Despite their name, hydrogen bombs are primarily uranium fission bombs[1]. What you've described is just another kind of fissile nuclear reactor, though surely

Despite their name, hydrogen bombs are primarily uranium fission bombs[1]. What you've described is just another kind of fissile nuclear reactor, though surely far less stable and likely far less efficient. The other problem is that materials weaken and swell (as in gain actual volume) when bombarded with radiation. It would be pretty difficult to make a piston that changes shape throughout its life. [1] http://en.wikipedia.org/wiki/Teller%E2%80%93Ulam_design http://en.wikipedia.org/wiki/Teller%E2%80%93Ulam_design