that produce the plasma-launching current run briefly rather than continuously -- was first developed in experiments on the small Helicity Injection Torus (HIT-II) at the University of Washington and the larger National Spherical Torus Experiment (NSTX) at PPPL prior to its upgrade; the process also had been modeled at PPPL. The experiments, which showed that transient CHI could be scaled up from smaller to larger machines, motivated the recent study, said Roger Raman, a University of Washington physicist on long-term assignment to PPPL and a coauthor of the paper.
The study found that the placement of CHI electrodes in the earlier experiments "could exhibit a severe weakness when scaled up to a reactor," Hammond said. He then analyzed an alternative electrode configuration similar to one presently used in QUEST, a spherical tokamak in Japan. The findings showed that the alternative configuration could scale up well in a future spherical tokamak-based fusion facility designed at PPPL. "The good news from this study is that the projections for startup in large-scale devices look promising," Hammond said.
Valuable potential
The CHI technique has valuable potential, concurred Tom Brown, a principal engineer at PPPL who helped design the concept of the future spherical facility. "If successful, CHI could provide space for interior components that could enhance the performance of spherical devices," Brown said. However, he added, "further engineering details need to be developed at the experimental level that also can work within a higher-level [demonstration] device and also in an eventual fusion power plant."
Researchers have thus far tested the CHI scaling in simulations conducted on the Tokamak Simulation Code, a computer program created by PPPL physicist Stephen Jardin that has modeled plasmas around the world. Jardin, a coauthor of the Physics of Plasmas report, worked with Raman to produce the simulation referred to in the paper. "Although CHI has never been tested on a large reactor-scale device," Hammond said, "we are optimistic that the same relationships will hold on the larger size with stronger magnetic fields."
Future experiments are scheduled on URANIA, a solenoid-free spherical tokamak at the University of Wisconsin-Madison. The new experiments will test the startup of plasma with two independently operated transient CHI electrodes -- a configuration that could produce greater flexibility for optimizing the promising system.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
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