The Future of Fusion Energy
(Inside Science) -- The United States, along with 34 other nations, is making a massive investment in time and money to help to build a huge experimental nuclear fusion reactor in the south of France that bills itself as one of the most ambitious energy projects in the world today.
Already more than a decade in the making, critics have questioned its large budget, its ability to keep on schedule and other issues. But proponents say it has the potential to prove out the ability of fusion power plants to provide limitless, clean energy and secure the planet’s future.
Fusion -- it’s how the sun makes energy. And every day, the sun sends out an enormous amount of energy. It radiates more energy each day than the entire Earth uses in one year, and provides more energy in one hour than the entire U.S. can use in a year!
Now imagine if we could re-create even a fraction of that energy using the same process the sun does.
That’s exactly what scientists across the globe plan to do with a mega-project called ITER. It’s a nuclear fusion experiment and engineering effort to bridge the valley toward sustainable, clean, limitless energy-producing fusion power plants of the future.
Dennis Whyte of Massachusetts Institute of Technology said, “It’s a very large international collaboration. The United States is part of it. In fact, most of the industrial world is part of this collaboration.
“So right now for instance we expect the very first operations of it in about a decade. And by the latest schedule, the first time it will actually try to get net energy is roughly 20 years away. So ITER is a very exciting experiment, but it’s a little bit frustrating though that it’s taking a while as well too,” said Whyte.
The project officially began in 2006, with an estimated finish date of 2016. Scientists are now aiming for the year 2025 for completion. Researchers acknowledge it’s been an ever-changing journey.
“When we started off, I think, when the agreement was signed, there was still a lot of work to be done on the design and things to be figured out. So, the estimates of time and budget were, you know, not that, not that accurate at that stage. So, the world has been working through all of the issues, and we’ve now closed that out; the design of this machine is, is now finished. Nearly all of the parts have gone out to contract and are now being worked upon,” said Richard Buttery of General Atomics, in San Diego, California.
When it’s finished, the future of energy will be amazing. Unlike fission that happens in a traditional nuclear power plant, where the energy comes from the splitting of heavy atoms, nuclear fusion happens when two lighter atoms come together -- releasing huge amounts of energy. It produces much less waste than even the most advanced nuclear power plants and fossil fuel plants of today -- it’s good, clean energy. But it has its challenges.
“The barriers are largely technological. They are primarily materials. How are the materials going to withstand? We want to make a huge flux of neutron radiation. That’s the whole idea. And we want to create plasmas that are hundreds of millions of degrees hot,” said John Scoville of General Atomics.
Traditional power plants rely mostly on fossil fuels, or water. ITER relies on a tokamak. Inside a tokamak, the energy produced through the fusion of atoms colliding is absorbed as heat in the walls of the tokamak. A fusion power plant will use the heat to produce steam and then electricity.
“So, you have a magnetic field going around the doughnut that holds everything together very strongly and then we drive a small plasma current through this, and that gives us our magnetic structure that works. And so, that is the Tokamak concept,” said Buttery.
In the ITER tokamak, temperatures will reach 150 million degrees Celsius, or over 270 million degrees Fahrenheit. That’s ten times the temperature at the core of the sun.
“And so, can the materials of the tokamak withstand the power levels that we are going to be able to put into the machine in the next generation?” said Scoville.
“It will be able to destroy itself if we don’t be careful. So, we’re going to have to be able to control the instabilities that we’re investigating largely with the variable voltage beams. That’s going to help us investigate a lot of instabilities,” said Scoville.
The goal of ITER is to prove it's possible to produce a net gain of energy. That means it will produce more power than it takes to make it. It will produce 500 megawatts of output power but only use 50 megawatts of input power.
The fuel for ITER comes from deuterium, also called ‘heavy water,’ which is found in the earth’s oceans.
“The fuel is abundant and plentiful and cheap. The top one inch of San Diego Bay has enough fuel to provide San Diego with power for 50 years in a fusion power plant.” said Scoville.
With the huge abundance of potential fuel and minimal waste output, the ITER project sets the stage for the future of power plants.
“And the idea is, is that you would have multiple followers to ITER, each country making its own variants, that take the crucial knowledge we learn from ITER and take some of the things that we learn from other facilities, and build that into something that can run continuous, generate power continuously,” said Buttery.
“It’s probably the largest scientific experiment we’ve ever tried, like humanity has ever tried. And because of that scale, then it requires and has required a level of political and economic, you know, pooling, which is almost unprecedented as well,” said Whyte.
“We’re going to have to provide energy for humanity for thousands of years. And fusion really is the only way I see that that’s going to happen,” concluded Scoville.