Can p-B11 fusion deliver net power?

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  • November 11, 2014 at 6:28 pm #1633
    Andrew Palfreyman
    Participant

    A comment recently posted on NatureNews:
    the maximum ideal Q is only 3 to 4 (as for p-11B), the electric power output is not much greater than the electric power input. When you include the non-plasma power drains such as vacuum pumping, coolant pumping, cryogenics, HVAC, etc., the power balance is negative.
    Comments?

    November 12, 2014 at 2:38 am #13508
    Tim1
    Participant

    Could you post a link to NatureNews so we can get some context. Also I don’t understand why there would be a maximum ideal Q. Wouldn’t higher Q always be better? I would expect people to talk about a minimum Q that will allow one to get back enough energy to power the next pulse in addition to provide a reasonable output. Focus Fusion has the ability to be viable at relatively low Q because it gets its energy back as electricity rather than heat so that it can avoid Carnot cycle losses.

    November 12, 2014 at 3:04 am #13509
    Andrew Palfreyman
    Participant

    http://www.nature.com/news/plasma-physics-the-fusion-upstarts-1.15592

    November 13, 2014 at 12:50 am #13511
    Tim1
    Participant

    Thanks. The article covers most everyone except LPP as alternatives to the over priced IETR. LPP was mentioned in the comments. There was nothing that explained why Q should be limited in p-B11 fusion. Happily, it looks like Focus Fusion works with a Q of less than 2. If we got 3 or 4 things will be great.

    November 24, 2014 at 8:45 am #13515
    Andrew Palfreyman
    Participant

    That’s not much of a retort. What about the true energy balance?

    November 24, 2014 at 9:06 pm #13517
    vansig
    Participant

    there are so many factors.

    your basic p + B11 –> 3 alpha + 8.7 MeV is a lot of energy.
    the reaction needs at least 50 keV and is best at about 600 keV;
    a fraction of your plasma reacts in the pulse;
    you want your magnetic fields to be strong enough to inhibit bremsstrahlung losses (gigagauss fields);
    you want your exit beam to be tightly focused and heading in the right direction;
    you have to keep your plasma hot and your anode cool;
    and you have the energy transformation.

    all these things need to be optimized systematically

    November 24, 2014 at 9:18 pm #13518
    Andrew Palfreyman
    Participant

    vansig wrote: gigagauss fields

    1 Gga = 100,000 Tesla! That wasn’t on the menu as far as I knew.

    November 25, 2014 at 10:54 pm #13519
    Tulse
    Participant

    You might find this chart helpful:

    http://lawrencevilleplasmaphysics.com/sankey-diagram-focus-fusion-energy/

    November 29, 2014 at 7:38 am #13522
    Andrew Palfreyman
    Participant

    It seems, therefore, that Focus Fusion will deliver between 200% and 300% of the input power, having discounted all sources of costs and losses in an industrial production context. Am I low or am I high with this estimate, and why? Indeed, has anyone taken the trouble to do a serious economic quantification of the cost benefits of Focus Fusion? One has to include, for example, the mundane cost of getting the boron on-site.

    Does FF work better as a space drive than as a power station, and why?

    November 30, 2014 at 12:00 am #13523
    Francisl
    Participant

    A lot of the economic numbers that you are asking for will be gathered during the next 1 or 2 years of fusion experiments. The numbers that you have seen so far are based on current science and best estimates.

    November 30, 2014 at 12:51 am #13524
    Andrew Palfreyman
    Participant

    Yup. And clearly scale is a factor too. The higher the Q of a process, the more the absolute power margin and the smaller one can afford to scale it and still take care of the ancillaries.

    December 3, 2014 at 10:41 pm #13527
    Tulse
    Participant

    Andrew Palfreyman wrote: has anyone taken the trouble to do a serious economic quantification of the cost benefits of Focus Fusion? One has to include, for example, the mundane cost of getting the boron on-site.

    Right, but you also get to exclude standard power plant costs for things such as turbines and generators, along with all their associated overhead (e.g., extra staff, extra space, etc.).

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