Fusion reactors

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Fusion reactors

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2stellarexplorer
Fév 21, 2016, 12:38pm

I sure hope we're close. But after hearing the promise and the failures for decades, I long ago decided not to hold my breath. On the the hand, I have no doubt success will be had eventually. Now? I dunno.

3richardbsmith
Modifié : Fév 21, 2016, 1:29pm

Stellar, I remember my excitement over the first article about cold fusion. : )

Anyway, I met a man this morning at the gas pump and he started telling me about fusion reactors. I asked how they achieve the necessary temperature and he started describing the Tokamak device.

https://en.wikipedia.org/wiki/Tokamak

When I got home I searched a little to find the linked and many other articles. It looks like at least progress is being made. I had not been aware we were anywhere close to reaching fusion temperatures.

4stellarexplorer
Modifié : Fév 21, 2016, 2:46pm

Interesting about the gas station guy. But I remember excitement over the Tokamak design in the '70s. The same conversation might have been had 40 years ago.

5daschaich
Fév 21, 2016, 6:41pm

I'm sure at least some of you have heard the saying: Fusion reactors are only twenty years away -- and always will be.

I recall a reasonable amount of media coverage when this stellarator in Greifswald was completed in the fall. I read this from the BBC, and Science has a more detailed piece that seems to be freely available.

I'm more familiar with tokamaks and laser-driven inertial confinement fusion (ICF) than with stellarators, so I'm not sure how seriously to take suggestions that the recent progress in Greifswald "could mark a turning point" and "might save nuclear fusion" (both quotes from the Science article linked above). This new 'Wendelstein 7-X' machine cost ~$1billion and seems much less ambitious than the world's flagship tokamak and ICF facilities. The ~$20billion tokamak (Iter, currently under construction in France) aims to produce ten times more power than it needs to run, while the ICF facility (the National Ignition Facility, NIF, in California) attempted to produce as much power as it needed to run. (In all these cases, the power produced isn't being captured for electricity, just measured to assess the technology.)

Of course, Iter has been an organizational fiasco (here's a small selection of press coverage) and NIF's 2009--2012 National Ignition Campaign failed. (NIF has made some progress since then, but its main focus has shifted to weapons and its successor energy project has been cancelled.) So stellarators may end up the best by default...

That said, I remember reading something a couple of years ago about yet another alternative being explored, which also needs to catch up to the main technologies but might become competitive in the future. Let me see if I can track it down... Ah, it was the Magnetized Liner Inertial Fusion experiment at Sandia, which only costs ~$5million per year but "still falls well short" of producing as much power as it needs to run. I can't find the article that I recall, but this one should suffice for the curious.

6richardbsmith
Fév 21, 2016, 7:23pm

The article I linked had the French tokamak at $50 billion. Perhaps rrp is right about that one. : )

daschaich,

I missed the announcements in the fall. But for the guy at the gas station today I would have missed this announcement from Germany.

I think I will go back to the good old days of wishing for cold fusion. : )

7daschaich
Juin 13, 2016, 5:21pm

Possibly of interest...

Good News for Stellarators: New simulations of an alternate fusion reactor design reveal that it can be stable against turbulent fluctuations.

The research article itself also provides a popular summary of its own.

8richardbsmith
Juin 13, 2016, 5:44pm

So, maybe in 20 years or so?

9jjwilson61
Juin 13, 2016, 6:14pm

Two weeks.

10davidgn
Modifié : Juin 13, 2016, 7:08pm

For my money, the one to watch is the late Bussard's (of "Bussard collector" Star Trek fame) Polywell reactor. This presentation from 2012 is still riveting: Bussard's Google Talk The past few years have seen Bussard's successors quietly iterating the engineering with funding from the Navy. The discussion hub for the technology is here.

"We spent $15 billion dollars studying tokamaks, and what we learned about them is that they are no damn good." --Bussard, Google Talk, 2012.