British tokamak is ready to supply fusion energy for industry

(ORDO NEWS) — Oxford-based British technology company Tokamak Energy has reached a milestone in privately funded fusion research.

The ST-40 spherical tokamak has reached 100 million °C, which engineers say is the threshold for commercial use of fusion energy.

For over 75 years, the promise of a utilitarian fusion reactor has remained elusive, for a variety of reasons. Such a technology could supply humanity with an almost unlimited supply of cheap and clean energy, making a real revolution in the energy market – so scientists did not stop trying year after year.

Nuclear fusion in the service of mankind

The principle of nuclear fusion is relatively simple. Just take hydrogen atoms and put them under the same amount of heat and pressure that our Sun does. Do this long enough and eventually the atoms will fuse together to form heavier helium atoms, releasing a huge amount of energy in the process.

Unfortunately, this is a classic example of violin playing: in theory it is very easy, but in practice it is incredibly difficult and is achieved through a lot of trial, error and practice. Simply put, balancing the three main factors (heat, pressure, and time) for fusion is not that difficult.

In fact, during the New York World’s Fair in 1964, an event was organized where the public could watch the work of a desktop fusion reactor in real time – albeit for only a fraction of a second.

Since then, one of the most difficult tasks has been to come up with a reactor that could produce practical amounts of energy in a stable mode and in quantities greater than the amount needed to start the reaction – that is, the “output” of energy must be greater than the “input”.

What is a tokamak and how it works

British tokamak is ready to supply fusion energy for industry 2An illustration of how magnetic fields are arranged in a tokamak

One of the most promising areas in this branch of energy was the tokamak reactor, first developed in the Soviet Union in the 1950s. The basic design is a hollow ring surrounded by coils that create a magnetic field inside.

The ring contains a vacuum in which hydrogen atoms are introduced. The magnetic field compresses these atoms as they heat up to millions of degrees.

This process strips them of their electrons and turns them into plasma as the atoms revolve around the ring. When the heating, pressure and time interval reach the required parameters, synthesis occurs – the fusion of atoms.

Most tokamaks built in the last 70 years have been government-funded research reactors that have focused on studying the behavior of hydrogen plasma and the challenges that would be faced in building a practical reactor.

This means that these tokamaks tend to be extremely large and expensive, and the amount of energy circulating is such that if accidentally released during the fusion process, the entire machine bounces around like an ocean liner trying to take off.

Private initiatives

British tokamak is ready to supply fusion energy for industry 3Tokamak magnetic coils

In addition to research reactors, there are also privately funded projects such as Tokamak Energy’s ST40 spherical tokamak.

While government reactors have already hit the 100 million °C mark , doing so with a much smaller £50 million (US$70 million) commercial reactor is quite an achievement – ​​especially as the success of the private reactor is to be confirmed. independent outside observers.

The goal of the ST40 is to focus on commercial applications of fusion energy, the company said. In particular, the goal is to make reactors economically viable.

Where conventional tokamaks have large toric chambers, a spherical reactor (such as the ST40) is much more compact and replaces the all-encompassing magnets with those found in the center of the chamber in a rack-like manner.

This gives the reactor a flattened shape, making it look like an apple. This configuration allows the magnets to be closer to the plasma flow, so the magnets are smaller and consume less power, but generate stronger fields.

British tokamak is ready to supply fusion energy for industry 4Spherical tokamak device

In addition, the ST40 uses high temperature superconducting (HTS) magnets made from rare earth barium copper oxide (REBCO) and formed into narrow ribbons less than 0.1mm thick.

They operate at temperatures ranging from -250 to -200 °C, which is approximately the temperature at which nitrogen liquefies. This makes cooling the reactor magnets much cheaper than liquid helium magnets.

Such a setup makes the reactor smaller and simpler, and the plasma remains much more stable under conditions that support the fusion reaction. However, the overall pressure in the reactor is less than in conventional tokamaks, and the central support is vulnerable to decay due to the plasma and needs to be replaced regularly.

The company is currently working on a more advanced ST-HTS reactor that will be operational in a few years and will hopefully inform the design of the first true commercial facility in the 2030s.

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