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05 Jun 2024
New facility in Denver to feature world’s largest nonlinear optical pulse compression system.
Xcimer Energy, the US-based startup aiming to develop a krypton fluoride (KrF) excimer laser system for fusion energy, has raised $100 million in a series A round of venture funding.
The Denver firm says that it will use the cash to establish a new facility and equip it with a prototype laser system that will represent the world’s largest nonlinear optical pulse compression system.
Scaling to 10 MJ
The idea is to recreate the kind of conditions that have enabled the National Ignition Facility (NIF) system to generate laser fusion with energy gain, but with much less complicated and cheaper optical technology.
As Xcimer points out, NIF’s 192-beam solid-state design, which delivers around 2 MJ of energy in a nanosecond pulse, cost $3.5 billion and cannot be scaled economically to the levels demanded for reliable energy generation.
“The laser technology is far too expensive to scale to 10 MJ, which is the energy level needed for robust fusion target operation,” points out Xcimer on its web site. “The NIF contains over 120 tons of high quality laser glass, as well as over 4000 square meters of optical surfaces to direct the laser beams to a target.
“Even at 2 MJ of energy, the NIF experiences a significant amount of damage to its optics on every shot - over $40 million per year is spent on refurbishment of the optics. Going to one shot every few seconds would simply be unaffordable.”
KrF lasers
Instead, the startup’s plan is to leverage laser technology originally conceived as part of the US Strategic Defense Initiative (aka “Star Wars” program) of the 1980s, using 248 nm-emitting KrF sources that have since played a key role in semiconductor manufacturing as the light source in deep-ultraviolet lithography systems.
“Xcimer’s laser architecture will produce up to ten times higher laser energy at ten times higher efficiency and over 30 times lower cost per joule than the NIF laser system that achieved fusion scientific breakeven in December 2022,” it claims, with CEO Conner Galloway adding:
“This Series A financing enables us to achieve key milestones along the path to commercial inertial fusion energy. We’re thrilled that our industry-leading investors, as well as our partners from US national labs, academic institutions, and private industry, are joining us on our mission to bring safe, reliable, zero-carbon and economical energy to the world.”
DOE projects
Xcimer is already participating in three different laser fusion development “hubs” backed by the US Department of Energy under the “IFE-STAR” (Inertial Fusion Energy Science and Technology Accelerated Research) program, a presidential “Moonshot” effort to demonstrate a proof-of-concept for several different types of fusion power plants by 2032.
That involvement will have helped to convince series A investors led by UK-based Hedosophia, with participation from others including Breakthrough Energy Ventures, Lowercarbon Capital, Prelude Ventures, Emerson Collective, Gigascale Capital, and Starlight Ventures.
The funding will also enable Xcimer to expand its technical team in Denver, where it recently moved the majority of employees. The company has just hired aerospace executive Giovanni Greco as its senior VP of engineering, who will lead the design, development, and manufacture of the prototype laser system.
According to the company the major elements of the system are “maximally decoupled”, with the laser sitting up to 50 meters away from the low-mass fuel capsule target and able to enter the reactor chamber through only two very small openings.
Burn propagation
Like NIF, Xcimer’s fuel capsules are based on deuterium-tritium, but Xcimer plans to use a much larger size and mass, yielding higher performance, easier manufacturing, and more robust operation.
“The higher performance means a power plant can operate at lower repetition rates (below 1 Hz) than conventional IFE concepts,” it explains. “Fusion takes place in about a cubic centimeter in the center of the target chamber and is far removed from the ‘plasma-facing first wall’ of the chamber with no physical connection.
“This also enables the use of molten salt coolant flow to protect the chamber[’s] first structural wall from the fusion output.”
Xcimer also claims that the short confinement time and high density in the target means it will undergo “burn propagation”, where ignition of only a small amount of fusion fuel can release enough energy to ignite the rest of the fuel - akin to using a match to light a fire.
“This leads to high facility ‘wall-plug’ gains, even with a 5-10 per cent efficient laser,” it says.
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