image source,Philip Saltonstall
Inside the fusion facility at Lawrence Livermore National Laboratory
American scientists announced a major breakthrough in nuclear fusion (nuclear fusion) research, realizing for the first time the net energy gain of a fusion reaction, that is, the energy generated from a fusion experiment is more than the energy that initiates the reaction.
Physicists have been studying the technology for decades because of its promise as a potential source of near-infinite clean energy.
But experts say there is still some way to go before fusion can power the average home.
The experiment was performed at the National Ignition Facility at Lawrence Livermore National Laboratory (LLNL) in California.
Dr Kim Budil, director of Lawrence Livermore National Laboratory, said: “This is a historic achievement … thousands of people have contributed to this effort over the past 60 years , we need real vision to get here.”
The principle of nuclear fusion reaction is the same as that of the sun and other stars releasing energy, so it is called “little sun” by the scientific community, and also known as the “holy grail” in the field of energy.
Its working principle is to use 192 lasers to heat hydrogen fuel spheres to more than 100 million degrees Celsius, and apply a pressure of more than 100 billion times the earth’s atmospheric pressure to fuse hydrogen atoms and release energy.
It is the opposite of nuclear fission technology currently used in nuclear power plants. In nuclear fission, heavy atoms split into lighter atoms, a process that produces large amounts of radioactive waste.
Fusion produces more energy, produces only a small amount of radioactive waste, produces no greenhouse gas emissions, and therefore does not contribute to climate change.
But one of the challenges is that forcing the elements to fuse together requires very high temperatures and pressures. Previously, no experiment had been able to generate more energy than needed to make it work.
The National Ignition Facility in California cost $3.5bn (£2.85bn).
In announcing the breakthrough, Dr. Marvin Adams, deputy administrator for defense programs at the National Nuclear Security Administration, said the lab’s laser delivered 2.05 megajoules of energy to the target, which then produced 3.15 megajoules of energy. Fusion energy output.
Professor Gianluca Gregori, professor of physics at the University of Oxford, said: “Today’s success is due to the work of many scientists in the US, UK and around the world. With ignition now achieved, not only fusion energy is being unlocked, and the door to new science is opening.”
Jeremy Chittenden, professor of plasma physics at Imperial College London and co-director of the Center for Inertial Fusion Research, called this “a real breakthrough moment”.
“It proves that the long-sought goal, the ‘holy grail’ of nuclear fusion, can indeed be achieved,” he said.
On the question of how soon humans might see nuclear fusion being used to generate electricity, Lawrence Livermore National Laboratory Director Budier said that there are still major obstacles, but “with concerted efforts and investment, decades of research on the underlying technology research and we can build a power plant.”
Currently, major hurdles include reducing costs and scaling up energy output.
How far are we from a fusion energy future?
Rebecca Morelle, BBC Technology Editor
The amount of energy they generated in this experiment was tiny — just enough to boil a few pots of water — but the implications it represented were enormous.
This brings us one step closer to a fusion powered future. But there is still a long way to go before this becomes a reality.
This experiment shows that the scientific principle works. It needed to be repeated and perfected, and the power it produced had to be significantly boosted, before scientists might even consider scaling it up.
The experiment has cost billions of dollars—nuclear fusion doesn’t come cheap. But the commitment to clean energy sources is sure to be a big boost in overcoming these challenges.
