Making Helium-3

[Cryptonix]

Bumpp

Edited September 5, 2013 by Cryptonix

[John Cuthber]

Your post doesn't make sense so there's no point in bumping it.

You would do better if you explained what you thought 1K meant.

[Enthalpy]

http://en.wikipedia.org/wiki/Helium-3

obtained from decay of tritium, produced itself in nuclear reactors by neutron irradiation of lithium.

 

Shortage of both tritium and helium-3 in sight, so new sources are sought by the nuclear industry, despite the present thread looking unprofessional.

 

The Wiki articke cites existing and prospective uses but doesn't tell what the main ones are. Fusion in tokamaks and laser reactors is out of reach; capabilities of the Z-machine aren't widely public. I'd imagine that research tries to replace tritium with stable helium-3 in the boosters of nuclear bombs - I had suggested lithium but igniting D-Li is more difficult.

Edited September 14, 2013 by Enthalpy

[Enthalpy]

D-Li does not produce the proper energetic particles for a booster. D-³He is doubtful as it expels less favourable protons.

http://en.wikipedia.org/wiki/Nuclear_fusion#Criteria_and_candidates_for_terrestrial_reactions

http://en.wikipedia.org/wiki/Aneutronic_fusion

 

Produce ³He... only in faint amounts, and using much energy.

p-Li looks like a candidate for a beam+target apparatus.

D-D is much more easily conduced, it produces ³He and ³H that decays to ³He over decades.

 

D is available commercially in big amounts, and D-D is readily conduced in a fusor:

http://en.wikipedia.org/wiki/Fusor

"just" a matter of produced amounts and consumed energy... Powerful long-term operation would also pollute through neutron activation.

[Enthalpy]

³He [is] a naturally occurring nuclide, and it separates spontaneously from ⁴He at 2K. Just cool enough, get one layer on top of the other, how easy.

The terrestrial proportion of 1.37ppm means: process 1,000 tons to get 1.37kg... So one better puts the separation plant at the helium well directly.

 

Liquefying helium in big amounts isn't easy nor cheap. An alternative would be a molecular pump or a gaseous diffusion plant. Better, do both simultaneously: have a many-stage pump (for instance as an axial turbomolecular pump) and put a gaseous diffusion shunt around each stage, if natural leakage doesn't suffice. Each stage is more efficient at ⁴He while each shunt lets ³He leak better.

• Because the masses differ significantly, each step has an interesting yield.
• This can work at room temperature, with the speed attained by an optimized metallic axial pump. Cold improves.
• Natural helium would be introduced near the "depleted" (purer ⁴He) exit, so most flow absorbs little pumping power.
• Enriched ³He would exit at the pump's extreme inlet, after many steps that most helium does not pass.

Many other methods must work. Gas chromatography can use many (many) short fibres in parallel, I suppose with oscillating pressure at the natural helium side so that ⁴He has no time to diffuse to the end of the fibres.

 

I wanted to use a superconducting leaking ceramic to repel ³He as is done with O₂, or a ferromagnet to alter the diffusion of ³He versus ⁴He, but since a nucleon is a weaker magnet than an electron, the effect is tiny at room temperature - much smaller than the contrast in diffusion speed.

 

³He seems 10 times better than Li to produce ³H from a neutron flux, that is at a nuclear reactor. That can explain the query for ³He.

[Enthalpy]

Separating ³He from all produced natural helium would supply a bit more than the present demand, a handful of kg a year.

 

Though, I begin to guess a different need for ³He, in much bigger quantity... Because tokamaks such as Iter need tritium to run, and must regenerate tritium to be credible, which is a very strong obstacle: sheer feasibility and pollution, as one consumed tritium makes a single neutron needed to regenerate a tritium from a ⁶Li, so dirty neutron multipliers must offset the losses. I tell it for years, maybe tokamak proponents get slowly forced to look into the problem.

 

One other way would let ⁷Li absorb the 14MeV neutron produced by the D-T fusion. ⁷Li splits into ⁴He and T, and releases a neutron - but with energy too low to react with ⁶Li nor ⁷Li. This secondary neutron could react with ³He to make a second T.

 

Well thought guys, but this needs ³He in big amounts, not available from terrestrial helium deposits, and of course not obtained from T decay. This can be a reason for the query at ³He artificial production.

 

It can also be the reason why some people and agencies consider mining ³He "for nuclear fusion" where it is less scarce: on the Moon or from gas giant planets. It's not for D-³He fusion, which is hugely more difficult than the already remote D-T fusion: it's for regeneration of tritium in D-T reactors.

 

Well, sorry folks, but isolation from normal terrestrial helium just makes a few kg a year. And despite being a space visionary, I don't really imagine affordable Selene mines. But for a few millions instead of many billions, we would have cheap electricity storage that enables wind and Solar energy on the big scale.

Edited November 2, 2013 by Enthalpy

[Drop]

It was shown to me use h3 and o3 to create he3 using a spining method to seperate h3 and o3 to create he3 and the shape matters of the disk for seperation hope this helps and use a high quality alunimum for the chamber. Also this will create a weightless enviornment and using the left over o will create perpulsion.