Live data from Hacker News

More invested in nuclear fusion in last 12 months than past decade

growthbusiness.co.uk

231–240 of 686 posts

Re: More invested in nuclear fusion in last 12 months than past decade

#231
post #82

Earlier quoted context omitted.

Yeah. And Wind, Gas, Hydro, etc. Basically everything except fission, tidal and a portion of geothermal. Admittedly it's not a terribly useful classification.

Fission is just solar from different star.

The energy in fission ultimately came from gravitational collapse, not fusion.

Re: More invested in nuclear fusion in last 12 months than past decade

#232

But where are the fusion neutrons? (See Voodoo Fusion [1]) [1] https://vixra.org/pdf/1812.0382v1.pdf I'm a professional fission guy. I started out in fusion and switched to advanced fission. These days I don't see why we don't just build lots more regular old LWR fission reactors. Imagining that somehow fusion is going to a) work, b) be cheap (fuel cost is only 5% of total nuclear fission cost so who cares), and c) n…

How long will the fuel last? Sabine Hossenfelder references studies in which we have enough Uranium for 50 years max. 6:08 here: https://youtu.be/0kahih8RT1k

If you fully fission the U + Th in an average chunk of crustal rock (using breeding so you can use the 238U and 232Th) then said rock releases fission energy equal to the combustion energy of 20x its mass in coal. So with breeders we can in effect treat the entire Earth's crust as something an order of magnitude more energy rich than coal.

(Whether breeders are practical or competitive is another matter, but then fusion looks pretty challenged in that respect also.)

Re: More invested in nuclear fusion in last 12 months than past decade

#233

The only true form of green energy other than geothermal. fission, solar, wind, waterfall energy all have their own negative environmental impacts

Geothermal, and all thermal power energy, have a big issue: thermal pollution.

You need a lot of water for the cooling phase of the thermodynamic cycle that transform heat into electricity.

That's why during drought episodes fission plants have to be stopped.

There is however a non-thermal path to fusion energy, aneutronic fusion with direct energy conversion. In this scheme, the fusion reaction produces no neutrons and the kinetic energy of ions is directly converted to electricity.

Re: More invested in nuclear fusion in last 12 months than past decade

#234

Earlier quoted context omitted.

No, it's not "too good".

So the fear is we’ll use the extra energy to literally warm the planet? Seems like a scale mismatch. Climate “engineering” like blocking out the sun seems like a much more real danger

Not "warm", because with fusion filling this cache, energy usage wouldn't lead to CO2 pollution. They're suggesting it would lead to increases in consumption which means waste. Notwithstanding that a) life won't necessarily get more affordable for people, and stuff costs money, b) there are innovations now, and expected in the future, which would drastically curtail waste, though some regulatory measures might be necessary to do better with this.

So I'm also skeptical.

Re: More invested in nuclear fusion in last 12 months than past decade

#235

Earlier quoted context omitted.

Yes, clearly that's why SpaceX was successful in an industry where the adage was "How do you become a millionaire in aviation? Start with a billion!".

Has SpaceX disclosed whether they're profitable or still burning investor money?

They obviously aren't profitable right now since they're working on two megaprojects simultaneously, but the Falcon 9 program is obviously profitable and clearly successful given their flight rate and economics.

Re: More invested in nuclear fusion in last 12 months than past decade

#236
post #207

But where are the fusion neutrons? (See Voodoo Fusion [1]) [1] https://vixra.org/pdf/1812.0382v1.pdf I'm a professional fission guy. I started out in fusion and switched to advanced fission. These days I don't see why we don't just build lots more regular old LWR fission reactors. Imagining that somehow fusion is going to a) work, b) be cheap (fuel cost is only 5% of total nuclear fission cost so who cares), and c) n…

Is it wise to write off safety issues? Chernobyl, Fukushima and three mile island all seem pretty bad. There is also the Robert Heinlein story "Blowups happen". I'm just not understanding how this can all be hand waved away.

From the viewpoint of a utility, what matters is not large accidents (because their liability is capped) but rather smaller accidents that could ruin their investment. The TMI accident didn't kill anyone, but it gravely damaged the owner of the power plant, as they had just lost a large investment.

Because of this, fusion is likely WORSE from the utility's point of view than fission. While fusion reactors are less likely to have catastrophic accidents with large external effects, they are probably more likely to have localized accidents that ruin the reactor. In any case, a fusion reactor will have to be designed to be extremely reliable because repairing it after any accident will be so difficult, as it will be too radioactive for anyone to get in to repair it. All repairs will have to be done remotely.

Re: More invested in nuclear fusion in last 12 months than past decade

#237

Earlier quoted context omitted.

Yes, clearly that's why SpaceX was successful in an industry where the adage was "How do you become a millionaire in aviation? Start with a billion!".

SpaceX is not successful as an industry It is a government funded project at this point

Most of SpaceX's funding as well as most of their launches are private.

Re: More invested in nuclear fusion in last 12 months than past decade

#238

Earlier quoted context omitted.

How long will the fuel last? Sabine Hossenfelder references studies in which we have enough Uranium for 50 years max. 6:08 here: https://youtu.be/0kahih8RT1k

If you fully fission the U + Th in an average chunk of crustal rock (using breeding so you can use the 238U and 232Th) then said rock releases fission energy equal to the combustion energy of 20x its mass in coal. So with breeders we can in effect treat the entire Earth's crust as something an order of magnitude more energy rich than coal. (Whether breeders are practical or competitive is another matter, but then fus…

This shocking factlet is repeated, verified, and credited to you in the writeup in my sibling comment.

Re: More invested in nuclear fusion in last 12 months than past decade

#239

Earlier quoted context omitted.

You keep bringing up climate change, like the only alternative is coal. Do you really think that nuclear fission can be a key player in reducing emissions to net zero? It seems far too expensive and slow to set up for something this urgent.

Fossil + biofuel makes 80% of our energy today. Getting rid of that will require vast amounts of zero-carbon energy. Wind and solar need to be built out at breakneck speed if we want to be serious. Much faster than what we're doing now. So does nuclear fission. I assume you're only looking at the slow and expensive nuclear builds? China is looking to build 150 new reactors to meet its goals. https://www.bloomberg.com…

By expensive, I mean in $/kWh - yes we could build enough nuclear power plants to stop carbon emissions, but if the cost of energy is multiple times greater than that of renewables, why not invest in those instead?

I've heard this idea that we should "do everything", but I don't get that, why don't we do the best thing as well and as fast as we can?

Re: More invested in nuclear fusion in last 12 months than past decade

#240
post #207

Earlier quoted context omitted.

Is it wise to write off safety issues? Chernobyl, Fukushima and three mile island all seem pretty bad. There is also the Robert Heinlein story "Blowups happen". I'm just not understanding how this can all be hand waved away.

Also hand waving away the fact that the waste products have to be managed for civilisation-length time scales.

Only if we never use fast reactors, which fission almost all the long-lived stuff. Take what's left, encase it in glass and bury it, and it'll be back to the radioactivity of the original ore in 300 years.
Post reply on HN