Still a nuclear reactor. Unsafe. Radioactive Waste. Not an Option
Ahh, misread it. It’s about fusion, not fission. Ok then!
Compact nuclear fusion reactor is 'very likely to work,' studies suggest
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Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest
#42I never quite understood the math behind power densities in a fusion reactor. In the sun, isn't energy production occurring at something like 100-1000 W/m3? So, if you want to build a multiple MW fusion plant, shouldn't these plants be ridiculously huge compared to, say, a wind turbine rated at a couple of MW? Is the density of the plasma so much higher in a fusion reactor? Also, something else I never grokked, how d…
> In the sun, isn't energy production occurring at something like 100-1000 W/m3?
It's just an average. Fusion occurs only in the core, which is pretty tiny, relatively speaking.
> The plasma heats up, but how do you turn that into useful electrical energy?
The same way you can turn any kind of heat into useful energy.
Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest
#43I never quite understood the math behind power densities in a fusion reactor. In the sun, isn't energy production occurring at something like 100-1000 W/m3? So, if you want to build a multiple MW fusion plant, shouldn't these plants be ridiculously huge compared to, say, a wind turbine rated at a couple of MW? Is the density of the plasma so much higher in a fusion reactor? Also, something else I never grokked, how d…
Even at the center of the sun's core, the power density doesn't go above 300 W/m^3. At the core boundary it's Terrestrial reactors try for much higher reaction rates. But most designs still have power density issues that would make them uneconomical even if they could make net power. Net power is actually a very low bar, corresponding to an EROI of 1.
Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest
#44> Sparc would be far smaller than ITER — about the size of a tennis court, compared with a soccer field
If we could make efficient fusion reactors the size of a truck, the solar system will become our backyard.
Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest
#45Earlier quoted context omitted.
so you get the plasma spinning and you have two problems: containment and instability. better magnets and faster control systems are the two big things that (in my layman's-bad-at-physics understanding) have really advanced in the last decade.
The intense non-linearity of magnetic phenomena is a source of major issues here. Why can't natural laws be more simple and linear? (joking, sure, but it does feel that way sometimes)
It often times boils down to turbulence.
Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest
#46Here's the actual summary: "Although many significant challenges remain, the company said construction would be followed by testing and, if successful, building of a power plant that could use fusion energy to generate electricity, beginning in the next decade." In other words, "very likely" in this case means "if several roadblocks are overcome, it might be a net-positive power generator in a decade". Even so, this…
Speaking pedantically, the next decade actually starts 1-Jan-2021.
Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest
#47Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest
#48Here's the actual summary: "Although many significant challenges remain, the company said construction would be followed by testing and, if successful, building of a power plant that could use fusion energy to generate electricity, beginning in the next decade." In other words, "very likely" in this case means "if several roadblocks are overcome, it might be a net-positive power generator in a decade". Even so, this…
> this is still exciting given how anemic advancement in the fusion space has been for 50+ years At the top of my list for when I'll be king for a day is - massive, national-scale investments (think: reaching towards one percent of GDP) in fusion research. This is a major roadblock, but things look awesome on the other side. We just need to get our stuff together to hop over this fence somehow.
I couldn't agree more. Once you realize that energy is the fundamental unit which powers everything else in the economy, not only from every movement of ourselves to those of our machines as well, you realize the more we advance in our ability to produce more and more energy at cheaper and cheaper costs in increasingly reliable ways, the more we can accelerate, without exception, every other industry.
Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest
#49The papers on the SPARC reactor seem to be here:
https://www.cambridge.org/core/journals/journal-of-plasma-ph...
Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest
#50Basic thermodynamics. Particle energy grows as T (because energy = 3/2 kT). Thermal radiation energy grows as T^4. At fusion temperature up to 80% of energy is in radiation. Energy density of radiation in this case is close to energy density of metals. It's impossible to contain such radiation.