A scientific institute in the United States is about to make a “huge breakthrough” in nuclear fusion research.
The National Ignition Facility ( NI F ) in Livermore, California – which uses a powerful laser to heat and compress hydrogen fuel – is one step away from reaching a gigantic nuclear fusion.
According to an experiment carried out this month, the lab will soon achieve the goal of “ignition,” where the energy released by fusion will exceed that released by the laser.
Harnessing nuclear fusion, the process that powers the Sun, could provide us with a clean and unlimited source of energy .
What is the merger?
That capsule contains deuterium and tritium, which are different forms of hydrogen, natural isotopes.
This process compresses the fuel to 100 times the density of lead and heated to 100 million degrees Celsius, hotter than the center of the sun . They are conditions that help drive thermonuclear fusion.
“A huge advance”
An experiment that was carried out on August 8 produced 1.35 megajoules (MJ) of energy, about 70% of the laser energy delivered to the fuel capsule.
Reaching ignition will mean obtaining a fusion performance greater than the 1.9 MJ introduced by the laser.
“This is a huge advance for nuclear fusion and for the entire (scientific) community,” Debbie Callahan, a physicist at the Lawrence Livermore National Laboratory, which houses the NIF, told the BBC.
As a measure of progress, the performance of this month’s experiment is eight times the previous NIF record, set in spring 2021, and 25 times the performance of experiments conducted in 2018.
“The pace of improvement in energy production has been rapid, suggesting that we will soon be able to reach more energy milestones, such as exceeding the energy input of the lasers used to start the process,” said Professor Jeremy Chittenden, co-director of the Center for Inertial Fusion Studies at Imperial College London, UK.
In addition, the NIF scientists also believe that they have now achieved something called “fiery plasma” , which occurs when the fusion reactions themselves provide the heat for further fusion.
This is vital for the process to be self-sustaining .
“Self-sustaining [fuel] burning is essential for high performance,” Callahan explained. “The combustion wave has to propagate into the high-density fuel to extract a lot of fusion energy.”
“We believe this experiment is at that point, although we are still doing analysis and simulations to make sure we have a good understanding of the result.”
As for the next step, Callahan said the experiments will be repeated. “It is fundamental for experimental science; we need to understand how reproducible and how sensitive the results are to small changes,” said the scientist.
“After that, we will generate ideas on how to improve and l design , and start working on them next year.”
“The megajoule of energy released in the experiment is really impressive in terms of fusion, but in practice this is equivalent to the energy required to boil a kettle,” explained Professor Chittenden.
He added: “Much higher fusion energies can be achieved through ignition if we can figure out how to hold the fuel together for longer, to allow it to burn more . This will be the next horizon for inertial confinement fusion.”
Fusion, fission and nuclear weapons
Existing nuclear energy is based on a process called fission, in which a heavy chemical element is divided to produce lighter ones.
Fusion works by combining two light elements to make one larger and heavier.
Construction of the NIF began in 1997 and was completed in 2009. The first experiments to test the power of the laser began in October 2010.
The other function of the NIF is to help ensure the safety and reliability of the United States’ nuclear weapons arsenal .
At times, scientists who want to use the huge laser for fusion have been squeezed by experiments aimed at national security.
In 2013, the BBC reported that during experiments at the NIF, the amount of energy released through fusion had exceeded the amount of energy absorbed by fuel, a breakthrough and a first for any fusion facility in the world.
The results of these tests were later published in the scientific journal Nature .
NIF is one of several projects in different parts of the world aimed at promoting nuclear fusion research. These include the Iter facility , with an investment of billions of euros, currently under construction in Cadarache, France.
Iter will take a different approach to laser-driven fusion at NIF; The facility in southern France will use magnetic fields to contain hot plasma, electrically charged gas. This concept is known as magnetic confinement fusion (MCF).
But building commercially viable fusion facilities that can power the grid will require another big leap.
“Converting this concept to a renewable source of electrical energy will likely be a long process and will involve overcoming substantial technical challenges, such as being able to recreate this experiment several times per second to produce a constant source of energy,” Chittenden summarized.
