In an experiment called Demonstration Using Flattop Fissions (DUFF), the scientists used a heat pipe to cool a small nuclear reactor and power a Stirling engine at the Nevada National Security Site’s Device Assembly Facility.
According to the LANL, DUFF "is the first demonstration of a space nuclear reactor system to produce electricity in the United States since 1965", following the invention of heat pipe technology at Los Alamos in 1963. As a result of the experiment, the researchers concluded that DUFF "confirms basic nuclear reactor physics and heat transfer for a simple, reliable space power system". In this specific setup, the technology delivered 24 watts of power. If combined with other modules, the technology could deliver a total of about 1 kilowatt, which would be substantially above the power supply in current space missions, which "generate about the same amount of electricity as one or two household light bulbs," LANL said.
Increased power supply could potentially result in faster data transmissions to Earth, or increase the number of instruments run simultaneously on a spacecraft. Perhaps most importantly, the technology seems to be efficient to develop and deploy. The project was taken from concept to completion in six months for less than a million dollars, LANL said.