SpaceNukes receives DARPA award to ground test kilopower reactor

The Space Nuclear Power Corporation (SpaceNukes) was awarded an other transaction agreement from the Defense Advanced Research Projects Agency (DARPA) to design, build, and conduct a nuclear ground test of a kilopower reactor in collaboration with Los Alamos National Laboratory, the company announced.

The project was awarded under DARPA's Fast Capacitance (Fat Cat) program, which seeks to advance reactor operations, including reactors designed for propulsion systems, as a source of reliable power for systems in extreme, remote environments.

Extending KRUSTY: The Kilopower Reactor Using Stirling Technology (KRUSTY) was the prototype reactor in the NASA-led Kilopower Project, which aimed to power both planetary missions and deep space travel.

KRUSTY was a 5-kWt solid fuel uranium-235 reactor that used boron carbide control rods. It was tested in phases in 2017 and 2018 and was found to be highly tolerant of failure conditions and operational transients.

According to the Fat Cat website, small, fast reactors such as KRUSTY operate without a moderator, which, combined with faster neutrons and smaller control rods, makes them highly responsive while reducing size and weight.

The trade-off is that rapid physical transients can be too complex for human operators to manage independently, requiring reliable autonomous controllers.

SpaceNukes project: Through the OTA award, SpaceNukes and LANL will design an autonomous reactor and advance the project through procurement, integration, and a ground demonstration. The project will include active control rod operation, compared with the passively controlled architecture that was used in the 2018 KRUSTY test.

"There is no substitute for demonstrated technology when American national security objectives are at stake," said Andy Phelps, CEO of SpaceNukes. "This award lets us advance the work begun in the KRUSTY program and bring another tested capability forward for the nation."

Integration work will be led by Marc Gibson, chief engineer at SpaceNukes, who was previously the lead engineer for the Kilopower Project when he worked at NASA. SpaceNukes chief technical officer David Poston and chief operational officer Patrick McClure both worked on the Kilopower Project when they worked at LANL, as the chief reactor designer and project lead, respectively.

Fat Cat program: Managed by Tabitha Dodson in DARPA's Defense Sciences Office, the Fat Cat program seeks to address a lack of small, on-demand controllable reactors while developing systems capable of managing the dynamic behavior of small, fast reactors.

According to the program website, Fat Cat aims to demonstrate "autonomous nuclear control on a fully functional fast reactor in conjunction with Los Alamos National Laboratory at the Device Assembly Facility." The program seeks to enable fully autonomous reactor operation by cataloguing nuclear transient conditions; developing nuclear reactor physics models; evolving design tools for nuclear engineers; and progressing to real-world testing, including building hardware, developing software, and designing reactor experiments.

"This award recognizes the maturity and continuity of the team that designed, built, and tested KRUSTY in 2018," said McClure. "We are proud to work alongside Dr. Dodson and Los Alamos National Laboratory to deliver the next demonstrated step in American nuclear power."