Idaho National Lab studies fusion safety and tritium supply chain

This is a close-up view of an X-ray photoelectron spectroscopy system used at the Idaho National Laboratory measuring surface chemistry on a potential candidate material to be used for fusion.

Masashi Shimada has been researching nuclear fusion since 2000, when he joined the graduate program at the University of California, San Diego. He is currently the Principal Scientist at the Tritium and Safety Applied Research Facility (STAR) at the Idaho National Laboratory, one of the federal government’s premier scientific research laboratories.

The field has changed a lot.

Early in his career, fusion was often the butt of jokes, if anything. “Fusion is the energy of the future and always will be” was the crack Shimada heard all the time.

But that is changing. Dozens of startups have raised nearly $4 billion in private funding, according to the Fusion Industry Association, an industry trade group.

Investors and Department of Energy Secretary Jennifer Granholm have called fusion power the “holy grail” of clean energy, with the potential to deliver nearly limitless energy without releasing greenhouse gases. and without the same type of long-lived radioactive waste as nuclear fission. has.

There’s a whole bumper crop of new young scientists working in fusion, and they’re inspired.

“If you talk to young people, they believe in the merger. They will succeed. They have a very positive and optimistic mindset,” Shimada said.

For his part, Shimada and his team are currently researching the management of tritium, a popular fuel that many fusion start-ups are pursuing, in hopes of preparing the United States for a bold new fusion industry.

“As part of the government’s new ‘bold vision’ for the commercialization of fusion, the manipulation and production of tritium will be a key part of their scientific research,” Andrew Holland, CEO of the Fusion Industry Association, told CNBC. .

masashi shimada

Photo courtesy of Idaho National Laboratory

Investigate the tritium supply chain

Fusion is a nuclear reaction when two lighter atomic nuclei are brought together to form a single heavier nucleus, releasing “massive amounts of energy”. This is how the sun is powered. But controlling fusion reactions on Earth is a complicated and delicate process.

In many cases, the fuels for a fusion reaction are deuterium and tritium, both of which are forms of hydrogen, the most abundant element in the universe.

Deuterium is very common and can be found in seawater. If fusion were carried out on a large scale on Earth, one gallon of seawater would have enough deuterium to produce as much energy as 300 gallons of gasoline. , according to the Department of Energy.

Tritium, however, is not common on Earth and must be produced. Shimada and his team of Idaho National Lab researchers have a small tritium lab 55 miles west of Idaho Falls, Idaho, where they are studying how to produce the isotope.

“Since tritium is not available in nature, we have to create it,” Shimada told CNBC.

Currently, most of the tritium used by the United States comes from Canada’s national nuclear laboratory, Shimada said. “But we really can’t rely on those supplies. Because once you use it, if you don’t recycle it, you’re basically using all the tritium,” Shimada said. “So we have to create tritium while we’re running a fusion reactor.”

There’s enough tritium to support pilot fusion projects and research, but bringing it to market would require hundreds of reactors, Shimada said.

That’s why we need to invest now in tritium fuel cycle technologies” to create and recycle tritium.

Idaho National Lab scientist Chase Taylor measuring the surface chemistry of a potential material for use in fusion with X-ray photoelectron spectroscopy.

Photo courtesy of Idaho National Laboratory

Security protocols

Tritium is radioactive, but not in the same way as nuclear fission reactor fuel.

“The radioactive decay of tritium takes the form of a weak beta emitter. This type of radiation can be blocked by a few centimeters of water,” World Nuclear Association spokesman Jonathan Cobb told CNBC.

The half-life, or the time it takes for half of a radioactive material to decay, is about 12 years for tritum, and when it decays the product released is helium, which does not is not radioactive, explained Cobb.

By comparison, the nuclear fission reaction splits uranium into products such as iodine, cesium, strontium, xenon, and barium, which are themselves radioactive and have half-lives ranging from days to tens of thousands of years.

That said, the behavior of tritium still needs to be studied because it is radioactive. In particular, the Idaho National Lab is studying how tritium interacts with the material used to build a fusion machine. In many cases, it is a doughnut-shaped machine called a tokamak.

For a fusion reaction to occur, the fuel sources must be heated in a plasma, the fourth state of matter. These reactions occur at exceptionally high temperatures, up to 100 million degrees, which can potentially impact the amount and rate at which tritium can penetrate plasma-containing material, Shimada said.

Most fusion reaction containers are made of special stainless steel with a thin layer of tungsten inside. “Tungsten was chosen because it has the lowest tritium solubility of any element on the periodic table,” Shimada said.

But the high-energy neutrons generated by the fusion reaction can cause radiation damage even in tungsten.

Here at the Idaho National Lab, Sandia National Laboratories collaborator Rob Kolasinski works with a glove box for the Tritium Plasma experiment.

Photo courtesy of Idaho National Laboratory

The team’s research aims to provide fusion companies with a data set to help them determine when this might be happening, so they can establish and measure the safety of their programs.

“We can do a fusion reaction for 5, 10 seconds probably without worrying too much” about what material would be used to contain the fusion reaction, Shimada told CNBC. But for commercial-scale power generation, a fusion reaction would need to be maintained at high temperatures for years.

“The goal of our research is to help the designer of fusion reactors predict when tritium buildup in materials and tritium permeation through the vessel reach unacceptable levels,” Shimada told CNBC. “This way, we can define protocols for heating materials (i.e. bakeout) and removing tritium from the vessel to reduce the risk of potential release of tritium in the event of an accident.”

While the Idaho National Lab studies the behavior of tritium to set safety standards for the burgeoning industry, its waste is far less problematic than today’s nuclear fission facilities. The federal government has been studying how to create a permanent repository for fission waste for more than 40 years and has yet to find a solution.

“Fusion doesn’t create any long-lived radioactive nuclear waste. That’s one of the advantages of fusion reactors over fission reactors,” Shimada told CNBC.

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