Nuclear fusion prepares for its close-up

For more than half a century, the prospect of nuclear fusion feeding the modern power grid has been a long but unrealistic dream.

But on Tuesday in a city in southern France, the assembly will officially begin in a massive device designed to show that nuclear fusion has applications that can eventually lead to the construction of commercial power plants, generating a virtually inexhaustible energy source without emitting Greenhouse gases and leave without long-lived nuclear waste behind.

And playing a big role in this is San Diego-based General Atomics, which manufactures the heart of the assembled device.

“I think it will completely change the world’s energy economy if the merger continues,” said John Smith, director of magnetic technology at General Atomics.

The project is called ITER, which in Latin means “the way” and is pronounced “dining room”, and it will be the largest nuclear fusion device in the world. It is an international effort with components from 35 partner countries, including the United States.

Construction has been ongoing since 2010 and towers above the city of Cadarache on a site that covers approximately 445 acres. The recent arrival of a vacuum container from South Korea paved the way for machine assembly to begin this week.

French President Emmanuel Macron will host a ceremony to mark the merger experiment and will feature comments from officials representing the United States, the European Union, China, Russia and other countries involved in the project.

ITER’s figurative and literal center is a central solenoid, an incredibly powerful magnet that will allow the device to create and maintain fusion on a scale never before seen by humans. Six modules, each 7 feet tall, 14 feet in diameter, and 250,000 pounds, will be stacked on top of each other to create the solenoid.

The ITER central solenoid kit poses in front of the modules.

The ITER central solenoid team poses in front of the modules to be shipped to France. The modules were assembled and tested at the Magnet Technologies Center on the General Atomics campus in Poway.

(General atomic)

A team of General Atomics scientists, engineers, and workers in the company’s 60,000-square-foot warehouse in Poway has overseen the manufacturing and testing of the modules. A seventh module, a spare, is also being built in case something goes wrong with one of the others.

Each module is surrounded by 3.6 miles of conductive segments and wrapped with six layers of electrical tape totaling more than 180 miles.

One at a time, each module will be transported by a specially designed trailer to the Texas Gulf Coast, then shipped to Marseille, France, before being trucked to ITER. The first module is expected to head to France in the fall.

“I’ve been to the ITER site, and you stand at the bottom where the whole device comes in and you look up and say, ‘Wow, this is great,'” Smith said.

ITER has been dubbed “the world’s largest scientific project”, but its goals are not trivial. In trying to demonstrate that fusion may one day lead to power generation on a commercial scale, the project requires replicating nothing less than what the sun creates.

Nuclear fusion differs from nuclear fission, which is the process used in commercial nuclear power plants, such as the now-closed San Onofre Nuclear Generation Station. Fission divides the nuclei of the atoms to create energy, while the fusion causes the hydrogen nuclei to collide and merge into helium atoms that release enormous amounts of energy.

If any alteration occurs during the fusion process, the plasma cools in seconds and the reaction stops, thus avoiding the risk of a fusion or accident like the one in Fukushima.

While fission plant operators have to deal with spent radioactive fuel or remaining waste, the activated components in a fusion reactor are low enough that the materials can be recycled or reused within 100 years.

Fusion technology was critical in the development of the hydrogen bomb, but as an energy source, there are no fusion reactors. In fact, the fusion power has been generated only for very short periods in the laboratory.

ITER will attempt “to run a fusion experiment for several hundred seconds, which has never been done at the power levels mentioned,” Smith said. “And most importantly, they are going to show what they call the ‘fusion gain.’ That’s where the power it takes to create the fusion reaction will actually get 10 times more reaction power than they put in. “

In the fusion process, a huge donut-shaped chamber called the Tokamak heats the hydrogen until it turns into a cloud-like ionized plasma, which is then formed and controlled by 10,000 tons of superconducting magnets. The fusion occurs when the plasma reaches 150 million degrees Celsius, 10 times hotter than the nucleus of the sun.

The high-energy neutrons from the fusion transmit energy in the form of heat, and the water circulating on the Tokamak’s walls absorbs the leaked heat and generates steam that, in a commercial power plant, would generate electricity through steam turbines.

The components for the ITER Tokamak come from project partners around the world.

“Building the machine piece by piece will be like putting together a three-dimensional puzzle in an intricate timeline,” Bernhard Bigot, CEO of ITER, said in a statement. “We have a complicated script to follow for years to come.”

ITER’s initial demonstration of its functionality, called “first plasma” by scientists and engineers, is scheduled for December 2025.

“Perhaps 15 years ago, I might have had my doubts” about coordinating such a complex effort, Smith said. “Now that I have seen him meet and then work closely with the world group, I have no doubt that he will join.”

Fusion has its share of skeptics, however. The development of commercial fusion reactors has been debated since the 1950s, prompting a continuing joke in the energy industry that fusion as an energy source is always 30 years away.

ITER has been behind schedule and over budget. Twenty years ago, the project was expected to cost around $ 7 billion, but the latest estimates say that by the time the project is operational, the cost could be 10 times higher.

The United States contribution represents approximately 9% of ITER’s costs.

Smith said he is confident ITER can achieve its goals, but it will still be years before commercial nuclear fusion plants become a reality.

“There has to be another demonstration reactor after ITER,” said Smith. “You cannot go from ITER to a power plant. There’s something in between. ”