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

imperial.ac.uk

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

#451

Post by xondono »

SuoDuanDao wrote: post #368
xondono wrote: post #347

Earlier quoted context omitted.

> Of course, the consequences of climate change are billions cast into abject poverty That may be true, but I was referring to the effects of switching to renewables too early . Since given our technology, the cost per MW is higher from renewables, switching to renewables (as a society) has massive costs. If we rise the price of the MW a 10%, that's a +10% on every MW from now until we find something better . That co…

I hope we could agree though, that the cost of switching to renewables too early is negligible compared to the cost of switching too late. If that can be agreed on by all, the relevant questions are 1) when do we think it would be too late? 2) how certain are we of that date? 3) how long will it take to switch to renewables? and 4) How certain are we of that date? I don't disagree with your basic premise. Personally…

> that the cost of switching to renewables too early is negligible compared to the cost of switching too late.

Smaller yes, but I wouldn't call it negligible.

> the more the economy grows before the switch to renewables is complete, the harder it becomes to make the switch.

That one I think you got reversed. Think that one through, the economy now is way greater than it was in 1980, do you really think we were better prepared for the switch back then?

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

#452

Post by Xixi »

pronlover723 wrote: post #433
ClumsyPilot wrote: post #371

Earlier quoted context omitted.

The capsules are tiny and do not generate usefull amount of energy. ITER is planned to generate 500,000,000W. Thats actually usefull

According to Sabine Hossenfelder, ITER will only actually generate 0.57 of what's put in. The large number out isn't the full story. http://backreaction.blogspot.com/2021/10/how-close-is-nuclea... > You have seen in the earlier quotes about ITER that the energy input is normally said to be 50 MegaWatts. But according to the head of the Electrical Engineering Division of the ITER Project, Ivone Benfatto, ITER will con…

The roadmap has always been: ITER, DEMO [1] and then PROTO [2].

"DEMO refers to a proposed class of nuclear fusion experimental reactors that are intended to demonstrate the net production of electric power from nuclear fusion." [1]

So indeed the road is long, and ITER is not DEMO, and DEMO is not PROTO. I've read a lot of good arguments against ITER, but ITER not being DEMO is not one of them.

By the way, just to be pedantic: ITER will not actually generate 0.57 of what's put in. It would only generate 0.57 of what's put in, if someone bothered to hook a generator to it. But since no generator will be hooked, it will generate exactly 0 Watts of electricity. Generated heat will simply be dissipated away. To be net positive in production of electricity, EU DEMO is expected to have a Q of 25...

[1] https://en.wikipedia.org/wiki/DEMOnstration_Power_Plant

[2] https://en.wikipedia.org/wiki/PROTO_(fusion_reactor)

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

#453

Post by andy_ppp »

nomel wrote: post #292
andy_ppp wrote: post #166

Earlier quoted context omitted.

I wonder if it’s possible to create air conditioning that generates electricity. It seems like you’re removing energy from the air.

Think of it like water flowing down a hill. The heat is in your room because it flowed down to a cooler space with less energy, just like the water flowed down to a space with less potential energy. Moving that heat back to a higher energy area, back outside, is the same as pumping the water back up a hill. It always takes more than one unit of energy to move one unit of energy back “up”. You can only capture energy…

That’s a great analogy, thanks!

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

#454

Post by MertsA »

snypher wrote: post #427
tsimionescu wrote: post #411

Earlier quoted context omitted.

The bigger problem is the precision-machined hohlraum the pellets sit in for ignition. That costs millions of dollars, is crucial for actually achieving anything, and is destroyed in the process.

I wondered why these things were so expensive until I read: -literally made of gold or uranium -walls must have surface roughness less than 1 micron Are there other reasons too? I'm not sure where to find machinable uranium on McMaster

Uranium is pretty cheap, they don't need enriched uranium (although I'd be interested to know if using the fusion as a neutron source could trigger a decent amount of fission in the hohlraum), they just need a very dense metal.

You should take a look at the LLNL's page on targets.

https://lasers.llnl.gov/about/keys-to-success/targets

https://www.lanl.gov/conferences/tfm/presentations/08-21-12-...

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

#455

Post by pfdietz »

CuriouslyC wrote: post #346
xondono wrote: post #214

Earlier quoted context omitted.

What a great way to not answer what OP is asking. If you don’t like fracking, that’s alright, but sustaining ourselves without it it’s not really an option. Right now our options are: 1) Use coal, accept the consequences of the increased climate change. 2) Keep using gas, reduce the future costs of climate change, deal later with the speculative consequences you mention. 3) Switch to renewables and drastically increa…

Option 4, use a mixture of modern nuclear and renewables. Power prices go up slightly, environmental footprint goes down a lot.

Nuclear and renewables do not mix well. If you optimize for a minimum cost grid, one or the other dominates. Mixed solution s have higher cost.

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

#456

Post by Andrew_nenakhov »

scoopertrooper wrote: post #409
Andrew_nenakhov wrote: post #184

Earlier quoted context omitted.

The 1000 miles road starts with a first step, and it's not like we can't pursue several approaches at once. People like grandparent poster suggest us drop everything and concentrate on the idea he likes best. That is a very bad and harmful idea.

No one is saying we shouldn't invest in exploring fusion. But we shouldn't sit on our hands on the interim. We need to invest heavily in the best alternative resource available right now till such time as fusion is a viable alternative to solar. Keep in mind horses and cars co-existed as mainstream transportation choices right up till the end of world war 2.

> No one is saying we shouldn't invest in exploring fusion.

Actually, jhallenworld's comment was saying exactly this: "We should put more resources into storage now, fusion can wait".

That's what prompted my response about horses in the first place. Analogy is apt, because first engines were wildly inefficient compared to horses, yet, if people back then would never pursue them, we would never have eventual progress. So no, while we should invest in storage, fusion CAN NOT wait.

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

#457

Post by pfdietz »

Qwertious wrote: post #298
meltedcapacitor wrote: post #180

Earlier quoted context omitted.

Yes, but bulk of the demand is heat and industry, so you're quickly back to having to build a lot of "storage" in the form of buildings with high thermal inertia and spare capacity for production, so that you can keep the high energy plants idle at inconvenient times. Hard to say if that is more efficient than building actual energy storage. Every little helps I guess, but getting people not to shower on cloudy days…

Heat is fairly trivially stored for months on a mass scale, check out Polar-night Energy's system - basically, you heat up (usually with just resistive heating) a bunch of sand in a 40metre-wide insulated cylinder, and when you want to use that heat you use fans to blow air through ducts that are surrounded by the sand. The amazing thing is that every single part of the tech is old and boring - resistive heating is l…

Sand can be used as a surprisingly effect store for electrical energy (round trip efficiency > 50%).

https://arpa-e.energy.gov/sites/default/files/2021-03/07%20D...

I am particularly taken by the fluidized bed heat exchanger. What an neat concept, and so compact.

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

#458

Post by pfdietz »

mikewave wrote: post #175
pstrateman wrote: post #159

Earlier quoted context omitted.

There really aren't many things that can be off for significant periods of time without making them useless. Indeed I can't think of any that can be off for more than a day. Can you?

There are companies that will drive your "smart" thermostat and purport to save you money by strategically controlling it, but in the end if you want to save money on your house's climate control, you're going to end up being warmer/colder than you would like.

In our last house we had a box attached to the AC compressor that let the utility turn it off for 3 hours at a time, a prescribed number of times per month. We got a $10/month discount for this.

We never noticed any effect on comfort.

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

#459

Post by chadcmulligan »

thangalin wrote: post #366
chadcmulligan wrote: post #355

Earlier quoted context omitted.

Here's an article about why fusion is a bad idea [1] and its from the bulletin of atomic scientists so they should know. I'd love to hear it refuted but doesn't seem to have happened. [1] https://thebulletin.org/2017/04/fusion-reactors-not-what-the...

https://www.youtube.com/watch?v=L0KuAx1COEk https://www.reddit.com/r/fusion/comments/67rqqg/comment/dgtm... "For the record The Bulletin of Atomic Scientists is a [sic] anti-nuclear advocacy group. They often resort to fear mongering or using the straw man fallacy to advocate their point." https://news.ycombinator.com/item?id=14203206

Thats good, thanks

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

#460

Post by pfdietz »

tsimionescu wrote: post #281
gene-h wrote: post #238

Earlier quoted context omitted.

This report found that ICF could reach LCOE as low as $25/MWh "with optimistic but not obviously unrealistic inputs."[0] This does require hohlraums cost about $2 each and are fired every 20 seconds. With mass production and process optimization it may not be ridiculous to reduce hohlaum cost to this amount. However, the yield is about 5 gigajoules which is equivalent to about 1 ton of TNT. Making equipment that can…

"Optimistic but not obviously unrealistic inputs" include reducing the cost of hohlraums from the million dollar range to 10$ (not even sure if that accounts for the price of the gold itself), a reactor capable of resisting 50 million pulses before needing replacement, and a few others. It also considers the price of a fusion power plant to be less than that of a fission power plant, based entirely on the observation…

This paper was not well received on reddit.

https://www.reddit.com/r/fusion/comments/ja879n/nuclear_fusi...

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