Nuclear fusion energy research passes milestone with ‘fusion ignition’

Posted on

For the first time, researchers have created a fusion reaction that resulted in a net energy gain. The results, from Lawrence Livermore National Laboratory in California, mark an important step in the very long road towards generating clean energy from nuclear fusion.

“Last week, lo and behold, they shot a bunch of lasers at a fuel pellet, and more energy was released from that fusion ignition than the energy from the lasers that went into it,” said White House Office of Science and Technology Policy Director Arati. Prabhakar said at a press conference announcing the achievement today in Washington, DC. “I just think this is such a great example of what perseverance can really achieve.”

“A great example of what persistence can really achieve”

Nuclear fusion occurs when atoms collide, “merging” to create a heavier atom, releasing energy in the process. In the sun and other stars, hydrogen nuclei fuse to form helium and generate massive amounts of energy. To achieve nuclear fusion on Earth, humans have to heat atoms to enormous temperatures — millions of degrees Celsius, which is why it was so difficult to achieve a net energy gain.

In this case at 1:03 a.m. local time on December 5, the national lab used 192 high-powered laser beams to hit a solid target of hydrogen isotopes only about the size of a peppercorn. The target is enclosed in a carefully crafted diamond casing.

A glowing orb is contained in a transparent cylindrical capsule with metal fittings at each end.  Blue rays of light emerge at both ends.

An artist’s illustration of a fuel capsule used in the NIF experiments.
Image: LLNL

“Today’s shells are almost perfectly round. They’re 100 times smoother than a mirror, and they have a tiny tube attached to them that’s about a 50th the diameter of a hair that fills the fuel into the shell,” said Michael Stadermann, Target Fabrication Program manager at Lawrence Livermore National Laboratory: “As you can imagine, perfection is really hard, and so we’ve got to get there — we still have little flaws in our shells, smaller than bacteria.”

The experiment produced 3.15 megajoules of energy, about 50 percent more than the 2.05 megajoules that the lasers used to start the reaction. By doing this and reaching a scientific energy break-even, the researchers achieved what is called “fusion ignition.”

Exploiting nuclear fusion could be revolutionary – giving people an abundant source of energy without the nasty side effects of greenhouse gas emissions or long-term radioactive waste. However, this depends on overcoming huge technical hurdles. After decades of experimentation, today’s announcement represents a small but significant victory over one of those hurdles. But there’s still a long, long way to go before nuclear fusion can make clean energy dreams come true.

The US government has been funding fusion energy research since the 1950s. Around the world, the chase has raised tens of billions of dollars in funding. And at the end of last year, scientists with the Joint European Torus (JET) in the UK had generated a record 59 megajoules of energy from nuclear fusion. The big problem is that until now nuclear fusion in a laboratory had not been possible Lake energy than was needed for the reaction to take place.

It is an important milestone, but there are still some important caveats to note. An important point is that the DOE bases this victory solely on the Exit of the lasers, which are quite inefficient. It takes 300 megajoules of energy from the grid to get it those two megajoules of laser energy. So today’s announcement depends on a narrow definition of ‘net energy gain’.

Lasers aren’t the only way to achieve nuclear fusion. Other efforts, including JET, include a magnetic device called a Tokamak to contain and heat up plasma. Whatever the method, we are probably decades away from generating energy in a power plant this way. It will take a lot more money and incremental wins to get there, and today’s announcement is one of them.

“With real investment and real focus, that timeline can get closer,” Kim Budil, director of Lawrence Livermore National Laboratory, said at the news conference. “We were in a position for a very long time where it never got closer, right? Because we needed this first fundamental step. So we are in an excellent position today to understand what it takes to take that next step.”

For starters, scientists need to be able to get back to ignition. “This is one ignition capsule, one time. To realize commercial fusion power, you have to do many things; you have to be able to produce a lot of fusion ignition events per minute,” Budil said. “There are very significant hurdles, not only in science but also in technology.”

One hurdle is that the lasers used in future efforts will need to be much more efficient. The system used in this experiment, called the National Ignition Facility, is the largest, highest-energy laser in the world—larger than three football fields. But it’s still based on 1980s technology. Modern lasers are more efficient, and future efforts will likely try to incorporate newer technology into experiments.

“This shows that it is possible. That threshold being crossed allows them to start working on better lasers, more efficient lasers, on better containment pods, etc,” Budil said. “We need the private sector to get involved. It’s really important that there are incredible a lot of US government dollars have gone into this breakthrough, but any steps we will take to get this to a commercial level will still require public inquiry and private inquiry.

Leave a Reply

Your email address will not be published. Required fields are marked *