This was the first Soviet nuclear submarine. Originally designed with a single extremely large torpedo tube for the nuclear T-15 weapon, it was redesigned as an attack submarine. It had the two VM-A reactors and was capable of speeds in excess of 30 knots. Also shown is the Project 645 variant, which had two liquid metal reactors (lead-bismuth) to test the feasibility of test reactors, which could operate at both higher temperatures and lower pressures, generating superheated steam.