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Radical hydrogen-boron reactor leapfrogs current nuclear fusion tech?

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Re: Radical hydrogen-boron reactor leapfrogs current nuclear fusion tech?

#171

Post by DennisP »

jandrese wrote: post #166
lallysingh wrote: post #163

Earlier quoted context omitted.

If these reactors are low heat, not radioactive, and use plentiful fuel, what's the threat model? Is it just worried about availability of power?

"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.

Re: Radical hydrogen-boron reactor leapfrogs current nuclear fusion tech?

#172

Post by DennisP »

joshvm wrote: post #165
sf_rob wrote: post #158

Earlier quoted context omitted.

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 l…

D-T fusion would have security and decommissioning costs, but neither would be an issue for aneutronic fusion.

Re: Radical hydrogen-boron reactor leapfrogs current nuclear fusion tech?

#173

Post by LeifCarrotson »

goda90 wrote: post #157
throwaway894345 wrote: post #146

Earlier quoted context omitted.

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…

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.

Re: Radical hydrogen-boron reactor leapfrogs current nuclear fusion tech?

#174

Post by goda90 »

LeifCarrotson wrote: post #173
goda90 wrote: post #157

Earlier quoted context omitted.

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…

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 c…

I'm not very knowledgeable about fusion, but it looks like this system is aneutronic fusion, so those concerns would be lessened too. https://en.wikipedia.org/wiki/Aneutronic_fusion#Boron

Re: Radical hydrogen-boron reactor leapfrogs current nuclear fusion tech?

#175

Post by smolder »

njarboe wrote: post #128
acidburnNSA wrote: post #92

Earlier quoted context omitted.

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 t…

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.

Re: Radical hydrogen-boron reactor leapfrogs current nuclear fusion tech?

#176

Post by ekimekim »

DonHopkins wrote: post #132
willis936 wrote: post #69

Earlier quoted context omitted.

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.

Re: Radical hydrogen-boron reactor leapfrogs current nuclear fusion tech?

#177

Post by Retric »

DennisP wrote: post #171
jandrese wrote: post #166

Earlier quoted context omitted.

"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…

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.

Re: Radical hydrogen-boron reactor leapfrogs current nuclear fusion tech?

#179

Post by phaemon »

LaMarseillaise wrote: post #106
pier25 wrote: post #105

Earlier quoted context omitted.

> How many miracles do we need? Right, but humanity won't scale up fission to power everything.

Why not?

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.

Re: Radical hydrogen-boron reactor leapfrogs current nuclear fusion tech?

#180

Post by frankus »

wtracy wrote: post #170
acidburnNSA wrote: post #76

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…

> 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. Can anybody comment on whether that makes sense?

Huge if true.

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.

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