Unconventional Fusion Methods: Fusion without Neutrons?

[DavidPex]

Is it possible to achieve fusion without generating neutrons? What alternative fusion methods can be explored to eliminate the challenges associated with neutron radiation, such as material degradation and the need for heavy shielding? Could this lead to safer and more efficient fusion reactors?

Link Removed by Admin

[Rich Gorski]

Yes, there are many fusion reactions that do not produce neutrons as the chart below shows. However it also shows that the DT reaction will be the easiest to achieve meaning the lowest temperature as it has the largest cross section (around 64keV). That's why most potential Q>1 experimental reactors will use the DT reaction. The DD reaction that we do in our fusors has two 50% branches of which only one produces neutrons. The other branch produces a proton. Also I believe the proton-proton cycle in stars also does not directly produce neutrons.

Rich G.

[Richard Hull]

The P+B11 reaction is the ideal, but just can't be done without extreme effort and great net loss. it is ideal due to the 3 charged alphas. This has been the proposed and much touted direct conversion of electrical energy via the alphas to usable electricity without the ugly and lossy steam turbine cycle using fusion debris kinetic energy to a heat cycle, then to steam then to electricity.

Sadly D-T is the one and only easy one, relying on the non-extant, man-made Tritium.
D-D is the most earthly abundant fueled second easiest one, albeit of less energy per fusion than D-T
Any process involving T of 3He involves gases that are non-extant on a commercial power producing scale.

In most any scenario, even the alpha only cycle, some neutrons will be produced by secondary or even tertiary reactions at huge power levels demanded for commercial power distribution.

In short, there is no ideal aneutronic reaction at power energy levels.

Almost no one here will remember the "Hull-Willis" prize of several hundreds of dollars offered here years ago. There was, back then, a few bold, blow-hard, chair bound, posters that claimed they might try P-B11 fusion at the amateur level. Carl Willis and I threw in together to offer this monetary reward for any amateur fusioneer who could do and prove to us that they had, indeed, achieved P-B11 fusion with alpha production. Oddly no one in the blow-hard camp came forward and all discussion ended. I retired and due to tight money in retirement, withdrew my promised prize money. Carl remained steadfast and the prize for P-B11 fusion is now the "Willis Prize".

Richard Hull

[Rich Feldman]

What's that uncommented link doing in OP? Is it supposed to be a signature line?
The visible text says " Ideal temperature guide for deep-frying "
and link URL appears to be

phish.gif (5.52 KiB) Viewed 1902 times

I'm not a good enough hacker to follow the link safely.

[Frank Sanns]

It seemed a legitimate email and a valid question so I approved the original post.

Thanks for catching the link that was added Rich. I have edited it out of the original message.

The next response, if any, by the OP will determine if they stay or vanish forever.

[Daniel Harrer]

Apart from the obvious difficulty to even achieve p+B11 fusion: how would one check for that? I think the tiny amount of alpha/He4 in the output would be completely hidden in the natural amounts.

[Richard Hull]

You would have grave difficulties detecting the alphas, indeed! It is the very reason we leaped down the throats of the P+B11 blowhards and offered a nice big bucks prize to:

1. Do the P+B11 fusion (huge voltage demanded and acquiring the enriched poison boron tri-floride or borane needed)
2. Prove to us by specific methodology for alpha detection, and that you had the gear and setup needed to supply this proof!

Number 1 was tough enough
Number 2 would stop any amateur in their tracks.(as you posit)

P+B11 is a joke fusion reaction at the amateur level, as well as at the commercial and supposed power fusion ideal. Nobody works on this reaction.

Richard Hull

[Bob Reite]

Why would one need the boron tri-floride or borane? Do Beam on Target, the target being Boron and the beam being protons. It will still be a very tough nut to crack to detect the alphas.

[Rich Gorski]

Bob,

I had the same thought. A BOT device would be the approach I would use and with the crystyline B11. This approach would require use of a hydrogen ion source with some simple focusing optics and acceleration voltage near 100kV. At 100kV the fusion cross section is close to where we are with the DD reaction. The B11 material would be inside a cup of beryllium so the high energy alphas could produce neutrons that we could detect.

Just my crazy thought.

Rich G.

[Frank Sanns]

Natural boron is 80% B-11.

Boron Carbide (B4C) is a ceramic used for ballistic armor. It is ubiquitous and cheap.

It would be around 68% B-11. For quick and dirty attempts attempts it would work as proof of concept albeit failed but worth a go.

I have some boron carbide here and was going try BOT with 100kv on it with my opposing polarity 50K Glasssmans but never got to it. Far down on the list of priorities. Still, somebody has to try it and report on it whatever the result or failure.

[Richard Hull]

The BOT concept with Boron carbide is a good idea in a beryllium cup. If successful, and producing the alpha-Be = N reaction, this would produce fast neutrons which could be detected with a bubble dosimeter directly or surrounded in a moderator with a sensitive 3He electronic detection system.

As always, waiting for someone to give it a shot. The blowhards probably did not think this through and certainly did not have the kit or know how to make it happen. They never did any fusion here at all, and left after blowing a P+B11 wind over the deck of our fusion ship set sail in the waters of the internet. We get these types every now and then as some of you know.

Again, they were positting this as a direct conversion future controlled fusion system for electrical power and suggested we give it a whirl here as another amateur fusion effort doing another type of fusion. We threw it back in their face, as always. Why don't you do it? Here is some money if you go for it here, and "git 'er done"

Richard Hull

[William Turner]

With the pB11 cross-section already small in the energies accessible by the amateur, compounding this with the cross-section of Be+alpha for the neutron production would probably be a detection challenge (with high confidence). If one had an extremely fast pulsed proton source, then coincidence timing could be used to improve the situation.

The idea of a "monitor" reaction is a good one though and there has been some work on evaluating secondary reactions (neutrons and gammas) from N14. A boron nitride target is used (a ceramic with good thermal properties) in that situation.

B10+alpha -> neutron is also a possibility.

However, I think a simpler approach with a beam-on-target setup is using a surface barrier detector (with an ultra-thin foil to reject electrons and any fragments) to look for alphas.

[Bob Reite]

Yeah and good luck with work at 100 KV plus. Up to 50 KV it's not a big deal, above that everything becomes a big deal. Corona becomes a major headache. You need the room to be able to make all curves gentle. No sharp points allowed. To say nothing of the x-rays that will be produced in large quantity along with the desired results.