Actually, if you google "Quantum Nucleonic Reactor" you'll get plenty of hits. Its primary use seems to be for use in scramjets, but I don't see why you couldn't have it superheat water instead of air. Use a closed loop system, run the steam through a turbine and then a condenser, and you're in business. Draw off 1/60th of the power generated to power the X-ray magentron (I think that's what they're called. Memory fails me here.) and then you have a system that'll spit out electricity until the halfnium-178 decays.

The primary problem with such a system, as far as I can glean off the top of my head, would be radiation shielding. How much would you need? How small can you shrink the entire system? I imagine the X-ray diode acting as a filiment, with a "bulb" of thin halfnium enclosing it. High temperature tubing wrapped around the "bulb" to maximize efficiency... man, I wish I were an engineer. I'd have one of these powering my house, even now.

Large power plants would be easy, since size wouldn't be too much of a concern. You could even store excess heat. Molten salt, anyone?