At the close of the Second World War, the Soviet Union found itself in a precarious position when it came to the production of modern submarines in general, and nuclear submarines in particular. The Soviet Navy knew it was behind the United States and Great Britain in submarine design, as the Soviet Union built few submarines during the war and every submarine was a pre-war design, but evaluation of captured German Type XXI and Type XXIII U-boats would show just how far behind the power curve the Soviet Navy truly was.
Delayed by the state priority to develop nuclear weapons, the Soviet Navy followed the U.S. and Great Britain in attempting to achieve higher submerged speed and endurance through the use of closed-cycle engine propulsion systems. Nuclear submarine design and production wasn’t a Soviet Navy priority until Stalin made it a priority in September 1952.
If the Soviet Union was slow to start nuclear submarine design and production, it made up for it with a vengeance. Within four decades it produced 30 different classes of combat submarines, not counting three major conversions or any of the largely experimental submarines newly built or converted. All told from 1958–95, 245 nuclear submarines were built and commissioned into the Soviet/Russian Federation Navy as combatants.