Compact nuclear fusion reactor is 'very likely to work,' studies suggest

Post by acchow » Wed, Sep 30, 2020, 4:55 AM UTC

beervirus wrote: post #136

elil17 wrote: post #24

Earlier quoted context omitted.

You're correct, that's a good ballpark for the average heat generation rate in the sun. However, 99% of heat generation in the sun occurs in the core (approximately the center 25% by radius) and this area is much more energy dense. Further, fusion reactors could achieve an even higher volumetric heat generation rate then the sun's core does. To collect energy, heat would be transferred to a working fluid (e.g., molte…

There's something that feels so archaic about using a nuclear reactor to... boil water and spin a turbine. It's disappointing that we haven't figured out a better way to convert to electrical energy than what we were using in the 1800s.

Post by isoprophlex » Wed, Sep 30, 2020, 5:13 AM UTC

Baeocystin wrote: post #77

isoprophlex wrote: post #8

I 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…

>The plasma heats up, but how do you turn that into useful electrical energy? I appreciate that many people are commenting 'you couple the plasma to a working fluid', but I think the original comment was more along the line of how you couple a confined plasma to a working fluid. By definition the plasma is in a hard vacuum, magnetically bottled. What, then, is the coupling method? Thermal photons escaping confinement…

Post by zaroth » Wed, Sep 30, 2020, 5:32 AM UTC

beervirus wrote: post #136

elil17 wrote: post #24

Earlier quoted context omitted.

You're correct, that's a good ballpark for the average heat generation rate in the sun. However, 99% of heat generation in the sun occurs in the core (approximately the center 25% by radius) and this area is much more energy dense. Further, fusion reactors could achieve an even higher volumetric heat generation rate then the sun's core does. To collect energy, heat would be transferred to a working fluid (e.g., molte…

There's something that feels so archaic about using a nuclear reactor to... boil water and spin a turbine. It's disappointing that we haven't figured out a better way to convert to electrical energy than what we were using in the 1800s.

Post by ivanb » Wed, Sep 30, 2020, 5:34 AM UTC

maccam94 wrote: post #214

ivanb wrote: post #50

Basic 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.

The SPARC design uses a combination of extremely high strength magnetic fields to contain charged particles inside the vacuum chamber and a molten-salt blanket (FLiBe) for neutron capture and cooling. They believe this will be a viable containment system.

Post by dehrmann » Wed, Sep 30, 2020, 5:50 AM UTC

ElFitz wrote: post #137

mdorazio wrote: post #16

Here'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. "Nuclear fusion. 30 years away since 1950" Joking aside. I too am glad to see some progress of any kind, and new (seemingly credible) initiatives being funded and pursued