Concerns over both carbon emissions and dependency on imported energy have led to renewed interest in renewable fuels, including biofuels and electrofuels. Electrofuels are a class of synthetic fuel generally made by combining hydrogen extracted from water with nitrogen or carbon extracted from atmospheric carbon dioxide. The chemical processes require inputs of electricity and heat and the use of nuclear reactors to provide these was examined by militaries as early as the 1960s. This paper describes work undertaken in a UCL undergraduate project to size a synthetic fuel plant for use on the marine environment, based around a representative containerised 5MWe micro nuclear reactor with a Brayton cycle power conversion system. The study considered direct carbon capture and also carbon provision via densified biofuel material, with the aim being to quantify the size of plant needed per modular reactor. The paper concludes with discussion of ship impact and an outline of a possible synthetic fuel generating RFA.