Always happy to see people doing new and interesting stuff with fusion. I got into nuclear technology because of ITER back in the early 2000s. Worked on it continuously (mostly in advanced fission) ever since.
> "The timeline question is a tricky one," he says. "I don't want to be a laughing stock by promising we can deliver something in 10 years, and then not getting there. First step is setting up camp as a company and getting started. First milestone is demonstrating the reactions, which should be easy. Second milestone is getting enough reactions to demonstrate an energy gain by counting the amount of helium that comes out of a fuel pellet when we have those two lasers working together. That'll give us all the science we need to engineer a reactor. So the third milestone is bringing that all together and demonstrating a reactor concept that works."
The fourth step is to deliver the reactor concept as promising machine. The fifth step is to attach it to power generating equipment and demonstrate the power plant. The sixth step is to scale up a supply chain capable of delivering multiple units that compete with other sources of commodity electricity (or other energy products). The seventh step is to scale to large scale without being unduly burdened by either supply chain (raw material, skilled labor) or regulatory impact/public concern that inevitably scales with any large fleet of any new tech.
Fission made it to step 7 and then faltered and is now teetering depending on where you look. It never scaled past 5% of total world primary energy.
The promise of fusion is to deliver nuclear energy with less public concern than fission because it makes less radiologically hazardous material. The challenge is to go through the physical, engineering, and commercial viability phases as a power plant.
A number of these steps become easier if the reactor is physically small. A plant that fits in a shipping container has a way easier path to commercial viability.
Small plants require less capital. They're easier to manufacture. They can iterate faster. They have less environmental impact, and therefore fewer regulatory hurdles. They require less labor to build and a smaller supply chain.
I expect that the engineering is harder, because scale can bring efficiencies. But still, I think the winner is going to be a small device, not a behemoth, if only because a small device can come online years earlier.
I expect that you lose efficiencies with respect to security. I.e., it's not easy to secure one large nuclear reactor (fission or fusion), but it's a lot easier than securing dozens of small reactors.
Nuclear fission reactors need more security than other power plants because of the implications of stolen fuel/waste, or fallout from sabotage. A fusion reactor like the one this group is working on probably doesn't have as high as security concerns. In fact the only concern might be that it is critical infrastructure(like our entire power grid), and a distribution of smaller reactors would be better for reliability anyway.
Traditional fusion reactors do produce fast neutron radiation, which, in addition to causing problems like weakening the structure (which can be mitigated with better materials, better engineering, and by replacing subcomponents over time) is able to irradiate U238 into PU239.
Drop a chunk of U238 in/near the fusion reactor somewhere, let it absorb stray neutrons, and you'll soon have some plutonium. That's bad for control of nuclear weapons proliferation, which relies on high-energy neutron sources like breeder reactors being difficult to build and expensive.
Not sure about the radiation profile from this system though.
The general anti-proliferation challenge is harder than that. It includes guarding against the production of weapons material with the collusion of the host country and plant operators. Consider e.g. the degree of assurance needed to provide North Korea with a new power plant that can never aid its nuclear weapons program.
If the security concerns decrease, perhaps they can get to the point of how security is done for ISP and power substations. If so, many smaller nodes across a city are much more feasible.
"Not Radioactive" is the trick. Even if the fuel isn't hazardous you have lots of radiation being kicked off by the reaction that irradiates the surrounding equipment and the waste products.
The HB11 reaction doesn't produce neutron radiation. I've seen claims that there would be side reactions, generating neutron radiation totaling under 1% of the energy output, but the only source of that I can think of is if deuterium isn't removed from the hydrogen, and we could do that if necessary. It might not be, since neutrons from deuterium fusion are a lot less energetic than D-T neutrons.
The energy output of HB11 consists of fast-moving alpha particles, which is good because that's the energy you capture, along with x-rays. None of this would activate reactor components. The waste product is non-radioactive helium.
It’s not that simple. 1% of even 1MW is a lot of radiation so it comes down to what the walls are made of more than the total neutron flux. ITER style lithium blankets would be recycled for tritium without producing much net waste. Light water nuclear reactors have several feet of water to absorb fast neutrons, which makes a huge difference. The walls of this are a more open question.
So I looked it up, and found there actually are two side reactions from the primary fuels, no deuterium required. In a thermal plasma the resulting neutrons would carry less than 0.2% of the energy output. I don't know what the percentage would be for this reactor, since the fuel isn't a thermal plasma while fusion is happening.
Interestingly, that page says the thermal neutrons in a conventional nuclear reactor are better at activating materials than fast neutrons.
According to a presentation I saw by the leader of MIT's fusion program, the inner wall of a D-T tokamak would be activated by the neutrons, but would only need to be stored for a few decades. D-T releases 80% of its energy as 14 MeV neutrons.
According to LPP, which is working on a different boron fusion design, a 20MW reactor would activate the walls with short-lived radiation, but it could be safely opened for maintenance after about twelve hours (iirc).
According to the article, the energy is generated by alpha particles, which are in principle a very dangerous form of radiation. It's not clear to me, though, whether the radiation stops as soon as the fusion does or not.
Substances which continuously emit alpha particles are dangerous.
This is something different. With every laser shot there will be a burst of alpha particles. Then they'll slow down and just be plain old helium. If the direct energy conversion works, they'll get slowed down very quickly.
Up until a decade or two ago, tritium--which emits alpha radiation--was commonly on wristwatch dials, precisely because they were not dangerous. Alpha radiation is easily stopped; it's only dangerous if you breathe it (or drink it, if that's even possible).
There might also be less security needed if you have dozens of smaller reactors. You have to secure the one because losing it affects so much. If losing a couple is not as big a problem, you an rely more on the redundancy of the system than on the redundancy of the component.
This depends on the threat model to some degree, but there's security in knowing that it's vastly harder for a threat to affect multiple targets at once, no matter the threat.
There's not much security around existing power plants, even nuclear ones. There's vastly more security around a casino or even a large shopping mall. I don't think it's a limiting factor, especially for non-weaponizable fusion reagents.
Isn't this just the same scenario as we currently have, just with different underlying technology? Do coal-powered plants have additional security outside of a few private guards?
For fission reactors that is not the case, a fission core can be as small as few liters in volume without losing power, but are artificially kept to less dense forms, such that runaway supercritical events(intended or not) can only result in Fukushima and not a Nagasaki.
That might be different for this fusion device, but for outdated looking fission reactors it’s artificial dilution for NPT purposes and by no way a technological limitation.
Off-topic question: is there some software part in nuclear energy systems that is restricting plants or research? I'd like to contribute to the industry as a non-physicist, but it's hard for me to imagine what kind of software might be missing or is being sold by too expensive specialist companies.
I imagine most software is tied to the specific devices they run on, but perhaps there's coupling or analytical software that could be better geared towards the problem domain. Is there any fundamental issue that is waiting for a good software solution?
It just so happens that a nuclear fission reactor analysis framework recently emerged on github partially with hopes that people like you would be interested in contributing. It hasn't been widely publicized and is pretty esoteric but is there.
I'm not an expert at all, but I follow news about fusion energy with keen interest. Getting to conditions where fusion reactions can take place requires modeling the physics with supercomputers. I think the physicists have a handle on the software required to do that modeling; they also have access to the computers.
I think if you have a software background and want to contribute, you should consider applying for a job with one of the projects themselves. General Atomics lists 135 software jobs (https://www.ga-careers.com/search-jobs/software/499/1) for instance.
I think it must be mentioned that in addition to fission and fusion (ITER) work, General Atomics is the creator of the MQ-9 Reaper, which is commonly used for drone strikes. A software job at this company may involve work on these aircraft.
And that's bad because drones are evil? I'm sure I don't agree with a blanket statement to that effect. They're a tool of warfare and I don't see how they're particularly worse than other ways of killing your enemies. I can think of a few ways they're better.
While you may not agree, you can surely recognise that others may appreciate the heads-up. I can easily imagine some people may be pleased to work on fusion, but not on drones.
Your parent merely notified us that more than one type of product is in development at that company and one that is not fusion is specifically designed to kill people.
another factor is clearance. people may be unwilling or unable to obtain security clearances that General Atomics requires for all their engineers, if they're a major defense contractor.
I've dreamed about getting into fusion research myself, and concluded the best pivot would be to help with the plasma simulations at a university while obtaining a PhD.
I've been trying to find affordable software for modeling my proposed fusion reactor, but some of the software packages I've looked at cost upward of $50k, with no guarantee that they will be able to give the answers I need. It seems to be a problem of low demand for highly specialized software, and scale issues in the different regimes within the device.
In my device, sometimes, some ions will be traveling in a vacuum with a high mean free path, and at other times, the plasma will be as dense as lead. It's VERY difficult to simulate, to the point that it's almost better to just estimate and start building to see if I can start to get close to a solution through careful experimentation.
> The fifth step is to attach it to power generating equipment
The part that jumped out at me as strange is that they claim their process generates electricity "directly" without having to drive a turbine. Supposedly they produce helium cations, and that can drive a circuit.
The main Proton-Boron reaction produces charged particles instead of neutrons. You can capture the charged particles directly as a source of voltage with no intermediate step. Just stick a piece of metal in the way and hook up wires.
Conventionally, neutrons are used to generate heat which is then used to drive steam turbines.
Wouldn't it produce high-velocity charged particles?
Thus you would capture the energy with a "reverse coilgun", "regeneratively braking" the particles down to a non-relativistic speed, rather than just using them to charge a capacitor plate.
Once the capacitor plate has a voltage in the range of the kinetic energy of the particles, this is exactly what will happen. The particles convert their kinetic energy into electrical energy by rolling "uphill" against the electric potential.
Most fission plants throw away about two-thirds of their energy output as waste heat (according to: https://www.answers.com/Q/How_much_of_the_heat_generated_in_...), and their cooling towers are so much bigger than the reactor itself that they've become a symbol of the plants as a whole.
Sorry to get away from some really nice physics and suggestion of some really good news for some of relevant reality:
The cooling towers? The photographs in the news commonly show huge clouds of water vapor escaping from the tops of the towers with a picture caption about "nuclear" power or some such.
So, the suggestion is that nuke plants generate huge clouds of dangerous radioactive byproducts.
Such news content is easy: (1) Suggest that the cooling towers are the nuclear reactors and (2) don't mention that what is coming out is just water vapor, from water recently in some river or lake. Now the news people have their audience by their eyeballs for ad revenue and/or politics as in
“The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety)
by an endless series of hobgoblins,
most of them imaginary.”
In principle this could be more efficient than a heat engine, although the Wikipedia page seems to say that an "economically feasible" version would have around 60% efficiency, which is the same as a combined-cycle power plant.
I don't know whether this is a legit breakthrouhg. But technological progress is often a sigmoid (S-shaped) growth curve, it may take a while to get past certain steps but once you are through, money flows and more people devote time to that technology which accelerates the process. It is not hard to imagine, say, 20 years from now, we have power plants running on fusion given the interest we have in solving the climate crisis.
High temperature superconductors are absolutely an interesting pathway to make magnetic confinement fusion significantly easier than the big tokamaks like ITER. I have friends working at Commonwealth Fusion who are good people and I wish them much success. That said there are still a lot of phases to go through, from physical viability at stage 1 to scaled commercial fleet at stage 7, and that pathway is impossible to predict without getting on the ground and going through the stages. I certainly think it's worth running through the stages.
I really hope that fusion power can become a major power source in the future and humanity really needs it to expand off planet, but like you said above, nuclear fission power got to stage 7 and then stalled. I think the nuclear fusion community should drop the word nuclear completely from their vocabulary or they are likely to end up with the same fate, if they ever get to stage 7.
If we can figure out fusion as a power source, maybe we can also figure out how to improve the quality of people's information exposure too, leading to a smarter population. Currently we try to hide the best information behind paywalls or in private knowledgebases, we neglect schools or profiteer through them (US in particular), and we inundate people with stupefying advertisements and misinformation.
Although both things are very difficult, the knowledge needed to create a commercial fusion reactor is very different to educating a whole populous not to be so afraid of radiation (which is natural and found everywhere all the time).
There is no actual expectation of ever getting useful power generation from magnetic confinement fusion (ITER, Tokamak): it has always been, instead, a jobs program for high-neutron flux physicists, to maintain a population to draw on for weapons work.
p-boron fusion is interesting as a possibly practical energy source. The hurdles are a matter of engineering and finance, not fundamental design flaws. But it's useless as a jobs program for weapon experts, so must rely on commercial investment.
I think that you have that backwards. It's the laser driven inertial confinement fusion approach that is useful for weapons insights. The very low density and slow kinetics of fusion in a tokamak are much less like weapon fusion reactions.
Lawrence Livermore -- a nuclear weapons lab -- has studied inertial confinement fusion for decades. They don't have a tokamak.
> The alpha particles generated by the reaction would create an electrical flow that can be channeled almost directly into an existing power grid with no need for a heat exchanger or steam turbine generator."
It isn't that simple. This thing will be DC, and at some random voltage. They will need huge bits of kit to convert the output into some sort of usable power. It is electricity yes, but not clean useful power.
Spot on analysis. There is one loophole which is Total Cost of Ownership (TCO).
If you energy production solution can achieve a lower TCO in an existing market segment, steps six and seven (production and supply chain) take care of themselves. The poster child for this was 'on premise PV generation.'
Once a nuclear technology demonstrates a lower TCO for baseline power generation, its game on.
Tangent, but assuming fusion energy generation will be a reality in the next 30 years, what do you believe the price/KWH will be? I am not knowledgeable enough to parse the estimates I've seen and want to believe in the post-energy-scarcity future.
Price per kwh is not solely about generation efficiency, it's also about distribution and infrastructure. There will always be a cost associated with that which will rise with inflation. Even if we went totally renewable and all your electricity was "free" then you'd still have to account for on demand storage and infrastructure costs.
The main benefit of nuclear is its relatively low carbon footprint and in theory less risk of spiking fuel costs because we run out of raw materials. That's the dream of fusion anyway.
Nuclear power infra is not cheap and even fusion will have security and decommissioning costs.
Forget cost as the main factor, grid power will never be free. That's a fantasy - even publicly owned utilities will/are funded by taxation. You're paying for price and power stability. Domestic fusion means you don't need to rely on foreign resources (eg Russia cutting off the gas).
Putting renewable generators in your home has a high capital cost, but people forget that you're also cushioning yourself against grid outages. It's insurance more than anything else.
What's the fun of tech forecasting if you don't over-promise?
A fusion reactor the size of a shipping container? Plop one down between my neighbor's house and my house. Right where our backup generators now sit. It's about the same footprint.
No more distribution costs. Well, except for Amazon's fees to drop off the uranium now and then. :)
Uranium is for fission, not fusion. Fuel for this fusion reactor would be some compound of hydrogen and the most common boron isotope. There's plenty of that in a regular box of Borax.
I doubt we are even anywhere near close to being able to calculate that because there’s still too many unknowns with regards to materials required to build, their rate of depreciation, and other things we discover in the scaling/commercialisation phases, and also exactly how much net energy will be produced!
You don't get to precisely choose which isotopes are produced by the reaction. Even among the light elements, there are radioactive isotopes, such as tritium. And it doesn't take much of it, to render the entire mixture hazardous unless refined in some fashion. One hope is that the refinement process can return the radioactive stuff to the cooking pot, so that the ultimate waste products are safe.
Neutrons produced in this reaction, being chargeless, cannot be contained within the electromagnetic field, thus leaving plasma and reacting with the surrounding material (e.g. tokamak chamber walls) and producing radioactive elements. This leads to activation and radioactive degradation of the reactor itself.
27 comments and not one hit of the word “inertial”! The line about not being thermonuclear and the description of the device in question (a sphere with lasers) points towards an inertial confinement fusion (ICF) device. Most of the fusion research eggs are in the thermonuclear basket, specifically magnetic confinement fusion. It is good to research a diverse set of approaches, but there are more engineering challenges to ICF reactors than there are to MCF reactors. Pulses on the order of 1-2 Hz requires a mechanical system that can cycle out the exhaust and replace the pellet in that time. Going to reactor scales also requires high load thermal cycles. MCF ain’t easy, and brings it’s own engineering challenges. The ones I always hear are things like wall materials and fuel recycling, but these are largely solved or in the process of being solved. The engineering challenge I see as the most difficult for MCF are related to steady state operation. Tokamaks have no way of being steady state. Stellarators do, but now the next problem is wall conditioning. Wall materials outgas in hot plasma. A lot. Like more than the fuel puffed in. The way this is handled in science machines is with glow discharges of various species: plasma just below the temperature to cause wall sputtering, coating the wall with carbon and boron for their absorptive properties, etc. No one’s run a steady state hot plasma before, so no one knows if these will be a non issue in reactors. Keeping the plasma clean may be a challenge to keep the plasma from terminating. Aside from that MCF is ready for prime time. It needs a big reactor for scaling laws to make it energy profitable (and potentially money profitable). We just need some very expensive test reactors to smooth out these issues.
It seems easy to conflate any or all approaches as fringe when no one's done it yet, and especially if there are political and program-$ecurity concerns overriding doing what's best, but some approaches scream magical thinking with unexplained reasoning more than others (like one or more cold fusion proposals in the early 1980's). OTOH, it seems like ICF and tokamak are the officially-sanctioned dogma and all other approaches are discounted automatically.
Q0: Without bias from my opinion, how fringe or potentially legitimate does IEC seem?
Q1: Props to the article's team that they invented some awesome lasers. Is there enough experimental data yet on their novel approach to backup their claims to justify funding a prototype? Would such a team be able to test this on a shoestring budget without spending millions?
"Millions" is pretty much a shoestring budget for fusion projects. There is some experimental data, but without actual fusion since the lasers weren't powerful enough yet.
This team didn't invent the lasers. They've been waiting for the lasers to get sufficiently powerful to attempt fusion with them. Those lasers are finally becoming available for researchers to use, so it should be quite inexpensive to test this idea. Worst case, they have to build one for tens of millions, which is comparable to other private fusion projects, but hopefully they can run the experiment on other people's lasers.
Personally, without drawing from rigorous empirical proof that doesn’t exit, I don’t think things like unique IEC approaches are based in fairy tales. Fusion science used to be very tribal and dogma was important. That era has largely passed. Tokamak, stellarator, ps laser, steam machine, whatever. If you can find the money to make it and do the science to show its performance, great. Everyone wants you to do that. This idea of pulling resources away is tricky to navigate, because there is finite resources spent on research and getting any one design to work takes significant effort. That’s why so much is being poured into ITER instead of other promising leads. Humans are ready to see a machine work. It’s painful to get there. It’s not my first pick on a machine. But in order to keep progress moving a real reactor needs to be made of some kind.
You misinterpreted what I said. I said that I don't have evidence that inertial electrostatic confinement is not based in fairy tales. As in, they are a reasonable route to explore.
Double negatives are tricky! Now you seem to be saying they probably are based in fairy tales, or at least have no reason to think otherwise. The first time around, you seemed to mean the opposite, which is what you say you actually meant.
As an absolute dummie I had to think of ASML where they repeatedly hit molten tin droplets in flight with CO2-lasers, to produce some plasma, to get extreme ultraviolet light out of it. 50.000 times per second. So the part to hit something very small in flight, in a vacuum, precisely and repeatedly exists on an industrial scale already. Though not simple, small and cheap. Should ask Cymer or Trumpf who do this. And forget about all that unnecessary light generating stuff, just ripping out the necessary parts and adapt for their application. And of course harden it against the FUSION happening. Simple, isn't it?
Complete layman to this, but are these approaches fundamentally incompatible with one-another, or is it just that each one on its own seems to be “enough” to get a reactor to work? Could you have a reactor that just combines all these confinement approaches at once?
They're not incompatible in the sense that they assume different physics, but they are very different strategies.
The fusion triple product is the go to figure of merit for napkin calculations, it's temperature X confinement time X ion density
MCF strategies go in on maximizing confinement time, while ICF jack up temperature and ion density. This particular ICF approach, (if I'm understanding their paper correctly) is going so high on both that they're leaving the thermal regime behind and doing an honest to glob nuclear chain reaction with having the alpha products prompt other boron nuclei to accelerate up to fusion speed causing more reactions, which is pretty exciting.
Laser inertial confinement causing a nonthermal chain reaction has been making headlines since 2015. I don't think that aspect of this approach is the exciting part. It's how promising their simulated performance improvement is from the use of a laser that causes additional magnetic confinement (I'm a little iffy on how that exactly happens).
I don't have the Physics chops to untangle the likelihood of this tech and the credibility of the process and its authors, so I'm hoping the HN crowd will be able to pad out the story behind this.
Certainly, from my layperson's perspective, their website isn't exactly encouraging... https://www.hb11.energy/
- ed re: last line - "books and covers, and all that"
Check the publications page for the encouraging part. They might be wrong but they're doing real science. I've personally spoken to a fusion scientist who thought they might be on to something.
Exponential progress does sometimes have results that seem too good to be true. In this case the progress has been in picosecond lasers, which for a while have been getting ten times more powerful every three years or so.
What's great about this is it should be pretty cheap to test. The petawatt lasers only cost tens of millions in the first place, and China is finishing up a 30PW laser which they plan to let other researchers use. If Hora is right then that should be powerful enough. Even more powerful lasers are being planned elsewhere.
HB11 isn't the only company working on aneutronic fusion. The largest is TAE (formerly Tri Alpha), with about $700 million invested. There's also Helion and LPP.
>Check the publications page for the encouraging part. They might be wrong but they're doing real science. I've personally spoken to a fusion scientist who thought they might be on to something.
I checked the publications page and so far I'm not seeing any real theory here. That doesn't mean it's wrong, but it certainly feels weird. The most in-depth equation I saw in any of their linked papers is the definition of the electromagnetic field tensor.
I'm not saying you couldn't develop a fusion reactor by doing purely experimental work with bleeding-edge laser technology. But I'd feel a lot more confident if they were to produce, for example, some kind of prediction of their net power, or a relation between e.g. laser power and fusion yield, or some other quantitative prediction about something.
For example, I'm not sure what prediction they exceeded by a factor of a billion in TFA. Shouldn't you mention that somewhere?
Another poster mention's Todd Rider's thesis, a famous barrier to creative fusion. In this particular case I think the way they evade Rider is by using higher laser powers and shorter reaction times than Rider considered to be possible. One of the important exceptions Rider acknowledges (and that I remember) is ultradense fusion; ultrafast fusion seems to be at least similar in principle.
I think the factor of a billion relates to the expectation for boron fuel with spherical compression. See for example their latest paper, page three, right column.
They do seem to be making quantitative predictions based on simulations. I don't think I've seen them boil it down to a simple scaling law though.
One of the reasons that it is difficult to predict power output exactly is not knowing exactly how much will be lost down to Bremsstrahlung, (ELectromgnetic Braking Radiation).
In any event, ultimately practical proven results will always trump whatever the current theory may suggest.
Thanks to yourself and randallsquared below for your responses - I'd since posting read the following Abstract by the authors, which hinted that the underlying science was viable: https://www.cambridge.org/core/journals/laser-and-particle-b... , however my only awareness of existing 'laser fusion facilities' was the American National Ignition Facility (https://en.wikipedia.org/wiki/National_Ignition_Facility) , which I think I'd always written off as a covert testing facility for weapons that skirted Nuclear Testing limitation treaties.
That purpose isn't covert, it is funded by the National Nuclear Security Administration(NNSA) under the Stockpile Stewardship Program, which built the facility to mimic fusion conditions to assure the viable of the US nuclear weapon stockpile. From time to time other scientist get to use it for other fusion experimentation.
The science is difficult for a layperson (such as myself) to pick apart, but the above-mentioned publications page[0] links directly to at least one paper[1] which contains some promising detail.
The Hydrogen Boron reaction is real and well-known to be a way to do fusion without lots of stray neutrons. The sticking point has always been that it's more difficult to cause that reaction than deuterium/tritium or deuterium/deuterium.
The big problem with H-B11 and other heavier fusion processes is that the energy radiated away as brehmsstrahlung is greater that the energy gain from the fusion. This was worked out by Todd Rider in his 1995 PhD thesis.
Yeah, in theory it might be possible to capture the brehmsstrahlung and pump it back into the reactor with sufficiently high efficiency, but we're pretty far away from that.
That being said, all these fancy fusion reactor schemes are interesting. Just make them work on boring old D-T fuel first, then lets see if these other fuels are usable, no?
Yes, but Rider based that on various assumptions, and included an appendix on various ways those assumptions might be violated to achieve net power with aneutronic fuels. I think this reactor would qualify, since it doesn't rely on thermal heating.
I can’t tell for sure from the article but I think they are accelerating protons with TNSA (target normal sheath acceleration). I worked in a lab in undergrad that was doing something similar, except with lithium instead of boron. The main challenges that I recall from a decade ago with TNSA are (WARNING: there almost certainly has been progress since a decade ago):
-Conversion efficiency of laser energy into ion (proton) kinetic energy
-TNSA accelerates mainly the contaminated layer on the back of targets, which may not be a big deal if you are interested in accelerating protons
-TNSA protons are not beam like. They do not have a uniform kinetic energy, and they have a wide angular divergence.
-Various laser related issues (prepulse, focal spot size/shape).
I also anticipate that it will have the same engineering problem as ICF/NIF, in that it will need to continuously replenish targets.
After reading the article and skimming some of the innumberable references (the article is all references) it seems like the unobtanium part of using laser pondermotive force to accelerate blocks high density plasma from solid state is that the laser "contrast ratio" has to be very high. In the paper it cites many failed replication efforts to use this particular laser pondermotive force due to lack of "contrast ratio".
I have no idea what "contrast ratio" means, it isn't defined, and isn't in the references. Does anyone know what "contrast ratio" means in terms of high power pulsed lasers?
> the laser pulse contrast ratio (LPCR) is a crucial parameter to take into consideration. Considering the laser pulse intensity temporal profile, the LPCR is the ratio between its maximum (peak intensity) and any fixed delay before it. A low contrast ratio can greatly modify the dynamics of energy coupling between the laser pulse and the initial target by producing a pre-plasma that can change the interaction mechanism.
It seems to be how fast the laser turns on, the rate of change of intensity.
Do a google search for "laser induced fission". Generating plasmas with CPA lasers is becoming more common, but isn't widespread yet because the technology is very new.
These plasmas can be the source for all kinds of particles and energy in particular forms, so they may have lots and lots of uses.
One person in particular is proposing to use a CPA laser to accelerate nuclear decay, to allow radioactive waste to decay faster and become less toxic more quickly.
Of course, my own concern would be that being able to induce fission with a table top laser means that the tech may eventually exist to create a fission or fusion bomb without a nuclear trigger....
If they succeed in creating a viable p-B11 fusion power plant and that gets developed into a bomb, wouldn't it be a good thing in the sense that it could replace many thousands of fission-based bombs that have huge fallout risk?
I don't know. I think a really flashy website would be more concerning. This is a serviceable website that gets it's point across without consuming a gig of bandwidth on a video in the header background.
Yeah I've become wary of "scientific breakthrough" articles that never seem to materialize into anything.
But ITER uses huge tower cranes and trucks in the thousands of tons of material required to sustain a temperature hotter than the surface of Sol because of their fuel selection.
It seems the small player with a new approach that perhaps demands less complexity in their scaled up commercial reactor could win a commissioning contract with a lower bid during late 2020s early 2030s international bidding.
"First milestone is demonstrating the reactions, which should be easy."
And "chirped pulse laser amplification" is the recent discovery Hora says will make it possible.
As a researcher I really like 'scientific breakthrough" articles where the impact never seems to materialize. It reminds me that technology development works very differently on earth than it does in my imagination.
Breakthroughs happen everyday but the road to real impact is longer and more failure prone after you make the breakthrough than before it.
Not a physicist, but I thought it seemed fishy as well. I’m curious how they plan to sustain a reaction, since their setup didn’t seem to be useful for more than a single shot…
This reads like a type of ICF which normally has a stream of pellets being fed in after the initial pellet has reached a hot enough temperature to sustain the fusion reaction.
I don't think the goal is to sustain the reaction here... I think the goal is to make a pulsed reactor, where you start the reaction on each pellet in turn. You could imagine a laser firing at 1000 pulses per second, and firing a stream of 1000 pellets per second into the reaction vessel that each pulse hits.
Pellets could turn out to be the size of a grain of sand.
To shed a different light on this: think of temperature as walking through mud. Your legs lose energy trying to slowly pull a lot of mud behind you. Now think about skiing. A lot less snow is dragged with you but it flies fast.
Here, what is interesting is if one fusion reaction does happen, then the alpha (helium) particles leave at 2.9 MeV. After two collisions with protons, if the second proton they have hit hits in turn a boron nucleus, then it will have exactly the right energy (612 keV) to have maximum chances at initiating a second fusion reaction.
612 keV is like almost 7 billion degrees °C if considered as thermal energy, and no experiment anywhere will get that hot for long. But compared to the energy of the exiting helium nuclei, it's still much lower (0.612 MeV vs 2.9 MeV).
In other words, instead of cascading all the energy down and hoping the sea of particles rises to a few billion degrees so enough particles do fusion to keep the sea of other particles hot, here, the energy is preempted by proton atoms after just 2 collisions and used immediately to start a second reaction, which yields more helium nuclei at 2.9 MeV, essentially producing an "avalanche" effect.
Finally, yes, they seem to have devised a way to obtain at least a small part of the energy electrically, without relying on thermal energy, via direct electric field deceleration of very fast charged particles.
This is like "the ultra rich (very fast particles) manage to create value among themselves without having to cascade their wealth down to the crowd (cold particles), and then upload that value to hyperspace (the electric field from the electrodes), without ever interacting with the mass of the crowd (the mass of the target), until a sufficient amount of fusion reactions have been realized"
And yes, a petawatt (the energy of present day ultra-fast lasers) is a lot of power. It was just chance that there was very little practical use to this kind of power - until now.
That being said, I am not a true expert myself of this topic, so the true barriers laying in front of this concept might be better explained by the other comments here.
> This is like "the ultra rich (very fast particles) manage to create value among themselves without having to cascade their wealth down to the crowd (cold particles), and then upload that value to hyperspace (the electric field from the electrodes), without ever interacting with the mass of the crowd (the mass of the target), until a sufficient amount of fusion reactions have been realized"
This was actually a helpful analogy for me. I'll have to take your word on the accuracy of it, though.
https://www.nature.com/articles/srep01170 ehich is the first linked paper in that section explains it well. The laser fires through the hole and ablates material from the back disc. The electrons from the created plasma reach the other side of the disc first before the ions because they are lighter, causing a buildup of negative charge on the other side. This charge differential drives a current between the two plates, which creates a magnetic field inside the coil.
"the ultra rich (very fast particles) manage to create value among themselves without having to cascade their wealth down to the crowd (cold particles), and then upload that value to hyperspace (the electric field from the electrodes), without ever interacting with the mass of the crowd (the mass of the target)"
Are you saying this kind of fusion is anti social justice? We should ban this immediately!
Sigh: Second milestone is getting enough reactions to demonstrate an energy gain by counting the amount of helium that comes out of a fuel pellet when we have those two lasers working together. That'll give us all the science we need to engineer a reactor.
I love the work, I love that they have exploited the fact that we can build things (lasers) now that we could not economically build before. But the fact is that so many many things die on the aforementioned step from the article.
That is the step wherein the science doesn't give you a way to engineer a reactor, instead it illuminates something you didn't know before and so that you now realize you can't ever build a reactor that way.
So when I read these papers and the science isn't all figured out, I temper my enthusiasm. High hopes, low expectations, that's a good motto here. Unlike the stellerator where all the science is "known" and they are engineering an implementation step by step by step.
I've added it to my fusion project collection under "interesting long shots", check back in 5 years to see what the science taught them.
Upvoted — the first minute or so of the video is very helpful; it shows (what looks like) PowerPoint slides with drawings of a proton (1H nucleus) hitting a boron nucleus (5B11); the proton fuses into the boron nucleus to create what presumably is a single carbon nucleus (6C12), which then splits into three helium nuclei (each 2He4) without emitting free neutrons.
(The very-crude video technique was fascinating to this non-artistic person: Create PowerPoint slides, add subtitles for "narration" that float in and out, and finally add stock music for background. That might be useful for flipped-classroom courses.)
The rough explanation I've heard before is to satisfy conservation of momentum and energy together. But on doing some more digging this seems wrong. C12+gamma is an output, just only for 0.01% of reactions. No idea why the different byproducts have different rates though.
> Why would the carbon split? Why not stay carbon?
Don't know — I'm not knowledgeable enough in this area to do more than take WAGs about it. The sequence might be different: For example, the 1H proton might not ever fuse with the 5B11 to form 6C12; instead, the fusion reaction might be that the 5B11 fissions into two 2He4 and one tritium 1H3, after which the 1H proton fuses to the tritium to form the third 2He4.
> And wouldn't this technically be fission energy then?
> and most rely on a deuterium-tritium thermonuclear fusion approach that requires the creation of ludicrously hot temperatures, much hotter than the surface of the Sun, at up to 15 million degrees Celsius (27 million degrees Fahrenheit).
I think they might be thinking of the corona of the sun
> The temperature in the corona is more than a million degrees, surprisingly much hotter than the temperature at the Sun's surface which is around 5,500° C
Fusion happens in the core of stars but is powered by gravity. “Temperature” in this case is individual particle speed (in eV) because the particle speed distribution is not necessarily Boltzman. Higher particle speeds are needed because our confinement fields are weaker than the force of gravity inside a star.
Most SF stories have artificial gravity generators, because it simplifies plots and lowers production costs. But is there actually a chance in hell that we'll ever have that kind of control over gravity?
The Expanse offers a more realistic take to the same effect:
With sufficiently efficient fuel, the fastest path from A to B is by constantly accelerating (more or less) towards it until you reach halfway, then flipping and constantly decelerating until you arrive.
Under this kind of trajectory, you're under constant acceleration of, say, 1g the whole time. This means you effectively have gravity for the entire trip, as long as you've designed your ship such that the floor is in the same direction as you apply thrust - think less traditional ship decks and more like a skyscraper.
Another realistic option, of course, is a rotating section. But this generally requires massive, "ugly" ships to work so it's pretty rare in fiction.
Probably not, but it does help with storytelling. You need things like exotic matter and time travel. Space magic seems to mostly be all the same thing: negative mass.
Assuming you're talking about the temperature, it's always been a source of human pride to me that the hottest place in the entire universe, as far as we are aware, has been created at the LHC on Earth.
Barring other species as intelligent as ours elsewhere (which is of course possible, but unknown), the very hottest thing in the entire unimaginably-large universe full of exotic stars and black holes and supernovae, was created by a tiny group of apes on a minuscule planet orbiting a smallish, boring star on the unfashionable side of a galaxy.
That strikes me as... a strange claim, considering how fast the OMG particle whizzed by.
Per Wiki:
> The energy of this particle is some 40 million times that of the highest energy protons that have been produced in any terrestrial particle accelerator.
Presumably wherever these extreme energy protons are coming from is rather warm.
Is there some reason to think the LHC has higher temperature?
Not a physicist; could be something like LHC having larger bunch sizes... but since we don’t know what causes these particles, it seems like we don’t really know the source temperature.
Cool thing about this is that it will be a direct energy capture if I understand it correctly.
"The hydrogen/boron fusion creates a couple of helium atoms," he continues. "They're naked heliums, they don't have electrons, so they have a positive charge. We just have to collect that charge. Essentially, the lack of electrons is a product of the reaction and it directly creates the current."
Yes it seems like you could generate extreme levels of electrostatic force by collecting the Helium nuclei. Do that on one side of a capacitor, periodically short it out (producing ordinary Helium) to clear both plates, and repeat. So yeah a machine which takes hydrogen and boron and emits helium gas and electricity. Sounds like it's worth doing, at least for the sake of children's birthday parties.
Nobody will bother with Dyson spheres, or any sort of solar power collection, once they have portable fusion generation. Once you have that, stars and planets are superfluous except as raw material.
Presumably the lasers have produced enough energy to ionize helium generated in the target. It's quite unclear how a net energy gain will be extracted simply by grabbing the moving ions electrically. That sounds like a huge extra challenge on top of achieving net positive controlled fusion.
There will inevitably be a lot of heat produced that has to be cooled. Generally people plan to use the coolant as the working fluid in the power cycle.
If there's an innovation here it'd be cool if they put it way more up front.
The coolant will be forced air to clear the reaction chamber for the next shot. When you are collecting enough power from the accelerated nuclei and X-rays by direct conversion, heat is uninteresting.
This doesn't sound like it would be more energy-dense than a chemical reaction. How much power can you extract - electrically - from two alpha particles?
Depends on how fast they're going. Fusion generates quite a lot of energy per reaction.
According to HB11's papers, each shot would have about 30 kilojoules input power via laser, consume 14 grams of fuel, and produce over a gigajoule output power, or 277 kWh.
They think within a decade the lasers will be capable of one shot per second. Right now it's more like one per minute.
There is a warning sign. Without actually running the number, I believe the energy generated by the proposed HB11 fusion should be several order of magnitude higher compared to the electric energy alpha particle can carry. So extreme hot temperature will be created regardless.
Edit: actually read the paper :)
From the paper: H + 11B = 3 x 4He + 8.7 MeV
when alpha particle absorb the electron to become helium, it can carry about 50 eV energy. So vast majority of the energy generated will be kinetic energy or photon energy which translate into very hot temperature at macro level.
The whole "electrical energy directly so no steam generators necessary" part of the discussion is fairly irrelevant.
Steam generators might have fairly low efficiency, but if hydrogen fusion works at all it'll use so little fuel and have such a low marginal cost that we can just do more of it to make up for any efficiency losses.
Except steam generators are pretty cheap - they're off the shelf, and will be a drop in the ocean compared to the total costs of the first fusion plants.
Well, that depends. ITER is tens of billions. The most expensive part of this reactor would probably be the petawatt laser, which is tens of millions for one-off experimental devices. A turbine and generator is about a million dollars per megawatt, so it could be a significant percentage of total reactor cost, especially in mass production.
I think the idea is to capture the kinetic energy of the Helium ions not through cooling but slowing them down with electromagnets. The high-speed Helium ions carry a large current, it's not about the ionization energy.
I suppose the idea is that most of the energy will be expelled as kinetic energy of the alpha particles, that then can be converted into electric potential energy?
Yeah, I thought the electrical output seemed fishy too. Why are the electrons stripped from the helium? And is that actually due to the energy of the fusion reaction? And how much of the fusion energy is left after?
Only the helium nucleus is formed as part of the fusion reaction, so it starts off being positively charged, and not later stripped of its electrons. That, in principle, creates a current which can be used almost directly.
Well, it creates a region in space with a high charge density that can be accelerated to a plate that has a voltage applied to it which it bumps into which then causes a current.
Importantly, this doesn't have to happen in the reactor vessel. The charged gas can be pumped somewhere else.
It does have to happen in the reactor vessel. It's not just that it's a charged gas. It's that it's a charged gas which is exploding with almost 300 kWh of energy per shot.
I am just learning about this reaction, but can anyone explain what is wrong with the following naive idea?
- Fire a stream of hydrogen ions with a particle accelerator at a chunk of Boron 11.
- The hydrogen and boron combine and release heat and helium.
- Use the heat from that to run a turbine and keep running your particle accelerator.
It seems like you would be ending up with lower-energy collection of atoms. Does that work but it is just not efficient enough to keep running the accelerator, or what?
The problem with firing a stream of hydrogen ions at a chunk of Boron 11 is that most of the collisions between the hydrogen and the Boron are glancing blows that will dissipate the energy very quickly. Only a small fraction of the collisions result in a fusion reaction.
This is the reason why most fusion approaches rely on thermal systems. In a thermal system, the ions have a bell-shaped distribution of energies and undergo many collisions before they leave the region in which they are confined and their energy leaves the system.
To achieve net gain, the temperature, density and energy confinement time must be above a certain threshold. If the system is non thermal, like a stream of hydrogen ions where the distribution of energies is a spike, the energy in the hydrogen ions that are deflected by glancing blows must be recaptured somehow.
>fire a stream of hydrogen ions with a particle accelerator at a chunk of Boron 11.
This is what's wrong. The energy required to accelerate the ions is much higher than the energy which can be harvested this way.
The concept under discussion substitutes a simpler setup that accelerates particles using laser induced plasmas from a very small table top laser. The thing could "almost" be battery powered.
Can someone explain why this is considered fusion? The reaction involves shooting a proton (hydrogen) at a boron nuclei and outputting 3 alpha particles. That seems more like the nuclei being split apart than fused together.
The explanation I've heard from a fusion scientist is that as far as they're concerned, if you're initiating the reaction by colliding nuclei, it's fusion, and if you're initiating it by hitting a large nucleus with a neutron, it's fission.
I has to do with something called the Binding Energy Per Nucleon. If you march up the curve from small numbers to get energy you are fusion. If you march down the curve from high numbers, you are fission. If you march up the curve from small numbers and go all the way to large numbers even though that's endothermic, you are a supernova.
(TLDR version: proton-boron fusion is a less energetically efficient alternative to 3He fusion, but with the howlingly significant advantage that boron -- the fuel -- is lying around in heaps and drifts on Earth, rather than being so exotic a substance that annual global production is measured in single-digit kilograms and a significant energy economy would require mining it from the Lunar regolith. It's not as well-known as 3He fusion, though, because the space cadets don't see the point -- there are no Moon colonies required. Advantages of 3He or B + p fusion over D-T fusion: it doesn't produce a surplus of neutrons, so there's less radioactive waste created as a by-product of the process.)
space cadets would love to have that kind of a reactor on a deep solar system exploration mission, especially if you could make it into a rocket engine by spitting the resulting super high energy helium out of the business end without negative side effects.
I don't want to be a nay-sayer but I did my PhD on Hydrogen implantation and spentt enough time as a PostDoc to find a few thing odd here:
- All work seems to be purely theoretical although the setup needed is not that hard to come by. For 1000 USD / hour you can rent a proton implanter and check the principle mechanisms of the reaction.
- Everything is published in realativly low impact journals. There are a ton of smart people in academia that love to "think outside the box" but nobody seems to think that this is promising. This basicaly seems to be a one man show of H. Hora.
- It doesn't seem to be that radically new but the first paper was published. I have not found what they have done in the meantime.
Straight from fusion to electricity without a steam turbine with helium to harvest?
I've seen it said here on HN that the amount of helium out of a deuterium/tritium is so small it is negligible.
From article: "My question is: Would that setup produce a continuous fusion for some period with positive net energy generation?
Here is my argument why I think it would: Since Boron is solid at room temperature, it's density is high, so I think the fusion rate per nucleon would be quite high. As far as I know 100keV is the energy needed for Hydrogen-1 and Boron-11 to fuse, while the resultant three He-4 nuclei should have about 8MeV of energy. So indeed if all accelerated protons fuse then the energy produced should be quite higher than the input. The problem that immediately comes to mind is that as the container starts to rapidly heat up as a result of the reactions the Boron inside would no longer be solid and may even start to leak through the opening. But before that happens, would there be at least a brief period where an efficient fusion can be sustained?"
I think he's dechirping a convergent laser wavefront to get a 10-petawatt pulse with which to accelerate hydrogen into a ¹¹B target to run an alphavoltaic battery from an aneutronic p-¹¹B fusion avalanche resulting within a plasma sphere contained by optical tweezers. Is that right?
> the design is "a largely empty metal sphere, where a modestly sized HB11 fuel pellet is held in the center, with apertures on different sides for the two lasers. One laser establishes the magnetic containment field for the plasma and the second laser triggers the ‘avalanche’ fusion chain reaction. The alpha particles generated by the reaction would create an electrical flow that can be channeled almost directly into an existing power grid with no need for a heat exchanger or steam turbine generator."
> HB11 says its generators would be compact, clean and safe enough to build in urban environments.
The big problem I have is the direct conversion approach being suggested. The idea, as I understand it, was that the target is placed at the center of a large sphere, and is negatively charged, so the alpha particles from fusion slow down as they go up the potential to the surrounding spherical collector.
You see the problem with this, I hope. The violent and energetic event at the target will produce gas and plasma, and lots of free electrons. What is stopping that from shorting out this megavolt vacuum capacitor?
The direct conversion stuff doesn't seem that critical. If that doesn't work out immediately, surely the first generation can use good old steam rankine power conversion (or sCO2 Brayton, if that is deemed mature enough).
My worry is whether the specific fusion reactor concept itself is viable.
It's very critical. Without direct conversion, it's just another source of heat, and all externally heated power cycles are becoming uncompetitive now.
And yes, the physics of the target is also something that needs external verification.
It's a private company in Australia that likely needs more funding, so probably so, if you meet your government's requirements for investing in that sort of thing.
Can somebody with more understanding tell me if this idea I had is stupid or has some merit?
Fusion will deliver an incredible amount of energy, making it cheap. Everybody then turns up their energy consumption since it costs nothing. Raise heating in houses, use AC everywhere, longer showers, more transportation, etc.
All this energy eventually becomes heat. Can it get to a threshold where it can influence temperature on a global scale even if it lowers carbon emissions? What am I missing?
There's waste heat from our power plants today, but it's an extremely minor factor compared to carbon emissions. However, if we were to continue our current rate of exponential energy growth on this planet, we would boil the oceans in 400 years.
On the other hand, compact fusion power would make for some great rockets, so by the time it's common it would probably make sense to move most of the growth off planet.
Orders of magnitude. Total Earth solar irradiance is in the order of hundreds of petawatts, while total world installed power plant capacity sits in at a few terawatts.
We're simply unable to measurably increase the amount of heat on the surface of Earth directly.
> energy [...] costs nothing. Raise heating in houses, use AC everywhere, longer showers, more transportation
Yey, can we get to this future faster?! Joking aside, all the current eco-friendly tech diminishes comfort by a loooot... we need low-energy habitats that are actually comfortable ffs.
For example, traveling around Europe, I see that the new trend in the developed/western part is to shiver you ass out during the cold months and to melt your brains out during the hot ones in almost all public spaces! Like we're back in the pre-AC era! You need to get to Eastern Europe's bigger cities to enjoy comfy heating/cooling habits like proper heating in the winter (yes, I want my >25 C in winter!) and proper cooling in the summer (<18 C please!)... It's wasteful, but very much enjoyable! Snow fighting after/before coming out/in of a 30+ C heated house is bliss :D Same a blasting through an enjoyable heatwave after jumping out of a 15 C office and then back in. Life's little pleasures.
After we invest so much of our lives in developing technology, we should at least enjoy the simple comforts and pleasures it freaking offers!
Are you actually serious and would heat your house in winter to a temperature 5-15(!!) ℃ more¹ than you would cool it to during summer?
I mean - it can be enjoyable for short periods, to warm up/cool off, but why would you do that for extended periods, instead of going for a sauna or swimming? Do you wear coats inside during summer?
If you are comfortable at <18 ℃ and at >25 ℃ (humans are highly adaptable), then why go for the opposite of outside temperature? You are probably doing yourself a disservice, making the outside temperature way less tolerable (adaptation takes time), and the temperature shock can be dangerous for less resilient people.
¹ If you are in a high humidity area, the temperature is not the only factor - you need to get the humidity to acceptable levels, which is often done via AC/heating.
I have never understood this. Why keep indoor temperatures so warm in the winter? Everyone is already wearing warm clothes when they come in from outside, so why make it like a sauna inside? I'm already sweating before I can get my coat off.
You should be far more worried about CO2, methane and other greenhouse gases than worried about waste heart because that is just a drop in the ocean compared to greenhouse gas issues.
Can someone provide a list of how much each item that is relevant to this technology is likely to cost?
I’d really like to know how much each laser, pellet, metal case, etc will likely cost in this and how difficult it will be to create each one.
I would have to imagine that these lasers will be the most difficult part of all of this. It will also be good to know how long each laser lasts and how much power they require to operate effectively.
"Naked Helium" -- What a nice way to say "we output alpha radiation"
> "The hydrogen/boron fusion creates a couple of helium atoms," he continues. "They're naked heliums, they don't have electrons, so they have a positive charge. We just have to collect that charge. Essentially, the lack of electrons is a product of the reaction and it directly creates the current."
“The fusion energy gain factor, usually expressed with the symbol Q, is the ratio of fusion power produced in a nuclear fusion reactor to the power required to maintain the plasma in steady state.” [1]
Currently zero, because the necessary lasers are just now becoming available.
In theory, they've got a kJ laser to generate the magnetic field, a 30kJ laser hitting the fuel, and a GJ energy output, for Q over 30,000 minus whatever losses you have in the lasers and electricity harvesting.
There have been experiments, but only at lower power than required for fusion. From their latest paper:
> A significant case of nonlinear deviation from classical linear physics was seen by the measurements, how the laser opened the door to the principle of nonlinearity and could be seen from the effect measured by Linlor [9] followed by others (see [7] p. 31) when irradiating solid targets with laser pulses of several ns duration. At less than one MW
power, the pulses heated the target surface to dozens of thousand °C and the emitted ions had energies of few eV as expected in the usual way following classically. When the power of the nanosecond laser pulses was exceeding a significant threshold of few MW, the ions – suddenly – had thousand times higher energies. These keV ions were separated with linear increase on the ion charge indicating that there was not a thermal equilibrium process involved.
Lasers adequate for fusion are just now becoming available.
Not convinced. The excited atom will travel in a straight line without slowing until it contacts another atom same as in a pellet. The mean free path is longer, but the chance of collision is about the same?
The paper says the fuel is a low energy plasma of "solid state density". It's not a solid chunk of HB11, which AFAIK doesn't exist. The primary factor limiting the feed is the repetition rate of the laser.
Seems like the jury is still out on whether they can reliably generate more energy than it takes to initiate the reaction? It won’t go anywhere if it can’t clear that hurdle.
I have long thought this fuel was a far better fit. Really in a practical sense, you don't get that much benefit from most tritium fusion reactors compared to fission. Meaning that compared to what we have now, fusion and fission are so much more efficient anyway.
The primary problem for fission is state regulation and large cost even if you didn't have to pass regulation. And most fusion concepts can't really address that much better.
Directly creating current rather then having a whole heat to electricity transformation might allow the whole thing to be much cheaper.
What i find disturbing is when I start looking for other sources, google gives me a news item on https://newsroom.unsw.edu.au/news/science-tech/pioneering-te... but there the article has been retracted? Also another one that is behind a paywall it seems (cannot tell as the paywall is broken). So I have 1 story on 1 website and the company website itself. The news-site claims on their about page that they value old-school journalistic values (I assume they mean, they investigate a story before publishing) but it's hard to take that claim seriously without more credible sources. For me this is interesting technology to keep an eye on, but without more confirmation and research, this is cold-fusion for now.
On paper, this sounds absolutely awesome and a huge game changer.
I'm super concerned about the military applications tho. Giving functionally endless, mostly free power to warmonger countries with the ability to field drones is something extremely concerning for me.
they basically already have endless, mostly free power in the sense you are getting at. that it isn't clean is irrelevant to their use case.
china, iran, the united states, etc. militaries are not hurting for energy and already make heavy use of small nuclear reactors where just hauling fuel is not an easier choice.
Not unless you could somehow bang three of them together at once to get to C-12. That seems unlikely with current technology. We can't even get C-N-O cycle fusion in the dinky little star we live next to.
So that's at least 20 years away from being 20 years away from being 20 years away. And you could just make more alpha particles, anyway. It's not like the universe is short on hydrogen.
Not cow burps. Cow burps do not contain helium gas. Helium is formed as a product of natural radioactive decay. It tends to get trapped within the earth in the same ways that natural gas does. Thus, helium is often present as an impurity in natural gas. This is what the previous commentator was referring to, but of course, CH4 is not actually a very good source of helium.
There certainly is enough fusion fuel on earth to power humanity at 10 or 100x current consumption until the sun explodes without emitting any CO2.
Same can be said for fission, but it only powers 5% of the world due to what can be called complications (even though many scientists insist that it's safe and responsible).
Fusion is expected to have fewer complications, but we won't know until we scale up a fleet of fusion power plants and understand all the nuance.
Certainly the generation of radioactive material in fission plants was considered potentially fatal all the way back to Fermi, who said way back when:
> It is not clear that the public will accept an energy source that produces this much radioactivity and that can be subject to diversion of material for bombs.
However, the nuclear fission industry has arguably shown that it can technically manage radioactive wastes without undue harm to the populace. Fission plants have killed up to 4000 people while producing 5% of the world's energy. Fossil kills 4.2M people/year at 84% total energy. The math suggests that nuclear fission has been highly successful. But the public largely still doesn't like it.
Fusion indeed has a better going-in position. Potential complications involve how hard/complex/expensive it is to realize the engineering challenges.
Aneutronic fusion plants, like fossil plants, will likely also have an EOL from a thermal creep, corrosion, cracking, etc. POV. Normal fusion plants will definitely have a EOL from neutron doses to structural materials.
Appreciate all your comments here. As someone that knows a lot about this stuff, may I ask... would you have any concerns living near (say 5 miles) from a deep geological repository, like what is described here:
I spent the first 17 years of my life 5 miles from an operating nuclear power plant. The stored nuclear waste from this plant is still there (though the plant itself was decommissioned). When I visit my family, I am right there next to it. It sits in dry casks exactly like these [1]. I feel 100% safe being in that situation at all times, and I know in elaborate detail the characteristics of nuclear waste and radiation in general.
If the waste was 500m below ground in a designed deep geologic repository I wouldn't feel that much safer (because I already feel totally safe from the dry casks). But it would be at least a little more out of reach for terrorists and whatnot so from that perspective, yeah I'd prefer if it was underground.
I would gladly put my house and raise my family directly on top of a deep geologic nuclear waste repository. This really isn't reckless. I have a Geiger counter. I know what levels of radiation are safe. I know the risks. It's exceedingly low. I am far more worried about hamburgers.
Just reading Wikipedia at random, made me feel like the solution to the waste problem and global warming is simply to build lots of breeder reactors and forget about non-proliferation. Everything else is just avoiding the only feasible solution. Take the waste and burn it to make more power.
I have heard of efforts in India and China to develop and build out nuclear fission plants, though I do not know the scale of these plans. However, even ITER (the largest fusion project right now) has a budget of only $10-20 billion. I have high hopes for ITER, but even that has been protested by anti-nuclear organizations such as Greenpeace. I worry that fusion, despite its many advantages, may be stalled or stopped in the same way fission has been. If we cannot solve this issue with a currently-available zero-emission power source, I just cannot see how a new one based on the same principles can succeed.
It's hard to imagine anyone successfully protesting a power source which is non-polluting, very close to non-radioactive, dispatchable, and likely cheaper than any other system with those properties. However, if the U.S. does turn out to be that silly, we'll likely get over it when we find ourselves being outcompeted by China, which will certainly have no qualms.
I'm still hoping China will take up the torch since current administration in the USA seems hellbent on going downhill and regressing technology rather than making progress in this arena.
Because fission is insanely expensive. The nuclear fanboys like to try and divert the conversation to safety as they think they can argue that point, but the fact is that nuclear is overpriced garbage.
I'll believe it when I see it. Radical new technology is always leapfrogging conventional fusion and has been overtaking and rendering it 'obsolete' for the past 30-40 years.
Yes. This was my favorite quote. With slightly more context:
You know what's amazing? Heinrich is old, he's 84 or so. He called this in the 70s, he said this would be possible. It's only possible now because these brand new lasers are capable of doing it. That, in my mind, is awesome.
On its own, this isn't a very substantial comment. Can you elaborate on why your friend is sceptical and what effort they put in to come to that conclusion?
He says it's a wild dream which everyone who has studied it knows due to the physical properties. He has a Ph.d. and worked on the Prague-based fusion reactors. I think it's useful to know that people with expertise consider it wild even though they're not exactly sure why themselves. You don't need to take it into consideration if you know better.
Not to be a downer, but if you say your technology is working a billion times better than expected, one of two things is probably true: you are trying to stir up media hype, or you don't really understand the underlying technology to begin with.
Google polywell the US military has been funding this for the past 20 years. There are some issues that might be solved with scaling the device. A company called emc2 was spun off this US military project.
“ This cascading avalanche of reactions is an essential step toward the ultimate goal: reaping far more energy from the reaction than you put in. The extraordinary early results lead HB11 to believe the company "stands a high chance of reaching the goal of net energy gain well ahead of other groups."
Its a great read, but it sounds like its still a net energy loss.. one more brick on the road though.
> "The timeline question is a tricky one," he says. "I don't want to be a laughing stock by promising we can deliver something in 10 years, and then not getting there. First step is setting up camp as a company and getting started. First milestone is demonstrating the reactions, which should be easy. Second milestone is getting enough reactions to demonstrate an energy gain by counting the amount of helium that comes out of a fuel pellet when we have those two lasers working together. That'll give us all the science we need to engineer a reactor. So the third milestone is bringing that all together and demonstrating a reactor concept that works."
The fourth step is to deliver the reactor concept as promising machine. The fifth step is to attach it to power generating equipment and demonstrate the power plant. The sixth step is to scale up a supply chain capable of delivering multiple units that compete with other sources of commodity electricity (or other energy products). The seventh step is to scale to large scale without being unduly burdened by either supply chain (raw material, skilled labor) or regulatory impact/public concern that inevitably scales with any large fleet of any new tech.
Fission made it to step 7 and then faltered and is now teetering depending on where you look. It never scaled past 5% of total world primary energy.
The promise of fusion is to deliver nuclear energy with less public concern than fission because it makes less radiologically hazardous material. The challenge is to go through the physical, engineering, and commercial viability phases as a power plant.
Small plants require less capital. They're easier to manufacture. They can iterate faster. They have less environmental impact, and therefore fewer regulatory hurdles. They require less labor to build and a smaller supply chain.
I expect that the engineering is harder, because scale can bring efficiencies. But still, I think the winner is going to be a small device, not a behemoth, if only because a small device can come online years earlier.
Drop a chunk of U238 in/near the fusion reactor somewhere, let it absorb stray neutrons, and you'll soon have some plutonium. That's bad for control of nuclear weapons proliferation, which relies on high-energy neutron sources like breeder reactors being difficult to build and expensive.
Not sure about the radiation profile from this system though.
The energy output of HB11 consists of fast-moving alpha particles, which is good because that's the energy you capture, along with x-rays. None of this would activate reactor components. The waste product is non-radioactive helium.
https://en.wikipedia.org/wiki/Aneutronic_fusion#Boron
Neutron energy would be a bit under 3 MeV, comparable to fast fission neutrons but in much lower quantity for the power output.
https://en.wikipedia.org/wiki/Neutron_temperature
Interestingly, that page says the thermal neutrons in a conventional nuclear reactor are better at activating materials than fast neutrons.
According to a presentation I saw by the leader of MIT's fusion program, the inner wall of a D-T tokamak would be activated by the neutrons, but would only need to be stored for a few decades. D-T releases 80% of its energy as 14 MeV neutrons.
According to LPP, which is working on a different boron fusion design, a 20MW reactor would activate the walls with short-lived radiation, but it could be safely opened for maintenance after about twelve hours (iirc).
This is something different. With every laser shot there will be a burst of alpha particles. Then they'll slow down and just be plain old helium. If the direct energy conversion works, they'll get slowed down very quickly.
Only if you eat or inhale them. A sheet of paper will stop alpha particles.
It might also be worth pointing out that "It must be safe! They even put it on wristwatch dials!" is not, historically, a sound argument.
This depends on the threat model to some degree, but there's security in knowing that it's vastly harder for a threat to affect multiple targets at once, no matter the threat.
That might be different for this fusion device, but for outdated looking fission reactors it’s artificial dilution for NPT purposes and by no way a technological limitation.
I imagine most software is tied to the specific devices they run on, but perhaps there's coupling or analytical software that could be better geared towards the problem domain. Is there any fundamental issue that is waiting for a good software solution?
https://github.com/terrapower/armi
Some more open source things in the domain can be found here: https://github.com/paulromano/awesome-nuclear/blob/master/RE...
I think if you have a software background and want to contribute, you should consider applying for a job with one of the projects themselves. General Atomics lists 135 software jobs (https://www.ga-careers.com/search-jobs/software/499/1) for instance.
Your parent merely notified us that more than one type of product is in development at that company and one that is not fusion is specifically designed to kill people.
I've dreamed about getting into fusion research myself, and concluded the best pivot would be to help with the plasma simulations at a university while obtaining a PhD.
In my device, sometimes, some ions will be traveling in a vacuum with a high mean free path, and at other times, the plasma will be as dense as lead. It's VERY difficult to simulate, to the point that it's almost better to just estimate and start building to see if I can start to get close to a solution through careful experimentation.
The part that jumped out at me as strange is that they claim their process generates electricity "directly" without having to drive a turbine. Supposedly they produce helium cations, and that can drive a circuit.
Can anybody comment on whether that makes sense?
Conventionally, neutrons are used to generate heat which is then used to drive steam turbines.
Thus you would capture the energy with a "reverse coilgun", "regeneratively braking" the particles down to a non-relativistic speed, rather than just using them to charge a capacitor plate.
Most fission plants throw away about two-thirds of their energy output as waste heat (according to: https://www.answers.com/Q/How_much_of_the_heat_generated_in_...), and their cooling towers are so much bigger than the reactor itself that they've become a symbol of the plants as a whole.
The cooling towers? The photographs in the news commonly show huge clouds of water vapor escaping from the tops of the towers with a picture caption about "nuclear" power or some such.
So, the suggestion is that nuke plants generate huge clouds of dangerous radioactive byproducts.
Such news content is easy: (1) Suggest that the cooling towers are the nuclear reactors and (2) don't mention that what is coming out is just water vapor, from water recently in some river or lake. Now the news people have their audience by their eyeballs for ad revenue and/or politics as in
https://www.peakprosperity.com/2019-year-in-review-part-1/#c...
“The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety) by an endless series of hobgoblins, most of them imaginary.”
~ H.L. Mencken
https://www.exeloncorp.com/locations/power-plants/limerick-g...
The same imagery shows up on the covers of nuclear textbooks:
https://www.amazon.com/Nuclear-Engineering-Handbook-Mechanic...
If anything, laypeople think that radiation is scary because it's invisible, tasteless, and odorless.
In principle this could be more efficient than a heat engine, although the Wikipedia page seems to say that an "economically feasible" version would have around 60% efficiency, which is the same as a combined-cycle power plant.
What is your opinion on SPARC and tokamak energy?
p-boron fusion is interesting as a possibly practical energy source. The hurdles are a matter of engineering and finance, not fundamental design flaws. But it's useless as a jobs program for weapon experts, so must rely on commercial investment.
Lawrence Livermore -- a nuclear weapons lab -- has studied inertial confinement fusion for decades. They don't have a tokamak.
https://en.wikipedia.org/wiki/National_Ignition_Facility
It's seems bizarre to ignore the impact HTS tape would have on the plausible operation of MCF.
> The alpha particles generated by the reaction would create an electrical flow that can be channeled almost directly into an existing power grid with no need for a heat exchanger or steam turbine generator."
If you energy production solution can achieve a lower TCO in an existing market segment, steps six and seven (production and supply chain) take care of themselves. The poster child for this was 'on premise PV generation.'
Once a nuclear technology demonstrates a lower TCO for baseline power generation, its game on.
The main benefit of nuclear is its relatively low carbon footprint and in theory less risk of spiking fuel costs because we run out of raw materials. That's the dream of fusion anyway.
Nuclear power infra is not cheap and even fusion will have security and decommissioning costs.
Forget cost as the main factor, grid power will never be free. That's a fantasy - even publicly owned utilities will/are funded by taxation. You're paying for price and power stability. Domestic fusion means you don't need to rely on foreign resources (eg Russia cutting off the gas).
Putting renewable generators in your home has a high capital cost, but people forget that you're also cushioning yourself against grid outages. It's insurance more than anything else.
A fusion reactor the size of a shipping container? Plop one down between my neighbor's house and my house. Right where our backup generators now sit. It's about the same footprint.
No more distribution costs. Well, except for Amazon's fees to drop off the uranium now and then. :)
Why is there any radioactive material produced by a fusion reactor ?
Neutrons produced in this reaction, being chargeless, cannot be contained within the electromagnetic field, thus leaving plasma and reacting with the surrounding material (e.g. tokamak chamber walls) and producing radioactive elements. This leads to activation and radioactive degradation of the reactor itself.
For ICF, a long-pulse laser is used like a hammer to heat and compress the material to fusion conditions.
This scheme, as far as I can tell, uses the large EM fields of a short-pulse laser to accelerate a ‘beam’ of ions into cold material to induce fusion.
Q0: Without bias from my opinion, how fringe or potentially legitimate does IEC seem?
Q1: Props to the article's team that they invented some awesome lasers. Is there enough experimental data yet on their novel approach to backup their claims to justify funding a prototype? Would such a team be able to test this on a shoestring budget without spending millions?
"Millions" is pretty much a shoestring budget for fusion projects. There is some experimental data, but without actual fusion since the lasers weren't powerful enough yet.
This team didn't invent the lasers. They've been waiting for the lasers to get sufficiently powerful to attempt fusion with them. Those lasers are finally becoming available for researchers to use, so it should be quite inexpensive to test this idea. Worst case, they have to build one for tens of millions, which is comparable to other private fusion projects, but hopefully they can run the experiment on other people's lasers.
* https://en.m.wikipedia.org/wiki/Polywell
https://www.reddit.com/r/fusion/comments/dmqgd5/is_the_polyw...
(stupid grin)
The fusion triple product is the go to figure of merit for napkin calculations, it's temperature X confinement time X ion density
MCF strategies go in on maximizing confinement time, while ICF jack up temperature and ion density. This particular ICF approach, (if I'm understanding their paper correctly) is going so high on both that they're leaving the thermal regime behind and doing an honest to glob nuclear chain reaction with having the alpha products prompt other boron nuclei to accelerate up to fusion speed causing more reactions, which is pretty exciting.
I don't have the Physics chops to untangle the likelihood of this tech and the credibility of the process and its authors, so I'm hoping the HN crowd will be able to pad out the story behind this.
Certainly, from my layperson's perspective, their website isn't exactly encouraging... https://www.hb11.energy/
- ed re: last line - "books and covers, and all that"
Exponential progress does sometimes have results that seem too good to be true. In this case the progress has been in picosecond lasers, which for a while have been getting ten times more powerful every three years or so.
What's great about this is it should be pretty cheap to test. The petawatt lasers only cost tens of millions in the first place, and China is finishing up a 30PW laser which they plan to let other researchers use. If Hora is right then that should be powerful enough. Even more powerful lasers are being planned elsewhere.
HB11 isn't the only company working on aneutronic fusion. The largest is TAE (formerly Tri Alpha), with about $700 million invested. There's also Helion and LPP.
I checked the publications page and so far I'm not seeing any real theory here. That doesn't mean it's wrong, but it certainly feels weird. The most in-depth equation I saw in any of their linked papers is the definition of the electromagnetic field tensor.
I'm not saying you couldn't develop a fusion reactor by doing purely experimental work with bleeding-edge laser technology. But I'd feel a lot more confident if they were to produce, for example, some kind of prediction of their net power, or a relation between e.g. laser power and fusion yield, or some other quantitative prediction about something.
For example, I'm not sure what prediction they exceeded by a factor of a billion in TFA. Shouldn't you mention that somewhere?
Another poster mention's Todd Rider's thesis, a famous barrier to creative fusion. In this particular case I think the way they evade Rider is by using higher laser powers and shorter reaction times than Rider considered to be possible. One of the important exceptions Rider acknowledges (and that I remember) is ultradense fusion; ultrafast fusion seems to be at least similar in principle.
They do seem to be making quantitative predictions based on simulations. I don't think I've seen them boil it down to a simple scaling law though.
In any event, ultimately practical proven results will always trump whatever the current theory may suggest.
[0] https://www.hb11.energy/news-and-publications [1] https://aca3d9dd-3b9c-446b-8797-0ba1cdb49ccb.filesusr.com/ug...
1 proton + (5 protons, 6 neutrons) -> 3 * (2 protons, 2 neutrons)
https://www.hb11.energy/our-technology
Yeah, in theory it might be possible to capture the brehmsstrahlung and pump it back into the reactor with sufficiently high efficiency, but we're pretty far away from that.
That being said, all these fancy fusion reactor schemes are interesting. Just make them work on boring old D-T fuel first, then lets see if these other fuels are usable, no?
https://www.reddit.com/r/fusion/comments/dmqgd5/is_the_polyw...
Bremsstrahlung
FTFY
-Conversion efficiency of laser energy into ion (proton) kinetic energy
-TNSA accelerates mainly the contaminated layer on the back of targets, which may not be a big deal if you are interested in accelerating protons
-TNSA protons are not beam like. They do not have a uniform kinetic energy, and they have a wide angular divergence.
-Various laser related issues (prepulse, focal spot size/shape).
I also anticipate that it will have the same engineering problem as ICF/NIF, in that it will need to continuously replenish targets.
https://www.hb11.energy/news-and-publications
I have no idea what "contrast ratio" means, it isn't defined, and isn't in the references. Does anyone know what "contrast ratio" means in terms of high power pulsed lasers?
edit: To answer my own question, ref: https://cdn.intechweb.org/pdfs/24813.pdf
> the laser pulse contrast ratio (LPCR) is a crucial parameter to take into consideration. Considering the laser pulse intensity temporal profile, the LPCR is the ratio between its maximum (peak intensity) and any fixed delay before it. A low contrast ratio can greatly modify the dynamics of energy coupling between the laser pulse and the initial target by producing a pre-plasma that can change the interaction mechanism.
It seems to be how fast the laser turns on, the rate of change of intensity.
These plasmas can be the source for all kinds of particles and energy in particular forms, so they may have lots and lots of uses.
One person in particular is proposing to use a CPA laser to accelerate nuclear decay, to allow radioactive waste to decay faster and become less toxic more quickly.
Of course, my own concern would be that being able to induce fission with a table top laser means that the tech may eventually exist to create a fission or fusion bomb without a nuclear trigger....
But ITER uses huge tower cranes and trucks in the thousands of tons of material required to sustain a temperature hotter than the surface of Sol because of their fuel selection.
It seems the small player with a new approach that perhaps demands less complexity in their scaled up commercial reactor could win a commissioning contract with a lower bid during late 2020s early 2030s international bidding.
"First milestone is demonstrating the reactions, which should be easy."
And "chirped pulse laser amplification" is the recent discovery Hora says will make it possible.
Breakthroughs happen everyday but the road to real impact is longer and more failure prone after you make the breakthrough than before it.
- with some exceptions
On ignoring the H B-11 reaction with high intensity lasers: https://www.nature.com/articles/ncomms3506
On the reaction avalanche: https://www.cambridge.org/core/journals/laser-and-particle-b...
On the conversion of alpha particles to electricity: https://www.cambridge.org/core/journals/laser-and-particle-b...
Pellets could turn out to be the size of a grain of sand.
Here, what is interesting is if one fusion reaction does happen, then the alpha (helium) particles leave at 2.9 MeV. After two collisions with protons, if the second proton they have hit hits in turn a boron nucleus, then it will have exactly the right energy (612 keV) to have maximum chances at initiating a second fusion reaction.
612 keV is like almost 7 billion degrees °C if considered as thermal energy, and no experiment anywhere will get that hot for long. But compared to the energy of the exiting helium nuclei, it's still much lower (0.612 MeV vs 2.9 MeV).
In other words, instead of cascading all the energy down and hoping the sea of particles rises to a few billion degrees so enough particles do fusion to keep the sea of other particles hot, here, the energy is preempted by proton atoms after just 2 collisions and used immediately to start a second reaction, which yields more helium nuclei at 2.9 MeV, essentially producing an "avalanche" effect.
Finally, yes, they seem to have devised a way to obtain at least a small part of the energy electrically, without relying on thermal energy, via direct electric field deceleration of very fast charged particles.
This is like "the ultra rich (very fast particles) manage to create value among themselves without having to cascade their wealth down to the crowd (cold particles), and then upload that value to hyperspace (the electric field from the electrodes), without ever interacting with the mass of the crowd (the mass of the target), until a sufficient amount of fusion reactions have been realized"
The avalanche process is explained in Hora's 2016 publication, with a schematic page 9: https://aip.scitation.org/doi/10.1016/j.mre.2017.05.001
And yes, a petawatt (the energy of present day ultra-fast lasers) is a lot of power. It was just chance that there was very little practical use to this kind of power - until now.
That being said, I am not a true expert myself of this topic, so the true barriers laying in front of this concept might be better explained by the other comments here.
This was actually a helpful analogy for me. I'll have to take your word on the accuracy of it, though.
https://www.cambridge.org/core/services/aop-cambridge-core/c... I found this overview a bit confusing and sort of low quality, but at least it references a lot of papers. (But haven't started hunting down any of them.)
Are you saying this kind of fusion is anti social justice? We should ban this immediately!
I love the work, I love that they have exploited the fact that we can build things (lasers) now that we could not economically build before. But the fact is that so many many things die on the aforementioned step from the article.
That is the step wherein the science doesn't give you a way to engineer a reactor, instead it illuminates something you didn't know before and so that you now realize you can't ever build a reactor that way.
So when I read these papers and the science isn't all figured out, I temper my enthusiasm. High hopes, low expectations, that's a good motto here. Unlike the stellerator where all the science is "known" and they are engineering an implementation step by step by step.
I've added it to my fusion project collection under "interesting long shots", check back in 5 years to see what the science taught them.
They haven’t even demonstrated the reaction? What’s all the talk about results being “billions” of times better than expected?
(The very-crude video technique was fascinating to this non-artistic person: Create PowerPoint slides, add subtitles for "narration" that float in and out, and finally add stock music for background. That might be useful for flipped-classroom courses.)
Don't know — I'm not knowledgeable enough in this area to do more than take WAGs about it. The sequence might be different: For example, the 1H proton might not ever fuse with the 5B11 to form 6C12; instead, the fusion reaction might be that the 5B11 fissions into two 2He4 and one tritium 1H3, after which the 1H proton fuses to the tritium to form the third 2He4.
> And wouldn't this technically be fission energy then?
See the explanation in this thread at https://news.ycombinator.com/item?id=22383199 — it makes as much sense as anything.
Surface of the Sun - 6000 C
Center of the Sun - 15000000 C
> The temperature in the corona is more than a million degrees, surprisingly much hotter than the temperature at the Sun's surface which is around 5,500° C
https://scied.ucar.edu/solar-corona
With sufficiently efficient fuel, the fastest path from A to B is by constantly accelerating (more or less) towards it until you reach halfway, then flipping and constantly decelerating until you arrive.
Under this kind of trajectory, you're under constant acceleration of, say, 1g the whole time. This means you effectively have gravity for the entire trip, as long as you've designed your ship such that the floor is in the same direction as you apply thrust - think less traditional ship decks and more like a skyscraper.
Another realistic option, of course, is a rotating section. But this generally requires massive, "ugly" ships to work so it's pretty rare in fiction.
https://www.youtube.com/watch?v=10AP7tio408
Barring other species as intelligent as ours elsewhere (which is of course possible, but unknown), the very hottest thing in the entire unimaginably-large universe full of exotic stars and black holes and supernovae, was created by a tiny group of apes on a minuscule planet orbiting a smallish, boring star on the unfashionable side of a galaxy.
Per Wiki:
> The energy of this particle is some 40 million times that of the highest energy protons that have been produced in any terrestrial particle accelerator.
Presumably wherever these extreme energy protons are coming from is rather warm.
Is there some reason to think the LHC has higher temperature?
Not a physicist; could be something like LHC having larger bunch sizes... but since we don’t know what causes these particles, it seems like we don’t really know the source temperature.
"The hydrogen/boron fusion creates a couple of helium atoms," he continues. "They're naked heliums, they don't have electrons, so they have a positive charge. We just have to collect that charge. Essentially, the lack of electrons is a product of the reaction and it directly creates the current."
Apart from literally saving humanity from a climate disaster, we can still use our MRIs!
And MRIs of the future will be constructed with REBCO magnets and cooled with liquid nitrogen.
There will inevitably be a lot of heat produced that has to be cooled. Generally people plan to use the coolant as the working fluid in the power cycle.
If there's an innovation here it'd be cool if they put it way more up front.
In any case there will still be a coolant.
According to HB11's papers, each shot would have about 30 kilojoules input power via laser, consume 14 grams of fuel, and produce over a gigajoule output power, or 277 kWh.
They think within a decade the lasers will be capable of one shot per second. Right now it's more like one per minute.
Edit: actually read the paper :) From the paper: H + 11B = 3 x 4He + 8.7 MeV
when alpha particle absorb the electron to become helium, it can carry about 50 eV energy. So vast majority of the energy generated will be kinetic energy or photon energy which translate into very hot temperature at macro level.
Steam generators might have fairly low efficiency, but if hydrogen fusion works at all it'll use so little fuel and have such a low marginal cost that we can just do more of it to make up for any efficiency losses.
The article talks about the advantage of not needing steam cooling apparatus. The stations could be located in urban areas.
These are IMO the fundamental questions.
Hydrogen + Boron -> 3×Helium + energy
The energy is mostly 2900keV kinetic energy for each Helium ion i.e. the He ions just fuck off really fast and leave the elections behind.
If a He ions hits H atoms a couple of times, the second H hit has just the right energy to then hit another Boron and create an an avalanche of reactions. https://aip.scitation.org/na101/home/literatum/publisher/aip...
Well that's frightening.
Importantly, this doesn't have to happen in the reactor vessel. The charged gas can be pumped somewhere else.
- Fire a stream of hydrogen ions with a particle accelerator at a chunk of Boron 11. - The hydrogen and boron combine and release heat and helium. - Use the heat from that to run a turbine and keep running your particle accelerator.
It seems like you would be ending up with lower-energy collection of atoms. Does that work but it is just not efficient enough to keep running the accelerator, or what?
This is the reason why most fusion approaches rely on thermal systems. In a thermal system, the ions have a bell-shaped distribution of energies and undergo many collisions before they leave the region in which they are confined and their energy leaves the system.
To achieve net gain, the temperature, density and energy confinement time must be above a certain threshold. If the system is non thermal, like a stream of hydrogen ions where the distribution of energies is a spike, the energy in the hydrogen ions that are deflected by glancing blows must be recaptured somehow.
This is what's wrong. The energy required to accelerate the ions is much higher than the energy which can be harvested this way.
The concept under discussion substitutes a simpler setup that accelerates particles using laser induced plasmas from a very small table top laser. The thing could "almost" be battery powered.
https://en.wikipedia.org/wiki/Nuclear_binding_energy#Nuclear...
(TLDR version: proton-boron fusion is a less energetically efficient alternative to 3He fusion, but with the howlingly significant advantage that boron -- the fuel -- is lying around in heaps and drifts on Earth, rather than being so exotic a substance that annual global production is measured in single-digit kilograms and a significant energy economy would require mining it from the Lunar regolith. It's not as well-known as 3He fusion, though, because the space cadets don't see the point -- there are no Moon colonies required. Advantages of 3He or B + p fusion over D-T fusion: it doesn't produce a surplus of neutrons, so there's less radioactive waste created as a by-product of the process.)
After that there is radioactive decay (the splitting).
To be fission you have to actually [actively] break the atom apart, which isn't happening here.
- All work seems to be purely theoretical although the setup needed is not that hard to come by. For 1000 USD / hour you can rent a proton implanter and check the principle mechanisms of the reaction.
- Everything is published in realativly low impact journals. There are a ton of smart people in academia that love to "think outside the box" but nobody seems to think that this is promising. This basicaly seems to be a one man show of H. Hora.
- It doesn't seem to be that radically new but the first paper was published. I have not found what they have done in the meantime.
I've seen it said here on HN that the amount of helium out of a deuterium/tritium is so small it is negligible.
From article: "My question is: Would that setup produce a continuous fusion for some period with positive net energy generation?
Here is my argument why I think it would: Since Boron is solid at room temperature, it's density is high, so I think the fusion rate per nucleon would be quite high. As far as I know 100keV is the energy needed for Hydrogen-1 and Boron-11 to fuse, while the resultant three He-4 nuclei should have about 8MeV of energy. So indeed if all accelerated protons fuse then the energy produced should be quite higher than the input. The problem that immediately comes to mind is that as the container starts to rapidly heat up as a result of the reactions the Boron inside would no longer be solid and may even start to leak through the opening. But before that happens, would there be at least a brief period where an efficient fusion can be sustained?"
https://www.fusionenergybase.com/organizations/
> HB11 says its generators would be compact, clean and safe enough to build in urban environments.
Video: https://www.youtube.com/watch?v=OxEX8UueZ4U
The big problem I have is the direct conversion approach being suggested. The idea, as I understand it, was that the target is placed at the center of a large sphere, and is negatively charged, so the alpha particles from fusion slow down as they go up the potential to the surrounding spherical collector.
You see the problem with this, I hope. The violent and energetic event at the target will produce gas and plasma, and lots of free electrons. What is stopping that from shorting out this megavolt vacuum capacitor?
My worry is whether the specific fusion reactor concept itself is viable.
And yes, the physics of the target is also something that needs external verification.
Fusion will deliver an incredible amount of energy, making it cheap. Everybody then turns up their energy consumption since it costs nothing. Raise heating in houses, use AC everywhere, longer showers, more transportation, etc.
All this energy eventually becomes heat. Can it get to a threshold where it can influence temperature on a global scale even if it lowers carbon emissions? What am I missing?
https://dothemath.ucsd.edu/2012/04/economist-meets-physicist...
On the other hand, compact fusion power would make for some great rockets, so by the time it's common it would probably make sense to move most of the growth off planet.
We're simply unable to measurably increase the amount of heat on the surface of Earth directly.
Yey, can we get to this future faster?! Joking aside, all the current eco-friendly tech diminishes comfort by a loooot... we need low-energy habitats that are actually comfortable ffs.
For example, traveling around Europe, I see that the new trend in the developed/western part is to shiver you ass out during the cold months and to melt your brains out during the hot ones in almost all public spaces! Like we're back in the pre-AC era! You need to get to Eastern Europe's bigger cities to enjoy comfy heating/cooling habits like proper heating in the winter (yes, I want my >25 C in winter!) and proper cooling in the summer (<18 C please!)... It's wasteful, but very much enjoyable! Snow fighting after/before coming out/in of a 30+ C heated house is bliss :D Same a blasting through an enjoyable heatwave after jumping out of a 15 C office and then back in. Life's little pleasures.
After we invest so much of our lives in developing technology, we should at least enjoy the simple comforts and pleasures it freaking offers!
I mean - it can be enjoyable for short periods, to warm up/cool off, but why would you do that for extended periods, instead of going for a sauna or swimming? Do you wear coats inside during summer?
If you are comfortable at <18 ℃ and at >25 ℃ (humans are highly adaptable), then why go for the opposite of outside temperature? You are probably doing yourself a disservice, making the outside temperature way less tolerable (adaptation takes time), and the temperature shock can be dangerous for less resilient people.
¹ If you are in a high humidity area, the temperature is not the only factor - you need to get the humidity to acceptable levels, which is often done via AC/heating.
I’d really like to know how much each laser, pellet, metal case, etc will likely cost in this and how difficult it will be to create each one.
I would have to imagine that these lasers will be the most difficult part of all of this. It will also be good to know how long each laser lasts and how much power they require to operate effectively.
> "The hydrogen/boron fusion creates a couple of helium atoms," he continues. "They're naked heliums, they don't have electrons, so they have a positive charge. We just have to collect that charge. Essentially, the lack of electrons is a product of the reaction and it directly creates the current."
“The fusion energy gain factor, usually expressed with the symbol Q, is the ratio of fusion power produced in a nuclear fusion reactor to the power required to maintain the plasma in steady state.” [1]
[1] https://en.m.wikipedia.org/wiki/Fusion_energy_gain_factor
In theory, they've got a kJ laser to generate the magnetic field, a 30kJ laser hitting the fuel, and a GJ energy output, for Q over 30,000 minus whatever losses you have in the lasers and electricity harvesting.
https://aip.scitation.org/doi/10.1016/j.mre.2017.05.001
> A significant case of nonlinear deviation from classical linear physics was seen by the measurements, how the laser opened the door to the principle of nonlinearity and could be seen from the effect measured by Linlor [9] followed by others (see [7] p. 31) when irradiating solid targets with laser pulses of several ns duration. At less than one MW power, the pulses heated the target surface to dozens of thousand °C and the emitted ions had energies of few eV as expected in the usual way following classically. When the power of the nanosecond laser pulses was exceeding a significant threshold of few MW, the ions – suddenly – had thousand times higher energies. These keV ions were separated with linear increase on the ion charge indicating that there was not a thermal equilibrium process involved.
Lasers adequate for fusion are just now becoming available.
https://www.hb11.energy/news-and-publications
The primary problem for fission is state regulation and large cost even if you didn't have to pass regulation. And most fusion concepts can't really address that much better.
Directly creating current rather then having a whole heat to electricity transformation might allow the whole thing to be much cheaper.
Is this the correct term for a group of wild patents? What do you call a group of wild patent trolls?
I'm super concerned about the military applications tho. Giving functionally endless, mostly free power to warmonger countries with the ability to field drones is something extremely concerning for me.
china, iran, the united states, etc. militaries are not hurting for energy and already make heavy use of small nuclear reactors where just hauling fuel is not an easier choice.
So that's at least 20 years away from being 20 years away from being 20 years away. And you could just make more alpha particles, anyway. It's not like the universe is short on hydrogen.
But practically, with CH4, our modern concern is not running out of it, but the associated GHG emissions of producing and burning it.
So we won't run out of He, so much as stop producing it.
If it works, is it the energy miracle humanity needs?
Same can be said for fission, but it only powers 5% of the world due to what can be called complications (even though many scientists insist that it's safe and responsible).
Fusion is expected to have fewer complications, but we won't know until we scale up a fleet of fusion power plants and understand all the nuance.
How's that for an answer?
> Same can be said for fission, but it only powers 5% of the world due to what can be called complications
But weren't these complications obvious before deciding to scale up fission power plants?
The ones I know about:
- Radioactive waste
- Risk of failure
- Unavoidable EOL
> It is not clear that the public will accept an energy source that produces this much radioactivity and that can be subject to diversion of material for bombs.
However, the nuclear fission industry has arguably shown that it can technically manage radioactive wastes without undue harm to the populace. Fission plants have killed up to 4000 people while producing 5% of the world's energy. Fossil kills 4.2M people/year at 84% total energy. The math suggests that nuclear fission has been highly successful. But the public largely still doesn't like it.
Fusion indeed has a better going-in position. Potential complications involve how hard/complex/expensive it is to realize the engineering challenges.
Aneutronic fusion plants, like fossil plants, will likely also have an EOL from a thermal creep, corrosion, cracking, etc. POV. Normal fusion plants will definitely have a EOL from neutron doses to structural materials.
https://www.nwmo.ca/en/A-Safe-Approach/Facilities/Deep-Geolo...
If the waste was 500m below ground in a designed deep geologic repository I wouldn't feel that much safer (because I already feel totally safe from the dry casks). But it would be at least a little more out of reach for terrorists and whatnot so from that perspective, yeah I'd prefer if it was underground.
I would gladly put my house and raise my family directly on top of a deep geologic nuclear waste repository. This really isn't reckless. I have a Geiger counter. I know what levels of radiation are safe. I know the risks. It's exceedingly low. I am far more worried about hamburgers.
[1] https://www.youtube.com/watch?v=EUvvIzH2W6g
> Fossil kills 4.2M people/year
Where does this number come from?
That number comes from the WHO: https://www.who.int/airpollution/ambient/health-impacts/en/
That's really sad.
2. No, because we already have fission reactors. How many miracles do we need?
Right, but humanity won't scale up fission to power everything.
I have heard of efforts in India and China to develop and build out nuclear fission plants, though I do not know the scale of these plans. However, even ITER (the largest fusion project right now) has a budget of only $10-20 billion. I have high hopes for ITER, but even that has been protested by anti-nuclear organizations such as Greenpeace. I worry that fusion, despite its many advantages, may be stalled or stopped in the same way fission has been. If we cannot solve this issue with a currently-available zero-emission power source, I just cannot see how a new one based on the same principles can succeed.
He knew it would work 50 years ago.
I imagine there are ideas being discussed today that will come to fruition 50 years from now.
... or 30 years. Our choice.
You know what's amazing? Heinrich is old, he's 84 or so. He called this in the 70s, he said this would be possible. It's only possible now because these brand new lasers are capable of doing it. That, in my mind, is awesome.
https://youtu.be/2IfCUsBpR-I
Its a great read, but it sounds like its still a net energy loss.. one more brick on the road though.