Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab • Hacker News Board

Re: Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab

#381

Post by PaulDavisThe1st » Tue, Oct 12, 2021, 11:42 PM UTC

mikewave wrote: post #172

myself248 wrote: post #108

Earlier quoted context omitted.

The best storage is no storage at all, it is demand-response. Things like responsive appliances and EV chargers that can schedule their load rather than insisting that limitless power be available instantaneously. I don't care when the dishwasher runs as long as the dishes are clean by tomorrow, you know? Of course right now, putting the word "smart" on an appliance doesn't imply any of that, and the way it ends up i…

> I don't care when the dishwasher runs as long as the dishes are clean by tomorrow, you know? You can already accomplish 95% of this now with any dishwasher made within the last 20 years that has a delay timer on it. Just load it up and tell it to run in 6 hours and then go to bed. I don't want some 3rd party company driving a huge team of middlemen sucking up a gigantic pile of data in order to determine when it mi…

> You can already accomplish 95% of this now with any dishwasher made within the last 20 years that has a delay timer on it. Just load it up and tell it to run in 6 hours and then go to bed.

With solar PV, sort of the opposite. Just load it up, and tell it to run in 4 hours, while you and most everyone else is at work :)

Re: Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab

#382

Post by pfdietz » Tue, Oct 12, 2021, 11:43 PM UTC

ChuckMcM wrote: post #365

grkvlt wrote: post #351

Earlier quoted context omitted.

are you suggesting that fusion plants will be petawatt sized? because that's really not the case. i think the lcoe of fusion is predicted to be around the same as natural gas, with the DEMO reactor costing twice as much.

No. There are a lot of unknowns around fusion plants (with the current big one being is it even feasible to build one). The last time I was looking at grid infrastructure questions the largest power plants on US grids stayed below 3GW because, as I was informed but cannot cite/verify, that was the limit on infrastructure carrying capacity of the western grid. One of the unknowns is what is the minimum cost to build a…

You have it backwards. Fusion will have much lower volumetric power density than fission, for fundamental reasons (one can circulate coolant through the core of a fission reactor, but not a fusion reactor). Fusion reactors will likely be much larger, and therefore much more expensive, than fission reactors.

Look at the power density of ITER (0.05 MW/m^3), of ARC (0.5 MW/m^3), and a PWR reactor vessel (20 MW/m^3).

Re: Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab

#383

Post by cbtacy » Tue, Oct 12, 2021, 11:44 PM UTC

mraison wrote: post #241

rfrey wrote: post #61

Meta-question about fusion energy -something I don't understand about the movement. I spent a few years as CTO of a company providing heat-to-electricity plants. We financed and built them off high-heat plants like natural gas turbines. The "fuel" was heat going up the stack - so it was essentially free. We still couldn't compete with conventional electricity plants, even with a $30/tonne price on carbon in Canada. G…

It's hard to compare a fusion plant and a geothermal plant if we don't know how much energy a single fusion plant could produce. Are there any estimates on that?

https://www.lockheedmartin.com/en-us/products/compact-fusion...

"A reactor small enough to fit on a truck could provide enough power for a small city of up to 100,000 people."

Re: Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab

#384

Post by ChuckMcM » Tue, Oct 12, 2021, 11:44 PM UTC

pfdietz wrote: post #380

ChuckMcM wrote: post #305

Earlier quoted context omitted.

Exactly. The future of whether or not fusion becomes the next big thing will be watching the LCOE for fusion plants vs everything else. It is interesting to compare fusion plants to fission plants in this regard. Fusion fuel extraction is much cheaper, fusion waste byproducts are minimal , plant failure risk and mitigation is much much cheaper (no fallout, no long live nucleotides etc), and the energy cycle produces…

> plant failure risk You don't have to worry as much about major accidents as in fission, but the risk of minor accidents that aren't a public safety risk but are a risk of ruining the plant is arguably much larger. A fusion reactor puts a large, very complicated thing, with many non-redundant parts, into a hot zone where hands on repair is impossible. The lesson of TMI is that even if the public is unharmed, an acci…

Absolutely agree. We don't know a LOT about how these things would go together once we get past making energy. If the probability of destroying your plant was such that the lifetime expectancy was shorter than the 20 - 30 years a typical plant is expected to operate then it would definitely raise the effective cost.

Re: Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab

#385

Post by fsckboy » Tue, Oct 12, 2021, 11:46 PM UTC

rfrey wrote: post #61

Meta-question about fusion energy -something I don't understand about the movement. I spent a few years as CTO of a company providing heat-to-electricity plants. We financed and built them off high-heat plants like natural gas turbines. The "fuel" was heat going up the stack - so it was essentially free. We still couldn't compete with conventional electricity plants, even with a $30/tonne price on carbon in Canada. G…

> high-heat plants like natural gas turbines. The "fuel" was heat going up the stack

if you're burning natural gas to run a gas turbine, a substantial part of the energy has being drawn off by the turbine, so the "waste heat" that you are trying to scavenge has much lowered potential energy to capture.

Re: Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab

#386

Post by pfdietz » Tue, Oct 12, 2021, 11:46 PM UTC

asdfge4drg wrote: post #356

rfrey wrote: post #61

Meta-question about fusion energy -something I don't understand about the movement. I spent a few years as CTO of a company providing heat-to-electricity plants. We financed and built them off high-heat plants like natural gas turbines. The "fuel" was heat going up the stack - so it was essentially free. We still couldn't compete with conventional electricity plants, even with a $30/tonne price on carbon in Canada. G…

for someone who worked in this area, you have an unbelievably short term view. humanity either has fusion reactors or it doesn't. imagine what we can do with them, the spacecraft we can build, submarine cities, one in every home. Mars, Europa. It's not where we'll be 10 years after we do it, but 100 years, 500 years. To get there, we've got to step forward now.

DT fusion reactors are useless for spacecraft. They don't do anything that fission reactors couldn't do better, more cheaply, and much more compactly.

Open Brayton cycle fission reactors would be outstanding on Titan, with all that cold gas to compress and reexpand after warming to quite moderate temperature.

Re: Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab

#387

Post by pfdietz » Tue, Oct 12, 2021, 11:48 PM UTC

NineStarPoint wrote: post #257

rfrey wrote: post #61

Meta-question about fusion energy -something I don't understand about the movement. I spent a few years as CTO of a company providing heat-to-electricity plants. We financed and built them off high-heat plants like natural gas turbines. The "fuel" was heat going up the stack - so it was essentially free. We still couldn't compete with conventional electricity plants, even with a $30/tonne price on carbon in Canada. G…

Fusion is different in that the math scales well with the size of the fusion plant you create (and also the power of the magnets you have access to). If it's technologically feasible to create a large enough fusion plant, it starts to be able to create ludicrous quantities of electricity compared to things like geothermal that have much harder limits. Of course, "technologically feasible" is doing a lot of heavy lift…

Fusion has diseconomies of scale. The larger a fusion reactor is, the worse its volumetric power density becomes.

Re: Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab

#388

Post by AlbertCory » Tue, Oct 12, 2021, 11:48 PM UTC

ChuckMcM wrote: post #278

AlbertCory wrote: post #263

Earlier quoted context omitted.

Skin in the game [1]. OP has actually done it ("CTO of a company providing heat-to-electricity plants"). Have you? Or you just read about it? [1] https://www.amazon.com/Skin-Game-Hidden-Asymmetries-Daily-eb... ?

I get that, 100% props for the experience. And I totally respect it. The GP question was "what makes fusion different", and the only thing that is different really is the economics of how much it costs vs how much energy you get out. Energy out is, by definition, the amount of heat differential you can generate. Cost is, again by definition, the total operating cost of the heat source. So this is where the author and…

I will admit that I'm not an engineer of any relevant area here. So I offer this only as a matter of general judgment & experience, which you are welcome to say "does not apply." (But please say why it doesn't.)

It's always been my impression that building things on a huge, factory-wide scale is a radically different problem than building a demo, or even reasoning about it. The latter is what you are all doing.

As long as "energy crisis" has been a Thing, I've been hearing about some uber-cool new thing a scientist did, which has the potential to transform everything. Usually that's the last you ever hear of it. I always wonder "whatever happened to X?"

I figure that "X" might look good in the lab, but no one can build a factory around it. The people who build factories (or power plants) are much less starry-eyed than we all are.

That's what we mean by "skin in the game (SITG)." Don't tell me what stocks to buy -- tell me what's in your portfolio.

So if I'm deciding whom to believe in an area where I know next to nothing, I'm much more likely to listen to someone who has, or had, SITG. Obviously if no one's ever built a fusion plant before, then exactly no one has had SITG. That makes it a tough one.

Re: Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab

#389

Post by pfdietz » Tue, Oct 12, 2021, 11:50 PM UTC

SuoDuanDao wrote: post #254

rfrey wrote: post #61

Meta-question about fusion energy -something I don't understand about the movement. I spent a few years as CTO of a company providing heat-to-electricity plants. We financed and built them off high-heat plants like natural gas turbines. The "fuel" was heat going up the stack - so it was essentially free. We still couldn't compete with conventional electricity plants, even with a $30/tonne price on carbon in Canada. G…

I don't think nuclear power - fission or fusion - can ever be profitable on a capital return basis. They're the best bang for your buck if the cost of capital is zero and among the worst if it's greater than zero. Nuclear physicists and engineers are smart enough that I think they could understand this problem if they spent a weekend grappling with it, but they're so specialised in their very difficult discipline tha…

There's also Upton Sinclair's famous comment: "It is difficult to get a man to understand something, when his salary depends upon his not understanding it."

Re: Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab

#390

Post by ashtonkem » Tue, Oct 12, 2021, 11:51 PM UTC

ransom1538 wrote: post #304

throwaway894345 wrote: post #243

Earlier quoted context omitted.

Of course, the consequences of climate change are billions cast into abject poverty, wars over resources and land, and so on. Moreover, if we do away with carbon subsidies (i.e., implement carbon pricing and border adjustments), then yes the cost of fossil fuel energy goes up, the consequence is the society adapts to using power more efficiently. We make less disposable shit, our industrial processes improve to keep…

"Of course, the consequences of climate change are billions cast into abject poverty" The only way to end climate change is to have a serious debate about population control. But no one wants difficult debates (at least people that matter). Nuclear fission once pulled off will make things much much worse. I foresee a population explosion into areas once uninhabitable.

> The only way to end climate change is to have a serious debate about population control.

It’s always disturbing how quickly this stuff goes from here to “we have to prevent other people from having kids rather than having Americans stop consuming”. Get your neighbor out of their F150 before trying to sterilize the global south.

> Nuclear fission once pulled off will make things much much worse.

Fusion. Fission has been done for your entire lifetime.

> I foresee a population explosion into areas once uninhabitable.

Apparently your foresight doesn’t involve actually bothering to check the fertility rate in any nation. If you’d done that, you’d realize that birth rates drop as nations get richer. Most of the world is below replacement rate, and world populations are expected to peak in the year 2100 and begin falling.

The thing that actually limits reproduction isn’t resources, but child mortality and interest. Once you can expect your children to survive infancy, most people want fewer of them.