NASA's Kilopower reactor development and the path to higher power missions

Abstract

The development of NASA's Kilopower fission reactor is taking large strides toward flight development with several successful tests completed during its technology demonstration trials. The Kilopower reactors are designed to provide 1-10 kW of electrical power to a spacecraft or lander, which could be used for additional science instruments, the ability to power electric propulsion systems, or support human exploration on another planet. Power rich nuclear missions have been excluded from NASA mission proposals because of the lack of radioisotope fuel and the absence of a flight qualified fission system. NASA has partnered with the Department of Energy's National Nuclear Security Administration to develop the Kilopower reactor using existing facilities and infrastructure and determine if the reactor design is suitable for flight development. The threeyear Kilopower project started in 2015 with a challenging goal of building and testing a full-scale flight-prototypic nuclear reactor by the end of 2017. Initially, the power system will undergo several non-nuclear tests using an electrical heat source and a depleted uranium core to verify the complete nonnuclear system design prior to any nuclear testing. After successful completion of the depleted uranium test, the system will be shipped to the Nevada National Security Site where it will be fueled with the highly enriched uranium core and retested using the nuclear heat source. At completion of the project, NASA will have a significant sum of experimental data with a flight-prototypic fission power system, greatly reducing the technical and programmatic risks associated with further flight development. To compliment the hardware rich development progress, a review of several higher power mission studies are included to emphasize the impact of having a flight qualified fission reactor. The studies cover several science missions that offer nuclear electric propulsion with the reactor supplying power to the spacecraft's propulsion system and the science instruments, enabling a new class of outer planet missions. A solar versus nuclear trade for Mars surface power is also reviewed to compare the advantages of each system in support of ascent vehicle propellant production and human expeditions. These mission studies offer insight into some of the benefits that fission power has to offer but still lacks a wider audience of influence. For example, mission directorates won't include a fission power system in their solicitations until it's flight qualified, and scientists won't propose new missions that require more power than what's currently proven and available. An attempt to break this chicken and egg effect has been ongoing with the Kilopower project with the goal of advancing the technology to a level that encourages a flight development program and allows scientists to propose new ideas for higher power missions.

Experimental investigations on start‐up performance of static nuclear reactor thermal prototype

“…The Kilopower space reactor concept was proposed by NASA and supported by the Department of Energy (DOE). It aims to generate 1 to 10 kW electrical power that can be used for space exploration, electric propulsion systems, or planet exploration . Kilopower is a small space reactor system that uses heat pipes to deliver thermal energy from a highly enriched uranium (HEU) core to the Stirling engines, to produce electricity.…”

“…It aims to generate 1 to 10 kW electrical power that can be used for space exploration, electric propulsion systems, or planet exploration. 24 Kilopower is a small space reactor system that uses heat pipes to deliver thermal energy from a highly enriched uranium (HEU) core to the Stirling engines, to produce electricity. NUSTER-10 and Kilopower are two novel reactor technologies with similar electrical power outputs, high safety features, and a wide range of applications.…”

Commercial lunar propellant architecture: A collaborative study of lunar propellant production

“…Most significantly, Kilopower has served as a pathfinder, demonstrating that with correct application of technologies, use of existing facilities, and lean management, nuclear fission programs can be both successful and affordable [63]. Kilopower was designed for notional lunar and Mars surface NASA missions with electrical loads such as landers, habitats, mobility and construction equipment, and science experiments, and total power requirements ranging up to only 10kWe [64]. Unfortunately, the Kilopower reactor, or even Kilopowerderived technologies, do not appear to be translatable into the industrial-level use-case of the lunar propellant plant.…”

A Kuiper Belt Object Orbiter Enabled By 10 kW Kilopower Electric Propulsion

“…Recent ground tests demonstrated a 1 kWe 'Kilopower' system is both simple and viable for future space missions. 2,3 Combining a fission power system, leveraged from the kilopower demonstration, with the NEXT ion propulsion system at 7 kWe enables orbiting very deep space objects including Kuiper Belt objects (KBOs). Given the ample power available when NEP is not operating it was found that both higher power active science instruments could be used as well as high data rate communications to return the data quickly (instead of months required by the power limited New Horizons S/C.…”

“…In 2018 the 1 kWe DC variant of the Kilopower design was successfully tested at a DOE site in Nevada. 3 This reactor was coupled to 8 Stirling convertors (2 convertors, 6 simulators) which convert the reactor generated heat to electrical power. It was assumed that 8 Stirling convertors (only 6 were required to operate and provide full power) would be integrated with the reactor and heat would be rejected via a heat pipe radiator.…”