Does Nuclear Fusion Mean Hot Fusion Only?
Nuclear fusion is the Holy Grail of energy research. It would deliver massive amounts of clean energy, producing no nuclear waste or carbon emissions, while using a fuel so abundant that it makes up the majority of matter in the universe.
It is also incredibly difficult to achieve, simply because the only way we know for nuclear fusion to occur is to replicate the conditions inside stars, with unfathomable pressure and temperature in the tens or hundreds of millions of degrees.
This can be achieved using powerful magnetic fields to contain and compress the ultra-hot plasma. Or with hundreds of powerful lasers all synchronized to aim for the same spot. However, all these methods struggle to sustain the fusion reaction for long enough to “pay back” the energy spent initiating nuclear fusion.
Source: IEEE
The complexity of nuclear fusion technology and its potential to solve our energy problem was discussed in further detail in our article “Nuclear Fusion – The Ultimate Clean Energy Solution on the Horizon.”
But what if nuclear fusion could happen in different circumstances, using material science, rare metals, and chemistry instead of high-power plasma physics?
This is the promise of “cold fusion,” a field that was long considered unscientific and derided by the scientific community. This was until a scientific paper was published in the prestigious journal Nature, titled “Observation of neutron emission during acoustic cavitation of deuterated titanium powder.”
History Of Cold Fusion
In 1989, researchers Stanley Pons and Martin Fleischmann claimed to have achieved cold fusion. Unfortunately, years of trying to replicate the findings by the scientific community have, so far, been unsuccessful, leading to accusations of poor-quality science or even outright fraud.
The following controversy permanently damaged the image of this concept. This also led to its strong popularity with amateurs, frauds, and un-serious “inventors” unwilling to expose their “discovery” to peer review and scientific scrutiny.
It is nevertheless still being worked on by a small number of scientists, usually under the less controversial names of Low Energy Nuclear Reactions (LENR), Condensed Matter Nuclear Science (CMNS), or Chemically Assisted Nuclear Reactions (CANR).
A renewed interest in the field has occurred in the 2020s, as people look to move past the stigma of amateur research. Notably, the US government agency ARPA-E announced in 2023 a handful of grants to fund research groups looking into low-energy nuclear reactions (LENR), following intriguing results achieved by NASA researchers in 2020.
The NASA team called their method “lattice confinement fusion.” They insisted that what they did was not cold fusion but a special form of hot fusion.
Still, causing fusion without plasma made clear that nuclear fusion can be achieved in more ways than previously thought, and actual cold fusion might also still be a possibility.
The Two Main Concepts For Cold Fusion
Metal-Driven Fusion
A proposed method for cold fusion, initially proposed by Pons & Fleischmann in 1989, involved using materials changing shape so that hydrogen atoms are trapped and forced to fuse together. To do so, hydrogen-infused metals like palladium, erbium, and titanium have been proposed.
The general concept is that by absorbing hydrogen atoms and bringing them close to each other, the metal lattice would change shape. And that this could somehow facilitate the merger of hydrogen atoms into helium.
While not completely impossible, physicists have been skeptical of the idea from the start, as the energy levels required to overcome the tendency of hydrogen nuclei to repel each other are gigantic.
Bubble Fusion
Another idea is that nuclear fusion could occur in bubbles when they collapse; for example, bubbles may form in water when submitted to ultrasounds, an idea also sometimes called sonofusion.
In theory, the shockwaves created by the collapse of a bubble in a liquid could be powerful enough to cause fusion, not completely unlike the way shockwaves induced by laser do.
It is also known that cavitation can be a very powerful force, for example, chewing with ease through the metal of boat propellers from just the force of bubble collapsing.
Source: Britannica
A contemporary subject of research involves the emission of light as the cavity produced by a high-intensity ultrasonic wave collapses. This effect, called sonoluminescence, can create instantaneous temperatures hotter than the surface of the Sun.
If sonoluminescence can be born from “temperatures hotter than the surface of the Sun”, in theory, so can nuclear fusion.
The idea is as controversial as the “classic” lattice cold fusion, with its main promoter widely criticized. But in 2013, the debate reignited:
According to a new investigative report into Oak Ridge National Laboratory records, a highly publicized finding from 2002 that cast the controversial tabletop nuclear fusion experiment into doubt has itself been cast into doubt.
In fact, the reporter who examined the Oak Ridge document dump also found possible vindicating evidence that might have supported some of the embattled researchers—including lead author Rusi Taleyarkhan, now at Purdue University.
Spectrum IEEE
Still, the renewed interest in 2013 failed to yield many new results, and the idea went back into the “would be nice but it doesn’t work” pile of science history.
The 2024 Discovery
This was until a single researcher, Max Fomitchev-Zamilov, President of Maximus Energy Corporation, in the USA, published the previously mentioned scientific paper in Nature.
The company specializes in selling tools for nuclear physics experiments, such as neutron detectors, gamma detectors, X-ray spectrometers, digital pulse processors, multichannel analyzers, and spectroscopy software.
In May 2024, Dr. Fomitchev-Zamilov claimed to have detected potential fusion events with bubbles of heavy water (made with deuterium instead of normal hydrogen) mixed with titanium particles.
This would, in theory, mix both of the theorized approaches for cold fusion, with a metal lattice of titanium and sonofusion.
We were able to sustain the neutron production for several hours and repeated the experiment multiple times under various conditions.
We hypothesize that the observed neutrons originate from nuclear fusion of deuterium ions dissolved in titanium lattice due to the mechanical action of the impinging cavitation jets.
Looking At Lattice Cold Sonofusion
The results of the experiment are very interesting. Not only was the peak neutron count “10,000x in excess of background, but it also only occurred when secondary acoustic waves constructively interfered resulting in massive, sharp pressure peaks on the order of a few thousand psi.“
The neutron production could also be sustained for several hours.
It is worth noticing that the experimental setup is remarkably compact and uses relatively “ordinary” components of nuclear physics detectors and tools, making it somewhat easy for other researchers to replicate and test.
Source: Nature
For that matter, Dr. Fomitchev-Zamilov’s willingness to share his raw data and experimental setup is a refreshing move in a field often dominated by “secret recipes.”
A Slow Progress
Maybe more valuable is the multiple admission in the published paper of what did not work, something cold fusion enthusiasts are rarely keen to do.
The cavitation of deuterium bubbles in mineral oil did not work, no matter the changes done to bubble sizes, pressure amplitude, frequency, or added surfactants. Deuterium droplets did not work either.
Such “failures” are important, as they show the detection of neutrons is just an error or a measurement artifact of the experimental setup. However, as soon as they added deuterated titanium particles with deuterated water (heavy water), they detected a neutron flux.
More interestingly, the neutron spike occurred regularly, in sync with the acoustic waves.
Source: Nature
Similarly, the neutron spike, different from background noise and other signals is clearly visible when looking at the sample for 5 hours, and then starting the acoustic waves.
Source: Nature
These results were consistently achieved over and over, and analyzed further over the course of 6 months, reducing further the chance of a fluke or an odd case that cannot be replicated.
Not A Definitive Proof Yet
The published paper acknowledges that cold fusion is still not the only explanation to justify the flux of neutrons.
What was demonstrated, and makes a groundbreaking discovery, is that with deuterated titanium particles + deuterated water + sound waves/cavitation, neutrons are emitted.
For example, the conditions of the experiment could create a phenomenon called spallation. This is where a high-energy input (like from high-energy particles) breaks a nucleus into its components, which could theoretically cause neutrons to be detected.
Source: Springer
So, further analyses of the reactions are required, apparently requiring additional spectroscopic studies.
Improving The Design
Of course, another comment we should make is that these results now need to be replicated by other researchers to be fully trusted.
More data needs to be collected from experiments to understand how to optimize neutron production and the potential fusion reaction.
Materials
We know from this publication that the Titanium/Deuterium powder in oil was stable against decay and separation for at least 6 months.
But before any discussion of the practical use of such potential cold fusion progress, we will need to know what is consumed in the process.
Mechanisms Of Lattice Cold Sonofusion
The working hypothesis is that the cavitation jets are the cause of the observed neutron spikes and assumed nuclear fusion.
These jets might “act as pistons compacting deuterium ions stored in the titanium lattice. In which case the material of the jets is not that important and H2O droplets should be as effective as D2O droplets”.
Or maybe “the jets must contain deuterium ions and the mechanism of action is that of an ion beam impinging on a deuterated target“.
Clarifying between the 2 hypotheses will likely be the next step for Dr. Fomitchev-Zamilov.
Echoes Of NASA Works?
We should notice that the “not-cold not-plasma fusion” method discovered by NASA scientists in 2020 used powerful electrons to trigger a sequence of particle collision, ultimately accelerating enough for an atom of deuterium to trigger fusion.
To overcome that barrier requires a sequence of particle collisions. First, an electron accelerator speeds up and slams electrons into a nearby target made of tungsten. The collision between beam and target creates high-energy photons, just like in a conventional X-ray machine.
The photons are focused and directed into the deuteron-loaded erbium or titanium sample. When a photon hits a deuteron within the metal, it splits it apart into an energetic proton and neutron. Then the neutron collides with another deuteron, accelerating it.
Could the cavitation, already known to be able to create instantaneous temperatures hotter than the surface of the Sun at the atomic level, replicate the same process but without a particle accelerator?
Clean Energy Solved?
If this discovery is confirmed and perfected, does that mean we solved nuclear fusion? And that clean, abundant energy is just a matter of time? Maybe, but one crucial data point is still missing: while we know neutrons are emitted, we do not know how much energy the system is emitting.
So, the problem that has hindered hot fusion so far, producing more energy than it consumes, could be a problem for cold fusion as well.
An encouraging point is that Dr. Fomitchev-Zamilov is working on a lab bench, far from the facilities like the U.S. National Ignition Facility (NIF) delivering 500 trillion watts of peak power in one spot through 192 powerful laser beams.
So while the energy output may be modest, we can infer that the input was as well.
Investing In Nuclear Fusion
As a scientific idea just emerging out of a bad reputation that was pretty much a career-killer to any physicist to even work on it, cold fusion is very much not accessible to investors today.
Heavy water is a very small market, with only $161M traded globally (and a bit more produced locally), and Canada is the largest exporter. One private supplier is the lab equipment and consumable giant Sigma-Aldrich, part of Merck KGaA (MRK.DE).
Currently, none of the companies dedicated to making hot nuclear fusion commercially viable are publicly listed either. This includes Helion, General Fusion, Commonwealth Fusion, TEA Technologies, ZAP Energy, and NEO Fusion.
You can find an extensive list of startups in the nuclear fusion space on the dedicated page of Dealroom.
One notable exception to privately-listed startups dominating the field is the publicly traded company Lockheed Martin Corporation, a giant of the defense industry.
1. Lockheed Martin Corporation
Since the early 2010s, Lockheed used to work on Compact Fusion, a nuclear fusion reactor it was expecting to see ready by the 2020s. However, it has since been announced that the work on the project was stopped in 2021.
The company has been very discreet about this project after a very enthusiastic initial announcement. To this day, it is unclear what could have prompted the company to abandon the idea.
At the same time, it seems that it did not fully abandon the concept, notably with investments in 2024 in Helicity, a startup developing a fusion engine.
The idea would be to propel spacecraft with short bursts of fusion. Helicity is planning to use a plasma gun, the same approach as taken by General Fusion.
Potentially, Lockheed’s own internal results have shown that their design could not sustain fusion in a way that is compatible with energy production.
But maybe, at the same time, short bursts are enough for the need for propulsion in space and much closer to becoming an actual product. It would also be a better fit with the overall aerospace and defense-focused profile of the company.
2. General Fusion
General is one of the startups leading the charge in making fusion a private sector venture, instead of a publicly-funded physics project.
The company was started as long ago as 2002 to develop Magnetized Target Fusion (MTF) technology.
MTF is expected by the company to be a shorter path to energy-positive fusion and to be a lot less costly. General Fusion was the first in the world to build and commission a compact toroid plasma injector at a power plant scale in 2010 and has reached many more milestones since.
Source: General Fusion
The company aims to reach fusion with 100 million degrees Celsius temperature in 2025 and to progress toward energy breakeven (positive return from nuclear fusion) in 2026. Before that, a 1/5th scale model was made in 2023, and its performance matched the expectations of computer models.
Overall, General Fusion has spent 2 decades building step by step each of the core technologies of its final design, testing each along the way and successfully validating the idea, at least so far.
Source: General Fusion
As a private company, it did not have to discuss and negotiate any design change, contrary to international projects like ITER. It could also pick technology on its own merit, without having to decide if a specific country should get the contract regardless of political reason.
This is why many expect General Fusion and a few of its competitors to manage what large government projects might not.
3. TAE Technologies
Formerly known as Tri Alpha Energy, the California-based company is focused on developing fusion energy tech. TAE Technologies is currently upgrading its fusion platform, Norman, to a sixth-generation machine called Copernicus.
Source: TAE
TAE technology relies on particle accelerators to inject energy into the plasma and “act as a thickening agent that makes it more manageable”.
The company also extensively uses 3D printing in the making of Copernicus, allowing for quick iterations of new parts and quicker problem-solving. For example, it managed to print some reactor components for half the weight of what conventional manufacturing would have achieved.
Source: TAE
If all goes smoothly, the company expects to build its first prototype power plant that could connect to the grid in the early 2030s, which would be scaled up to develop “robust and reliable” commercial power through the decade.
Fusion, according to its CEO Michel Binderbauer, would take us into a “paradigm of abundance.”
For the past 25 years, the company has operated on a “money by milestone” model, where each round of funding is only earned from investors based on delivering on milestones that were promised to them.
In 2022, Google and Chevron invested in TAE Technologies as part of the company’s $250 million funding raise. Google has actually been partnered with TAE for a decade now and provides the company with AI and computational power.
The company also offers life science services (Boron Neutron Capture Therapy -BNCT) and power solutions like batteries and e-mobility.
4. Helion
Helion aims to create fusion with deuterium and helium-3, instead of the more common approach to focus on fusion with tritium.
Normally helium-3 is very hard to find. But Helion has a method to produce it from deuterium in its own reactor. Otherwise, unproven alternatives like mining for it on the Moon would probably have been needed.
Like most private ventures in fusion, Helion uses plasma injection technology.
Another unique feature of Helion is targeting direct electricity capture from the plasma, using Faraday’s Law to induce a current, directly skipping the steam heating cycle common in nuclear power plants.
This move is rather bold, but also could increase the yield of future power plants by 2-3 fold, as heat-to-steam-to-power conversion is usually with a very low efficiency. It is also a very capex-intensive procedure.
Helion’s fusion power plant is projected to have negligible fuel cost, low operating cost, high up-time, and competitive capital cost. Our machines require a much lower cost on capital equipment because we can do fusion so efficiently and don’t require large steam turbines, cooling towers, or other expensive requirements of traditional fusion approaches.
Helion currently operates Trenta, its 6th generation reactor that has achieved 10,000+ pulses and 100 million degrees Celsius temperatures.
Source: Helion
It is currently moving to Polaris, its next model expected to have magnetic pulses 100x quicker than Trenta, which would make it the first nuclear fusion to produce a net gain of electricity.
It is worth noticing that Polaris would be 19m long, far from a giant installation compared to other, more classic fusion reactor designs.