posted on Dec, 25 2012 @ 08:40 PM
Consider the problem this way:
A hydrogen atom has a single proton in its nucleus; helium has two protons and two neutrons. Building helium from hydrogen then requires three
capture events and a couple of beta emission to turn two of the protons to neutrons. Messy and improbable, as protons repell each other violently.
Easier to create a helium from two deuteriums; everything is there, only one capture event, and you get your energy. If you use tritium, though, you
get the helium plus a free neutron, which can be captured to create another deuterium easily (no repelling force), thus making a start on the next
Unfortunately, like hydrogen, its isotopes, deuterium and tritium are gases, making them not dense enough for easy fusion. They can be condensed into
liquids (this is what Ivy/Mike did), but the refrigeration equipment is expensive & power hungry. There is another way, though. Lithium6, with 3
neutrons and 3 protons can be chemically bound to deuterium to make a form of lithium hydride. When the Li6 captures a neutron, it fissions to make
helium and tritium, so now you have the deuterium (from the hydride) and the tritium, and bang. This is what was expected of Castle/Bravo, but...
Lithium comes naturally as Li7; Li6 is only .08% (8 parts per 10,000). Like U235 Lithium has to be enriched in order to increase the amount of Li6
available. It is as expensive to do that as it is to enrich uranium. So the Lithium in Bravo was only 40% Li6. The Li7 was expected to be inert.
But it wasn't. Physicists had overlooked that with neutron capture, Li7 would fission into helium, tritium and a neutron. It was as reactive as the
Li6, a little more so in fact. Thus Castle/Bravo was 150% higher in energy output than expected; instead of 6 MT, it output 15 MT.
As to the argument that it's not "pure" hydrogen fusion, the response is, "who cares?" The energy released is far higher than any other reaction
occurring on Earth, with a lot less hassle and quite simpler mechanisms than would be required for purity.
So the answer to the OP is, yes, of course, fusion has been ongoing (in bombs) since about 1952. Every atomic power has mastered it to some extent.