Energy-positive laser fusion approach heads toward commercialization

With the promise of unlimited energy, Xcimer has raised over US$100 million from investors and the US Department of Energy to develop a high-energy laser system that's intended for use in a practical fusion power plant.

For over 75 years, scientists and engineers have been pursuing the dream of harnessing fusion energy as a practical power source. Though there have been remarkable achievements, the goal has remained elusive. However, the prospect of providing humanity with all the clean energy it could need or want is too big a prize not to pursue.

The primary contender for fusion power is the tokamak, which uses a doughnut-shaped magnetic field to squeeze and heat hydrogen plasma to tremendous pressures and temperatures many times that at the heart of the Sun. These have achieved fusion, which is relatively easy – it can also be done by any hydrogen bomb or lab bench lash up. The tricky bit is to achieve nuclear fusion while getting more energy out than you put in, which is called fusion ignition.

This was first accomplished on December 5, 2022 by the Lawrence Livermore National Laboratory (LLNL) National Ignition Facility (NIF), which used an alternative to tokamak called laser-driven inertial fusion. This involves focusing of a massive bank of lasers on a small frozen pellet of deuterium and tritium. The sudden blast from these combined beams causes the pellet to implode and set off a fusion reaction that produces more energy than was required to generate it. To date, the NIF can create 2.5 times more fusion energy than the laser energy delivered to ignite the fuel.

At first, this seems like a great breakthrough, and in many ways it is. Unfortunately, the LLNL installation is designed primarily for pure research. Its only practical application is to carry out fusion experiments to assure the safety and reliability of American nuclear warheads. It isn't designed as a way to achieve a practical fusion power plant.

That is where Xcimer Energy comes in. Since 2022, the Denver-based company has been working to turn the laser fusion concept into a practical source of power. The goal is to produce a new krypton-fluoride laser installation that generates 10 times higher laser energy at 10 times higher efficiency and over 30 times lower cost per joule than the NIF.

Using technology first developed for the US Strategic Defense Initiative (nicknamed the Star Wars program) in the 1980s, the Xcimer installation will use a laser system producing over 10 megajoules of energy. This will be focused on larger deuterium/tritium pellets that are easier to make and handle, and produce more energy when ignited.

Producing energy is useless if it isn't harnessed, so the fusion chamber has molten lithium salts flowing through it, not only to protect the wall from neutrons, which reduces maintenance, but to absorb the energy and carry it away to generate power.

The idea is that the lasers will stand at a distance of 164 ft (50 m) and focus their beams through two small holes to reach the target pellet. The system is designed to ignite only a small amount of the fuel, which produces the energy needed to ignite the remainder like a match set to paper. This is more efficient and economical.

"The benefits of fusion for humanity have never been more clear or more necessary," said Mark Cupta, Xcimer board member. "Xcimer has developed a game-changing approach to inertial fusion and assembled a team of the brightest minds in the industry to execute on it. I’m confident that with Xcimer leading us on this path, the world will see this transformative source of energy finally deployed at commercial scale."

Source: Xcimer