The Idaho National Lab studies fusion safety and the tritium supply chain


This is a close-up of an X-ray photoelectron spectroscopy system being used at the Idaho National Lab to measure surface chemistry on a potential candidate material for use in 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 Investigator for the Safety and Tritium Applied Research (STAR) facility 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 subject of jokes, if talked about at all. “Fusion is the energy of the future and always will be,” was the bang Shimada kept hearing.

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

Investors and Department of Energy Secretary Jennifer Granholm have called fusion power the “holy grail” of clean energy, with the potential to provide nearly unlimited power without emitting greenhouse gases and without the same kind of long-lived radioactive waste that nuclear fission has.

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

“When you talk to young people, they believe in fusion. you will make it They have a very positive, optimistic attitude,” Shimada said.

For his part, Shimada and his team are currently researching the manipulation of tritium, a popular fuel pursued by many fusion startups, in hopes of preparing the US for a bold new fusion industry.

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

Masashi Shimada

Photo courtesy of the Idaho National Lab

Investigating the tritium supply chain

Fusion is a nuclear reaction in which two lighter atomic nuclei are pushed 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 forms of hydrogen, the most abundant element in the universe.

Deuterium is widespread and can be found in seawater. If large-scale fusion is achieved on Earth, one gallon of seawater would have enough deuterium to generate as much energy as 300 gallons of gasoline, according to the Department of Energy.

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

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

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

There is enough tritium to support pilot fusion projects and research, but commercialization would require hundreds of reactors, Shimada said.

So now we need to invest in ‘tritium fuel cycle’ technologies to produce and recycle tritium.

A scientist at the Idaho National Lab, Chase Taylor, measures the surface chemistry of a potential material for use in fusion using X-ray photoelectron spectroscopy.

Photo courtesy of the Idaho National Lab

security protocols

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

“The radioactive decay of tritium takes the form of a weak beta emitter. This type of radiation can be blocked by a few inches of water,” Jonathan Cobb, spokesman for the World Nuclear Association, 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 isn’t radioactive, Cobb explained.

In 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.

However, the behavior of tritium has yet to be studied because it is radioactive. Specifically, the Idaho National Lab is studying how tritium interacts with the material used to build a fusion-containing machine. In many cases, this is a donut-shaped machine called a tokamak.

In order for a fusion reaction to take place, the fuel sources must be heated to form a plasma, the fourth state of matter. These reactions take place at extraordinarily high temperatures of up to 100 million degrees, which can potentially impact how much and how quickly tritium can get into the material holding the plasma, Shimada said.

Most fusion reaction vessels are made from a special type of stainless steel with a thin layer of tungsten on the 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 produced in the fusion reaction can cause radiation damage even in tungsten.

Here, at the Idaho National Lab, a Sandia National Laboratories employee, Rob Kolasinski, works with a glove box for the tritium plasma experiment.

Photo courtesy of the Idaho National Lab

The team’s research aims to provide merger companies with a dataset to find out when this might happen, so they can identify and measure the security of their programs.

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

“The goal of our research is to help fusion reactor designers predict when tritium accumulation in the materials and tritium permeation through the ship will reach unacceptable levels,” Shimada told CNBC. “This allows us to establish protocols to heat (i.e., bake out) the materials and remove tritium from the container to reduce the risk of potential tritium release in the event of an accident.”

While the Idaho National Lab is studying tritium’s behavior to set safety standards for the burgeoning industry, its waste is far less problematic than today’s fission-powered nuclear plants. The federal government has been studying how to create a repository for fission-based waste for more than 40 years and has not yet found a solution.

“Fusion does not produce long-lived radioactive nuclear waste. This is one of the advantages of fusion reactors over fission reactors,” Shimada told CNBC.


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