scientists reach for ‘ignition’ of nuclear fusion

The scientists behind the breakthrough in nuclear fusion late last year, who discovered the possibility of an infinite and clean source of energy in the future, have not yet been able to repeat their historic achievement. However, they are close to it.

Last month, a team at the Lawrence Livermore National Laboratory in California set off a nuclear fusion reaction that produced as much energy as it took to create it, when the world’s most powerful laser blew up a tiny capsule of diamond filled with hydrogen. This one-for-one equilibrium was little less than achieving “ignition” – the long-awaited point at which a controlled fusion reaction produces more energy than was put into it.

Nuclear fusion powers the stars, and “ignition” has become the holy grail for generations of scientists. The Livermore Laboratory, near San Francisco, received more energy than it used for the first time on Dec. 5, putting in 2.05 megajoules of energy through a laboratory laser and receiving 3.15 megajoules in return.

Since then, the lab has conducted eight similar experiments, but “ignition” has never been achieved, said Richard Towne, deputy director of the program. However, the experiment on June 5 showed “balance” – 1.87 megajoules of laser energy was introduced, and an equal amount of fusion energy came out. It was the second largest energy output in one of the lab’s experiments, or “shots,” Towne said in an interview.

Each time the team adjusts its approach. In this particular “shot,” the researchers used a slightly longer pulse from the laser to compress the hydrogen fuel and initiate fusion, and that seemed to increase the yield, Towne said. The team plans to achieve ignition again this year.

“We’re moving forward,” Towne said. “We haven’t had a big headline yet about 3 megajoules or more. But I think with every experiment we should ask ourselves, ‘What did we learn from this?'”

Today’s nuclear power plants use nuclear fission – the separation of atoms, while fusion combines atoms. In theory, it could provide power without generating nuclear waste, such as spent fuel rods from today’s fission-based reactors.