The successful nuclear fusion experiment could pave the way for abundant clean energy in the future, but major hurdles remain.
Scientists have confirmed that a breakthrough has been made that could pave the way for abundant clean energy in the future, after more than half a century of research into nuclear fusion.
Researchers at the US National Ignition Facility in California said the fusion experiments released more energy than the lab’s huge high-powered lasers, a historic achievement known as ignition or energy gain.
The technology is far from ready to become a viable power plant and is not on the cusp of solving the climate crisis, but scientists have hailed the breakthrough as evidence that star power can be harnessed on Earth.
The Doctor. Arati Prabhakar, director of policy at the White House Office of Science and Technology, said: “Last week… they fired a bunch of lasers at a fuel pellet and more energy was released from the fusion ignition than the laser energy . This is a tremendous example of what perseverance can really accomplish.”
Nuclear fusion power boosts prospect of plentiful clean energy
The reactions do not release greenhouse gases or radioactive waste by-products. A single kilogram of fusion fuel, made up of heavy forms of hydrogen called deuterium and tritium, provides as much energy as 10 million kilograms of fossil fuel. But it took 70 years to get to that point.
Speaking at Tuesday’s announcement, Jill Hruby of the National Nuclear Security Administration (NNSA) said the United States “has taken the first tentative step toward a clean energy source that could revolutionize the world.”
The National Ignition Facility is a vast complex at Lawrence Livermore National Laboratory near San Jose. It was built to conduct experiments that briefly and in miniature recreate the processes triggered inside nuclear bombs, allowing the US to maintain its nuclear warheads without the need for nuclear tests.
But experiments are also stepping stones to clearing fusion power. To get the reactions, the researchers fired up to 192 giant lasers at a centimeter-long gold cylinder called a hohlraum. The intense energy heats the container to over 3 million degrees Celsius, hotter than the surface of the sun, and bathes a peppercorn-sized fuel pellet in X-rays.
X-rays pierce the surface of the pellet and trigger a rocket-like implosion, raising temperatures and pressures to extremes only seen inside stars, giant planets and nuclear detonations. The implosion reaches speeds of 400 km per second and causes the deuterium and tritium to fuse together.
Each pair of fusing hydrogen nuclei produces a lighter helium nucleus and a burst of energy according to Einstein’s equation E=mc two 🇧🇷 Deuterium is easily extracted from seawater, while tritium can be obtained from lithium found in the Earth’s crust.
successful experience
In the most recent experiment, the researchers injected 2.05 megajoules of laser energy and got about 3.15 MJ, a gain of about 50% and a sign that the fusion reactions in the pellet were driving more fusion reactions. “Producing energy took less time than it takes light to travel an inch,” said Dr. Marvin Adams of the NNSA.
However, huge obstacles remain in the quest for fusion power plants. Although the pellet releases more energy than the lasers, the calculation doesn’t include the roughly 300 megajoules needed to turn on the lasers. NIF lasers fire once a day, but a power plant would need to heat targets 10 times a second. Then there is the cost of goals. The ones used in the US experiment cost tens of thousands of dollars, but for a viable plant they would have to cost pennies. Another problem is how to obtain the energy in the form of heat.
The Doctor. Kim Budil, director of the Lawrence Livermore National Laboratory, said that with enough investment, “a few decades of research could put us in a position to build a power plant.” A power plant based on alternative technology used on the Joint European Torus (JET) in Oxfordshire could be ready sooner, he added.
“In a way, everything changes; in another, nothing changes,” said Justin Wark, professor of physics at the University of Oxford and director of the Oxford High Energy Science Centre. “This result proves what most physicists have always believed: fusion in the laboratory is possible. However, the hurdles that need to be overcome to make something like a commercial jet are enormous and should not be underestimated.”
without certainties
He said that asking how long it would take to overcome the challenges was like asking the Wright brothers how long it would take to build a plane to cross the Atlantic right after its maiden flight. “I understand that everyone wants to think of this as the big solution to the energy crisis. It is not, and anyone who says that is certainly mistaken.
“It is highly unlikely that the merger will have an impact on a timescale short enough to affect our current climate change crisis, so we must not compromise in our efforts in this regard.
“The latest results also show that the basic science works, the laws of physics do not prevent us from reaching the goal, the problems are both technical and economic. As Niels Bohr, the Nobel Prize-winning atomic physicist, once said, “Forecasting is very difficult, especially when it comes to the future.”
The Doctor. Mark Wenman, professor of nuclear materials at Imperial College London, called the achievement “a fantastic scientific breakthrough, something we haven’t achieved in 70 years of trying”. But he said: “The challenges remain as to how you can get energy out of the system, how can you keep the energy long enough to make it useful, how do you increase that energy and can the energy be cheap enough to compete with other sources”. 🇧🇷
By Ian Sample. Article in English