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Bringing a Sun to Earth: Briefing Explains ITER Fusion Experiment

By Nadia Ramlagan

ITERPublished with permission of ITER


The Iter Device

A September briefing on Capitol Hill was held to drum up support for ITER funding in the Fiscal Year (FY) 2009 budget, after negotiations between Congress and the White House on the FY 2008 budget left $160 million of ITER funding nearly “zeroed out”.

As a result, ITER-related research received only $10.7 million in funding. However, funding could be restored next year, as both the House and Senate appropriations packages for FY 2009 include full funding for US contributions to ITER.

Ned Sauthoff, Director and Project Manager of the US ITER project at Oak Ridge National Laboratory (ORNL) discussed the science of fusion, the ITER experiment, and benefits of US participation. Representative Rush Holt (D-NJ) also spoke briefly, stressing the importance of participating in large-scale international research projects, and the enormous potential of fusion power to solve serious energy resource and environmental problems currently facing the US and the rest of the world.

ITER is an international project that aims to demonstrate the scientific and technological feasibility of fusion energy. In 2006, the United States, countries of the European Union, Japan, Russia, South Korea, and India signed an official agreement to build the experiment at Cadarache, in southern France. Built with hardware manufactured from all 6 parties, ITER will use strong magnetic fields to confine burning torus-shaped plasma at temperatures around 200 million degrees K,  producing nearly 500 million watts of power. Early construction of the ITER facility is underway, and the device is set to begin operation in 2016.

As the host country, France is expected to pay about 50 percent of total costs. Each of the other 5 parties pays roughly 9-10 percent, “but gets access to all data, the right to propose and conduct experiments, and is a joint owner of the intellectual property rights,” said Sauthoff.

ITER will fuse deuterium and tritium together to form helium and a neutron, while releasing 10 times the amount of energy originally needed to make the nuclei fuse. If all scientific objectives are met and ITER is successful, it will be the first fusion reactor to create significantly more energy than it uses.

Sauthoff showed images of Dr. Otto Octavius, the main villain in 2004’s Spider-Man 2. The comic’s notorious mad-scientist wants to overrun the world with cheap fusion power. “Hollywood says fusion is a part of our future,” he joked. Aside from its movie appeal, fusion is attractive for several reasons. It is safe, involves no emission of greenhouse gases, and is capable of large-scale energy production.  

To illustrate fusion power’s cleanness and efficiency, Sauthoff compared a 1,000 MW coal-fired plant to a 1,000 MW fusion plant (both provide enough energy to power 500,000 homes). Each day, a coal fired plant consumes 9,000 tons of coal and produces 30,000 tons of carbon dioxide, 600 tons of sulfur dioxide, and 80 tons of nitrogen dioxide. In stark contrast, a fusion plant would consume 1 pound of deuterium, 3 pounds of lithium-6 (1.5 pounds of tritium), and produce a mere 2 pounds of helium-4 (0.5 pounds of neutrons).

Self-sustaining fusion reactions or “burning plasma” can only occur at extremely high temperatures. Because the plasma is too hot to be contained by any material, strong magnetic fields are used to hold it in place, providing a shield from the walls of the reactor. The magnetic confinement of fusion is also inherently safe. “If the plasma hits the wall, it cools itself and the reactor shuts itself down,” explained Sauthoff.

Aside from personnel and funding for basic expenses, in-kind US contributions to ITER include hardware and instrumentation. The US will produce ITER’s 8,700 ton magnet system, using niobium stannide (Nb3Sn) coils to produce toroidal fields which will confine and stabilize the plasma. Positioning and shaping of the plasma will occur by niobium titanium coils, and a modular Nb3Sn central solenoid coil will be used to induce current in the plasma. “The US is supposed to supply 40 tons of niobium tin superconducting wire, so the superconducting industry is very excited about this,” Sauthoff said.  

The US will supply 20% of the tiles that absorb the power from the plasma, comprising blanket, port limiter, and diverter systems. In addition, 100% of the ion and electron cyclotron systems’ transmission lines will be supplied by the US. “We [the US] are also fueling the plasma,” Sauthoff said. ITER’s burning plasmas will be fueled primarily by injection of frozen hydrogen, deuterium, and tritium pellets into the tokamak. “We call that a snowball in hell,” Sauthoff noted. Once pellets enter the plasma they ablate, adding fuel particles to the plasma core that subsequently results in high fusion gain.  

“At home” research and development will ensure that the US is a future supplier rather than a buyer of fusion technology. The US ITER team (predominantly based at ORNL) is engaging industry and educational facilities across the nation in research and development, engineering, design, and fabrication. There are currently 160 companies and universities in 33 states and the District of Columbia working on ITER.

“Not only is ITER a scientific and technological experiment, it is equally an experiment in international collaboration. We have to learn how to work together and develop project management with other cultures,” said Sauthoff.

The briefing was sponsored by the American Society of Mechanical Engineers (ASME) and the Institute of Electrical and Electronics Engineers (IEEE), and held in conjunction with the Congressional Research and Development Caucus.

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Editor: Alan Chodos
Staff Writer: Ernie Tretkoff
Contributing Editor: Jennifer Ouellette
Science Writing Intern: Nadia Ramlagan