OK-650 reactor

The OK-650 reactor is the nuclear fission reactor used for the singular purpose of powering the Soviet Navy's Project 685 Плавник/Plavnik (Mike), Project 971 Щука-Б/Shchuka-B (Akula), and Project 945 Барракуда/Barrakuda, Кондор/Kondor, and Марс/Mars (Sierra) submarines, and in pairs to power the Project 941 Акула/Akula (Typhoon) and Project 949 Гранит/Granit and Антей/Antei (Oscar) third generation submarines.

This pressurized water reactor (PWR) uses 20-45% enriched uranium-235 fuel to produce 190 MW of power. Developed during the 1970s, these reactors were designed with the aim of minimizing accidents and malfunctions. Monitoring subsystems, designed for rapid detection of leaks, were included, along with newer-generation emergency cooling systems for the main reactor core. The reactor is now also used to power the new Project 955 Borei submarines.