World Largest Nuclear Fusion Experiment

 

Fusion power promises to provide limitless green energy using cheap and abundant fuel. 

Conventional nuclear power plants generate energy by splitting atoms, nuclear fusion involves smashing two atoms together. This produces dramatically more energy than the process of fission that we’ve already mastered and doesn’t produce long-lived radioactive waste. It also doesn’t rely on radioactive elements like uranium and plutonium for fuel, instead using abundant isotopes of hydrogen called deuterium and tritium.

The only catch is that trying to contain a nuclear fusion reaction is like trying to keep the sun in a box. It’s the same reaction that powers all stars, and trying to corral that kind of raw power and turn it into something we can use effectively is a challenge scientists have been struggling with for decades.

To get the fuel to fuse, it first has to be heated to 10 times the temperature of the sun’s core, which creates a superhot plasma. To maintain the fusion reactions, this plasma needs to be strictly confined and isolated from other components. Fortunately, plasmas can be manipulated using magnetic fields, and so gigantic electromagnets are used to keep the plasma spinning around a donut-shaped reactor called a tokamak.

The problem is that all this heating and magnetic confinement requires colossal amounts of energy. While we’ve managed to get fusion reactions running on Earth they’ve always used considerably more energy than they’ve produced. The International Thermonuclear Experimental Reactor (ITER) in France is designed to change that.

The project has been a long time in the making. The idea was formulated at the tail end of the Cold War as a multinational collaboration, but design work didn’t properly start until the turn of the millennium, and its parent organization wasn’t launched until 2007. Last week French president Emmanuel Macron hosted a ceremony to celebrate the beginning of the assembly of the reactor.

Over the past five years factories, universities, and national laboratories all over the world have been working to build the components for the plant, some of which weigh several hundred tons, including a magnet powerful enough to lift an aircraft carrier. It will take another five years to piece all the parts together and get the reactor ready for its first test run.

“Constructing the machine piece by piece will be like assembling a three-dimensional puzzle on an intricate timeline,” director-general of ITER Bernard Bigot said in a press release. “Every aspect of project management, systems engineering, risk management, and logistics of the machine assembly must perform together with the precision of a Swiss watch.”

The hope is that by 2025 the plant will be able to produce “first plasma,” a test designed to make sure the reactor works; the test will produce roughly 500 megawatts of thermal power. It will be another decade until the plant is expected to produce enough energy to be commercially viable, though. That will involve building an even larger plasma chamber to provide 10-15 times more electrical power.

Manufactured by India, the ITER cryostat is 16,000 cubic meters,” ITER officials said in a release. “Its diameter and height are both almost 30 meters and it weighs 3,850 tons. Because of its bulk, it is being fabricated in four main sections: the base, lower cylinder, upper cylinder, and top lid.”

Officials say the ITER nuclear fusion reactor is poised to be the most complicated piece of machinery ever built. It will contain the world’s largest superconducting magnets, needed to generate a magnetic field powerful enough to contain a plasma that will reach temperatures of 150 million degrees Celsius, about 10 times hotter than the center of the sun.