Welcome to the Utopia Forums! Register a new account
The current time is Fri Sep 24 00:30:50 2021

Utopia Talk / Politics / fusion?
Sam Adams
Wed Sep 08 17:48:33

Commonwealth Fusion Systems (CFS) and Massachusetts Institute of Technology’s Plasma Science and Fusion Center (PSFC) said on Wednesday that they completed the successful test of a key technology — a very powerful magnet — on Sunday at 6 a.m. at the MIT Plasma Science and Fusion Center in Cambridge, Mass.
The magnet is strong enough that when the team builds a its donut-shaped fusion machine, called a tokamak, with these magnets, it will be able to achieve “net energy,” meaning that the fusion machine makes more energy that it takes to initiate and sustain the reaction, CFS and MIT’s PSFC said
“Its a big deal,” Andrew Holland, Chief Executive Officer of the Fusion Industry Association, told CNBC. “This is not hype, this is reality.”
Thu Sep 09 06:30:17

It was hype. Building a big magnet is not the key issue in fusion power - it may help to make it more compact and thus improve the potential economics - particularly as HTS are already factored into the economic projections for DEMO.

Fundamentally, SPARC has the same mission as ITER: try and figure out whether the physics works well enough at scale to think about building a reactor, and start working out what the challenge is in terms of power plant engineering (i.e. things that experiments don't need to worry about like tritium breeding, component specifications to give acceptable costs, lifetimes, overall system design blah blah blah)

There are transport mechanisms and instability modes that do not really get going on C-Mod - once again they are relying on scaling laws derived from their particular geometry (which in tokamak terms is really just aspect ratio and curvature) without enough reference to the full data set.

IT's a nice complement to ITER, but it will not generate net energy - for a start the measure they are using is Q_Thermal not Q_engineerig. Rule of thumb, you need Q_thermal > 10 to get meaningful chance of generating more electricity than you consume from a full systems perspective.

Making an HTS magnet is not a huge breakthrough.
Thu Sep 09 06:34:04
That said, if you *can't* make a compact tokamak using HTS coils for one reason or another - that probably kills tokamak based fusion dead using current tech.

I can't see the conventional low density low field approach taken by ITER ever being economical.

HTS compact tokamaks or spherical tokamaks might work, if they can get them down to the 250MW output level. Even then, I can't see how there is a route to market for them unless they can get about 10 times cheaper per MWh of installed capacity than currently projected.
Thu Sep 09 06:43:02
Are we going to have commercial on the grind fusion in our lifetime? Or ever?
large member
Thu Sep 09 08:37:41
Loaded question as clinical immortality is closer than fusion and the first will ensure the 2nd happens in our lifetimes.
Thu Sep 09 09:26:21
Sneaky bastard, found a loophole in my question :)
Sam Adams
Thu Sep 09 09:58:26
"I can't see the conventional low density low field approach taken by ITER ever being economical."

Right. That would make quoted development fairly significant. An HTS that should work, at least briefly. Now of course, to make the HTS magnets work just as well when subjected to some few hundred MW of sustained heating. Should be interesting to see how they keep the magnets at 60K or whatever when the plasma stream is radiating assloads of energy.
Thu Sep 09 10:09:34

Lol. not so sure about that.


No, because there are loads of super conducting and plans for HTS already. ITER was not updated to use HTS etc. simply because the critical thing is to do proof of physics in burning plasmas.

Using HTS for the coils lets you get into relevant physics regimes needed to run those proof of physics scenarios with a smaller machine, but adds risk.

The real significant milestone is if they can assemble the machine, run the machine, not have any nasty quenches, then run a burning plasma without having any nasty quenches. Having a component that you can use to build such a machine is not that impressive.

The big problem with HTS compact designs is first orbit losses of alphas particles from fusion reactions.

Large machines are physically big enough to capture the alpha so very few ever get to the wall; more compact devices result higher densities in smaller volumes, but that small volume means that the alphas can hit the wall, which causes all sorts of other problems and potentially they can trigger quenches via local heating because there isn't much room in compact designs for thick insulation between the central solenoid and inner wall.

Thu Sep 09 10:13:47

I'm not going to say no, because there is always a chance that - probably a govt, possibly a billionaire - decides to build a one off totally uneconomical demo plant that produces electricity to grid.

But I doubt we will see fusion making a significant contribution to global electricity supply in our lifetime.

I think we are 20 years away from being able to build a commercial demonstration reactor, if such a thing is possible; and once we do that, I think we are at least another 20 years away from that scaling up, presuming that is economically viable.

So, all happy path, I reckon we'd be in our 80's.
Sam Adams
Thu Sep 09 10:21:07
"Having a component that you can use to build such a machine is not that impressive."

Unless its the main component. Like if you have invented the ICE, you basically have a car.
Thu Sep 09 10:31:51
Fair enough. We are stuck with fusion power by proxy for the foreseeable future.

Thu Sep 09 11:48:59

Yeah, but they haven't invented the ICE.

It's more like "wooo we've machined a piston out of steel".

They didn't invent the steel, they didn't invent the idea of an ICE using a steel piston, they aren't even the first tokamak to use pistons of this steel.
large member
Thu Sep 09 11:56:10

I know. Norwegian. But Equinor just invested in the company.

What hype can do in an environment with way too much liquidity.
Thu Sep 09 12:06:43
Wendelstein will save the world:


August 15, 2021

One of the most important optimization goals underlying the Wendelstein 7-X fusion device at Max Planck Institute for Plasma Physics (IPP) in Greifswald has now been confirmed. An analysis by IPP scientists in the journal Nature shows: In the optimized magnetic field cage, the energy losses of the plasma are reduced in the desired way. Wendelstein 7-X is intended to prove that the disadvantages of earlier stellarators can be overcome and that stellarator-type devices are suitable for power plants.

Thu Sep 09 12:53:19

My brother in law works there - he was one of my students for a while.

I'm not that convinced by W7x style stellarators either. HELIAS types coil design is far too complex and the magnetic volume costs are worse than tokamaks by a long way - i.e. they will be too expensive to make power plants from.

The main thing that they set out to solve: steady state / long pulse operation through not requiring current in the plasma to get closed flux surfaces has already been solved.

All this stuff about neo-classical transport suppression is stuff that's already been solved in tokamaks, so while it's interesting to solve them for Stellartor schemes, I'm not sure it is necessarily going to lead to a more viable approach to fusion.

What I'd love to have seen was the Princeton NCSX spherical tokamak/stelerator hybrid.

It had a much simpler coil geometry plus the high aspect ratio.

Unfortunately the guy leading it was a muppet at the institutional politics and cared naught for budgetary rules: massively exceeded the budget without permission and the whole thing was shut down.
Thu Sep 09 12:57:14
Hold on, I'm getting my programmes mixded up.

I'm talking about a successor to NCSX after it got cancelled - spherical stellarator.

show deleted posts

Your Name:
Your Password:
Your Message:
Bookmark and Share