The Focus Fusion Society › Forums › Innovative Confinement Concepts (ICC) and others › p-Li7 fusion
I’m not a nuclear physicist so my knowledge on this is limited, from what (little) I have read p-Li7 fusion would be aneutronic and produce nearly twice as much power per mol as p-b11 fusion. So what is wrong with p-Li7 fusion?
Transmute wrote: I have read p-Li7 fusion would be aneutronic and produce nearly twice as much power per mol as p-b11 fusion. So what is wrong with p-Li7 fusion?
According to
http://www.faqs.org/faqs/fusion-faq/section1-physics/
p-Li7 is aneutronic only 20% of the time and yields a neutron in an endothermic reaction 80% of the time.
p-Li6 is better, as it is entirely aneutronic. but p-B11 is also, and produces more energy.
Li6 then (which I think I what I originally meant, but never mind that) why is it inferior to boron?
On the Fusion FAQ page I previously cited it states that the p-Li6 reaction gives up 4.0 MeV energy, whereas the p-B11 reaction gives up 8.7 Mev energy, more than twice as much.
However, according to
http://home.earthlink.net/~jimlux/nuc/reactions.htm
(“Nuclear Reactions of Interest”.)
there is a secondary reaction. p-Li6 produces He3 and He4. He3 further reacts with Li6 to produce 16.9 Mev energy.
The p-B11 reaction requires a higher operating temperature. I do not know how much higher.
As x-ray production (and x-ray cooling) is proportional to the square of the charge (Li=+3, B=+5), the Boron reaction produces 25/9 more x-rays than the Lithium reaction, almost 3 times as much. However, Dr. Lerner has stated that the Magnetic Effect may mitigate that problem.
The Li6:Li7 abundance ratio is only 8:100, but isotopic separation is said to be not difficult.
I think that Lithium-6 should be investigated as a potential alternative fuel, and not dismissed outright.
Excuse my ignorance but are there alternatives to boron as a fuel for focus fusion? In case of boron scarcity can isotopes of beryllium, carbon or nitrogen be used instead?
Boron is not scarce
has anyone heard about this type of fusion
I think I found the reactions I was looking for:
1. p + Li6 -> He4 + He3 + 4 MeV
2. 2He3 -> He4 + 2p + 26.2 MeV
or
3. He3 + Li6 -> 2He4 + p + 16.9 MeV
Total = 20.9-30.2 MeV
Far more energy productive then p+B11, the only problem maybe that it require multiple steps which might night happen in a F2 reactor if its pulse time is too quick.
I have also raised the possibility of using lithium as fuel. But skeptics such as Jimmy T and others like to point out the fact that p-B11 is the so – called ” Holy Grail ” of fusion. There’s no doubt that the p-B11 reaction has it’s advantages, which is why Lerner chose it above all other aneutronic reactions. However, I was thinking more along the lines of lithium as a partial supplement rather than a complete substitute for boron. If fuels like He 3 or Li 6 can be made to ignite at lower temperature and pressure, it may help to preheat the plasma and give p-B11 a little extra more energy boost than the electric power supply alone can provide.
The pulse duration in picoseconds may indeed present a problem, however. These multi – step reactions helping to kick – off the next reaction all have to occur within only 6 picoseconds or less.
But then again, if a fuel that first ignites at lower temperature helps to further preheat the fuel prior to boron ignition……then might that possibly extend the available nuclear reaction time longer than only 6 picoseconds ?
If so, it might open a window of whole new possibilities for many more sucessive reaction events to take place.