The way scientists think about fusion changed forever in 2022, when what some called demonstrated for the first time that fusion can be a viable source of clean energy.
Authors
- George R. Tynan
Professor of Mechanical and Aerospace Engineering, University of California, San Diego
- Farhat Beg
Professor of Mechanical and Aerospace Engineering, University of California, San Diego
The experiment, at Lawrence Livermore ³Ô¹ÏÍøÕ¾ Laboratory, : a fusion reaction generating more energy out than was put in.
In addition, the past few years have been marked by a , principally in the United States.
But a whole host of engineering challenges must be addressed before fusion can be scaled up to become a safe, affordable source of . In other words, it’s engineering time.
As engineers who have been working on and in nuclear fusion for decades, we’ve seen much of the science and physics of fusion reach maturity in the past 10 years.
But to make fusion a feasible source of commercial power, engineers now have to tackle a host of practical challenges. Whether the United States steps up to this opportunity and emerges as the global leader in fusion energy will depend, in part, on how much the nation is willing to invest in solving these practical problems – .
Building a fusion reactor
Fusion occurs when two types of hydrogen atoms, deuterium and tritium, collide in extreme conditions. The two atoms literally fuse into one atom by heating up to (100 million degrees Celsius), 10 times hotter than the core of the Sun. To make these reactions happen, fusion energy infrastructure will need to endure these extreme conditions.
There are two approaches to achieving fusion in the lab: inertial confinement fusion, which , and magnetic confinement fusion, .
While the “experiment of the century” used inertial confinement fusion, magnetic confinement fusion that it can break even in energy generation.
Several privately funded experiments , and a large, internationally supported experiment in France, ITER, . Both are using magnetic confinement fusion.
Challenges lying ahead
Both approaches to fusion share a range of challenges that won’t be cheap to overcome. For example, researchers need to develop new materials that .
Fusion reactor materials also as they are bombarded with highly energetic particles. Researchers need to that can decay within a few years to levels of radioactivity that can be disposed of safely and more easily.
Producing enough fuel, and doing it sustainably, is also an important challenge. Deuterium is abundant and can be extracted from ordinary water. But , which is usually produced from lithium, will prove far more difficult. A single fusion reactor will need hundreds of grams to one kilogram (2.2 lbs.) of tritium a day to operate.
Right now, conventional nuclear reactors produce tritium as a byproduct of fission, but these cannot provide enough to sustain a fleet of fusion reactors.
So, engineers will need to develop the ability to produce tritium within the fusion device itself. This might entail surrounding the fusion reactor with lithium-containing material, which .
To scale up inertial fusion, engineers will need to develop lasers capable of repeatedly hitting a fusion fuel target, made of frozen deuterium and tritium, several times per second or so. But no laser is powerful enough to do this at that rate – yet. Engineers will also need to develop control systems and algorithms that direct these lasers with extreme precision on the target.
Additionally, engineers will need to scale up production of targets by orders of magnitude: from a few hundreds handmade every year with a price tag of to millions costing only a few dollars each.
For magnetic containment, engineers and materials scientists will need to develop more effective methods to heat and control the plasma and more heat- and radiation-resistant materials for reactor walls. The technology used to heat and confine the plasma until the atoms fuse needs to operate reliably for years.
These are some of the big challenges. They are tough but not insurmountable.
Current funding landscape
Investments from private companies globally have increased – these will likely continue to be an important factor driving fusion research forward. Private companies have attracted over US$7 billion in private investment .
Several startups are developing with the aim of adding fusion to the power grid in coming decades. Most are based in the United States, with some in Europe and Asia.
While private sector investments have grown, the U.S. government continues to play a key role in the development of fusion technology up to this point. We expect it to continue to do so in the future.
It was the U.S. Department of Energy that invested about US$3 billion to build the ³Ô¹ÏÍøÕ¾ Ignition Facility at the Lawrence Livermore ³Ô¹ÏÍøÕ¾ Laboratory , where the “experiment of the century” took place 12 years later.
In 2023, the Department of Energy announced a four-year, $42 million program . While this funding is important, it likely will not be enough to solve the most important challenges that remain for the United States to emerge as a global leader in practical fusion energy.
One way to build partnerships between the government and private companies in this space could be to create relationships similar to that . As one of NASA’s commercial partners, SpaceX receives both government and private funding to develop technology that NASA can use. It was the first private company to space and the International Space Station.
Along with many other researchers, we are cautiously optimistic. New experimental and theoretical results, new tools and private sector investment are all adding to our growing sense that developing practical fusion energy is no longer an if but a when.
