Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Fusion reactors: Not what they’re cracked up to be

thebulletin.org

Post reply on HN
Print view View original

51–60 of 222 posts

Re: Fusion reactors: Not what they’re cracked up to be

#51

Post by VLM »

Robotbeat wrote: post #43
DigitalJack wrote: post #39

Earlier quoted context omitted.

I have to think there are major ecological concerns with blocking sunlight over large areas. They may not be negative impacts, but surely it isn't a no-impact situation.

There is always some impact. There's a disease in our energy discussions where if something has ANY effect or can be measured at all, it is considered a big no-no. We lack a sense of proportion. Radiation is SUPER easy to measure even tiny amounts, for instance, since you can look for the signature of a certain decay tree, so people hear that you can measure radiation from Fukushima and lose their minds. Likewise, pe…

"The sense of scale is entirely lacking."

Agree and it extends to risks. Better to kill 100K people per year with coal, than possibly maybe hundreds might die (but almost certainly zero actually will) in a nuclear accident. Your diet and your car are far more likely to kill you than global warming.

Re: Fusion reactors: Not what they’re cracked up to be

#52

Post by Robotbeat »

short_sells_poo wrote: post #46
Robotbeat wrote: post #41

Earlier quoted context omitted.

High latitudes (above 50 degrees) have a big problem with solar power. Luckily, almost the only people who live that far from the equator are Northern Europeans, who tend to have access to hydro and nuclear. (this is why it's so stupid for Germany to shut down their nuclear power... they're replacing it with coal, brown coal, and gas!) The vast, VAST majority of the world's population lives FAR closer to the equator.…

I haven't ignored the part where you mentioned overprovisioning. Where do you propose to put the excess power during sunny days? Stable baseline sources like nuclear cannot just be shut down or spun up on a moment's notice to accomodate a vast number of solar energy entering or leaving the grid. At the same time, we don't have a capability to store electricity at sufficient scale so we do need the stable baseline to…

This really is not a big technical problem. You simply don't output the power. This is trivial with any kind of decent power-optimizing inverter setup commonly available today. Solar PV isn't spinning a turbine that needs to find a load. If you disconnect a solar panel, it doesn't damage itself, it just sits there.

But I'm sure we'd eventually find uses for this extra energy. Like producing ammonia for agriculture.

Re: Fusion reactors: Not what they’re cracked up to be

#53

Post by Robotbeat »

short_sells_poo wrote: post #50
fao_ wrote: post #47

Earlier quoted context omitted.

> Furthermore, you need to plaster a vast area in the desert with solar plants, which brings along all sorts of concentrated security risks. I mean, most of the same security risks appear in oil pipelines and extraction.

True, and this is a issue today as well. Which is why I think that proposing a solution that compounds this issue even further should not be taken lightly. Edit: put differently, why should we adopt a new solution that is even more exposed to the already known risks?

A large solar field makes for a pretty diffuse target. You might be able to target the connection to the grid, but that's no worse than it is today (and would be easily repaired).

And I don't think our current electrical grid has a major problem that even a slight attention to infrastructure couldn't fix.

Re: Fusion reactors: Not what they’re cracked up to be

#54

Post by OJFord »

mrfusion wrote: post #34
Robotbeat wrote: post #26

There's nothing quite like trying to get fusion to work for a while to make you appreciate how awesome fission technology is. If we applied even half the cleverness needed for fusion to making better fission technology, we'd probably be way better off. ...and then there's solar. Why even bother with producing the energy, just capture it with a very thin solid state device! Just need to automate the planting of solar…

Not just deserts. You could also float them in the ocean, no? We have 70% of our planet we're not using. Spread them far enough apart and add some movement and shadows wouldn't hurt wildlife much.

> You could also float them in the ocean, no?

Yes, offshore wind and solar farms do exist.

Re: Fusion reactors: Not what they’re cracked up to be

#55

Post by VLM »

erikgrinaker wrote: post #23

Much of the (valid) criticism in this article relates to the deuterium-tritium fuel cycle. This is the easiest reaction to accomplish on Earth, so most experimental reactors are designed with this fuel in mind, and we're certainly having a hard enough time making even this work. However, I've always considered D-T fusion an intermediate step on the path to aneutronic fusion, such as Helium-3 or proton-Boron reactions…

The nice thing about fusion neutrons is you get to control the isotopes, you have no control over fission waste isotopes.

Some fission isotopes are really icky to deal with, as everyone has heard...

On the other hand if you don't like dealing with cobalt-60 waste at your fusion plant, simply stop using cobalt alloys in your reactor vessel.

It turns out to be "not that big of a deal" to design a fusion plant where neutron activation isn't important. The quotes are because nothing is easy in fusion but as a problem its pretty low on the list.

Re: Fusion reactors: Not what they’re cracked up to be

#56

Post by Nadya »

cfv wrote: post #48

This is one article that can be greatly improved by adding "fucking" before every instance of "sun". I would also appreciate a number of citations, since it's hard for me to take things at face value after this modern fake news panic thing

>since it's hard for me to take things at face value after this modern fake news panic thing

A part of me is glad to see more people becoming increasingly skeptical. A part of me is sad to see that people think that the problem is only a modern one.

Re: Fusion reactors: Not what they’re cracked up to be

#57

Post by Spare_account »

leephillips wrote: post #45
Spare_account wrote: post #38

Earlier quoted context omitted.

The BBC article linked above describes a very specific scenario which matches neither of your described options. " The amount of energy released through the fusion reaction exceeded the amount of energy being absorbed by the fuel " This doesn't describe the relationship between the amount of energy injected by the lasers and the energy emitted by the fusion reaction. Presumably a lot of the energy injected by the las…

'This is a step short of the lab's stated goal of "ignition", where nuclear fusion generates as much energy as the lasers supply.' Which is just what I was pointing out. And it's a large step from honest break-even, where you count the energy input into the laser system (it's not 100% efficient). And a huge step from practical break-even, where you count the energy required to run the plant.

I was attempting to build on your contributions, but I decided to do it the same level as your comment because it made more sense to address SomeStupidPoint directly.

Attempt at constructive criticism: I think your answers were a little too concise for some members of this audience and I decided to help out by expanding on your points a little.

I've factored your comment about input energy into the lasers in my reply above.

Re: Fusion reactors: Not what they’re cracked up to be

#58

Post by labcomputer »

short_sells_poo wrote: post #40
Robotbeat wrote: post #26

There's nothing quite like trying to get fusion to work for a while to make you appreciate how awesome fission technology is. If we applied even half the cleverness needed for fusion to making better fission technology, we'd probably be way better off. ...and then there's solar. Why even bother with producing the energy, just capture it with a very thin solid state device! Just need to automate the planting of solar…

How exactly do you propose to get that electricity from the desert to say Finland? Furthermore, you need to plaster a vast area in the desert with solar plants, which brings along all sorts of concentrated security risks. The alternative is to have many smaller plants dispersed, which results in a big loss of efficiency. I'm all for clean energy, but you seem to be handwaving away pretty huge issues as "thought exerc…

> Furthermore, you need to plaster a vast area in the desert with solar plants, which brings along all sorts of concentrated security risks

This sentence seems to be at odds with itself. How does needing a large area concentrate security risks? If anything it seems to disperse them.

Unlike a coal or nuclear plant, you can't just walk up to a critical part of a solar farm and blow it up. Any part that you damage is relatively isolated from the parts you don't damage. Thus, it takes considerably more effort to take the entire plant offline.

Re: Fusion reactors: Not what they’re cracked up to be

#59

Post by short_sells_poo »

Robotbeat wrote: post #53
short_sells_poo wrote: post #50

Earlier quoted context omitted.

True, and this is a issue today as well. Which is why I think that proposing a solution that compounds this issue even further should not be taken lightly. Edit: put differently, why should we adopt a new solution that is even more exposed to the already known risks?

A large solar field makes for a pretty diffuse target. You might be able to target the connection to the grid, but that's no worse than it is today (and would be easily repaired). And I don't think our current electrical grid has a major problem that even a slight attention to infrastructure couldn't fix.

Ok so you are saying that the new solution isn't any worse in terms of security than the current one, so it's fine?

In any case, you cannot compare this to oil pipelines directly because we can stockpile oil. Even if all the pipelines are taken out, many countries stockpile oil that can bridge them over until an alternative solution is found. If a considerable part of the electricity comes from some remote site in a desert and the connection is taken out, that'll immediately plunge the country into darkness.

I like your optimism about all the problems being trivial, but with your mindset every problem we currently face is trivial.

At this point, why don't you just propose that we go and harvest Helium-3 from Jupiter? I mean, we already sent some probes that far, it's just some engineering issues, right?

There are a whole host of political, engineering and social issues that need to be sorted before something like you propose can be done. It can work for individual countries in certain regions, but it is not in a state where it can fix the energy problems of the world or liberate us of the carbon dependence.

Re: Fusion reactors: Not what they’re cracked up to be

#60

Post by scriptkiddy »

Robotbeat wrote: post #26

There's nothing quite like trying to get fusion to work for a while to make you appreciate how awesome fission technology is. If we applied even half the cleverness needed for fusion to making better fission technology, we'd probably be way better off. ...and then there's solar. Why even bother with producing the energy, just capture it with a very thin solid state device! Just need to automate the planting of solar…

Spoken like someone who has never visited a desert.

As a Southern California native, I am intimately familiar with the Mojave, Anza Borrego, and Sonora deserts. I will tell you that these deserts are far from "crappy land that nothing can grow on" as you put it.

The North American deserts are areas of huge ecological and geological diversity. They are also some of the most beautiful and awe-inspiring landscapes that exist on this planet.

We do utilize a lot of area in the Western Mojave for solar and wind power. For instance, there is a HUGE field of wind turbines in the San Gorgonio pass near Palm Springs at the intersection of the 10 and the 62.

That said, I am no way in favor of scarring any more of our deserts by covering "a fifth to a tenth" of them in solar panels. However, I am not against concentrated solar facilities several square miles in area as long as they remain contained.

I have thought about how we can "disperse" a solar panel network into a system of smaller panels and batteries and the best idea I can come up with is requiring all commercial buildings to cover their roofs in solar panels and maintain on-site battery banks. Also requiring all homes and apartment buildings to have at least one solar panel per household. These ideas come with their own trade-offs although.

Post reply on HN