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

Compact nuclear fusion reactor is 'very likely to work,' studies suggest

nytimes.com

Post reply on HN
Print view View original

201–210 of 373 posts

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#201

Post by pleasedontbanme »

Retric wrote: post #185
fghorow wrote: post #165

Earlier quoted context omitted.

"Non Radioactive Fuel" is technically correct. But. The fusion produces neutrons.[1] That means that at least some parts of the infrastructure can't avoid becoming radioactive. Decommissioning -- at the very least -- is still a problem. Any actual nuclear physicists want to chime in here? [1]Yes, the concept of "Aneutronic fusion" exists: https://en.wikipedia.org/wiki/Aneutronic_fusion >. But read the parts about the…

Deuterium is a stable isotope, but Tritium’s half life is only 12.32 years making it quite radioactive. There is significant effort put into using lithium blankets to create tritium at which point arguably the fuels are lithium and deuterium. But that’s also going to require irradiate the relevant equipment.

Tritium is worth $30,000 a gram.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#202

Post by waterhouse »

aaronblohowiak wrote: post #58
coldtea wrote: post #33

Earlier quoted context omitted.

So in the end it's a glorified boiler!

as far as i am aware, solar power is the only prevalent power source that does not derive from spinning a dynamo. Besides wind (and perhaps there, too) almost all of the force used to spin dynamos includes some kind of boiling (eg: dams happen to use the force of the water after the "boil"/evaporation, nuclear, coal, natural gas, etc are all steam-based thermo-mechanical power plants.)

Dumb question: Is it possible to make a photovoltaic cell that works with infrared or longer wavelengths? ... Googling says there is research and some claimed results.

In theory, one could have "generate heat, and have the apparatus surrounded by a vacuum, surrounded by infrared photovoltaics" be the new universal backend for power generation. I have no idea about the associated efficiencies, of course.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#203

Post by tootie »

Tossrock wrote: post #150

I wish these people the best, and I really hope they get a working fusion plant soon. That said, I can't resist sharing Admiral Rickover on academic reactors vs practical reactors: Important decisions about the future development of atomic power must frequently be made by people who do not necessarily have an intimate knowledge of the technical aspects of reactors. These people are, nonetheless, interested in what a…

This isn't an academic reactor. MIT is involved because they did the theory work, but it's venture funded with a plan to build a working reactor in a few years.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#204

Post by Robotbeat »

maccam94 wrote: post #199
JustAPerson wrote: post #75

https://www.youtube.com/watch?v=KkpqA8yG9T4 Here's a video lecture from the MIT Professor (Dennis Whyte) who was leading the research group that provided some of the key designs for the SPARC reactor. As the NYT article explains, that research has been spun out into a startup that raised $200M. The key breakthrough is the advancement of REBCO tape superconductors which allow you to (1) generate record breaking magnet…

Timeline (in case you want to skip over some parts): 00:01:00 - introducing Dennis Whyte, MIT department head for nuclear science 00:04:24 - presentation starts 00:06:00 - identifies breakthrough with REBCO magnets 00:07:25 - explains deuterium-tritium fusion 00:12:30 - basic metrics for reactor performance 00:17:15 - energy output of other previous fusion experiments 00:19:00 - examines ITER and the problems of its…

I think they're using Yttrium (i.e. YBCO), right? It's hard to find that info.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#205

Post by jasonwatkinspdx »

tgsovlerkhgsel wrote: post #164
gorkish wrote: post #63

Earlier quoted context omitted.

Yep; the key technology that took magnetic confinement fusion from 'ITER will probably work' to 'Maybe we should just go ahead and skip ITER' is rebco tape. The problem is that all known superconducting materials known will lose their ability to superconduct when exposed to a sufficiently strong magnetic field. The large field strengths induce eddy currents in the material which disrupt the propagation of the cooper…

Would it be feasible to upgrade ITER into a much more powerful plant with the new magnets, or are they basically spending another 15 years building a huge thing that is already obsolete?

ITER is not obsolete even if better magnet designs are now possible. It's an incredibly huge and complex project with many critical details. It's literally spawned 10's of thousands of research papers. It's a pathfinding project with far more value than just this one aspect.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#206

Post by jasonwatkinspdx »

woeirua wrote: post #90

After watching the video posted in the top comment, I have to wonder why we would keep dumping money and time into ITER. I know, don't put all your eggs in one basket, but if the ITER design is so out-of-date, why wouldn't we just scrap it in favor of something that we could build 10 years faster and for much less money? It seems that if we can't make fusion work for SPARC it won't likely work in ITER either since th…

This is a vast oversimplification, and not a particularly useful way of thinking about it.

See my other brief comment: https://news.ycombinator.com/item?id=24634894

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#207

Post by rrdharan »

ada1981 wrote: post #159
tunesmith wrote: post #151

Earlier quoted context omitted.

That's a version of "The Wait Calculation". For instance, it would be a waste of resources to build a starship right now to visit the closest other solar systems, because given our current maximum velocity and our rate of technological increase, it's a virtual certainty that in the future we would be able to build a second starship that would catch up and overtake it. Eventually there is a break even point (for the c…

This is a great mental model. I'm curious about applying this in areas of one's own life. Certain things that you'd actually accomplish faster, by starting later and leveraging the compounded time / resources that would have been spent pursuing it earlier.

The 80,000 hours folks generally apply this kind of reasoning to explain why it’s better for most people to just focus on a corporate job, stockpile a ton of cash, and donate it all when you die, instead of quitting to join a cause / non-profit - if your only goal is to optimize your impact.

Obviously people are free to choose differently and there are exceptions, unique circumstances etc.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#208

Post by rfrey »

m0zg wrote: post #88
Retric wrote: post #56

Earlier quoted context omitted.

There is ~zero expectation in the scientific community that fusion is going to be cheap at scale. It might eventually be cheaper than fission due to several factors. But, even that’s looking a long way off.

How so? Unlimited, non-radioactive fuel and inherent safety of the system alone could tip this scale pretty severely in favor of fusion once it becomes energy-positive. And remember, once that happens, investment is going to be through the roof, which will accelerate progress. Either the "scientific community" (whatever that means) is either too pessimistic about this, or you've just made this up.

The cost of the power plant can easily dominate the cost of the fuel. I build power plants fuelled by waste industrial heat (10-20 MW scale) and even though the fuel is all but free it can be tough to identify economically viable projects.

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#209

Post by [deleted] »

closetohome wrote: post #182
ElFitz wrote: post #137

Earlier quoted context omitted.

> this is still exciting given how anemic advancement in the fusion space has been for 50+ years. "Nuclear fusion. 30 years away since 1950" Joking aside. I too am glad to see some progress of any kind, and new (seemingly credible) initiatives being funded and pursued

> "Nuclear fusion. 30 years away since 1950" Those projections usually include the caveat "if properly funded" - https://i.imgur.com/3vYLQmm.png

[deleted]

Re: Compact nuclear fusion reactor is 'very likely to work,' studies suggest

#210

Post by willis936 »

closetohome wrote: post #182
ElFitz wrote: post #137

Earlier quoted context omitted.

> this is still exciting given how anemic advancement in the fusion space has been for 50+ years. "Nuclear fusion. 30 years away since 1950" Joking aside. I too am glad to see some progress of any kind, and new (seemingly credible) initiatives being funded and pursued

> "Nuclear fusion. 30 years away since 1950" Those projections usually include the caveat "if properly funded" - https://i.imgur.com/3vYLQmm.png

I’m not sure why this is being downvoted. Reactor studies come out every decade and validate this study every time.
Post reply on HN