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Nuclear Fusion Breakthrough Confirmed: California Team Achieved Ignition

Hamartia Antidote

Nov 17, 2013
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United States
United States

A major breakthrough in nuclear fusion has been confirmed a year after it was achieved at a laboratory in California

Researchers at Lawrence Livermore National Laboratory's (LLNL's) National Ignition Facility (NIF) recorded the first case of ignition on August 8, 2021, the results of which have now been published in three peer-reviewed papers.

Nuclear fusion is the process that powers the Sun and other stars: heavy hydrogen atoms collide with enough force that they fuse together to form a helium atom, releasing large amounts of energy as a by-product. Once the hydrogen plasma "ignites", the fusion reaction becomes self-sustaining, with the fusions themselves producing enough power to maintain the temperature without external heating.

Ignition during a fusion reaction essentially means that the reaction itself produced enough energy to be self-sustaining, which would be necessary in the use of fusion to generate electricity.

If we could harness this reaction to generate electricity, it would be one of the most efficient and least polluting sources of energy possible. No fossil fuels would be required as the only fuel would be hydrogen, and the only by-product would be helium, which we use in industry and are actually in short supply of.

The problem with fusion energy at the moment is that we do not have the technical capabilities to harness this power. Scientists from across the world are currently working to solve these issues.

In this latest milestone at the LLNL, researchers recorded an energy yield of more than 1.3 megajoules (MJ) during only a few nanoseconds. For reference, one MJ is the kinetic energy of a one tonne mass moving at 100mph.

"The record shot was a major scientific advance in fusion research, which establishes that fusion ignition in the lab is possible at NIF," said Omar Hurricane, chief scientist for LLNL's inertial confinement fusion program, in a statement

"Achieving the conditions needed for ignition has been a long-standing goal for all inertial confinement fusion research and opens access to a new experimental regime where alpha-particle self-heating outstrips all the cooling mechanisms in the fusion plasma."

In the experiments performed to reach this ignition result, researchers heat and compress a central "hot spot" of deuterium-tritium (hydrogen atoms with two and three neutrons, respectively) fuel using a surrounding dense piston also made from deuterium-tritium, creating a super hot, super pressurized hydrogen plasma.

"Ignition occurs when the heating from absorption of α particles [two protons and two neutrons tightly bound together] created in the fusion process overcomes the loss mechanisms in the system for a duration of time," said the authors in a paper publishing the results in the journal Physical Review E.

This landmark result comes after years of research and thousands of man hours dedicated to improving and perfecting the process: over 1,000 authors are included in the Physical Review Letters paper.

Despite repeated attempts having not been able to achieve the same energy yield as the August 2021 experiment, all of them reached higher energies than previous experiments. Data from these follow-ups will aid the researchers to further streamline the fusion process and further explore nuclear fusion as a real option for electricity generation in the future.

"It is extremely exciting to have an 'existence proof' of ignition in the lab," Hurricane said in a statement. "We're operating in a regime that no researchers have accessed since the end of nuclear testing, and it's an incredible opportunity to expand our knowledge as we continue to make progress."
(Reuters) -U.S. scientists have achieved net energy gain in a fusion reaction for the second time since December, the Lawrence Livermore National Laboratory said on Sunday.

Scientists at the California-based lab repeated the fusion ignition breakthrough in an experiment in the National Ignition Facility (NIF) on July 30 that produced a higher energy yield than in December, a Lawrence Livermore spokesperson said.

Final results are still being analyzed, the spokesperson added.

Lawrence Livermore achieved a net energy gain in a fusion experiment using lasers on Dec. 5, 2022. The scientists focused a laser on a target of fuel to fuse two light atoms into a denser one, releasing the energy.

Related video: U.S. Scientists Repeat Breakthrough Fusion Reaction (Dailymotion)

That experiment briefly achieved what's known as fusion ignition by generating 3.15 megajoules of energy output after the laser delivered 2.05 megajoules to the target, the Energy Department said.

So excited about this. We might actually see clean energy in large volumes. I wonder if it will be used for profiteering like the current forms of energy are?
So excited about this. We might actually see clean energy in large volumes. I wonder if it will be used for profiteering like the current forms of energy are?
Once the technology is mature enough it will probably be passed on to GE and Westinghouse for commercialization.

What will be interesting is how long it will take to get the permits to build commercial scale power plants.
That experiment briefly achieved what's known as fusion ignition by generating 3.15 megajoules of energy output after the laser delivered 2.05 megajoules to the target, the Energy Department said.
After how many MJ wasted electric energy to create these 2 MJ of laser energy? 200 MJ? 2 GJ?
Net energy gain is amazing.
It is not at all, because you need to take into account all the energy used. And the problem with all the lasers and their optics is: The efficiency is a catastrophy.
Even if you would use super efficient laserdiodes with 70%, after all the optics you lose something around 70-90%. So at the end you have maybe, at best, something around 10% from eletric>laser. But you also have all the other cooling equipment etc. pp so you will end at around something like 5% in the future. At best!

This means, you need at least 20 times the fusion energy you have invested as electric energy. The carnot efficiency for converting this thermal energy will be somwhere around other thermal processes, 30-40%. So you will end up around 60 times (!), more likely 100 times fusion energy needed only to generate the same energy you have invested before.

Here is something to read:
Omar Hurricane, chief scientist of Livermore’s inertial-confinement fusion programme, says that they now plan to “reprioritize” their work to push for higher, reproducible gains by boosting NIF’s laser energy in steps of about 0.2 MJ. They also intend to study the effect of varying the thickness of the nuclear fuel inside the capsules and reducing the size of the cylinder’s laser entrance holes. However, he points out that NIF was never designed to demonstrate practical fusion energy – given that the facility’s main purpose is providing experimental data to support the US’s (no longer tested) stockpile of nuclear weapons. As such, NIF is extremely inefficient – its 2 MJ flash-lamp pumped laser requiring around 400 MJ of electrical energy, which equates to a “wall-plug” efficiency of just 0.5%.

Riccardo Betti of the University of Rochester says that modern lasers pumped by diodes could reach efficiencies as high as 20% but points out that margins required for power plants (including energy lost during conversion of heat to electricity) means that even these devices will need target gains of “at least 50–100” (compared to NIF’s 1.5). They will also have to “fire” several times a second, while NIF only generates a shot about once a day. This high repetition rate would require mass-produced targets costing at most a few tens of cents, compared to the hundreds of thousands of dollars needed for those at NIF (which are made from gold and synthetic diamond).


In other words, to make it short: Magnetic confinement fusion is the future, not inertial.

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