Can Focus Fusion be used to make a fusion bomb?

Q:

Can focus fusion could be used to make a bomb?  Electrical power for less than a tenth of current cost sound great. But if it allows the Timothy McVeighs, Osama bin Ladens and Gerry Adams of the world to build city-leveling bombs then I have some pretty severe reservations. [question from A. Becker]

The safety of the focus fusion derives in part from the extremely tiny amount of fuel that is burned in each shot. The speck that is raised to several billion degrees is only a few microns to tens of microns across. So even when all the fuel, or nearly all, is burned, the yield will be only about 20 or 30 kilojoules—the energy a 100 W light bulb burns in a few minutes. It is only by pulsing the device a thousand times a second do you get 20 MW out of it.

Unfortunately, the technology to use fusion for warfare was perfected fifty years ago--the hydrogen bomb. A typical H-bomb releases several trillion times as much energy as a single focus fusion pulse, or as much energy as a focus fusion reactor will produce in a century.  If you look at how nuclear bombs work, you will see that the focus fusion reactor can’t possibly be used to make a bomb.  Basically, a fusion bomb is fusible material wrapped up in a fission bomb, wrapped up in high explosives.  You blow up the explosives to trigger the fission reaction - e.g., to set off the fission bomb.  The fission explosion in turn compresses the fusion materials encased within it and triggers the fusion reaction. 

As you can see, getting a fusion reaction to occur is so difficult that in making bombs it requires the explosion of a fission bomb.  This is great news, because, if you want to detonate a fusion bomb, you need to have the ability to make a fission bomb.  So, if we promote focus fusion and get people to adopt it, we SKIP the fission step, and countries with fusion don’t have the materials or fission reactors necessary to develop fission bombs.  And if they can’t develop fission bombs, they certainly can’t develop fusion bombs.

What we are attempting with the focus fusion reactor is to get a fusion reactions to occur in a microscopic area with repeated pulsing to generate sustained power.  The issue isn’t “will it blow up” but “can it even be achieved or sustained?”

Aside from high voltage warnings that are par for the course for any typical electricity generating power plant, a focus fusion reactor can’t be used as a weapon unless you pick it up and drop it on someone’s head.