FAQ - How to boost fusion in operation - Wall loading and cooling

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Mark Rowley
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Re: FAQ - How to boost fusion in operation - Wall loading and cooling

Post by Mark Rowley »

That’s very good info Jim. I’ll probably refrain from coating the walls. Not worth causing a bunch of instability with current control.

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Richard Hull
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Re: FAQ - How to boost fusion in operation - Wall loading and cooling

Post by Richard Hull »

This is the kind of discussion that will make this FAQ valuable. Open source experiment and discussion....That's the ticket!

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Fusion is the energy of the future....and it always will be
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Re: FAQ - How to boost fusion in operation - Wall loading and cooling

Post by Jon Rosenstiel »

Richard,

I tried your suggestion of heating the endcaps with the chamber valved off. It was somewhat difficult to keep everything (pressure / current / voltage) under control but the end result was that heating of the endcaps seemed to have no discernable effect on neutron production. (Neutron count-rate from heating of the endcaps appeared to be no different than that from residual D2 already in the chamber)

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Richard Hull
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Re: FAQ - How to boost fusion in operation - Wall loading and cooling

Post by Richard Hull »

I figured it would be a bear to control the pressure/voltage and current valved off. Try running the system again, doing a lot of fusion. Shut off the D2 flow. This should cause glow extinction as the pressure drop to 0. Next shutdown the HV power (no fusion taking place) and in just a few seconds with the turbo on, the chamber pressure should plunge almost instantly once the gas flow is cut off. quickly valve off the chamber at high vacuum. You now have no D2 pressure in the chamber. Heat the end caps and see if the outgassing is D2 by doing the terrible balancing act of voltage, pressure and current. This should see if there is a hint of fusion due to outgassing of D2.

The key is to get rid of residual D2.

Remember the selection of chamber metal and even alloys affect absorption and desorption of hydrogen/deuterium.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: FAQ - How to boost fusion in operation - Wall loading and cooling

Post by Mark Rowley »

This evening marked the 4th consecutive night I’ve ran the fusor for the purposes of “wall loading”. From a non wall-loaded cold start the fusor can hit a TIER of 1.5E+06 n/s. In this capacity it’s fairly thirsty for a moderate flow of deuterium and current. However, as I progress with daily loading runs, I’ve noticed the fuel consumption is much more efficient and the neutron output increases by roughy 50% or more. As of tonight’s run, I hit 3.89+06 n/s (101 bubs in 2 minutes at 17cm). If things progress accordingly the fusor should be firmly in the 4-4.5E+06 n/s range with tomorrow’s run.

The reduction of deuterium flow with such a high neutron output really amazes me. Gas flow can be throttled back to a pittance and the neuts keep on coming. I’ve yet to increase gas flow under these conditions but I’m guessing that will have a positive effect as well.

I can only attribute it to a heavy load of deuterium on the aluminum walls and very efficient cooling. It’s also important to note that I keep the chamber between 10-20deg C with ice cold coolant.

Mark Rowley.
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Richard Hull
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Re: FAQ - How to boost fusion in operation - Wall loading and cooling

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Yes, I remember and have posted for years here, my daily rise in output prior to every HEAS event over several days. I have always attributed this to wall loading and the fact that I always did better right off the bat in each run group as days went on and then, each day hit a ceiling. I know that was due to the accumulated heat in the uncooled device run over time each day. When I hit that ceiling I would shut down with a bit more deuterium in the walls for the next day.

Thanks for the update and great data Mark.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: FAQ - How to boost fusion in operation - Wall loading and cooling

Post by Bob Reite »

Once I cure my internal arcing, I will be able to do experiments with system as my vacuum chamber has a water jacket provision. Yes , I'll have to build a cooling system, but in theory I should be able to run tests in which the only variable that changes is the temperature of the inside wall of the chamber.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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Re: FAQ - How to boost fusion in operation - Wall loading and cooling

Post by Richard Hull »

I write this to note that this is one of those FAQs where the replies add mightily to the content of my original PDF. Experiences will vary, person to person and over a larger number of different fusor designs, geometries, sizes and operational experience. This is what "open source" is all about and why this site is so valuable to the amateur fusioneer.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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