Scientists at a federal nuclear weapons facility have made a significant step forward in thermonuclear research that could lead to an abundant source of energy in the future, according to a government official.
The move is expected to be announced by the Department of Energy on Tuesday, which says a “major scientific breakthrough” has been made at the Lawrence Livermore National Laboratory in California. Jennifer Granholm, energy secretary, White House and other Department of Energy officials are expected to attend. The The Financial Times reported on Sunday that scientific progress involves the National Ignition Facility, or NIF, which uses giant lasers to create conditions that rapidly simulate nuclear weapon explosions.
An unnamed government official discussing the results that have not been made public says that the fusion experiment at NIF has achieved what is known as ignition, in which laser-powered fusion energy begins to react. . Ignition is also called an energy boost.
Such a development would improve the ability of the United States to maintain nuclear weapons without nuclear testing and could set the stage for future advances that could one day lead to the use of nuclear weapons. using laser fusion as an energy source.
Although not widely publicized, the news quickly spread among physicists and fusion scientists.
“Yesterday, a scientist friend sent me a note saying that Livermore exceeded the energy gain of a week ago and will publish the results on Tuesday,” said Stephen Bodner, a physicist. plasma, who has long criticized the NIF, said in an article. email on Monday morning. “They deserve to be commended for achieving their goals.”
What is Consolidation?
Fusion is the fusion reaction that powers the sun and other stars – the fusing of hydrogen atoms into helium. The mass of helium is slightly less than that of the original hydrogen atoms. Thus, according to Einstein’s iconic E=mc² equation, that difference in mass is converted into a burst of energy.
Fusion that can be produced in a controlled way on Earth could mean an energy source that doesn’t produce greenhouse gases like coal and oil, or dangerous, long-lived radioactive waste, like current nuclear power plants.
How do you make fusion without a star?
Most fusion efforts to date have used donut-shaped reactors known as tokamaks. In reactors, hydrogen gas is heated to a temperature hot enough for electrons to be separated from the hydrogen nucleus, creating what is known as a plasma – clouds of positively charged nuclear and negatively charged electrons. The magnetic field holds the plasma in a donut shape and the nuclei fuse together, releasing energy in the form of neutrons that fly out.
However, Tuesday’s announcement involved a different approach. The NIF consists of 192 giant lasers that fire simultaneously at a metal cylinder the size of a pencil eraser. The cylinder, heated to about 5.4 million degrees Fahrenheit, vaporizes, creating an explosion of X-rays, which in turn heats and compresses a BB-sized frozen pellet of deuterium and tritium, the two heavier forms of hydrogen. . The explosion fuses hydrogen into helium, creating a fusion reaction.
What advances have been made in laser fusion to date?
The main purpose of the NIF, which was built at a cost of $3.5 billion, was to conduct experiments that would help the United States maintain nuclear weapons without the need for nuclear test explosions. Proponents also say it could advance fusion research that could lead to viable commercial power plants.
However, initially NIF hardly induces any fusion. In 2014, scientists Livermore finally reported successbut the energy produced is then very small — equivalent to the energy consumed by a 60-watt light bulb for five minutes.
Last year, Livermore scientists reported a huge leap, a burst of energy — 10 million million watts — equal to 70% of the energy of laser light hitting a hydrogen target.
But the explosion – essentially a miniature hydrogen bomb – lasted only 100 trillionths of a second.
The Financial Times reported on Sunday that Livermore will announce that in the latest experiment, the fusion energy generated exceeds the amount of laser energy hitting the hydrogen target.
For that to happen, the fusion reaction must be self-sustaining, meaning that the flow of particles from the hot spot in the center of the pellet is heated around the hydrogen atoms and causes them to fuse as well.
What are the obstacles to fusion energy?
An important caveat is the claim to focus on laser energy hitting hydrogen targets. NIF’s lasers are extremely inefficient, meaning that only a fraction of the energy used to power the lasers actually turns it into a beam.
More modern technology such as solid-state lasers will be more efficient but still a long way from 100% fusion; For this to happen, the output fusion energy must be at least several times greater than the energy of the incident lasers.
Does Tuesday’s announcement mean we’ll have cheap fusion power soon?
No.
Even if scientists figure out how to create larger thermonuclear explosions, huge technical hurdles will still exist.
The NIF experiments were studied one at a time.
An actual fusion power plant using this concept would require a machine gun’s laser firing rate with new hydrogen targets sliding into place for each explosion. Then, the stream of neutrons released from the fusion reactions would have to be converted into electricity.
The laser complex fills a building the size of three football fields — too big, too expensive, too inefficient for a commercial power plant.
A manufacturing process for mass production of precise hydrogen targets would have to be developed.
