Science and Roadmap Details for Commonwealth Fusion Systems

Here are a Lawrence Livermore and ARPA-E presentation on the science and roadmap details for Commonwealth Fusion Systems (CFS). CFS has completed and validated their 20 Tesla magnet system which is critical for massively reducing the size of a commercial Tokamak.

CFS has raised $215 million and now have a staff of over 240. They are targeting a net energy gain demo in 2025 and a commercial fusion reactor in 2033.

30 thoughts on “Science and Roadmap Details for Commonwealth Fusion Systems”

  1. I'm seeing an awful lot of "some people say" numbers being thrown around in that piece. But the real problems are,

    1) Focus only on Uranium, and ignoring the more plentiful Thorium. That more than doubles the supply.

    2) Ignoring that natural processes are adding both to the sea as fast as we could use them.

    3) Forgetting that crustal rock actually has enough of both in it to be a useable ore in extremity.

    I personally see SPS taking over for many applications by the end of the century, but fission is still feasible for geological periods of time, and fission will have great use in space.

    Here's somebody running the numbers: (That chart is a log chart, by the way…)

    https://whatisnuclear.com/blog/2020-10-28-nuclear-energy-is-longterm-sustainable.html

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  2. Those estimates usually ignore the use of dissolved fissiles in the sea, or any other unconventional source, and settle for analyzing proven terrestrial reserves of Uranium; A few centuries if you assume no reprocessing, a few thousand years if you permit it.

    But proven reserves are just what people have found it economically sensible to prove at current prices, they're not actually the total supply. And it ignores such sources as remediation of coal ash; Your average coal power plant is producing ash containing tens of tons of potential fuel each year; The ash actually contains more usable nuclear power than the coal did chemical…

    They also tend to ignore anything but Uranium; Reserves of Thorium are considerably larger.

    And the amount of dissolved fissile fuel in the oceans is absurdly large, (About 4B tons) and continually replenished by erosion of the land.

    So, Leonidas is right: Fission would be perfectly capable of powering our planet until the Sun goes off the main sequence and fries it.

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  3. How about, instead, applying fusion technology to fission reactors? I'm a big fan of the dusty plasma fission fragment reactor. Lets you do direct conversion for very high efficiency. The fission products are easily separated for continuous reprocessing. And the magnetic fields required to contain the plasma are much more modest than for fusion.

    https://www.researchgate.net/publication/228875834_Dusty_Plasma_Based_Fission_Fragment_Nuclear_Reactor

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  4. ITER is premised on the notion that tokamak performance improves with size, so, build one really, really big. They might even be right about that. Or maybe if you build them really big, eventually you just find new instabilities. But that's why it's so huge.

    So the idea is that the performance is bunching just under breakeven because research reactors are too small.

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  5. If that's true, why do we keep getting high and low pressure areas that seem to drive winds? Wouldn't they quickly smooth out, if not driven by active heating and cooling?

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  6. Many areas will have weeks-long dim sky periods nearly every year, and probably don't want to have a power emergency every year.

    Batteries are really good for smoothing rapidly varying supply, and pretty good for shifting a modest fraction of generated electricity to smooth out peaks. Maybe batteries would be a bit better than synthesizing fuel to run through a turbine to generate power at night.

    But batteries are probably not the best idea to handle 'gray weeks', as you'd need 10x or 20x as many to get through that, compared to a single night's storage. Also, if part of the country has sun and lots of spare energy sitting around while another area is running out of energy, transporting syn-fuel will be more efficient than transporting charged batteries.

    So I'm thinking that if we go fully renewable, we'll need to create and store syn-fuel in preparation for gray weeks – plus have turbines with generators.

    But if you're going to have those anyway, why not use them every night, and need even fewer batteries? Economics probably forces that decision, once you've settled on building syn-fuel turbine generators – a few more fuel tanks to cover one night will be much cheaper than energy-equivalent batteries. And we've already GOT a lot of gas turbines that would otherwise become obsolete – might as well use them.

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  7. Often when one puts new constraints on something one wants to achieve, creative new solutions are spotted, by breaking un-recognized assumptions about how something must be done that have trapped one at a local maxima.

    I've often wondered if maybe the physicists who work on fusion have a bias that, if reversed, might give a different perspective on how to go about creating fusion power. Naturally they focus on the fusion device – how to make fusion happen, how to make enough happen to exceed energy input, how to make it happen more continuously without destroying the device, etc.

    What if they started at the other end – thinking about the best way to generate electric power based on the possible forms energy might be generated by a fusion device. High temperature/velocity/pressure plasma shooting through coils to generate electriciity? High temperature hydrogen plasma that can be magnetically separated into protons and electrons, creating a current? Maybe radiation splitting water so that the hydrogen protons get pulled by a static electric field through a membrane one way and hydroxide ions another, both creating a current and forming separated hydrogen and oxygen to use as fuel. Etc.

    Then work backwards – what would the fusion device have to be like to create the conditions those generators require? How might it still achieve fusion despite those constraints?

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  8. Well.. If things pan out as he envisions, then solar-wind-battery will kill coal in a decade. Then it will be hard to argue that he was really trying to perpetuate our dependence on coal, right?

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  9. Hm… I think that having diesel backup for hospitals and servers farms should suffice for the "once -in-a-century" krakatoa events, would you not agree?

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  10. Hm.. But Tony Seba made calculations for mew england, and there was enough sun there. So the places that lack enough sunlight would be Alaska and Island?

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  11. Or using Gen 4 reactors, we could use depleted uranium as fuel and power the world for a good 1000 years on radioactive waste alone.

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  12. What I see from the chart is the tokamak performance bunching up just under breakeven. That tells me we're reaching diminishing returns.
    ITER Projected for 2035 does nothing to reassure me. That's too far out.

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  13. Right,besides the sun will expand in a few billion years while there is enough U in the ocean to power the world for tens of trillion of years.

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  14. Tony and others are promoting coal and gas by opposing nuclear energy, great article Brian,CFS is the best approach to fusion although General Fusion is great as well, get a big ball of spinning metal and hit it with a bunch of hammers.
    I would hope that we would continue to invest in the one energy source that has avoided more Carbon than any other safely, fission,hydro provides energy but has killed hundreds of thousands.
    And obviously you can't build more hydro.Especially where and when needed.

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  15. I think fusion in the end will have many uses and advantages. One of those may even be to draw down CO2 on a massive scale. Another long term vision is to power vertical farming at scale to both protect from weather and also give back habitat. It’s time we reversed this global mass extinction event.

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  16. Removing 500MW continuous of heat from a small sphere of expensive physics and cold magnets isn't trivial.

    It looks like they're converting heat to electricity at 40% efficiency. So – a high temperature steam system. Probably around 650c.

    Do they have any idea what this heat removal system is going to look like, how their systems will perform at such high temperatures?

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  17. Looks like commercial production will get going earlier than I expected. Quite exciting, given the output we could get from fusion. I might be wrong about this, but I've always suspected that it could dwarf what we could generate from wind (for sure) and solar (perhaps, unless it's some kind of super efficient beamed power).

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  18. In fact, I've seen an analysis that says that there's not enough energy going into the weather systems to actually allow wind power to cover much of our energy needs; There's a lot of energy IN the weather system, it's like a low friction flywheel, but the actual sustainable power output isn't that impressive.

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  19. Don't you need a security baseload when a volcano erupts and puts the world into darkness for a few weeks. Or would we have enough cheap long term energy storage for such eventualities?

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  20. You are not wrong, except that wind will be hated because it removes energy from weather systems, causing inland areas to become drier.

    Plus what about all the space colonies beyond the snow line? The solar constant falls off with the square of the distance! We need nuclear of some kind for those.

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  21. You are still not optimistic enough!

    If energy becomes so cheap and clean the world will become incredibly rich and use petawatts at least.

    So solar and wind will be the boogeyman that shadow all the deserts and kill all the counterfeathered insect eating birds, only option left fusion.

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  22. I think they are too late.

    If Tony Seba is right, then solar + batteries and even wind + batteries will be so cheap by 2025 that it will not matter if they demonstrate Q>2. Wrights law will make solar and batteries so cheap that even the best production cost estimates of this fusion technology will seem very expensive.

    Note that I think MIT and Commenwealth Fusion Systems are doing the right thing and pursuing the right technology. It's great.

    But also to late…

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