Tokyo, Oct. 13 (Jiji Press)–The Japanese government is considering including in its revised three key security-related documents plans to study and research the possibility of introducing a nuclear submarine. Discussions have so far been led mainly by some eager politicians, and the purpose of the possible nuclear submarine introduction remains unclear. Aiming to revise the three documents by year-end, the government is expected to kick off full-fledged coordination with the ruling parties soon on the update, but discussions regarding nuclear submarines may be bumpy, pundits say. “I think the public understands the need for discussions” on Japan’s possession of a nuclear submarine, Defense Minister Shinjiro Koizumi said at a press conference Friday. Nuclear submarines, which can travel underwater for longer periods and at higher speeds than conventional submarines, “would allow crew members to engage in their duties while ensuring their safety at higher levels,” Koizumi stressed. However, opinions are divided within the government regarding what a nuclear submarine, if introduced, would be for. “There is no consensus whatsoever,” a government source said. In general, patrolling and striking are the two main missions of submarines. Citing the Chinese navy’s accelerating expansion into distant waters such as the western Pacific in recent years, a senior Japanese Self-Defense Forces official stressed nuclear submarines’ advantage in terms of patrolling. “It is difficult for conventional submarines, which can operate only in waters around Japan, to search for the enemy in waters as far as around Guam,” the official said. Meanwhile, a senior Defense Ministry official highlighted nuclear submarines’ strike capabilities. If equipped with long-range missiles that can be used for counterattacks, they would “usually stay underwater but would emerge and strike the enemy’s command base when the need arises,” the official said. Eagerness from the political side is said to be behind the government’s inclination toward including the study and research of a nuclear submarine in the updated security documents. Koizumi has been keen on introducing a nuclear submarine since he became defense minister in October 2025, apparently having in mind the decisions by Australia and South Korea to do so, according to informed sources. In June, the Japan Innovation Party, the coalition partner of the ruling Liberal Democratic Party, urged the government to “swiftly introduce” a nuclear submarine. “There’s no problem with study and research,” an LDP heavyweight said. However, coordination on the wording concerning study and research in the security documents is likely to be a tough task. Nuclear submarines have disadvantages such as huge construction costs, which are said to reach at least 1 trillion yen per unit, and the need for specialized knowledge of nuclear reactors. Furthermore, there are legal issues, including nuclear submarines’ compatibility with Japan’s atomic energy basic law, which limits the use of nuclear power to peaceful purposes. “There are problems in all aspects,” a veteran LDP lawmaker said. “There’s no point in studying and researching.” END [Copyright The Jiji Press, Ltd.]
