Results of the KRUSTY Nuclear System Test

TLDR

KRUSTY was a prototype 5‑kW thermal nuclear space reactor that used Stirling technology. The study reports results from a 28‑hour KRUSTY test that operated across a range of temperatures and power levels. The test varied thermal power from 1.5 to 5.0 kW with fuel temperatures up to 880 °C, using 80‑W(electric) Stirling converters that delivered about 90 W(electric) at roughly 35 % component efficiency and 25 % overall system efficiency. The reactor performed as expected, showing high tolerance to failure conditions and transients, and demonstrated load‑following capability to meet power conversion demand.

Abstract

The Kilowatt Reactor Using Stirling TechnologY (KRUSTY) was a prototypic nuclear-powered test of a 5-kW(thermal) Kilopower space reactor. This paper presents results from the KRUSTY nuclear system test, which operated the power system at various temperatures and power levels for 28 consecutive hours. The testing showed that the system operated as expected and that the reactor is highly tolerant of possible failure conditions and transients. The key feature demonstrated was the ability of the reactor to load-follow the demand of the power conversion system. The thermal power of the test ranged from 1.5 to 5.0 kW(thermal), with a fuel temperature up to 880°C. Each 80-W(electric)–rated Stirling converter produced ~90 W(electric) at a component efficiency of ~35% and an overall system efficiency of ~25%.