According to Wikipedia: "The 4,500/5,500-ton Type 091 (US Department of Defense designation Han-class, Chinese designation 09-I) was the first nuclear-powered submarine (SSN) class deployed by the China's People's Liberation Army Navy. The first Chief Designer of the submarine was an engineer and scientist of nuclear propulsion engineering Mr. Peng Shilu then in 1983 succeeded by Mr. Huang Xuhua. The first submarine in the class was commissioned in 1974 and the fifth and final boat of the class was commissioned in 1990. The Han-Class is the among the first generation of nuclear-powered submarines in the People's Liberation Army Navy."