Improvements and safety analysis on the technologies of current nuclear power systems for remote places and outer space

Abstract

A new age of space nuclear reactors is at hand. Current developments in both energy generation and thermal energy conversion are fueling new reactor designs. Some projects have already been tested on Earth, and the results were considered optimistic. This work discusses the latest designs in space nuclear reactors and their surrounding technologies in order to propose new improvements, further expanding their variety and possibilities. The objective was to identify the most promising new designs and propose updates to them that would increase safety and performance. Furthermore, this work was carried out within the scope of a safety analysis of the projects, calculating and simulating in the SAPHIRE software package the consequences of changing components and comparing the reliability of each possible configuration. At the end, the study discusses which designs are considered most suitable for new space projects involving nuclear power systems. The work also takes into account technologies that were not available during the development of older designs. It is possible to conclude that the subject is highly complex and that several different aspects should be considered when choosing the ideal space nuclear reactor for each mission, program, and country. Four different concept designs were proposed by combining components from known designs: two were obtained by changing the converter systems of NASA’s KRUSTY design, and two were space reactor concepts based on molten salt reactors. All of them used KRUSTY systems as a basis, as these are the best documented designs within the scope of safety analysis. The NASA-based proposals were less efficient, achieving outputs from 0.6 to 0.8 kWe, but were even more reliable, with one case showing twice the reliability of the original design. The molten salt reactor proposals were more open-ended, and their estimates should be interpreted with caution. The power output for the two molten salt concepts ranged from 60 to 75 kWe, and their reliability was comparable to that of the KRUSTY design. Although this work represents only an initial theoretical approach, it successfully proposed new designs and highlighted their safety aspects in comparison with existing ones. The data are likely to be refined in future studies, but the results are promising.