Fission power from nuclear reactors could provide abundant energy anywhere that humans or our robotic science probes might go. Fission, the splitting of the nucleus of an atom (commonly uranium), releases a great amount of heat energy: 1 pound of uranium fuel can produce as much energy as about 3 million pounds of burnable coal. With such a high energy density, fission power systems (FPSs) present an ideal solution for space missions that require large amounts of power, especially where sunlight is limited or not available.
Because of the great potential of fission power for space exploration, NASA Space Technology’s Game Changing Development (GCD) program is funding two projects in the Nuclear Systems area, both led by NASA Glenn Research Center, to demonstrate space fission power systems technology.
Building on prior work by a joint NASA and Department of Energy team, the Nuclear Systems Technology Demonstration Unit Project’s goal is to assemble and test laboratory hardware that functions like a space FPS. The technology demonstration unit (TDU) has three major subsystems: an electrically heated reactor simulator, a power conversion unit (PCU), and a heat rejection loop. Working together, these elements comprise a laboratory version of a space FPS that can be fully exercised in a simulated space environment. The TDU will demonstrate subsystem-level technology readiness for fission space power systems in a relevant environment. While the TDU is modeled on a 40 kilowatt configuration for Mars surface power, the demonstration establishes subsystem level readiness of space fission power broadly across the range of NASA’s future needs.
For NASA’s science missions in the 1-10 kilowatt regime as well as for lower power elements of human exploration missions, the Nuclear Systems Kilopower project applies the TDU lessons learned to small fission systems technology. For these power levels, the reactor core and heat transfer to the power conversion system differs from the Mars surface-class fission power configuration. A NASA/Department of Energy nuclear demonstration in 2012 at the Nevada National Security Site provided proof-of-principle benchtop validation that the technology needed for small fission power systems works, and can be demonstrated in existing Department of Energy ground facilities. The Kilopower Project will advance this small fission power system technology in three years to readiness for near-term space missions by conducting a full-scale nuclear demonstration in a relevant environment.