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MIT-designed project achieves major advance toward fusion energy

news.mit.edu

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Re: MIT-designed project achieves major advance toward fusion energy

#41

Post by MauranKilom »

TrainedMonkey wrote: post #35

This is exciting. Magnetic field strength is a key component for enabling magnetic confinement fusion. This is because energy gain and power density scales to the 3rd and 4th power with magnetic field strength but only ~linearly with reactor size. See following equations for more details: https://youtu.be/xJ2h3vbOag4?t=306 So, why is this particular announcement exciting? There are 3 factors: 1. This is a high temper…

Appreciate the rundown of why this is important!

> This is because energy gain and power density scale exponentially with magnetic field strength but only linearly with reactor size

Nit: It scales polynomially, not exponentially. Specifically (according to those formulas) energy gain scales with the cube of field strength and power density with the fourth power. Still massive scaling indeed, but exponentially would be something else.

> as far as I remember the substrate they are using needs to be cooled to 60-70 degK to achieve super conductivity

The video in the article shows 20 K. Could of course be that higher temperature is feasible and they just played it safe (or the video is wrong).

Re: MIT-designed project achieves major advance toward fusion energy

#42

Post by rory »

phicoh wrote: post #25
ChrisMarshallNY wrote: post #6

Earlier quoted context omitted.

The running joke has always been that “Fusion is 20 years away,” and has been, for the last 50 years. I really want this to work. I am a bit concerned, with how “the old guard” will react, once we have successful, productive, fusion. I foresee an astroturf NIMBY campaign against construction of fusion plants.

At the moment it is very far for clear that fusion will be cost effective. The article says this about the fuel of fusion: "The fuel used to create fusion energy comes from water, and “the Earth is full of water — it’s a nearly unlimited resource. [...]" They forgot to say that it is not the H2O that comes out of your tap. The earth is especially not full of tritium.

The fuel for fission comes from rocks. The Earth is full of rocks!

Re: MIT-designed project achieves major advance toward fusion energy

#43

Post by TrainedMonkey »

MauranKilom wrote: post #41
TrainedMonkey wrote: post #35

This is exciting. Magnetic field strength is a key component for enabling magnetic confinement fusion. This is because energy gain and power density scales to the 3rd and 4th power with magnetic field strength but only ~linearly with reactor size. See following equations for more details: https://youtu.be/xJ2h3vbOag4?t=306 So, why is this particular announcement exciting? There are 3 factors: 1. This is a high temper…

Appreciate the rundown of why this is important! > This is because energy gain and power density scale exponentially with magnetic field strength but only linearly with reactor size Nit: It scales polynomially, not exponentially. Specifically (according to those formulas) energy gain scales with the cube of field strength and power density with the fourth power. Still massive scaling indeed, but exponentially would b…

You are right on both counts, I will update the comment. 2020 paper referenced 7degK magnets. I am not sure where I got 70degK number from... https://www.cambridge.org/core/services/aop-cambridge-core/c...

Re: MIT-designed project achieves major advance toward fusion energy

#44

Post by MauranKilom »

JackFr wrote: post #23
soperj wrote: post #8

Earlier quoted context omitted.

It wasn't a joke, it was always based on an adequate level of funding. Everything is always off in the future if it never gets funded.

Ah yes, and how much money? The answer always seems to be “More”.

Please consult this graphic from 1976 if you are actually interested in the answer.

https://i.imgur.com/3vYLQmm.png

Re: MIT-designed project achieves major advance toward fusion energy

#45

Post by zardo »

MauranKilom wrote: post #41
TrainedMonkey wrote: post #35

This is exciting. Magnetic field strength is a key component for enabling magnetic confinement fusion. This is because energy gain and power density scales to the 3rd and 4th power with magnetic field strength but only ~linearly with reactor size. See following equations for more details: https://youtu.be/xJ2h3vbOag4?t=306 So, why is this particular announcement exciting? There are 3 factors: 1. This is a high temper…

Appreciate the rundown of why this is important! > This is because energy gain and power density scale exponentially with magnetic field strength but only linearly with reactor size Nit: It scales polynomially, not exponentially. Specifically (according to those formulas) energy gain scales with the cube of field strength and power density with the fourth power. Still massive scaling indeed, but exponentially would b…

There is a temperature dependent maximum field strength the material can take and keep superconducting. REBCO superconducts at 70k, but it can't take much current at that temperature.

Re: MIT-designed project achieves major advance toward fusion energy

#46

Post by apendleton »

JackFr wrote: post #23
soperj wrote: post #8

Earlier quoted context omitted.

It wasn't a joke, it was always based on an adequate level of funding. Everything is always off in the future if it never gets funded.

Ah yes, and how much money? The answer always seems to be “More”.

I mean, yes, obviously if the criticism is that they're getting too little money, clearly they want more. Some technologies are fundamentally expensive to develop (the Apollo program, the Manhattan project, etc.). That doesn't mean the people saying so are automatically charlatans, especially given that they've never gotten what they've asked for -- it's not like some bomber development project where they get what they want and then keep coming back for more. The relatively paltry amounts the US has been devoting to fusion energy research are lower than any of the scenarios laid out in a 1976 DOE planning document[1] about what it would take to achieve fusion power, and lower even than just continuing at 1970s levels (a plan they labeled in that document as "fusion never").

[1] https://books.google.com/books?id=KSA_AAAAQBAJ&lpg=PA234&ots...

Re: MIT-designed project achieves major advance toward fusion energy

#47

Post by apendleton »

zardo wrote: post #38
apendleton wrote: post #29

Earlier quoted context omitted.

I think the framing of what's happened so far as "failure" is probably the main thing responsible for this perception. It's true that progress has been slower than many had hoped and the most optimistic had projected, but "failure" sort suggests that the things the research community have been trying haven't represented meaningful progress towards the goal of power production, which isn't the case. Q (the ratio of en…

Would stellarators see the same benefits as tokomaks from higher field strength magnets?

Potentially yes, though stellarator research in general seems to be somewhat less mature than tokamak research. There's an outfit called Type One Energy, though, that looks to me like they're essentially CFS but for stellarators (i.e., take established stellarator designs but do them with HTS magnets): https://www.typeoneenergy.com/ . Their academic heritage seems to come out of the University of Wisconsin instead of MIT.

Re: MIT-designed project achieves major advance toward fusion energy

#48

Post by NiceWayToDoIT »

I remembered that in 2018 Japanese team manage 1200 T peak power. http://www.sci-news.com/physics/strongest-magnetic-field-ach...

In comparison, 20T does not look much, but again it is, I wonder with the Japanese technique what is the highest continuous magnetic field.

Re: MIT-designed project achieves major advance toward fusion energy

#49

Post by zetalyrae »

dfdx wrote: post #34

Plenty of skepticism in these comments. I've been following CFS for a while and can present a point of view for why this time might be different. Fusion energy was actually making rapid progress in the latter half of the twentieth century, going from almost no power output in the fifties and sixties to a power output equal to 67% of input power with the JET reactor in 1997. By the eighties there was plenty of experim…

I've always wondered: why exactly is ITER so expensive, and slow? Is the engineering required at such a standard that it should takes decades of planning and construction and tens of billions of dollars? The timeline is so dilated (started in 1988, first plasma planned for 2025!) it feels like the kind of project that's expected to be cancelled from the start.

It just doesn't strike me as obvious that reducing the major radius by a few meters would have such a huge impact on cost/timelines.

Re: MIT-designed project achieves major advance toward fusion energy

#50

Post by rnhmjoj »

anonuser123456 wrote: post #17
shmageggy wrote: post #7

These university press releases are always very positively framed. This one makes the new magnet seem incredibly promising and fusion seem like almost an inevitability now, but decades of failure have us conditioned for skepticism. What's the catch this time?

> What's the catch this time? This is D-T fusion. Which means you have to have T. Which currently comes from fission reactor and has a half life of 15 years. So the plan is to use a molten salt blanket with Be to breed T. But Be isn’t scalable for consumption, so maybe lead eventually. That’s probably do-able, it just slows down the rate new reactors can come online since Pb is not as good a neutron multiplier. Once…

> But are they surmountable AND cheaper than existing nuclear or other energy sources?

DT fusion solves the two biggest arguments that are always raised by nuclear energy opponents: storage of nuclear waste (it doesn't produce high-level waste) and safety (it's not perfect but it can't explode). I wouldn't call it a "meh", even if it comes off as much more expensive than fission.

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