MIT claim they will build the SPARC

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crowberry
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Re: MIT claim they will build the SPARC

Post by crowberry »

Brandon Sorbom, Commonwealth Fusion Systems will give a MIT PFSC seminar ARC and the path to high field fusion on Oct 9, 2020 12:30 PM Eastern Time (US and Canada) https://www.psfc.mit.edu/events/2020/ar ... eld-fusion.

Skipjack
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Re: MIT claim they will build the SPARC

Post by Skipjack »

Their seven papers are available for open access here:
https://www.cambridge.org/core/journals ... sics-basis

Skipjack
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Re: MIT claim they will build the SPARC

Post by Skipjack »

Giorgio wrote:
Thu Oct 01, 2020 3:23 pm
Skipjack wrote:
Thu Oct 01, 2020 12:23 pm
I don't think that the MIT sees any show stoppers for going forward with SPARC. I am a bit confused why you think they could not?
My concern is not that there is a "design" show stopper from the physics side, but engineering design for components like the divertor are simply not yet mature to be used in a commercial reactor or even to make full use of the actual test possibilities offered by the new superconductors in research reactors like SPARC.
And no one is putting "real" effort and money to overcome these limits.


I will take few examples from the very same papers that they are going to be presented in the coming APS meeting:

http://meetings.aps.org/Meeting/DPP20/Session/JO08.13
"The divertor heat flux problem is an important unresolved dilemma facing future reactor-level fusion devices. "


http://meetings.aps.org/Meeting/DPP20/Session/JO08.12
"Based on empirical scalings, the peak unmitigated divertor parallel heat flux in SPARC is projected to be greater than 10 GW/m2"
(Our best technology (for ITER) is now on the range of 20 MW/m2.)


http://meetings.aps.org/Meeting/DPP20/Session/JO08.15
"Fusion power fundamentally has two limits: core plasma pressure must reside within tokamak operation limits and plasma heat exhaust must be within technology limits."
(This paper also evaluates fusion power limits with with actual TRL (and by sacrificing some other factors) and sets it to 2GW fusion power. This should be an interesting paper to read if they will publish it.)
Moving this debate over from the Z- Pinch thread:
The Divertor design paper is available to the public already (along with the other papers above):
https://www.cambridge.org/core/journals ... ore-reader

There clearly are some uncertainties but they are trying to mitigate the problem a bit with the relatively short plateau of 10 seconds:

Giorgio
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Location: China, Italy

Re: MIT claim they will build the SPARC

Post by Giorgio »

Thanks for the links, I saw them from your previous post but I didn't notice that they was including also some of the papers of the coming APS presentation.
I will check them thoroughly during weekend relax time, but a a first quick read has given me the impression that the design didn't change much from last papers I read.
They are still going for a 20-30MW/m2 divertor and plan to limit its irradiation at ~1 sec over a 10/15 seconds total shot time to prevent the divertor from melting. It's a solution that might work to make experimental shots, but is not a solution for a commercial or demonstration reactor. Kinda like having an electric generator and turning it on and off every 10 seconds to prevent cylinder meltdown......

The potential solution they are considering is still the XPT divertor design, but that will limit SPARC max Q to 2 and the total power to 2 GW, and anyhow no real experimental result has still been obtained on the XPT design in a SPARC environment, so this is still just a theoretical design proposal with several numerical simulations but no meaningful experiment has been planned to fully understand the limits and potential of evolution of this design before adding it to SPARC (at least as far as I know).

This (and several others issues) are rising my fear that research in heat generation based tokamak is reaching the point where it will hit a roadblock because we are focusing too much on how to make the reactor work (thanks to the latest superconductors improvements) but we are not focusing enough on how to properly manage it in a safe and efficient way once it works.

I will try to read everything over the weekend and see if anything new inside these papers from what was my last understanding.
A society of dogmas is a dead society.

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