SBS 6 DEC 2015
As conventional clean power options such as wind and solar energy take focus at climate discussions in Paris, scientists around the world continue to work on a more ambitious solution to lowering emissions from energy production – nuclear fusion.
For three decades, scientists from a coalition of 35 countries have been working on an experimental technology, which they hope will pave the way for limitless clean-energy production.
What they are trying to produce is a reactor that can generate a nuclear fusion reaction, which is the fusing of atomic nuclei through exposing them to extreme force and heat, the chemical process that occurs naturally on the surface of the sun. If the energy released from this chemical reaction can be captured and stored, it could provide an abundant, man-made clean energy source.
The project is called ITER, or the International Thermonuclear Experimental Reactor, and is a US$20 billion experiment to create a star on earth and harness its energy.
As world leaders meet in Paris for the 2015 United Nations Climate Change Conference in the hope of securing an agreement on reducing global carbon emissions, nuclear fusion has been largely left out of the popular conversation.
ITER is funded by the European Union, the United States, Russia, Japan, India, South Korea and China, who hope the multibillion dollar experiment will create an energy source that if harnessed, could provide stable and safe power that is free of carbon emissions.
Although Australia is not an official partner to ITER, it has been contracted to work on imaging technology that measures plasma temperature and flow in the reactor.
Professor John Howard, director of the Plasma Fusion Research Facility at Australian National University (ANU), is in charge of Australia’s contribution to ITER, and said the issue for scientists is generating a fusion reaction that is net power positive – or requires less power to create than it emits.
“The way it works is it takes the primordial element hydrogen, and isotopes of hydrogen, brings it together under enormous pressure – because these nuclei like to push each other apart, like trying to push magnets together – and then when they get close enough the nuclear force grabs the particles and they fuse,” he said.
“When they fuse, they make a new element and it releases a lot of energy through E = mc2, and we catch that energy.”
According to ITER’s website, the most efficient fusion reaction in a laboratory setting is that between two hydrogen isotopes, deuterium and tritium, which is what it will use.
“At extreme temperatures, electrons are separated from nuclei and a gas becomes a plasma,” ITER’s website explains. “Fusion plasmas provide the environment in which light elements can fuse and yield energy.”
According to Professor John Howard, once this yield has been achieved with net power gain, there is a possibility to produce energy at significant scale.
“It’s a very hard thing to do but if you can make fusion go, then you’re burning isotopes of hydrogen, which are clean, and the by-product is helium, which is the gas that fills up balloons,” he said. “And the neutrons escape and carry the energy.”
“So there’s an essentially limitless amount of fuel – clean energy produced limitlessly, that is the allure of fusion.”
‘A big mistake’
To create a fusion reaction, the 23,000-tonne ITER reactor will contain temperatures of up to 150 million degrees Celsius – hotter than the core of the sun.
The reactor, which is being built in the south of France, began site preparation in 2007 with plans to begin trials around 2019. However due to delays, reports suggest this timetable is increasingly unlikely, and ITER has pledged to release a revised schedule for the project mid-2016.
But not everyone believes governments should be investing in an unproven technology.
Greenpeace nuclear and energy campaigner, Sebastien Blavier, said the cost and uncertainty of fusion mean investing in thermonuclear reactors at the expense of other available clean energy options is risky and ignorant.
“We are opposed to this argument of fusion being the future of power for humanity, that’s totally false for us,” he said. “Today the world is facing massive challenges like poverty, like access to electricity for people, poor people, for development.”
“We now how have the solution with renewables like solar and wind – they are affordable, they are cheap. For the moment ITER is presented as being the solution for the future power of humanity and I think that’s a big mistake.”
“If you look at the costs, it’s a massive amount of money that could be invested in renewables that are already ready to take off and be competitive; so it’s not a solution to future power, it’s only research.”
Nuclear fusion vs nuclear fission
What is commonly referred to as nuclear energy is the chemical process called nuclear fission, which captures the energy released by splitting, rather than fusing, the nucleus of most often uranium atoms.
Nuclear fission currently meets around 11 per cent of the world’s electricity demand, with more than 400 reactors currently in operation around the world. However it has its risks.
While a fusion reactor would remain dangerously radioactive for around 50 years after its use, it would leave almost no residual radioactive material. Fission reactors, on the other hand, produce a large quantity of atomic fragments that can remain radioactive for centuries.
“Fission reactors are inherently unsafe, the world has seen this over and over again, and this is why we’re reluctant and hesitant,” Professor Howard said.
“We can’t spoil our planet, but on the other hand we’re faced with the problem of spoiling the entire planet through global warming and the liberation of the by-products of energy production.
“Fusion reactors are inherently safe; they can never go unstable because there’s not a chain reaction. It’s like lighting a match and keeping it lit, or lighting a fire, you’ve got to keep adding fuel to the fire to keep it burning.”
While the science behind fusion energy has been well understood for decades, the quest to create fusion reactions on earth that can be harnessed as a power source has remained out of reach.
In 1997 the Joint European Torus (JET) reactor produced a record 16 megawatts of fusion power, however it took 24 megawatts of input power to create; a net loss. If successful, ITER will produce 500 megawatts of power for 50 megawatts of input power, a tenfold return.
Dr Cormac Corr works with Professor Howard at ANU and is researching how different materials interact with the intense heat of the plasma used inside ITER and other experimental fusion reactors.
He says one of the grand challenges of fusion science is to find materials that can withstand these extreme environments. At ANU, he and his team have developed a Magnetised Plasma Interaction Experiment (MAGPIE), which simulates conditions at the edge of a fusion reactor, on a small scale and in controlled conditions.
“In that device is a linear plasma device and we put materials into the way of the plasma and essentially bombard it – bombard the materials with energetic ions and neutral species, so atoms and molecules and so forth,” he said.
“It’s an experimental test bed if you like, for testing these materials under extreme conditions.”
Despite the progress being made, even the most hopeful scientists recognise that capturing and storing fusion energy for common use is likely half a century away.
Listen to the SBS Radio report: