OK-650 reactor

{{Short description|Nuclear fission reactor}}

File:Sierra III class SSN.svg Project 945 submarine]]

The OK-650 reactor is the nuclear fission reactor used for powering the Soviet Navy's

Project 685 Плавник/Plavnik (Mike),

Project 971 Щука-Б/Shchuka-B (Akula),{{cite web|title=AKULA! The Soviet Shark|url=http://www.subsim.com/ssr/akula2.html|publisher=www.subsim.com|accessdate=9 December 2012}} 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.

File:Project 955.jpg Project 955 submarine]]

This pressurized water reactor (PWR) uses 20-45% enriched uranium-235{{cite web|title=Russia hands over a nuclear submarine to India|date=6 March 2012 |url=http://fissilematerials.org/blog/2012/03/russia_hands_over_a_nucle.html|publisher=fissilematerials.org|accessdate=9 December 2012}} fuel to produce 190 MW of thermal 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.{{cite web|title=2.3 Development of naval reactors|url=http://www.bellona.org/reports/The_Russian_Northern_Fleet_report_chapters/1175895305.68|publisher=www.bellona.org|accessdate=9 December 2012|url-status=dead|archiveurl=https://web.archive.org/web/20101229223802/http://www.bellona.org/reports/The_Russian_Northern_Fleet_report_chapters/1175895305.68|archivedate=29 December 2010}} The reactor is now also used to power the new Project 955 Borei submarines. It was developed by OKBM Afrikantov.