Scientists break fusion power record

The quest to generate clean energy like that produced inside our Sun and other stars moved a step closer to reality recently when scientists in the United Kingdom broke the record for power released in a sustained fusion reaction.

In early February, scientists at the Joint European Torus (JET) facility reported producing 59 megajoules of energy over five seconds (11 megawatts of power) in a fusion reaction, more than doubling the previous record of 21.7 megajoules set in 1997 at the same facility.

Based near Oxford, England, JET is operated by the Culham Centre for Fusion Energy and is the focal point of Europe's fusion research. CCFE is a member of the EUROfusion consortium, which includes 30 fusion research organizations and universities from 25 European member states, plus Switzerland, Ukraine, and the UK.

Ultimate clean energy

Fusion power is considered by many to be crucial to a successful global strategy for addressing climate change with a safe, efficient, sustainable, and abundant low-carbon energy supply.

As the name suggests, nuclear fusion is the fusing of two or more atoms into one larger one, a process that unleashes a tremendous amount of energy as heat – the same fusion reaction that powers the Sun.

The fusion process at JET produces energy in a controlled environment using deuterium and tritium, two rare components sourced from hydrogen.

A magnetic field is needed to contain the hot temperatures required to carry out the fusion process, which can heat to 150 million degrees Celsius, 10 times hotter than the center of the Sun.

Pioneer in fusion research

JET studies nuclear fusion in conditions approaching those needed for a power plant. It is the only experimental laboratory that can operate with the deuterium-tritium fuel mix that will be used for commercial fusion power.

Since operations began in 1983, JET has made major advances in the science and engineering of the fusion process. Its success led to the construction of ITER, the first commercial-scale fusion power machine, and has increased confidence in the tokamak as a design for future fusion power-generating facilities.

Research at JET is focused on 'magnetic confinement' fusion, in which a hot gas, or "plasma," is controlled with magnets inside a ring-shaped chamber known as a "tokamak."

The program covers all the key areas of study in magnetic confinement fusion research, from theoretical and experimental physics to materials science and engineering technology.

Other milestones achieved at the JET Laboratory include installing a new beryllium-tungsten plasma facing wall in 2009 to test the configuration for ITER.

Small but mighty

Five seconds is the limit that JET's tokamak can sustain the power before its magnets overheat.

Though not a massive energy output – enough to boil nearly 60 kettles of water – the new record further validates design choices for a commercial-scale fusion reactor under construction in the south of France.

"If we can maintain fusion for five seconds, we can do it for five minutes and then five hours, as we scale up our operations in future machines," said Tony Donné, EUROfusion program manager, who credited the achievement to years-long preparation by the program's researchers across Europe.

"The record, and more importantly the things we've learned about fusion under these conditions and how it fully confirms our predictions, show that we are on the right path to a future world of fusion energy," Donné said. "This is a big moment for every one of us and the entire fusion community. Crucially, the operational experience we've gained under realistic conditions gives us great confidence for the next stage of experiments at ITER and Europe's demonstration power plant, EU DEMO, which is being designed to put electricity on the grid."

Game-changer for the climate

The record fusion reaction and what it means for the future of this power-generating technology is also considered a major win for lowering global dependence on carbon-burning energy sources.

"These landmark results have taken us a huge step closer to conquering one of the biggest scientific and engineering challenges of them all," Ian Chapman, Ph.D., chief executive of the UK Atomic Energy Authority, said in announcing the new record. "It's clear we must make significant changes to address the effects of climate change, and fusion offers so much potential."

Chapman said the achievement is the reward for over 20 years of research and experiments with JET's partners across Europe.

"We're building the knowledge and developing the new technology required to deliver a low carbon, sustainable source of baseload energy that helps protect the planet for future generations. Our world needs fusion energy," he added.

ITER Director General Bernard Bigot, Ph.D., said the JET results are a strong confidence builder that the giant project is on the right track as it moves forward toward demonstrating full fusion power.

"A sustained pulse of deuterium-tritium fusion at this power level – nearly industrial scale – delivers a resounding confirmation to all of those involved in the global fusion quest," he said.

ITER is a fusion research mega-project, organized in 2006 and supported by seven members – China, the European Union, India, Japan, South Korea, Russia, and the United States.

At ITER, an array of superconducting magnet systems with a combined stored magnetic energy of 51 Gigajoules will produce the magnetic fields that will initiate, confine, shape and control the plasma at temperatures reaching 170 million degrees Celsius.

The building blocks of the magnet system are high-performance, internally cooled superconductors called CICC (cable-in-conduit) conductors, made up of bundled superconducting and copper strands that are cabled together and contained in a structural steel jacket. ITER's extraordinary technical requirements and the sheer amount of material required – 200 kilometers, equivalent to 2,800 metric tons – resulted in a worldwide collaborative procurement effort involving ITER members.

With oversight by the ITER Organization and member countries, production has been underway since 2008. Furthermore, outside reference laboratories have contributed their expertise, performing third-party verification on critical acceptance tests.

For the project's most technically challenging raw material – niobium-tin (Nb3Sn) superconducting strands used in ITER's toroidal field and central solenoid magnet systems – 500 metric tons (more than 100,000 kilometers) of strand were produced by nine suppliers.

This large-scale industrial effort demanded a ramp-up of global production capacity from 15 metric tons to 100 metric tons per year, as well as the introduction of three new strand suppliers.

ITER is also a first-of-a-kind global collaboration. Europe is contributing almost half of the costs of its construction, while the other six members are contributing equally to the remainder.

Fusion not fission

Nuclear fusion is unlike the process used in nuclear power plants today. Instead, the energy at these facilities is created using a different process called nuclear fission, which relies on splitting, rather than fusing, atoms.

But the fission process creates waste that can remain radioactive for tens of thousands of years and is potentially hazardous when released into the environment.

Examples of such incidents include Japan's 2011 Fukushima disaster, which followed a deadly earthquake and tsunami near a nuclear power plant. Other notable nuclear accidents include Chernobyl, which rocked Ukraine in 1986 and Pennsylvania's Three-Mile Island in 1979.

Most fission power plants, however, have produced reliable and clean energy without incident during the past 50 years.

A fusion reactor, like the one at the JET laboratory, generates little waste and requires only small amounts of abundant, naturally sourced fuel, including elements extracted from seawater.