[Retric]

Except not all fusion research is particularly useful for building a fusion power plant. I mean if we where really desperate we could dig a large hole fill it with water, set a H-Bomb off under it and then extract energy from that water. However, while that works the ROI is rather limited compared to say just extracting geothermal energy in the first place.

PS: That could actually work, at 5% thermal efficiency a Castle Bravo device ~= 63,000TJ = 17500000000.014kwh *.05 = ~1GW for 1 month.

[uvdiv]

It couldn't work on that scale, because it's not practical to contain that big of an explosion. This is your Castle Bravo crater; it's more than a mile wide.

http://goo.gl/maps/KEfZ

Moreover, about 2/3rd of the energy in that device were from fission (not fusion), so for any possible claimed advantage of fusion over fission, it's not here. The lowest fission-fraction test to date was Tsar Bomba, at 3% yield from fission. That was also the largest explosion to date (50 megatons!), which makes it even less feasible.

I think this is a fundamental tradeoff: you can't make a mostly-fusion weapon unless it is extremely large, as there's some minimum size for a fission explosion that achieves fusion conditions.

http://nuclearweaponarchive.org/Usa/Tests/Castle.html

http://en.wikipedia.org/wiki/Tsar_Bomba#Design

There was research project at Los Alamos about this general idea (Project Pacer), but it didn't go anywhere. According to Richard Garwin, they thought it was hopelessly uneconomical.

http://en.wikipedia.org/wiki/PACER_(fusion)

http://www.aip.org/history/ohilist/4622_3.htmlz