A new reactor concept that combines Stirling engine with modern heat pipe cooling system might provide power to upcoming space missions. The invention was created by a group of researchers from NASA and Los Alamos National Laboratory.
The developers proudly show their simple, light and flexible design, which is easy to control. It is particularly suitable to replace the existing Pu-238 systems and help saving the limited stocks of the radioisotope.
The new reactor would have six separate sections: uranium core, core reflector, a control rod, radiation shielding and eight heat pipes, which are connected to eight Stirling engines. The unit will adjust its reactivity and power output following the principles of nuclear physics, which will make it much safer than existing reactors.
Future scaling-up of the designed would be particularly easy considering that it has an intended capacity of 500 We. This would also make it suitable for using for space propulsion as well as on the surface. In addition, it would be very easy to assemble, which would make the licensing process flow smoother.
The experiment called Demonstration Using Flattop Fission (DUFF) was conducted at the Device Assembly Facility of the Nevada National Security Site. Although the model produced only 24 We, it showed that the basic principles work.
According to David Poston, one of the engineers from Los Alamos, the nuclear characteristics and thermal power levels of DUFF are very similar to these of the space reactor flight concept. The difference is in the input temperature of the Stirling should be higher in order to reach the needed efficiency and power.
David Dixon from Los Alamos adds that the experiment took only 6 months in total with a budget of less than 1 million dollars. No other demonstrations of space reactors have taken place since 1965 in the US, so the designers are hopeful that it would give rise to new space explorations and research.