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Cold Fusion is Back (there's just one problem)
🕑 Added 2022-10-08 12:00:06 +0000 UTC[This is a transcript of the video.]
Cold fusion could save the world. It’d be a basically unlimited, clean, source of energy. It sounds great. There’s just one problem: it’s not working. Indeed, most physicists think it can’t work even in theory. And yet, the research is making a comeback. So, what’s going on? What do we know about cold fusion? Is it the real deal, or is it pseudoscience? What’s cold fusion to begin with? That’s what we’ll talk about today.
If you push two small atomic nuclei together, they will form a heavier one. This nuclear fusion releases an enormous amount of energy. There’s just one problem: Atomic nuclei all have a positive electric charge, so they repel each other. And they do so very strongly. The closer they are, the stronger the repulsion. It’s called the Coulomb barrier, and it prevents fusion until you get the nuclei so close together that the strong nuclear force takes over. Then the nuclei merge, and boom.
The sun does nuclear fusion with its enormous gravitational pressure. On earth, we can do it by heating a soup of nuclei to enormous temperatures, or by slamming the nuclei into each other with lasers. This is called “hot nuclear fusion”. And that indeed works. There’s just one problem: At least so, far hot fusion eats up more energy than it releases. We talked about the problems with hot nuclear fusion in this earlier video.
But nuclear fusion is possible at far lower energy, and then it’s called cold fusion. The reason this works is that atomic nuclei don’t normally float around alone but have electrons sitting in shells around the nucleus. These electrons shield the positive charges of the nuclei from each other and that makes it easier for the nuclei to approach each other.
There’s just one problem: If the atoms float around freely, the electron shells are really large compared to the size of the nucleus. If you bring these nuclei close together, then their electron shells will be much farther apart than the nuclei. So the electron shells don’t help with the fusion if the nuclei just float around.
One thing you can do is strip off the electrons and replace them with muons. Muons are basically heavier versions of electrons, and since they are heavier, their shells are closer to the nucleus. This shields the electric fields of the nuclei better from each other and makes nuclear fusion easier. It’s called “muon catalyzed fusion”.
Muon catalyzed fusion was theoretically predicted already in the 1940s and successfully done in experiments in the 1950s. It’s cold fusion that actually works. There’s just one problem: muons are unstable. They must be produced with particle accelerators and those take up a lot of energy. The muons then get mostly lost in the first fusion reaction so you can’t reuse them. There’s a lot more to say about muon catalyzed fusion, but we’ll save this for another time.
There’s another type of “cold fusion” that we know works, which is actually a method for neutron production. For this you send a beam of deuterium ions into a metal, for example titanium. Deuterium is a heavy isotope of hydrogen. Its nucleus is a proton with one neutron. At first, the beam just deposits a lot of deuterium in the metal. But when the metal is full of deuterium, some of those nuclei fuse. These devices can be pretty small. The piece of metal where the fusion happens may just be a few millimeters in size. Here is an example of such a device from Sandia Labs which they call the “neutristor”.
The major reason scientists do this is because the fusion releases neutrons, and they want the neutrons. It’s not just because lab life is lonely, and neutrons are better than no company. Neutrons can also be used for treating materials to make them more durable, or for making radioactive waste decay faster.
But the production of the neutrons is quite an amazing process. Because the beam of deuterium ions which you send into this metal typically has an energy of only 5-20 kilo electron Volt. But the neutrons you get out, have almost a thousand times more energy, in the range of a few Mega electron Volt. It’s often called “beam-target fusion” or “solid-state fusion”. It’s a type of cold fusion, and again we know it works.
There’s just one problem: The yield of this method is really, really low. It’s only about one in a million deuterium nuclei that fuse, and the total energy you get out is far less than what you put in with the beam. So, it’s a good method to produce neutrons, but it won’t save the world.
However, when physicists studied this process of neutron production, they made a surprising discovery. When you lower the energy of the incoming particles, the fusion rates are higher than theoretically expected. Why is that? The currently accepted explanation is that the lattice of the metal helps shielding the charges of the deuterium nuclei from each other. So, it lowers the Coulomb barrier, and that makes it more likely that the nuclei fuse when they’re inside the metal. This isn’t news, physicists have known about this since the 1980s.
But if putting the deuterium into metal reduces the Coulomb barrier, maybe we can find some material in which it’s lowered even further? Maybe we can lower it so far that we create energy with it? This idea had been brought up already in the 1920s by researchers in the US and Germany. And it’s what Pons and Fleischman claimed to have achieved in their experiment that made headlines in 1989.
Pons and Fleischman used a metal called palladium. The metal was inside a tank of heavy water, so that’s water where the normal hydrogen is replaced with deuterium. Ponds and Fleischman then applied a current going through the palladium and the heavy water. They claimed this created excess heat, so more than what you’d get from the current alone. They also said they’d seen some decay products of fusion reactions, notably neutrons and tritium. Everyone was very excited.
There was just one problem... Other laboratories were unable to reproduce the claims. It probably didn’t help that Pons and Fleischmann were both chemists, but nuclear fusion has traditionally been territory of physicists. And physicists largely think that chemical reactions simply cannot cause nuclear fusion because the typical energies that are involved in chemical processes are far too low.
A few groups said they’d seen something similar to Ponds and Fleischman, but the findings were inconsistent, and it remained unclear why it would sometimes work and sometimes not. By the early nineties, the Pons and Fleischmann claim was largely considered debunked. Soon enough, no scientist wanted to touch cold fusion because they were afraid it would damage their reputation. The philosopher Huw Price calls it the “reputation trap”. In fact, while I was working on this video, I’ve been warned that I, too, would be damaging my reputation.
Of course not everyone just stopped working on cold fusion. After all, it might save the world! Some carried on, and a few tried to capitalize on the hope.
One such case is that of Andrea Rossi who already in the 1970s said he knew how to build a cold fusion device. In 1998, the Italian government shut down his company on charges of tax fraud and dumping toxic waste into the environment. In the mid 1990s, Rossi moved to the USA and by 2011, he claimed to have a working cold fusion device that produced excess heat.
He tried to patent it, but the international patent office rejected the application arguing that the device goes “against the generally accepted laws of physics and established theories”. A rich Australian guy offered $1 million to Rossi if he could prove that the device produces net power. Rossi didn’t take up the offer and that’s the last we heard from him. There’s more than one problem with that.
In 2019, Google did a research project on cold fusion and they found that the observed fusion rate was 100 times higher than theoretically expected. But it wasn’t enough to create excess heat.
The allure of cold fusion hasn’t entirely gone away. For example, there are two companies in Japan, Technova Inc. and Clean Planet Inc, which claim to have produced excess heat. Clean Planet Inc has a very impressive roadmap on their website, according to which they’ll complete a model reactor for commercial application next year. There’s just one problem: No one has seen the world-saving machine, and no one has reproduced the results.
The people who still work on cold fusion have renamed it to “Low Energy Nuclear Reactions”, LENR for short. Part of the reason is that “cold” isn’t particularly descriptive. I mean, these devices may be cold compared to the interior of the sun, but they can heat up to some hundred degrees Celsius, and maybe that’s not everybody’s idea of cold. But no doubt the major reason for the rebranding is to get out of the reputation trap. So make no mistake, LENR is cold fusion reborn.
I admit that this doesn’t sound particularly convincing. But I think it’s worth looking a little closer at the details. First of all, there are two separate measurements that cold fusion folks usually look at. That’s the production of decay products from the nuclear fusion, and the production of excess heat.
An experiment that tried to shed light on what might be going on comes from a 2010 paper by a group in the United States. They used a setup very similar to that from Fleischmann and Pons but in addition they directed a pulsed laser at the palladium with specific frequencies. They claimed to see excess power generation for specific pulse frequencies, which suggests that phonon excitations have something to do with it. There’s just one problem: a follow-up experiment failed to replicate the result.
Edmund Storms who has been working on this for decades published a paper in 2016 claiming to have measured excess heat in a device that’s very similar to the original Ponds and Fleischman setup. In this figure (Figure 6) you see how the deuterium builds up in the palladium, that’s the red dots, and the amount of power that Storms says he measured.
He claims that the reason that these experiments are difficult to reproduce is that the nuclear reactions happen at appreciable rates only in some regions of the palladium which have specific defects that he calls nano-cracks. These could be caused by the treatment of the metal, so some samples have them and others not, and this is why the experiments sometimes seem to work and sometimes not. At least according to Storms. There’s just one problem: No one’s been able to replicate his findings.
There is also a 2020 paper from the Japanese company, Clean Planet Inc which I already mentioned. They use a somewhat different setup with nanoparticles of certain metals that are surrounded by a gas that contains deuterium. The whole thing is put under pressure and heated. They claim that the resulting temperature increase is higher than you’d expect and that their device generates net power. In this figure you see the measured temperature increase in their experiment with Helium gas and with a gas that contains deuterium. The Helium gas serves as a control. As you see there’s more heating with the deuterium. There’s just one problem: No one’s been able to replicate this finding.
The issue with these heat measurements is that they’re incredibly difficult to verify. For this reason it’s much better to look at the decay products. Those are in and by themselves mysterious. In a typical nuclear fusion reaction, there is a very specific amount of energy that’s released, and so the energy distribution of the decay products is very sharply peaked. In deuterium fusion, the neutrons in particular should have an energy of 2.45 MeV. In those cold fusion reactions, however, they see a fairly broad distribution of neutron energies and at higher energies than expected.
Here is an example. The red bars show the number of deuterium ions as a function of energy, the black ones are the background. As you can see the spectrum looks nowhere like the expected peak at about 2.5 MeV. Something is going on and we don’t know what. Forget saving the world for a moment, it’s much simpler, there’s an observation that we don’t understand.
In a recent paper, a group from MIT has put forward two different hypotheses that could explain why nuclear fusion happens more readily in certain metals than you’d naively assume. One is that there are some unknown nuclear resonances which can become excited and make fusion easier. The other one is that the lattice of the metal facilitates an energy transfer from the deuterium to some of the palladium nuclei. So then you have excited Palladium nuclei and those decay. Since the Palladium nuclei have more decay channels than are typical for fusion outputs, this can explain why the energy distribution looks so weird. There’s just one problem: We don’t know that that’s actually correct.
What are we to make of this? The major reason cold fusion has been discarded as pseudoscience is that most physicists think it can’t possibly be that chemical processes cause nuclear reactions. But I think they overestimate how much we know both about nuclear physics and chemistry.
Nuclear physics is dominated by the strong nuclear force which holds quarks and gluons together so that they form neutrons and protons. The strong nuclear force has the peculiar property that it becomes *weaker* at high energies. This is called asymptotic freedom. Arvin Ash recently did a great video about the strong nuclear force, so check this out for more details.
The Large Hadron Collider pumps a lot of energy into proton collisions. This is why understanding the strong nuclear force in LHC collisions is quite simple, by which I mean a PhD in particle physics will do. The difficult part comes after the collisions, when the quarks and gluons recombine to protons, neutrons, and other bound states such as pions and rhos and so on. It’s called hadronization, and physicists don’t know how to calculate this. They just extract the properties of these processes from data and parameterize it.
I am telling you this to illustrate that just because we understand the properties of the constituents of atomic nuclei doesn’t mean we understand atoms. We can’t even calculate how quarks and gluons hold together.
Another big gap in our understanding are material properties because we often can’t calculate electron bands. That’s especially true for materials with irregularities that, according to Storms, are relevant for cold fusion. Indeed, if you remember, calculating material properties is one of those questions that physicists want to put on a quantum computer exactly because we can’t currently do the calculation. So, is it possible that there is something going on with the nuclei or electron bands in those metals that we haven’t yet figured out? I think that’s totally possible.
But, let me be honest, I find it somewhat suspicious that the power production in cold fusion experiments always just so happens to be very close to the power that goes in. I mean, there isn’t a priori any reason why this should be the case. If there is nuclear fusion going on efficiently, why doesn’t it just blow up the lab and settle the case once and for all?
So, well, I am extremely skeptical that we’ll see a working cold fusion device in the next couple of years. But it seems to me there’s quite convincing evidence that something odd is going on in these devices that deserves further study.
I’m not the only one who thinks so. In the past couple of years, research into cold fusion has received a big funding boost, and that’s already showing results. For example, in 1991, a small group of researchers proposed a method to produce palladium samples that generate excess heat more reliably. And, I hope you’re sitting, research groups at NASA and at the US Navy have recently been able to reproduce those results.
A project at the University of Michigan is trying to reproduce the findings by the Japanese companies. The Department of Energy in the United States just put out a call for research projects on low energy nuclear reactions, and also the European research council has been caught in the act of supporting some cold fusion projects.
I think this is a good development. Cold fusion experiments are small and relatively inexpensive and given the enormous potential, it’s worth the investment. It’s a topic that we’ll certainly talk about again, so if you want to stay up to date, don’t forget to subscribe. Many thanks to Florian Metzler for helping with this video.
Comments
D Brown
Hope she makes it out before everything goes boom.
Pavel Kolinko
I was really happy how pragmatically and factually you covered this topic. It was consistent with how I felt on the topic - highly skeptical of "world-changing commercial fusion" due to coulomb barrier and unlikely to get sufficient fusion through tunneling, but further research certainly should be done so that the scientific community understands exactly what is going on with various 4+ sigma findings described in the video. Good things come when science gets to the bottom of unexplained experimental observations.
Pavel Kolinko
The taxpayers funds, appropriations bills, and grants are dependent on elected officials, their appointees, PR and the job is to a) good R&D and b) to present the R&D in the best possible light. If the money was tied to the quality of research, instead of taxpayers , the whole PR function would be unnecessary, because it would 'distort' the data.
Pavel Kolinko
PR is an equivalent of your Communist Party 'performance evaluator', in todays Capitalist world. The way the Capitalist world is set up is simple - the people who get money are those who earn the money in the markets / selling, not those whose ideas improve the world, otherwise Isaac Newton, Shockley / Bardeen would be zillionaires. Hence even fundamental R&D activities that are 'for the greater good' have to be run like commercial enterprises, PR, sales (proposals / grants) etc. I think the wheels started coming off the "cooperation train" somewhere in the 1970's
Stuart has to go to uni and study to get the qualifications to apply for grants now. 😀
It'll be some child genius who builds one for a school project, I reckon. 😆
Ha, cool!
Apply for a research grant!
I know someone who knows someone who knew them both at the time. Sounds sketchy, I admit, but I think everyone in this chain is trustworthy. He says that Pons & Fleischman felt badly misunderstood and were also rather offended for being made fun of when they were just doing their job. Make of this what you wish, but I doubt they were joking.
I hope not!
Thanks, I appreciate your support!
D Brown
"Cold fusion experiments are small and relatively inexpensive.." and therefore not driven by greed, making it less likely that it is given the needed funding. I would not be surprised to find the first news of success is in the form of a 100 foot crater where a garage one stood.
Pavel Kolinko
I updated my membership to $8 per month based on this video. Sabine does an excellent job covering the facts in a controversial science area.
You're right, Nicolas, it is normally impossible to quantify the degree to which one thing or another affects hiring decisions. However, in my case, the year was 2008-2009 when the financial crisis caused over half of the physics/astronomy faculty searches in the US to be canceled. There were 5 of us at the institution on our 2nd post-doc, all roughly equal qualifications and on the faculty job market. Only 2 of us had press on projects we had done. We ended up short-listed double the amount of our 3 friends and we were the only 2 to get faculty positions. The other 3 extended their post-docs for 6 months but ended up leaving academia altogether. 5 is too small a number to be useful, but astronomy is a pretty small community and what we saw at my institution was typical at others. In normal years, you are absolutely correct that the press would have been only a minor contributor to hiring decisions, but in this one year, it was a key contributor. When I first started here, I wondered why we did so much press on basically fluff. It's not like our undergrad students are doing ground-breaking research. I know that prospective students never read news and I thought for sure that their parents could tell that the stories were just fluff. However, when we poll parents and students why they come to even check us out or why they chose us, always on top of the parents' list are things from the fluff we put out (the kids just parrot their parents). I'm still amazed at how well our press-based advertising works because I feel exactly the same way you do on the subject.
So I'd like to introduce you all to my friend btw, a fellow Sabine aficionado. 😀
Facts. Destroying people's dreams one at a time.
Sure - this is how it works today; but I would argue that a good scientist would look at this and say "there is no control group"; you can't recreate doing another post-doc in the same conditions, - we can't go back through time. Plus we couldn't simulate a world with no PR department. I can see how, in a PR-filled-world, your non-PR'd post-doc might be overlooked and you wouldn't land that faculty job. But if no post-doc was PR'd, or, if there was another process in place, maybe you'd have landed that job still. I am not saying I know of a way to avoid PR (and advertisement more generally), it's probably impossible to avoid completely. But I know it is possible to minimize the influence of commercials (the worst of all, as they convey no other information than someone found funds to make that commercial) and other mass communications - since they have very little influence on me. Whenever I see a college-based communication, I assume it is profit-driven and therefore not trustworthy. It could pique my curiosity, and I'd read the actual paper, or check forums where they might discuss that paper. Or articles from media that I believe are more independent. Or listen to Sabine :). I wouldn't base any decision on those PR communications. As to the duty of reporting to the taxpayers - there are many departments (like intelligence services) that do not report publicly. I'm not saying I know how else this could work; maybe it's the least bad solution given our culture and general education with regard to the influence of advertisement. But I do hope we can find a better system, and have fewer conflict of interest in our work.
This is a pretty cool video. She messed up the definition of a plasma a little bit, but that doesn't detract from the story being told. This is part 1 where they set up the background science. I would guess that Part 2 will be out next week and in that part, they will actually build their own reactor.
ahhh.... I got it now. Sometimes I, too, feel as though Sabine's goal is to try to get the audience drunk. ...but there's just one problem...
I just found this video on YouTube, haven't watched it yet: https://youtu.be/piPbnKdve9M It's bound to be entertaining.
Interesting observations. I have always known palladium is a very interesting metal to work with, in particular due to its placing in the Periodic table - in the same band as nickel and platinum and next to silver. Given these findings, has anyone thought of using ultrasonic resonance on heavy water with a palladium sample in it to kick start such a process?
In retrospect, I started reading that chapter at home, I could've played a game where I took a sip every time I read that phrase.
'...the future is ... fixed except for occasional quantum events that we cannot influence.' repeated throughout in the chapter 'Has Physics Ruled Out Free Will?' Sabine's style of humour often lends itself to drinking-type games on various scales.
Unfortunately, we can't do that. Consider, for example, research conducted with data from NASA telescopes. Since NASA is paid for with taxpayer money, they have a duty to report back to the taxpayer what is going on with the data from these telescopes. We scientists write up our papers for other scientists, but the public is informed through press releases. In my case specifically, when it came to publicizing my 3-dimensional reconstruction of the Cassiopeia A supernova remnant, there was a lot of back-and-forth with the crafting of the headline, and it wasn't technically accurate, and we'll make sure there is an accurate sentence in the body, and so on. Although they bent over backwards to appease my concerns, it was made clear to me that my requests were becoming burdensome. The PR team had free reign to just run with my data products and do what they wanted with them because they belonged to the taxpayers. When my post-doc was finished and I was looking for a permanent faculty position, all of the press on my Cas A project helped me land just that. Any state college or university also has a duty to report back to the taxpayers but an even greater role of PR departments at all public and private colleges and universities is to make sure that there are plenty of news articles to attract new students. We work very closely with our PR people to get the word out about awards to current students and what kinds of research our students are doing. We couldn't survive without our PR people.
Tracey, my question is, why would scientists listen to PR departments? One way to reduce the power of PR departments is to stop paying attention to them.
I don't know about Pons&Fleischman being a practical joke... They basically fled to France to continue their research after the blow up. I would have pulled the emergency brake and gotten off the PR ride before anything went public, were I in their situation and it was all just a joke.
Hi Nicolas, I've made my fair share of Pons & Fleischmann jokes, but these two guys were definitely caught up in the media storm pushed by their University PR department. Their research was plausible at the time and they really thought they had measured something meaningful from it. I disagree with Richard below, I wouldn't throw away my reputation on a practical joke. Scientists need to have veto power over PR departments so that they can wait for peer review and independent confirmation before PR runs with it.
There are drinking games in 'Existential Physics'? How did I miss that? Do share...
re: Pons and Fleischman - If you are pushing hydrogen or deuterium into the metal crystal structure, sooner or later something has to give. You might, for example, get a phase change in the metal structure. Or produce a lot of defects that eventually merge producing another kind of phase change. Sudden increases in neutron radiance can simply be statistical variations which should be expected when you are looking at this kind of stochastic process. Paladium has several radioactive isotopes which will produce some 'noise' in this kind of experiment. One has to be very careful of side effects. In one example, a magnetic field was present and 'energy production' was seen due to magnetic hysteresis. - I tend to think that Pons and Fleischman was a practical joke that got out of hand.
Why are there drinking games in 'Existential Physics' and video scripts that I come across when I can't play them. Not fair! 😆
Thank you for the excellent and thoughtful video. Andrea Rossi (who is a personal friend) is still working, and has just launched a multi-year live camera of a working energy device. It can be reached here: https://e-catworld.com/
Great content again! Thanks Sabine for combing through all those papers and summarizing them for us. The media almost always distort what the papers say, probably so that they get more readers. I especially enjoy your independence of mind, combined with excellent thinking, which is the basis for good science.
