UW scientists break new ground on nuclear fusion, which could be the future of energy

A team of University of Wisconsin-Madison scientists has taken a major step toward creating a clean, reliable and powerful source of energy.

Four years in the making, it is part of a broader approach to using nuclear fusion energy that, unlike existing nuclear technology, does not create large amounts of radioactive waste.

To understand the importance, remember that phones, microwaves, refrigerators, cars – virtually everything we rely on today needs energy. Every year, the amount of energy needed goes up, and generating it comes at a huge cost.

Fossil fuels like coal, petroleum and natural gas, which account for 60% of the electricity used in the U.S., release enormous amounts of greenhouse gases, driving temperatures up, making living conditions intolerable, and fueling natural disasters like hurricanes and wildfires.

Renewable energy like solar and wind, which account for 21%, are often unreliable. And existing nuclear energy, which accounts for 19%, generates radioactive waste that will last centuries.

For answers to our energy needs, scientists have turned to the sun. What if we could replicate the reaction that has powered the sun for 4 billion years? It does not produce greenhouse gases, the radiation is easier to manage, and it burns hydrogen, which is plentiful. The problem? It's really hard to do.

Over the last 70 years, there have been several failed attempts to recreate and control the ongoing nuclear fusion reactions that power the sun. Several projects that seemed promising had to be closed down. But the last few years have seen a growing excitement in the field, and technological advancements are opening up new possibilities.

What is nuclear fusion?

Nuclear energy being created today uses a reaction called fission, which works by splitting uranium atoms, releasing large amounts of energy in the process. It's the process that is used in atomic bombs. In everyday use, it generates about 14% of electricity in Wisconsin, but it also creates significant radioactive waste. Finding a place to store it safely can be challenging.

Unlike fission, fusion binds atoms. And it relies on hydrogen, a readily available resource.

Most hydrogen atoms have one positively charged proton in the nucleus, one negatively charged electron outside and no neutrons. But there are two other forms of hydrogen. Deuterium has one neutron in the nucleus and tritium has two.

Under the right conditions, deuterium and tritium each will lose an electron and fuse to form one helium atom with two protons and two of the three neutrons. The nuclear fusion reaction happens when that third neutron is jettisoned, releasing a burst of energy.

It's the burst that powers the stars.

“It's a very common reaction in the universe,” said Bill Dorland, a professor of physics at the University of Maryland, “It's just that we don't have stellar conditions here on earth.”

How to harness nuclear fusion energy?

“To make fusion, you have to superheat hydrogen to hundreds of millions degrees.” Dorland said. It was achieved with the hydrogen bomb. But harnessing the energy generated from fusion reactions for more productive ends has been challenging. The key problem is control.

Atoms have to be very close together to fuse. But hydrogen is a very light gas and individual atoms will disperse unless they’re contained. On the sun, where fusion occurs naturally, the strong gravitational pull keeps hydrogen atoms from dispersing. Scientists can do the same thing with magnets, but that comes with another set of problems.

“Back in the day, they used copper magnets,” which require a lot of energy, Dorland explained. The two most successful previous attempts — dating back to the 1990s in Oxfordshire, England, and Princeton, New Jersey — were ultimately abandoned because they put out less energy than it took to run them, he said.

A new kind of magnet could be a game changer.

Rare earth barium copper oxide superconducting magnets created by Cambridge Fusion Systems in partnership with scientists at MIT are smaller, more powerful and need less energy to run. The Massachusetts based start-up is building its own fusion device , but they also made some magnets that landed in Wisconsin last week.

What is the UW-Madison fusion device?

The magnets from Massachusetts were the final piece of a device Carey Forest has been working on for the last four years. Forest is a professor of physics at UW-Madison and chief scientific officer at Realta Fusion. Last year , the project received more than $10 million from the U.S. Department of Energy and Khosla Ventures.

Although they are using magnets from Cambridge Fusion Systems, Forest's fusion device is very different. Forest worked with the team in Massachusetts on a magnet setup that he says is much simpler.

“We have a faster concept. So correspondingly we can fail quicker. If it's not going to work, we'll know sooner,” Forest said. The fusion prototype device is known as Wisconsin HTS Axisymmetric Mirror or WHAM.

WHAM looks like a long tube and has two magnets coiled around it. With the magnets in place, it got running on July 15.

First, they created powerful a vacuum and introduced a puff of hydrogen that was mostly deuterium. Then, “We hit it hard with a very powerful microwave,” that heats the gas up to about 1 million degrees Fahrenheit, Forest said.

The result of the super heated gas held in place by new age magnets was a 50 millisecond flash of plasma that validated four years of planning and building their device. It was a huge step, but still left a long way to go.

“This reactor is kind of a prototype,” Forest said, “It's not intended to make as much energy as we put in.”

Forest  will spend the next year testing his prototype. If the device works like they expect, they will start building a device that can generate energy. Forest reckons it will be at least 10 years before we see a fusion generator that powers our homes and industries.

Now that Forest’s team has shown they can create plasma, “They've got to demonstrate they can control it,” Dorland said.

He has been working on nuclear fusion for 30 years. Even though the technology is still several years away and faces many technological hurdles, he’s hopeful.

"It's pretty exciting that they have these new kinds of magnets and there's lots of good ideas for how to use them,” he said.

This article originally appeared on Milwaukee Journal Sentinel: UW scientists break new ground on nuclear fusion, which could be the future of energy