Read more at: http://phys.org/news/2012-11-scientists-power-space-video.html#jCp
A team of researchers, including engineers from Los Alamos National Laboratory, has demonstrated a new concept for a reliable nuclear reactor that could be used on space flights.
The research team recently demonstrated the first use of a heat pipe to cool a small nuclear reactor and power a Stirling engine at the Nevada National Security Site's Device Assembly Facility near Las Vegas. The Demonstration Using Flattop Fissions (DUFF) experiment produced 24 watts of electricity. A team of engineers from Los Alamos, the NASA Glenn Research Center and National Security Technologies LLC (NSTec) conducted the experiment.
Heat pipe technology was invented at Los Alamos in 1963. A heat pipe is a sealed tube with an internal fluid that can efficiently transfer heat produced by a reactor with no moving parts. A Stirling engine is a relatively simple closed-loop engine that converts heat energy into electrical power using a pressurized gas to move a piston. Using the two devices in tandem allowed for creation of a simple, reliable electric power supply that can be adapted for space applications.