Nuclear Fusion Reactions

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Astronuc
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Some principal nuclear fusion reactions which have been considered are:

1) D + T -> n + 4He

2) D + 3He -> H + 4He

3) D + D -> H + T / 3He + n

4) T + T -> 4He + 2n

5) T + 3He -> (various products)

6) H + 11B -> 3 (4He)

from G. H. Miley, H. Towner and N. Ivich, U. of Illinois Nucl. Eng. Report COO-2218-17 (1974)

with the reaction rates in the figure
 

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  • #2
Morbius
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Astronuc said:
Some principal nuclear fusion reactions which have been considered are:

from G. H. Miley, H. Towner and N. Ivich, U. of Illinois Nucl. Eng. Report COO-2218-17 (1974)

with the reaction rates in the figure
Astronuc,

Thank You.

We see why D-T fusion is the leading contender.

Boron fusion is at the bottom, and doesn't overtake D-T fusion until
you get to Megavolt temperatures; that is temperatures at which the
average kinetic energy of the material is on the same order as the
nuclear binding energy.

Dr. Gregory Greenman
Physicist
 
  • #3
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I have seen the first five as being considered canidates for fusion reactors, but I had no clue Boron was a practical material.

Morbius said:
average kinetic energy of the material is on the same order as the
nuclear binding energy
I take that as: fusion occurs because kinetic energy forces the atoms together because it overcomes the repulsion between the nuclei. Is that what you are saying?
 
  • #4
Morbius
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theCandyman said:
I have seen the first five as being considered canidates for fusion reactors, but I had no clue Boron was a practical material.



I take that as: fusion occurs because kinetic energy forces the atoms together because it overcomes the repulsion between the nuclei. Is that what you are saying?
That's a condition for any of the fusion reaction.

No I was making a comment pertinent to the curve from Miley, et al;
posted by Astronuc.

The graph shows that the D-T reaction has the highest reaction rate of
any of the reactions being considered, while the Boron reaction has the
lowest - over most of the temperature range.

It is only at the extreme high end that the that the Boron reaction
goes from last place to first place. However, the graph shows that this
happens at temperatures around 1000 KeV = 1 MeV, and above.

At temperatures of 1 MeV; the average kinetic energy of the particles
will be the same order of magnitude as the nuclear binding energy.

That means that a 1 MeV temperature is EXTREMELY, EXTREMELY HOT -
even by fusion standards.

Dr. Gregory Greenman
Physicist
 
  • #5
Morbius
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Morbius said:
It is only at the extreme high end that the that the Boron reaction
goes from last place to first place. However, the graph shows that this
happens at temperatures around 1000 KeV = 1 MeV, and above.
I see that I'm mistake here.

Upon closer inspection, I see the (T + He3) [curve 5] and ( H + B-11 ) [ curve 6]
don't cross - they "kiss" but the (H + B-11 ) turns over. It is the (T + He3)
[curve 5] that ends up taking first place from the D-T reaction - again only
at extreme temperature.

Dr. Gregory Greenman
Physicist
 
  • #6
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Morbius said:
I see that I'm mistake here.

Upon closer inspection, I see the (T + He3) [curve 5] and ( H + B-11 ) [ curve 6]
don't cross - they "kiss" but the (H + B-11 ) turns over. It is the (T + He3)
[curve 5] that ends up taking first place from the D-T reaction - again only
at extreme temperature.

Dr. Gregory Greenman
Physicist
Interesting:http://nuclearweaponarchive.org/Nwfaq/Nfaq4-3.html

Some handwaving:http://nuclearweaponarchive.org/Nwfaq/Nfaq4.html

and some first principles:http://nuclearweaponarchive.org/Nwfaq/Nfaq4-1.html#Nfaq4.1.7

if one cursors down, there are some graphs showing various reflector materials.
 

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