NIF’s Laser Fusion Experiment’s Energy Gain Passes Peer Review

Back in December of 2022, a team of researchers at the USA’s National Ignition Facility (NIF) announced that they had exceeded ‘scientific breakeven’ with their laser-based inertial confinement fusion (ICF) system. Their work has now been peer-reviewed and passed scrutiny, confirming that the energy put into fusing a small amount of deuterium-tritium fuel resulted in a net gain (Q) of 1.5.

Laser Bay 2, one of NIF's two laser bays
Laser Bay 2 at the NIF.

The key take-away here of course remains that ICF is not a viable method of producing energy, as we detailed back in 2021 when we covered the 1.3 MJ yield announcement, and again in 2022 following the subject of this now completed peer review.  The sheer amount of energy required to produce the laser energy targeting the fuel capsule and loss therein, as well as the energy required to manufacture each of these fuel capsules (Hohlraum) and sustaining a cycle make it a highly impractical proposition for anything except weapons research.

Despite this, it’s good to see that the NIF’s ICF research is bearing fruit, even if for energy production we should look towards magnetic confinement fusion (MCF), which includes the many tokamaks active today like Japan’s JT-60SE, as well as stellarators like Germany’s Wendelstein 7-X and other efforts to make MCF a major clean-energy source for the future.

53 thoughts on “NIF’s Laser Fusion Experiment’s Energy Gain Passes Peer Review

  1. The energy gain is between the laser energy absorbed by the target and the fusion energy emitted by the target. It conveniently ignores the far higher energy input required to operate the laser system, let along the energy expended in manufacturing the target.

    1. I think thats a relatively moot argument at this point, those are things we can optimize our way out of, the core process is sound so infrastructure and methodology can change to ultimately support this in a scalable manner. after all pumping a shit ton of photons from a fusion reaction back into a laser seems like a pretty doable kind of problem

      1. How can we optimize our way out of those things? How can the infrastructure and methodology change to ultimately support this in a scalable manner? You imply there already is a viable solution rather than starting that there may be a solution. The prices of fusion is “sound” inside the sun, that doesn’t mean that we can scale it down to happen on Earth scale. Photons are massless, so we literally CAN’T pump a shit ton of them anywhere.

        1. “Pumping photons” is laser speak the process of adding energy to the lasers gain medium.. I’m sure you know that though since you’re here.
          I think you just want to argue for the sake of arguing. Because it’s not really that difficult of a concept to understand what he was trying to say .

        1. To me it sounds more like saying that now we know how to burn small bits of wood, we can run a steam engine off of lots of them by repeatedly feeding more to it… and that sounds a lot like a pellet stove.

          1. The pellet has milligrams of fuel, and the energy output is 1.3 MJ. The useful energy output is about a third of that, so firing 1000 pellets PER SECOND would yield an output power of about 400 MW which is in the range of a commercial power plant. Right now they can fire one per how many hours? Days? Not to mention the fact that the pellet is made of gold…

            The all-included Q of the system right now is 0.0077 so you have to improve the efficiency by a factor of 130 to achieve actual break-even, and the entry level Q for commercial operation is 10 so you need to reach a 1300 fold improvement.

            Both of those factors combined means that you need to improve the system by a factor of a billion or a trillion to begin to make any sense. That’s why I compared it to powering a steam engine by striking individual matches.

          2. Yeah, ICF and MCF are different, the magnetic ones still would need to be even larger scale than they are to ever break even, while this particular version of ICF would need to do way more than break even to ever sell enough power to cover its own costs.

            But breaking even with such a tiny amount of fuel seems like it ought to tell us something that nuclear bombs don’t, since it’s so much smaller scale than they are. It’d need to get a lot better and be fabbed in very large quantities, or we’d need to use what we learned in a very different way, but this one was never meant to be the final test of a commercial power plant so hey.

            In your example, maybe before we would rub the wrong end of matches together to make them burn, and now we finally learned to strike them so that we get more energy out of them than we spent trying to light them. Before, you needed to ignite a lot of wood with your little ember to get a return, and now you just need to make up for all the energy spent manufacturing a match. A bit of an awkward analogy, but hey.

        2. The Wright Brothers worked for years at great expense to accomplish a few hundred feet of powered flight. Anyone could have said, “In that amount of time, do you know how far I could have walked at no cost?”

          While this may not be the end-all, scientific progress is made by learning.

          1. Yes, but with the difference that there was no technical reason they could not just keep going once they were in the air.

            Inertial confinement fusion is like an airplane without wings or propeller, that you throw into the air with a slingshot, and then reason “Well, we just have to set up slingshots every couple hundred feet and repeat”. Do you call that flying?

          2. If that’s what they had done to understand the process, understand the control aspect, understand what improvements needed to be made, then they would not have wasted effort. In fact, they did use a similar approach… they built their own wind tunnel, tested airfoil shapes, wing warping, speeds, etc. Was it called flying when they had a model I the wind tunnel? No. But it was a step in the process of finding what worked, and what did not.

          3. In a response to Dude: Do you think you could make a trebuchet to hurl things into space? And how big would it be and what would the cost be?
            I mean once you had it you would save millions with each launch.

            Maybe if they had made a rod inbetween the twin towers instead of a walking bridge and then had used that as pivot? :)
            Maybe the Grand canyon could be tried? put a beam across it as pivot and away you go.

          4. Ironically the only use seems to power a picosecond laser.
            So maybe a ring of a 1000 of such devices where each one powers the next one’s lasers and then you shave of a few percent of excess power along the way for other use :P

        1. It’s not intended to be a path to energy production, it’s a path to studying ignition behavior on a small scale. The issue with studying the ignition regime in large fusion reactors is that they need a comparably large amount of fuel, and the fuel involved is stupidly expensive and rare. As in, a power plant scale D-T fusion reactor would exhaust the Earth’s supply of tritium in like, a month, which is why you need breeder blankets (that you don’t know how to build yet).

    2. “It conveniently ignores the far higher energy input required”

      Because this isn’t designed to generate energy, it’s designed to study the plasma dynamics of a system in ignition.

        1. Doesn’t matter much: the unknown portions you’re trying to study are the nuclear physics. The plasma portions are constrained by other experiments. There are a *ton* of detectors surrounding the target here, so you get a very detailed view of the burn progression.

  2. Yeah, until the Q number is inclusive of what it takes to make that fusion occur…and how much carbon it took to get there….I won’t be impressed with this as an energy source.

  3. I think it’s myopic to write off ICF when we’re so early in the game. It’s well established that pressure is more efficient than temperature for making fusion occur; indeed, the only successful use of man-made fusion for releasing energy, the hydrogen bomb, uses pressure.

    MCF advancements to date have only been in the actual plasma control, not in improving the efficiency of heating, though that doesn’t write it off as a concept either, it’s just worth bearing in mind.

    1. The article is badly written and heavily biased. The comments is also badly written and heavily biased.

      While it is a fact that “ICF is not a viable method of producing energy,”that may change in the future, as you imply. Perhaps a viable technology will bridge concepts from both ICF and MCF. Nonetheless, I highly doubt that will see controlled nuclear fusion at scale in our lifetimes. Even military uses have some sort of a cost limit, however nebulous.

    2. Meanwhile, the JET fusion reactor recently ran a 5 second experiment releasing 62 MJ of energy out of 0.2 grams of hydrogen in a burning plasma.

      That’s much more than 1.3 MJ. It’s clear which system can more easily handle greater fusion energies.

      1. Also, both the JET and JT-60 have reached plasma conditions that extrapolate to a Q of 1.25 if they were using D-D fuel. Only the JET can actually burn plasma though, and it runs on D-T fuel which gives it about half the yield.

        The JT-60 could reach and extapolated Q of 1.25 with D-T plasma if it were capable of handling the fuel.

      2. >It’s clear which system can more easily handle greater fusion energies.

        Not JET, it’s being decommissioned and that run was beyond its design capabilities. It’s still impressive but the MCF gang are waiting for material science to catch up. It may well do but it’s very, very far from a solved problem and that will only get worse with longer runs. ICF could readily be redesigned with multiple ignition chambers, powered by a central laser pulse.

        That said, this is still a race with no clear victor and citing any one achievement as evidence of supremacy over the other either needs to read more or is carrying a bias.

        1. Well, yes. But that’s not the point.

          The X-7 has already shown continuous operation and control of the plasma that eases the requirements for the material science, so these efforts combined already show the potential and possibility of commercial nuclear fusion.

          ICF on the other hand has numerous show-stopping problems that nobody has any idea how to solve, like what materials (other than gold) to make the pellets out of, or how to fire thousands of them every second just to reach the levels of power required from a full sized power plant.

          1. In other words, the JET was already producing the equivalent of a small hydroelectric power plant for five seconds. 12.4 MJ per second is 12.4 MW of which about 4-5 MW can become electricity.

            Meanwhile the NIF simulations show that the best-case energy yield out of a single shot is about 7 MJ once per day. That is equivalent to 80 Watts of sustained power and 26 Watts of electric output. The entire facility would be just about capable of running my laptop.

          2. There’s “show-stopping” problems in both and there will be until we have a working product. Pointing to the output of JET and then the run time of X-7 is meaningless because those are two very distinct designs.

            Your information on the hohlraum material is very out of date, there’s plenty of ideas and new materials being tried. In fact, performance was increased (rather than compromised) very recently by alloying in tantalum and DU (which we have in abundance) is another promising material.

          3. > tantalum and DU

            Like that actually solves the issue. Say, each pellet weighs a gram, and you fire a thousand each second, so you’re burning through 86.4 tons each day to run a commercial sized power plant.

            Tantalum costs around $190 a kilogram, so the cost of the pellets alone excluding the fuel would run up to 16 million dollars per day. Then you have to deal with a reactor that puffs out a “smoke” made of tons and tons of vaporized tantalum or uranium.

          4. “In other words, the JET was already producing the equivalent of a small hydroelectric power plant for five seconds”

            Ignition burns at NIF are actually roughly equivalent to JET’s burn: the total energy’s off by about a factor of 10 because the burn percentage of the fuel’s still relatively low (4%). NIF in one shot burned a significant fraction of the tritium that took JET multiple seconds.

            That’s the issue with trying to study D-T fusion at a tokamak like JET: because you’re not in an ignition regime it’s not confined to an area/time where you can observe the dynamics.

    3. Early in the game? How long have they been at it? How can 1.8 nm
      (.0045 the wavelength of blue light) conductors be fabricated on Silicon Chips and we’re still chugging about in 35 mpg hydrocarbon-powered relics?
      ‘Energy Of the Future and Always will Be’ is for the dual purpose (1) of guaranteeing full employment for taxpayer funded researchers and (2) maintaining the illusion that “We’re making some progress but we still
      have problems to overcome.”–A goal that will always remain conveniently
      out of reach, meanwhile the public is convinced ‘Our top people are on it
      but it’s still a real struggle.’
      What horseshit.
      Meanwhile they’re driving cars in Europe that get 60+ mpg. but for are not allowed in the US …

      1. Europe uses the British gallon which is larger, and they cheat with the MPG tests a lot.

        In 2019 the EU average fuel consumption for light vehicles reached 6.0 L/100 km which translates to 39.2 US-MPG.

        1. This paper illustrates the problem:

          The data is a bit old, but the “mileage gap” has been growing for decades anyhow. The official figures show continuous improvements, but real world fuel mileage remains stagnant. A 2014 model car was officially getting 5.3 liters per 100km but real world mileage was about 7.2 L/100 km and that was basically the same as it ever was since the 90’s.

          You can’t beat thermodynamics. Getting the number down in recent years required having tax policies that favored smaller cars, and adding plug-in hybrids and electric cars to the average.

          1. “Getting the number down in recent years required having tax policies that favored smaller cars”

            Tax policies that favor smaller cars is just good policy no matter what, though. More efficient regardless of the fuel source.

          2. Yes, if you’re looking at it from the point of the state dictating individual consumer behavior and choices. However, the choices were not made on the point of efficiency, but on tax revenue, since transportation is necessary and a steady source of income for the state. Over half of the cost of fuel in the EU is tax.

            We also forgot diesel cars, which are very popular in the EU thanks to their greater fuel economy – but also very polluting.

          3. “point of the state dictating individual consumer behavior and choices”

            Unless consumers are the ones building roads, the state’s *already* dictating consumer behavior and choices.

  4. This is practical for weapons research??

    How big would the reactor and all it’s support equipment have to be to create a gun and how much energy would it use to fire? Can this be fit on an aircraft carrier now? And does the “cost per firepower” approach more conventional weapons?

    Did I forget getting trapped in a mine, breathing some strange gas and waking up in the 25th century?

    1. there’s been an international ban on nuclear weapons testing for quite some time now and the current generation of US nuke arsenal was never test fired…NIF allows for studying the plasma physics in ways that were not possible before, possibly resulting in better nukes…

    2. It’s not “create a weapon” research!

      It’s “understand the weapons we have” research. Unless you’d prefer them to study the ignition regime of fusion the old-fashioned way, by levelling islands?

    3. The NIF was not designed to research power plant technology. Its purpose was to produce fission reactions to improve the modeling of thermonuclear reactions since nuclear test ban treaties were enacted. One of the conundrums was that nuclear weapons age in storage and somehow we need to ensure that they will still operate as predicted. This is also a major purpose of the extremely large parallel high performance computer systems at the national labs. These are big complex simulations and the purpose of the NIF is to compare the simulations to real world experiments. In other words you simulate in the computer and run the NIF experiment and if the predictions match you have a good fusion reaction simulator. Does it have implications for fusion power? Sure, but that is not what it is designed to do.

  5. It is a perfect initiator for a neutron b0mb, i$f it can be scaled down.

    Lawrence Livermore National Laboratory director Harold Brown and Soviet General Secretary Leonid Brezhnev both described neutron b0mbs as a “capitalist b0mb”, because it was designed to destroy people while preserving property

    1. Since the NIF’s primary function is nuclear warhead “Stockpile Stewardship” (note the close proximity of the facility’s construction with the start of the nuclear testing ban treaty), I doubt they have funding problems. It and all of the other INCREDIBLY impressive hardware involved in that stewardship which you can legitimately find info about online if you dig, are necessary to make sure US nukes continue to work with aged components without testing and any effects of new, improved components. Also, making any changes to a previously developed nukes “physics package” requires the ability to accurately simulate the nuke in a supercomputer.

      That stewardship effort is, undoubtedly, one of the reasons that one of the nuke labs relatively recently started digitally restoring many of the old above-ground test films. As they explained in their video about this, from that they then can get more accurate yield estimates with modern analysis capabilities. I don’t’ know if they stated it in that video, but yields can be determined via the expansion rate of the fireballs. Think about why they would need this info: probably to compare the supercomputer simulations of those designs with the actual test results.

      National Ignition Facility

      Out of these changes came the Stockpile Stewardship and Management Program (SSMP), which, among other things, included funds for the development of methods to design and build nuclear weapons without having to test them explosively. In a series of meetings that started in 1995, an agreement formed between the labs to divide up SSMP efforts. An important part of this would be confirmation of computer models using low-yield ICF experiments.

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