Type 091-class (Han)

The Type 091, known by the NATO reporting name Han class, was the first nuclear-powered attack submarine produced by China. The program, designated Project 09, received authorization in 1958. Development proceeded independently after the Soviet Union declined to provide technical assistance in 1959. The project experienced delays due to the Great Leap Forward and the prioritization of nuclear weapons research, resulting in a temporary postponement between 1963 and 1965. Construction of the lead vessel began in 1968, and it entered service in 1974.

The design utilizes a teardrop hull and a loop-based nuclear reactor. The first two units, hulls 401 and 402, were shorter than subsequent vessels and experienced reliability issues regarding their propulsion systems and radiation shielding. Hulls 403, 404, and 405 were built to a modified specification with increased hull length and higher reactor power output. These modifications were intended to improve maintainability and crew habitability. Modernization efforts for the class included the installation of anechoic tiles, updated sensors, and seven-bladed screws. While the vessels were designed for anti-surface roles, technical limitations involving the torpedo ejection system delayed the integration of their primary armament until 1989.

A total of five Type 091 submarines were built at the Bohai Shipyard. Two units have been retired, with the lead boat, hull 401, transferred to the Chinese Navy Museum in Qingdao. Three vessels remain in active service. Operational history is characterized by deployment in local waters and several international encounters. In 1994, a Type 091 was involved in a standoff with a United States carrier battle group in the Yellow Sea. In 2004, a vessel entered Japanese territorial waters near Ishigaki Island, an event China later attributed to technical reasons. A proposed lease of a Type 091 to Pakistan in the early 1990s was not finalized.