Susana Reyes: Engineering the Future of Inertial Confinement Fusion

This article has been translated using artificial intelligence

Fusion energy is closer than ever. Thanks to breakthroughs at the National Ignition Facility, inertial confinement fusion has, for the first time, surpassed the scientific break-even threshold. But the biggest challenge remains: turning that physical milestone into a viable, repeatable, and economically competitive power plant.

At the Future Trends Forum organized by Fundación Innovación Bankinter, Susana Reyes, Vice President of Engineering at Xcimer Energy, delivered a clear and realistic perspective on what still needs to be solved. The problem is no longer physics—it’s engineering.

From a device design with just two laser beams and liquid walls to systems capable of firing repeatedly without damaging the structure, Reyes outlined the key elements that could take laser fusion from the lab to the power grid.

This article highlights the main insights from her talk and explains why the future of fusion now depends on scale, integration, and engineering simplicity.

If you’d like to watch Susana Reyes’ talk, you can find it in this video:

Susana Reyes: “Engineering and Integration in Inertial Confinement” #FusionForward

Designing the Future of Fusion: When Physics Is No Longer the Problem

In December 2022, something historic happened. For the first time, a scientific facility succeeded in producing more energy from a nuclear fusion reaction than was used to start it. This milestone—known as scientific break-even—was achieved by the National Ignition Facility (NIF) in the United States. It was a giant leap for a technology that has been promising an energy revolution for decades.

So, what now? Does this mean we already have fusion energy? Not quite. The next challenge is just as complex: turning that achievement into a power plant that can generate electricity continuously, reliably, and economically.

And this is where Susana Reyes enters the picture.

Who is Susana Reyes, and what is Xcimer Energy?

Susana Reyes is Vice President of Engineering at Xcimer Energy, a U.S.-based startup headquartered in Denver, Colorado, working on inertial confinement fusion reactors. Before joining the private sector, Reyes spent years in U.S. national labs and has been involved in pioneering fusion projects since the 1990s.

Her company is part of the U.S. Department of Energy’s public-private partnership program and has already raised over $100 million in funding to develop a new kind of fusion reactor.

In her talk at the Future Trends Forum, Reyes made one point very clear:

“Physics is no longer the bottleneck. What’s missing is engineering. The hard part now is building something that works every day.”

What is inertial confinement fusion (and why does it matter)?

To understand the challenge, you first need to understand the concept.

Nuclear fusion is about replicating the process that powers the Sun: fusing hydrogen nuclei into helium to release vast amounts of energy.

There are two main approaches to achieving this:

• Magnetic confinement, like in the well-known ITER project, which uses giant magnetic fields to contain superheated plasma.
• Inertial confinement, the approach used by Xcimer Energy and the NIF, which involves firing powerful lasers at a tiny capsule filled with hydrogen fuel, causing it to implode and trigger fusion conditions.

This second method has already proven that fusion is physically possible. But it’s still far from being a practical energy source. Why? Because the current systems—like NIF—are too large, expensive, and complex to scale.

The NIF Milestone Explained (and What’s Still Missing)

In December 2022, the National Ignition Facility (NIF) achieved something that once seemed impossible: producing more fusion energy than the fuel absorbed. This milestone is known as scientific break-even.

But does this mean we now have fusion energy ready to power the grid? Not quite. What NIF achieved was proof that the physics works—but only at an experimental scale.

To put it into perspective:

• NIF’s laser pulse delivered 2 megajoules of energy to a capsule the size of a pea.
• The fusion reaction produced 8.6 megajoules—over four times the energy deposited into the fuel.
• But… the full system required hundreds of megajoules from the grid to power the lasers.

In other words: the reaction works, but the facility consumes far more energy than it generates. The challenge now is not proving the physics—it’s making the entire system efficient and repeatable.

That’s where startups like Xcimer Energy come in, with proposals to simplify the design and cut costs to move from lab experiments to grid-scale power.

How Do We Get There? Xcimer’s Three Key Innovations

Susana Reyes clearly explains what her team is working on to overcome current barriers. These are the three main innovations that could make laser fusion viable at industrial scale:

1. Cheaper, more powerful lasers
NIF’s laser system covers the size of three football fields and uses 192 beams to ignite a single fuel capsule. It’s impressive—but inefficient.
Xcimer proposes using excimer laser technology, which could reduce the cost per unit of energy by up to 60 times. These lasers also deliver more energy per pulse, allowing for larger, easier-to-manufacture fuel capsules.

2. A reactor with only two beams
Instead of 192 beams firing from all directions, Xcimer’s reactor uses just two opposing laser beams entering the chamber from opposite sides.
This dramatically simplifies the design, reduces costs, and improves system reliability. Less is more.

3. A chamber with liquid walls
One of the most delicate parts of any fusion reactor is the reaction chamber, which is constantly exposed to intense heat and particles.
Xcimer offers an elegant solution: lining the chamber with a liquid wall made from a molten salt alloy called FLiBe. It absorbs the energy from each shot, cools down, and is reused.
This innovation extends the reactor’s lifespan and supports continuous operation.

When Could It Become Reality?

Xcimer is working toward having a pilot fusion power plant—named Athena FPP—operational by the middle of the next decade.

This isn’t some distant dream: the core technology already exists. The challenge is to integrate it, simplify it, and scale it up.

As Reyes puts it:

“We’re not saying it’s easy—but it is possible, if we apply engineering principles to fusion.”

Why It Matters

Fusion energy is the holy grail of energy: clean, safe, with no long-lived radioactive waste, and based on an almost unlimited fuel supply.
But to move from promise to reality, we need more than science. We need design, integration, and industrial engineering.

That’s what Susana Reyes offers: a clear, realistic, and achievable vision for the future of energy.

And most importantly—not in 50 years. Possibly in just 10.

This article is part of the analysis developed by the Future Trends Forum. The full report, “Fusion Energy: a Revolution in Progress” brings together insights from more than twenty international experts and outlines five critical pillars for scaling fusion as a climate, economic, and technological engine.

Download it here and discover in detail how we can start building tomorrow’s energy system—today.

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