C Fusion Reactors

Fusion Energy is dramatically different from Fission Energy. Fusion is the process that powers the sun by fusing lighter atoms such as hydrogen to produce heavier atoms such as helium. The process releases prodigious amounts of energy. There are numerous
advantages of fusion reactors over fusion reactors. These include: reduced radioactivity in operation and little nuclear waste, ample fuel supplies, and increased safety. However, controlled fusion has proven to be extremely difficult to produce in a practical and economical manner. Research into fusion reactors began in the 1940s, but to date, no design has produced more fusion power output than the electrical power input; therefore, all existing designs have had a negative power balance. For details on the complex process of producing nuclear fusion see https://en.wikipedia.org/wiki/Fusion_power

In recent years a number of companies have proposed methods to accelerate the production of fusion power over the massive ITER project.

MIT The MIT effort involves the use of high-temperature superconductors that have become commercially available in the past few years and will allow researchers from MIT and Commonwealth Fusion Systems (CFS) in Cambridge to strengthen the magnetic field that contains the hot-plasma fuel used in conventional tokamak reactors. That could pave the way for reactors that are smaller, cheaper and easier to build than those based on previous designs.

Tokamak Energy In the 1980s theorists predicted that changing the shape of the tokamak from a doughnut to a cored apple would improve plasma stability. Tokamak Energy is betting on that shape, called a spherical tokamak. It also aims to crank up the strength of the confining magnetic fields with superconducting magnets similar to the MIT approach.

In 2015, Tokamak Energy built a spherical tokamak just over a meter across and showed it could confine plasma at a million degrees. Now, it says its 2-meter device, called ST40, will be able to heat a plasma to 100 million degrees within a magnetic field of 3 tesla—as strong as the field in a medical MRI machine. It will use conventional copper wire magnets while researchers develop HTS magnets for a successor machine. Even without HTS magnets, ST40 could reach 100 million degrees by 2019, enough to validate this concept of spherical tokamaks for fusion power.

Tri Alpha Energy now TAE Technologies
Tri Alpha exploits a phenomenon called a
field-reversed configuration (FRC), a spinning smoke ring of plasma that produces its own confining magnetic field because of the currents of electrons and ions within it. Known since the 1960s, FRCs could be coaxed to last only for a fraction of a millisecond before fizzling out. In 2015, Tri Alpha revealed it could make an FRC last 5 milliseconds and confine plasma at 10 million degrees Celsius. In its 25-meterlong device, plasma guns at both ends fired FRCs at high speed toward the center, where they merged and converted kinetic energy into heat, boosting the temperature. The machine further heated and stabilized the merged FRC by bombarding it with particles. Over the past year, Tri Alpha has dismantled its machine and built a new one, 30 meters long, with more particle beams and better control of the heat loss from the plasma. When the researchers fire it up they hope to achieve 30-million degree plasmas lasting up to 40 milliseconds.

Chief Technology Officer Michl Binderbauer says they should learn enough physics from this machine to move on to much higher temperatures. That path may be long: Tri Alpha wants to use a different fuel, boron 11, that does not create hazardous high-energy neutrons, but requires billion-degree plasmas to fuse.

General Fusion (Canada)
This company also relies on self-confining plasma rings but will inject them into a spherical reaction chamber whose walls are coated with liquid lithium metal. Dozens of pneumatic pistons, sticking out from the chamber like porcupine quills, will then hammer down on the lithium in unison, generating a shock wave that converges on the plasma and crushes it, creating high temperature and pressure. With more than CA$100 million from the government and private sources, General Fusion since 2002 has been working separately on the three components of the system—plasma injector, lithium vortex, and pneumatic pistons. “Now we have to put it all together,” says CEO Chris Mowry. The final device may have as many as 400 pistons, and will take between 3 and 5 years.to build, he says. The aim is to heat plasma to 100 million degrees, close to energy producing conditions. Mowry says the device will rely on well-understood mechanical
systems, which will produce “an affordable and practical power plant.”

Science 356:360, 2018.

Lockheed Martin
A compact fusion reactor is being developed by the Skunk Works, the stealth experimental technology division of Lockheed Martin. It's the size of a jet engine and it can power airplanes, spaceships, and cities. Skunk Works claims it will be operative in 10 years. Skunk Works' Compact Fusion Reactor has a radically different approach to anything people have tried before.
The Skunk Works' new compact fusion reactor design.
The key to the Skunk Works system is their tube-like design, which allows them to bypass one of the limitations of classic fusion reactor designs, which are very limited in the amount of plasma they can hold, which makes them huge in size—like the gigantic International Thermonuclear Experimental Reactor. Skunk Works is convinced that their system—which
will be the size of a jet engine—will be able to power everything, from spaceships to airplanes to vessels—and of course scale up to a much larger size. At the size of the ITER, it will be able to produce 10 times more energy, McGuire claims.
In ten years they expect to have a fully operative model ready to go into full-scale production, capable of generating 100MW—enough to power a large cargo ship or a 80,000-home city—and measure 23 x 42 feet, so you "could put it on a semi-trailer, similar to a small gas turbine, put it on a pad, hook it up and can be running in a few weeks.”

Commonwealth Fusion Systems
Bringing together decades of government-funded fusion science with a recently developed materials science breakthrough in superconductors. Decades of government-funded research in fusion science have established the tokamak as the leading approach to confining fusion-grade plasmas with strong magnetic fields. Yet, in the past, even state-of-the art superconducting magnet technology required tokamaks to be enormous to produce net fusion energy. Recently, a new superconductor technology has reached industrial maturity: Rare-Earth Barium Copper Oxide (REBCO). CFS plans to engineer REBCO into high-field magnets, which enables much smaller tokamak-based fusion systems. Smaller means cheaper and faster development.

While the funding of most of these approaches is out of reach of our foundation, if they prove to be better or more promising than MSRs we can shift some of our funding to them.