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Major breakthrough on nuclear fusion energy

bbc.co.uk

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Re: Major breakthrough on nuclear fusion energy

#611

Post by IntrepidWorm »

0n34n7 wrote: post #606
jjeaff wrote: post #598

Earlier quoted context omitted.

110v can easily kill you. It's a little harder to get a good solid connection through your body and into the ground than 220v. But it certainly can and does happen.

Amps kill, not volts. Hence high voltage low amp Tesla coil spark shows.

Thats not quite accurate- it is true that high amp current is deadly in many scenarios, but it takes both amps and volts to kill. High amp, high voltage current is a killer for sure, but high current at sufficiently tiny voltages is not necessarily deadly. Similarly, high voltage at low currents is usually not deadly (but can be very painful).

Re: Major breakthrough on nuclear fusion energy

#612

Post by CamperBob2 »

tomp wrote: post #503
johnzim wrote: post #349

Earlier quoted context omitted.

It's also quite a helpful metric. Most British people are aware that the national grid used to spend a lot of time making sure they had the power available to draw during the commercial breaks of mass-media TV events (series finales, half time in a cup match etc) purely for the nation boiling water with electric kettles en masse. Great intersection of hard science (energy necessary to boil water + extremely efficient…

Makes you wonder if the US idea of using just 110 volts isn't better... not from an individual viewpoint (slower to boil water) but from the grid perspective.

Power is power. To the extent 110V is slower to boil water, it's a reflection of either inadequate power delivery capacity due to the higher currents required, or wasted heat in places other than the kettle. Either way, heat gets lost over time.

You're almost always better off with higher voltage and less current, when given a choice. An obvious exception being when you get shocked. :-P Or when corona losses come into the picture.

Re: Major breakthrough on nuclear fusion energy

#613

Post by orra »

baq wrote: post #587
pkulak wrote: post #575

Earlier quoted context omitted.

I kinda like that all but a couple outlets in my house can't kill me. Also, I boil my water on an induction stove plugged into 50 amps at 220 volts. I'm not waiting around, to put it mildly.

30A at 400V is how we roll in the EU.

Wow. A typical induction hob in the UK is 32A at 230V. 230V is of course the nominal voltage of a single phase, although in practice in the UK the voltage is closer to 240V.

That's only 7.35kW of power. Do you have significantly more powerful cookers?

Re: Major breakthrough on nuclear fusion energy

#614

Post by CamperBob2 »

0n34n7 wrote: post #606
jjeaff wrote: post #598

Earlier quoted context omitted.

110v can easily kill you. It's a little harder to get a good solid connection through your body and into the ground than 220v. But it certainly can and does happen.

Amps kill, not volts. Hence high voltage low amp Tesla coil spark shows.

High voltage from a Tesla coil not only has low average current, but is subject to the skin effect. So while it can still cause a painful shock to your superficial sensory nerves, not much of that energy ends up in contact with the motor nerves.

TL,DR: you probably don't want to be shocked by a big Tesla coil, even though it won't kill you.

Re: Major breakthrough on nuclear fusion energy

#615

Post by treis »

rytill wrote: post #281
treis wrote: post #251

Earlier quoted context omitted.

It runs into the spaceship problem where later iterations of a spaceship reach the destination first because new technology allows them to fly faster. At some point (maybe) materials and other technology will develop enough so that fusion becomes feasible on a decades or so timeline. Or solar & battery technology will develop to the point where fusion isn't really needed.

But if the first spaceship was never developed, would the second spaceship have been?

Sure because you develop technology while working on achievable goals. As an example, what could someone in 1920 do to help develop fusion power? Pretty much nothing that would be practically useful today. But they had stuff they could achieve which laid the groundwork to what we're doing today.

Re: Major breakthrough on nuclear fusion energy

#616

Post by tinco »

epistasis wrote: post #599
tinco wrote: post #594

Earlier quoted context omitted.

I think you're underestimating how small fusion reactors are. We're going to be needing not just fusion reactors per city, but per city block. If we manage to get them to break-even, they're going to be super plentiful. At least, that's what the promise is, we'll have to see of course.

I've never heard anyone suggest that fusion could scale to be really tiny like that. Do you have any pointers on where I could look to learn about something like that? Because every existing thermal electricity generator scales to be really big for the efficiency gains, and fusion is a thermal electricity generator as planned so far. Tiny steam turbines in each block does not sound cost effective, even if the heat is…

I'm basing this basically on the size of the experimental reactors currently being developed like sparc and the ST40. No doubt building larger plants is going to be more efficient, but if the fusion reactors themselves are going to be that small a single plant will probably have multiple ones.

I think fission reactors and ITER have shown the downside of building really large one off reactors, I don't think they're gonna make that mistake again.

Re: Major breakthrough on nuclear fusion energy

#617

Post by willis936 »

rnhmjoj wrote: post #480
Axien wrote: post #340

I noticed the waste output is helium. Does this fix the worldwide helium scarcity issue?

No, fusion power plants will likely need helium to run: it's necessary to cool the magnetic coils. Unless there will be a breakthrough in room-temperature superconductivity, helium will still be needed and consumed (through leakages) at a faster rate than the fusion reactions can provide. source: https://doi.org/10.1016/j.fusengdes.2013.01.059

Even with hypothetical very high temperature superconductors we still want to run cryogenics to push the critical current higher. At some point mechanical stress would be the limiting factor but there is no path towards discovering such a miracle material. If one were to be discovered it would revolutionize our world.

For the foreseeable, we use HTS materials, that can superconduct at LN2 temperatures, with helium.

Re: Major breakthrough on nuclear fusion energy

#618

Post by willis936 »

mklarmann wrote: post #253

According to Wikipedia (German) the Wendelstein 7-X already did 150 mega joules of "sustained fusion" [1]. So how is this record breaking? [1]: https://de.wikipedia.org/wiki/Wendelstein_7-X

That's the energy into the plasma. W7-X plasma did not produce any energy because it was not using nuclear fuel. Don't despair! W7-X is an incredible machine and Germany and IPP should be proud of their achievement. The ECRH system is awe-inspiring and the sheer length and power of the pulses is unmatched by any MCF machine on the planet.

Until recently no MCF device on Earth was nuclear. Today's headline is the return of JET's nuclear operations.

There are dozens of MCF machines operating right now and only one is nuclear. That means Q as a metric is only useful for one machine. Something to think about when people toss around Q-related rhetoric around here.

Re: Major breakthrough on nuclear fusion energy

#619

Post by dang »

soperj wrote: post #489
dang wrote: post #456

Earlier quoted context omitted.

" Eschew flamebait. Avoid unrelated controversies and generic tangents. " https://news.ycombinator.com/newsguidelines.html We detached this subthread from https://news.ycombinator.com/item?id=30272413 . (No, we're not trying to defend lizard people, great resets, population control, 5G, or whatever else comes up in this context. We're just trying to have an internet forum that doesn't suck. Repeating the same flamewa…

Saying Bill Gates isn't a good person is flamebait? Sorry then, it wasn't my intention.

Sure. It's just a classic flamewar topic, and completely a generic tangent (unless the story had been about BG).

I totally get that it wasn't your intention!

Re: Major breakthrough on nuclear fusion energy

#620

Post by dymk »

1_player wrote: post #582
dymk wrote: post #551

Earlier quoted context omitted.

> They're getting better. Solar is getting so much cheaper, at such a fast pace, that I really don't understand how one can disagree that it's the future of our energy grids. Installing solar is a no-brainer in some parts of the world now, and in the very near future (extrapolating from the last 10 years), it'll be every part of the world soon. What problems am I hand waving away? https://www.statista.com/chart/26085…

I don't get why you and many other commenters are so against the idea of fusion. Solar is decent, not perfect by any stretch, so we should just give up trying to solve the energy technology for the next 200 years? It's not even like it's one or the other. No one is abandoning solar to work on fusion. But fusion, if it works, is orders of magnitudes more efficient than solar is. It opens avenues that are considered im…

I'm not against fusion, there just is simply no viable fusion power that can be built today. It's not going to get here fast enough. We need to adopt renewables yesterday. There is no time to be wasted pretending that fusion provides any value aside from starry eyed theoretical aspiration.

We will not be here in 200 years to enjoy fusion if we don't adopt solar and battery _right now_.

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