Nuclear scientists say they are on the “threshold” of a breakthrough in nuclear fusion, raising hopes for a potentially unlimited source of clean energy.
The US National Laboratory Lawrence Livermore (LLNL) on Tuesday hailed the “historic” breakthrough after focusing 192 laser beams on a capsule the size of a peppercorn, creating an explosion of fusion energy eight times greater than ever before.
While the energy released only lasted 100 trillion seconds, the 1.3 megajoules it generated was equivalent to 70% of the energy used by the lasers that triggered the process.
This brings scientists closer to the holy grail of “ignition”, when the fusion process generates more energy than it uses.
“This result is a historic breakthrough for inertial confinement fusion research,” said Kim Budil, director of the LLNL.
The experiment was carried out on August 8 at the National Ignition Facility at LLNL in California. While plans to repeat the process are underway, it will take “several months” to complete them, the lab said in a statement.
What is nuclear fusion?
The nuclear fusion process “marries” two light atomic nuclei to create one heavy one.
This is the process that is at work in the stars, including our Sun.
In the experiment, the scientists used two isotopes of hydrogen, giving rise to helium.
Fusion is considered by some experts as a potential energy of the future because it does not produce greenhouse gases and little waste.
It differs from fission, the technique currently used in nuclear power plants, where the bonds of heavy atomic nuclei are broken to release energy.
“The NIF teams have done an amazing job,” said Professor Steven Rose, co-director of the Center for Inertial Fusion Studies at Imperial College London.
“This is the most significant advance in inertial fusion since its inception in 1972.”
But, warned Rose co-chair Jeremy Chittenden, making fusion a usable source of energy isn’t going to be easy.
“Transforming this concept into a renewable electric power source will likely be a long process and will involve overcoming significant technical challenges,” he said.
For this to happen, ignition, the process that produces more energy than it consumes, is essential and will be the holy grail for companies trying to commercialize fusion.
A statement from the LLNL said that what is essential about the experiment, the results of which have yet to be peer-reviewed, is that it takes an “important step towards ignition”.