A review of nuclear electric fission space reactor technologies for achieving high-power output and operating with HALEU fuel

• Published in: Progress in nuclear energy (New series) 2023-09, Vol.163, p.104815, Article 104815
• Main Authors: Peakman, Aiden, Lindley, Ben
• Format: Article
• Language: English
• Subjects: Fission surface power; Fuel; HALEU; NEP; Nuclear electric propulsion; Space propulsion
• ISSN: 0149-1970
• DOI: 10.1016/j.pnucene.2023.104815

There is substantial interest in space nuclear reactor systems capable of outputting at much higher powers than previous historic designs, which have been predominantly ≤0.1 MWe. In addition, many previous designs have used Highly Enriched Uranium (HEU), although there is a recent drive to consider only High Assay Low Enriched Uranium (HALEU) for non-proliferation reasons. This requirement in particular motivates a contemporary review. In this paper, we highlight the drivers for high-power outputs (≥1 MWe) and outline the technology options for space propulsion. Previous reviews in this area have either focused on nuclear thermal propulsion (NTP); a particular small subset of nuclear electric power systems; and/or have examined systems at lower powers. This study therefore focuses on higher power nuclear electric systems, which are comprehensively reviewed in the context of important design considerations. While the reactor core technologies (i.e. coolants, fuels, and core materials) are the focus of this paper, it is important to recognise the interplay between the reactor core, heat rejection, and power conversion systems. Therefore, a systematic and cross-cutting review of the underpinning technologies associated with such space reactor systems is performed, along with the technical maturity of underlying technologies. The most promising technologies for high-power HALEU designs are outlined, and important areas for research are also identified.