Technical resources on limitations of fusion

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RobertMendelsohn
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Technical resources on limitations of fusion

Post by RobertMendelsohn »

Hello all, after searching the forum I'm still looking for technical literature on why useful/breakeven fusion is nearly impossible [outside of weapons]. I have a somewhat simplistic understanding as-is: the reaction cross sections are pretty low, and the heated assembly cools down really quickly by thermal radiation. There must be technical reasons beyond the Lawson criteria / triple product? What resources (especially books) would you recommend to someone who is not math shy? Is there a rigorous treatment of this topic? Especially why large projects have failed to get anywhere near ignition.

I'd like to be able to understand the root causes of failure of these devices, and if someone suggests a prospective new approach, have an informed rubric for judging the viability (or more likely non-viability) of the approach/theory.

Please let me know if I've missed a comprehensive previous discussion and we can delete this.

Sincerely,

Robert
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Richard Hull
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Re: Technical resources on limitations of fusion

Post by Richard Hull »

Robert, You have a great grasp on why fusion is difficult and it is cross sections that holds it all back.

We must literally thank our lucky stars that cross sections are so low, even at fusion energies. We are lucky our stars do not see a large fusion cross section of their simple hydrogen fuel, even at their very cores!

The cores of stars are ideal fusion engines or reactors. they have all the right stuff. They have crushing gravitational containment, they have fusible nuclear fuel in abundance, and they have plasma at the right temperature to do fusion. Fortunate for us, main sequence stars burn simple hydrogen first! Simple hydrogen has an incredibly microscopic cross section. This make stars an incredibly inefficient fusion reactor. As such, in spite of satisfying all of the Lawson criteria, they burn long and slow, using up their fuel over billions of years. Yes, we can thank our lucky stars.

The sun also makes deuterium and tritium as well as other higher cross section fuels as hydrogen atoms fuse. These easier fusions occur, but are forever limited by the snails pace of simple hydrogen fusion needed to make these higher cross section fuels.

For the same reason when we do fusion in our D-D fusors we make one atom of tritium for each 2 fusions. Many here, in the past, figured, erroneously, that this would actually do the far more easy D-T fusion in our fusor over time. This would be true save for the slow pace of D-D fusion itself, for just like the stars, you have to do lower cross section D-D fusion first to make tritium!

If simple hydrogen had a high cross section, The universe would have destroyed itself in a virtual short epoch flash!

Nature abhors natural hydrogen, (protium), fusion. It abhors all forms of fusion! Fusion is a bad process in the eyes of nature. Still over billions of years of stellar burning, stellar death throws in nova and super nova events, and neutron star collisions, fusion has made all the elements known to man.

The uranium atom, just like coal contains stored fusion energy from long ago. Both are very easy to control burn as all the energy is there in the form of electronic bonds in wood and incredibly easily unlocked nuclear strong force bonds in Uranium, freeing it of its gross over burden of neutrons, splitting it in two.

There are no strong force bonds in protium. Therefore, tremendous outside forces must be brought to bear in very special circumstance to turn those energies into binding energy and the creation of a first single neutron which are all counted as mass in all complex atoms with neutrons. Neutrons are the font of nuclear binding energy, (Strong force and the first two fusions - deuterium and tritium).

Deuterium and Tritium are very easy fusions as they are far more easy to force to fuse since they have neutrons and binding energy within their nucleus. many of the light elements are very easy fusions as their nuclei are still small with limited binding energies and neutrons within them. Once the neutron numbers and their binding energies start to outnumber the protons, they are increasingly tough nuts to force together and fuse. The quantum tunneling barrier energy rises to shield the nucleus from even incredibly energetic would-be fusion opportunities. Normal stars can't fuse much past carbon. The energy, even in the core, can't do it.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.
Peter Schmelcher
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Re: Technical resources on limitations of fusion

Post by Peter Schmelcher »

A good book to start with is “Inertial Electrostatic Confinement (IEC) Fusion”. George H. Miley, S. Krupakar Murali 2013

https://books.google.ca/books/about/Ine ... edir_esc=y

-Peter
RobertMendelsohn
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Re: Technical resources on limitations of fusion

Post by RobertMendelsohn »

Thank you for your replies Richard and Peter. I've purchased the book Peter recommended, it looks like exactly what I am looking for. Thank you for the very approachable overview/review Richard.

Sincerely,

Robert
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Richard Hull
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Re: Technical resources on limitations of fusion

Post by Richard Hull »

It must be noted that fusion cross section is a form of synonymous linkage to the complex subject of quantum tunneling probabilities and this translates to a relative crap shoot. In effect, the dice of quantum uncertainty are loaded and always loaded against fusion that is sought to be readily done by us with any form of ease.

Fusion is the exact opposite of fission which is done with such great ease that it must be guarded against running away to great detriment, explosively. This control is easily accomplished as in starting and controlling a giant fire of coal or wood.

I do hope the book does not appear as a "Gordian Knot" to a full and simple understanding of the fusion process and why it appears, not an uphill battle, but instead, an impossibility using inertial electrostatic confinement.

It comes back to the full understanding that potential energies rule the universe. potential energies are "cocked energy guns" whereby we only need hunter-gather these cocked potential energy systems and pull the simple trigger to release kinetic energy to do our bidding. Nature, and ultimately, fusion done throughout the universe, freely cocks these potential energy sources. We are reduced to mere hunter-gatherers and very intelligent trigger pullers, cleverly directing the released potential energy to a form of kinetic energy to drive our wheelwork and make life easier.

We are also potential energy gun cockers, ourselves. We are smart cookies, indeed. However, there is no free lunch. In all cases we come to understand that more energy must be used to cock all potential energy sources. These cost us as wasted energy that we must supply in many cases. However, some processes are so important to us we are willing to create these potential energies, at a loss, for later release in some vital need.

Being smart cookies, we realize that there are bountiful free energies about us and use them at great net loss to create energy to drive our wheelwork. We don't consider the loss as these energies are truly free, at least, to us.

Solar cells operating at great inefficiencies take free sunlight and supply electricity. Wind is used at great net loss to turn geared-up turbine generators to make electricity. Gravity forces water from the highlands which is stored in giant lake reservoirs. We throw this water over a precipice to fall on turbine blades to make electricity. These are free energies gathered by we clever hunter-gatherers to do work and convert, again, at great net loss to do our bidding.

What creates the sunlight for solar cells?.... Fusion of a distant star. What creates the energy to stir our atmosphere and make wind?..... Fusion from a distant star. What lifts the water to the highlands to fall as rain to fill our reservoirs, cocking the gravitational potential energy "gravity gun"? Fusion from a distant star. What locked all those potential energies into wood and coal and Uranium? Fusion from a distant star applied over years or Millenia or dying distant stars over billions of years, in the case of Uranium.

What about the stars? How do they do fusion? Well at great net loss using massive gravitational potential energies to drive fusion only at the core to overcome rotten cross sections for protium, deuterium and tritium. Fusion may power the universe, but only potential energies drive fusion.

Potential energies drive the universe into forced kinetic energy always to great net losses in any all processes. Potential energies drive matter into kinetic action, moving bulk matter about locally, leaving in its wake a few new, diverse, cocked potential energy guns and waste heat radiation.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.
Matt_Gibson
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Re: Technical resources on limitations of fusion

Post by Matt_Gibson »

Now I’m all revved up to get my fusor going again! (Been spending time on its new psu upgrade).

-Matt
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Richard Hull
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Re: Technical resources on limitations of fusion

Post by Richard Hull »

I'll bet it will be time well spent. A little down time is always good for a fusor if we are working to improve operation or update components.
I hope it works well for you.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.
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