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ITER: World's largest nuclear fusion project begins assembly

bbc.co.uk

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Re: ITER: World's largest nuclear fusion project begins assembly

#341

Post by nucpal »

rini17 wrote: post #335

The elephant in the room: fusion is no better wrt radioactive waste than fission. ITER is projected to end up with 30000 tons of radioactive waste. https://thebulletin.org/2018/02/iter-is-a-showcase-for-the-d... "Surrounding the ITER tokamak, a monstrous concrete cylinder 3.5 meters thick, 30 meters in diameter and 30 meters tall called the bioshield will prevent X-rays, gamma rays and stray neutrons from reaching th…

That article is quite outdated, JET has 2020 D-T campaign.

More importantly, fusion is a thousand times better than fission with respect to waste.

No one is claiming there is no waste at all, but tritium has a half-life of 12.5 years so most of the waste will be safe within a few decades. The rest will largely be neutron embrittled steels/materials (classified as low level nuclear waste) that is easily stored.

Compare and contrast that to nuclear fission which generates high level waste, spent nuclear fuel rods and radioactive liquid which must be painstakingly petrified and processed before safe storage. Even then this waste will still be dangerous for over 100,000 years.

Re: ITER: World's largest nuclear fusion project begins assembly

#342

Post by nucpal »

saberience wrote: post #340

Dumb question here, but how is the actual power transmitted to the grid? I get we are trying to have some sustained reaction with plasma inside a magnetic field... but that just makes heat, not electricity. Other reactor types have water to heat up and make steam but where does this happen in a Fusion reactor? It seems as though there is no obvious "place" for there to be water to turn into steam. Again, sorry for du…

It's not a dumb question.

The answer is kinda dumb though, most working fusion reactors don't have a way to extract heat yet. But the plan is to use the same turbine (heat water into steam) technology from fission reactors. So you have cutting edge plasma physics in one part of the reactor and old school victorian-era steam turbines in the other.

Re: ITER: World's largest nuclear fusion project begins assembly

#343

Post by nucpal »

gautamcgoel wrote: post #2

I think fusion is cool, but I also think it distracts from more important and promising approaches to clean power. No one has ever demonstrated a self-sustaining, net positive fusion reaction. It will probably take >30 years to make this technology cheap , safe and reliable and another >20 years to deploy it at scale. We don't have 50 years to wait on clean energy, we need it today. We should be focusing our attentio…

agreed!

the CEO of JET (largest working fusion reactor, until ITER is finished) Ian Chapman said in a lecture that renewables (and nuclear fission) are key to holding off climate change until fusion is a more mature technology

why should the research be mutually exclusive though? there's resources and brainpower to pursue both.

Re: ITER: World's largest nuclear fusion project begins assembly

#344

Post by rini17 »

nucpal wrote: post #341
rini17 wrote: post #335

The elephant in the room: fusion is no better wrt radioactive waste than fission. ITER is projected to end up with 30000 tons of radioactive waste. https://thebulletin.org/2018/02/iter-is-a-showcase-for-the-d... "Surrounding the ITER tokamak, a monstrous concrete cylinder 3.5 meters thick, 30 meters in diameter and 30 meters tall called the bioshield will prevent X-rays, gamma rays and stray neutrons from reaching th…

That article is quite outdated, JET has 2020 D-T campaign. More importantly, fusion is a thousand times better than fission with respect to waste. No one is claiming there is no waste at all, but tritium has a half-life of 12.5 years so most of the waste will be safe within a few decades. The rest will largely be neutron embrittled steels/materials (classified as low level nuclear waste) that is easily stored. Compar…

So the waste output/power output is 1000 times better? Any sources pls?

And this "Neutron embrittlement" does not create any dangerous long-lived isotopes? Like, we just wait few years and then normally landfill the concrete or how should I imagine the process?

Re: ITER: World's largest nuclear fusion project begins assembly

#345

Post by ClumsyPilot »

korantu wrote: post #233
ClumsyPilot wrote: post #227

Earlier quoted context omitted.

All for nuclear, but the amount of land used is higely exadurated. It is actually totally trivial if you run the numbers. In reality >90% of worlds valuable land use is farming. Factories, cities, houses, etc. all hardly matter.

Well, one example. I live in Singapore, and for it to become energy independent, it would need a square kilometer for a nuclear plant. To achieve the same with solar, you need to pave the whole country with solar panels. Besides, to make these solar panels you need to spend energy too. and EROI for advanced solar is about 20, where for nuclear it is 80+. I think people should stop using nature when they can get the s…

I view renewables as energy farming, and city-states like Singapoure, lixemburg, etc. Are not very suitable for either form of farming :) for most countries the calculus is very different. UK has been developing sea based wind turbines quite succesfully, thats something that could work for singapore.

I view nuclear as a bit of a lost cause to be honest, they take long time to build, cost a lot upfront, you need a lot of expertise around them, and they would require a miracle of PR. It does not appear likely that countries that do not have an established nuclear industry will suddenly become nuclear powered. Thats just the way things appear to be heading, and its a shame.

Besides, don't underestimate the infrastructure needed to refine fuel, manufacture fuel rods, deal with waste, etc. If you outsource all of that, you are not terribly energy independent.

I think the only hope for nuclear industry is small modular reactors, and that's only if a massive amount investment comes through.

Re: ITER: World's largest nuclear fusion project begins assembly

#346

Post by nucpal »

pl-94 wrote: post #282

Can someone explain to me the advantages of fusion over fission? Except for the radioactive wastes and the enthusiasm of journalists I don't get it

It's mainly the waste.

Nuclear fission is a stable source of energy that does not produce carbon emissions in production. It's pretty much the answer to the climate crisis except that it produces dangerous waste that is horrendous to store and manage.

Fusion mainly avoids this :)

Re: ITER: World's largest nuclear fusion project begins assembly

#347

Post by ClumsyPilot »

epistasis wrote: post #245
ClumsyPilot wrote: post #225

Earlier quoted context omitted.

> won't be long before renewables are cheaper than a steam turbine and cooling infrastructure on a free heat source. That's an absolutely extraordinary claim. How could a wind turbine ever be cheaper than a traditional generator and turbine, since it consists of a generator + rotor + massive tower in a remote location with a very low utilisation rate? You know you cannot just assume a trend will continue infinitely,…

The steam turbine has to endure super heated steam, requiring very specific materials. Steam turbines also require boilers, cooling, etc. Wind turbines have the potential to require far less in terms of the input materials. And with solar, who knows how efficient we can get with that! We have been optimizing steam turbines for more than a century, but are just barely getting started on optimization for wind and solar…

Mist of this post is badly wrong, wind turbines are essentially a close cousin of steam turbine, and are massively more expensive per Mw of power. A single steam turbine can generate a GW and will weigh less than a wind turbine that generates a MW, a thousand time less!

We run steam turbines as high pressure because that gives us efficiency, not because we have to.

"he rate of improvement hasn't start to slow at all, so i am confident"

You have no evidence, so you are confident?

Also airdinamics are well understood, there are no miraculous effficiencies coming to wind turbines

Re: ITER: World's largest nuclear fusion project begins assembly

#348

Post by ClumsyPilot »

perl4ever wrote: post #238
ClumsyPilot wrote: post #203

Earlier quoted context omitted.

Says the man living in a world plagued by short termism, where companies forsake their future to improve their quarterly report, where we have condemned generations to suffer climate change just so that we could have 15% cheaper electricity and enjoy oversized cars. This going further down this path only lead to misery

Given that interest rates in developed countries are generally lower than in all of history, and mind-boggling amounts of surplus capital are being deployed by companies like Amazon, Softbank, Tesla, etc., it seems to me that the world is less "plagued by short termism" than any time in the last 13 billion years. I'm not debating your assessment in an absolute sense, or the direction that resources are deployed, I'm…

I am struggling to make any sence of your post.

COVID demonstrates lack of being prepared and future orientated, we did not have PPE stockpiles and did not takw actions that would contain the virus to save the economy now. The more future oriented you are, the safer you are.

Re: ITER: World's largest nuclear fusion project begins assembly

#349

Post by pfdietz »

willis936 wrote: post #269
pfdietz wrote: post #262

Looking at stories like this, you need to realize how far out of the running this technology is. The power density of ITER (gross fusion power of the reactor divided by the volume of the reactor, not just the volume of the plasma) is 50 kW/m^3. This is horribly low, about 1/400th the power density of a PWR reactor vessel. The power/$ is also horribly bad. The cost is going to have to come down by two orders of magnit…

You don’t speak for the people working on it, so your claim of sunk cost fallacy is null.

I am allowed to form my own opinion from the evidence we have.

The evidence is that fusion is a huge boondoggle that is extremely unlikely to deliver anything useful.

Asking people working in a field if it's promising is silly, since they are a biased sample. If they didn't think it was promising, they likely wouldn't be working in the field.

Re: ITER: World's largest nuclear fusion project begins assembly

#350

Post by pfdietz »

maccam94 wrote: post #330
ArtWomb wrote: post #190

Earlier quoted context omitted.

>>> small scale reactors I believe this is the DoE position. Leverage AI/ML to design smaller magnetic confinement. With the goal toward commercialized products and partnerships. JET was on track to breakeven. And I think most of the researchers involved believe they would have gotten there if the funding hadn't been cut. I think what they want is simply long term commitments. The sort of thing that is risky in fisca…

You don't need AI, just use stronger magnets[1]. ITER was conceived before high temperature superconducting magnets were discovered, so it has more trouble maintaining plasma stability. 1: https://www.youtube.com/watch?v=KkpqA8yG9T4&t=39m0s MIT-affiliated company building a reactor using these magnets: https://cfs.energy/technology

These reactor concepts are still very large for their power output, compared to fission reactors.
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