Several fusion projects are in the US, United Kingdom and Europe. France is home to the International Thermonuclear Experimental Reactor, on which thirty-five countries are collaborating — including main members China, the United States, the European Union, Russia, India, Japan and South Korea.
In the US, much of the work is happening at the National Ignition Facility at the Lawrence Livermore National Laboratory in California, where scientists recently achieved a net energy gain in a fusion reaction, the Financial Times reported, citing three people with knowledge of the experiment.
This is important because everyone hopes that fusion which until fission has no nasty waste and unlike coal, gas and oil emits no CO2, will be the magic fuel of the future. They only problem has been that experiments have taken more energy than they generate.
Scientists around the world have been studying nuclear fusion for decades, hoping to recreate it with a new source that provides limitless, carbon-free energy — without the nuclear waste created by current nuclear reactors. Fusion projects mainly use the elements deuterium and tritium — both of which are isotopes of hydrogen.
The National Ignition Facility project creates energy from nuclear fusion by what’s known as “thermonuclear inertial fusion.” In practice, US scientists fire pellets that contain hydrogen fuel into an array of nearly 200 lasers, essentially creating a series of extremely fast, repeated explosions at the rate of 50 times per second. The energy collected from the neutrons and alpha particles is extracted as heat.
In the UK and the ITER project in France, scientists are working with huge donut-shaped machines outfitted with giant magnets called a tokamak to try to generate the same result. Plasma needs to reach at least 150 million degrees Celsius, 10 times hotter than the core of the sun. The neutrons then escape the plasma, hitting a “blanket” lining the walls of the tokamak, and transferring their kinetic energy as heat.
The deuterium from a glass of water, with a little tritium added, could power a house for a year. Tritium is rarer and more challenging to obtain, although it can be synthetically made.
“Unlike coal, you only need a small amount of hydrogen, and it is the most abundant thing found in the universe,” Julio Friedmann, chief scientist at Carbon Direct and a former chief energy technologist at Lawrence Livermore, told CNN. “Hydrogen is found in water so the stuff that generates this energy is wildly unlimited and it is clean.”
News that finally, there is net energy is immense. It is theorized that a small cup of hydrogen fuel could potentially power a house for hundreds of years.
“If this is confirmed, we are witnessing a moment of history,” said Dr Arthur Turrell, a plasma physicist, told the FT. “Scientists have struggled to show that fusion can release more energy than is put in since the 1950s, and the researchers at Lawrence Livermore seem to have finally and absolutely smashed this decades-old goal.”
Whereas fusion fuses two or more atoms together, fission is the opposite; it is the process of splitting a larger atom into two or more smaller ones. Nuclear fission is the kind of energy that powers nuclear reactors around the world today. Like fusion, the heat created from splitting atoms is also used to generate energy.
The big challenge of harnessing fusion energy is sustaining it long enough so that it can power electric grids and heating systems around the globe. The successful US breakthrough is a big deal, but it’s still on a far smaller scale than what’s needed to generate enough energy to run one power plant, never mind tens of thousands of power plants.
“It’s about what it takes to boil 10 kettles of water,” said Jeremy Chittenden, co-director of the Centre for Inertial Fusion Studies at Imperial College in London. “In order to turn that into a power station, we need to make a larger gain in energy — we need it to be substantially more.” East Bay Times
