Results of the KRUSTY Warm Critical Experiments

TLDR

KRUSTY was a prototype 5‑kW thermal nuclear space reactor using Stirling technology. The paper reports results from KRUSTY warm critical experiments conducted before the final system test. The experiments began with cold criticals, followed by three warm criticals heating the core to 200 °C, 300 °C, and 450 °C. The warm criticals yielded data that validated models, supported regulatory approval, and benchmarked nuclear codes, with predictions matching experiments closely.

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 warm critical experiments, which were completed prior to the final system test. The first set of criticals comprised cold or zero-power criticals; i.e., the core was not heated by fission power. These were followed by three warm criticals, where fission power heated the core to 200°C, 300°C, and 450°C, respectively. These criticals provided the data, confidence, and regulatory framework that were needed to proceed with the KRUSTY nuclear system test. The criticals also provided valuable data for the benchmarking of codes applicable to all nuclear systems. Finally, a comparison of KRUSTY results to pretest predictions is provided, and overall, the models matched the experimental results very closely.