In the tritium recovery processes, the microreactor is used for conversion of the various tritiated streams to water. Microreaction technology offers many advantages for chemical reactions, mainly a high surface-to-volume ratio, a well-defined residence time in the microchannels, and good thermal transport. Also, from an oxidation point of view, the microreactor is proven to be safer by comparison with a conventional oxidation reactor. Another major advantage is that the microreactor can be designed to provide a high recombination efficiency (more than 99.9%), if required. This paper aims to present the issues related to the design, calculation, and manufacturing of a high-efficiency microreactor that can be used to convert the tritiated streams to water.