Korea's nuclear-powered submarines could take on broader Indo-Pacific role
North Korea's submarine Hero Kim Kun Ok, which Pyongyang claims is capable of launching tactical nuclear weapons, is unveiled during a ceremony in North Korea, Sept. 6, 2023. Yonhap
Experts point to Pyongyang deterrence, sea lane protection, alliance cooperation
As South Korea moves ahead with plans to acquire nuclear-powered submarines, the debate is shifting from whether the country needs them to where and how they should operate.
South Korean military experts say Seoul has a strong case for acquiring nuclear-powered submarines to counter North Korea, even if their initial mission is focused on waters around the Korean Peninsula. Over time, however, they expect the submarines’ role to expand into the broader Indo-Pacific, from protecting vital sea lanes to supporting undersea cooperation with the United States.
The assessments come after a U.S. Navy official said last week that South Korea needs a clear security rationale and concept of operations for the costly assets, reviving questions over whether Seoul needs nuclear-powered submarines if they are to operate mainly close to home.
Moon Keun-sik, a submarine expert who formerly headed the nuclear-powered submarine project team at Navy Headquarters and is now a professor at the Graduate School of Public Policy at Hanyang University in Seoul, said that argument overlooks the ability of nuclear-powered submarines to remain submerged and undetected for extended periods.
“Diesel-powered submarines have to come close to the surface several times a day to recharge their batteries, exposing themselves in the process,” Moon told The Korea Times. “A nuclear-powered submarine can remain submerged for a long time and surface only when necessary.”
That capability would be critical for continuously tracking North Korean submarines capable of carrying nuclear weapons, he said. Pyongyang is also pursuing a nuclear-powered submarine, which would be difficult for a conventional diesel-electric submarine to keep pace with.
Moon, however, said Seoul should not confine its future nuclear-powered submarine fleet to the peninsula.
South Korea relies heavily on sea lanes that carry energy supplies from the Middle East through the Indian Ocean and the Strait of Malacca. In a contingency around the Strait of Hormuz or other critical waterways, nuclear-powered submarines could be rapidly dispatched for long-range missions, he said.
President Lee Jae Myung discusses a plan for developing nuclear-powered submarines during the inaugural Future Defense Strategy Meeting in Jinhae, Changwon, South Gyeongsang Province, May 26. Korea Times photo by Wang Tae-seok
Moon has also argued that the submarines could protect South Korea’s sea lines of communication and enable more reciprocal undersea cooperation with the U.S. Navy in the Indo-Pacific, rather than leaving Seoul dependent on U.S. nuclear-powered submarines.
Cheng Seong-chang, vice president of the Sejong Institute, similarly said the primary mission should be deterring North Korea’s nuclear-powered submarines, while the strategic implications would extend further.
“The primary objective is, of course, to counter North Korean nuclear-powered submarines,” Cheong said. “But secondarily, they could help maintain the balance of power in Northeast Asia and take the South Korea-U.S. alliance to another level.”
He said a South Korean nuclear-powered submarine fleet would inevitably complicate China’s strategic calculations and could ultimately support U.S. strategy in the Indo-Pacific.
The debate follows remarks last week by a U.S. Navy official who said Seoul must identify a “valid reason” for acquiring nuclear-powered submarines and warned against pursuing them simply for national prestige given their enormous cost. Adm. Daryl Caudle, the U.S. chief of naval operations, previously suggested that South Korea might not need such submarines if it had no plans to operate them beyond nearby waters.
Seoul, meanwhile, is moving ahead with the program.
President Lee Jae Myung last month described the project as one that could symbolize the future of a stronger, more constructive South Korea-U.S. alliance and called for faster progress.
The Ministry of National Defense aims to launch the first submarine in the mid-2030s and put it into service in the late 2030s. It says the vessel’s prolonged underwater endurance and high mobility would make it a key asset against North Korea’s submarine-based nuclear and missile threats.
The government has also allocated 100 billion won ($74.4 million) in next year’s defense budget for initial design and research work and has formally notified the International Atomic Energy Agency of its intention to begin consultations related to the program.
Defense minister nominee Kang Shin-chul has described nuclear-powered submarines as providing a “persistent and stealthy deterrent” against North Korea, while also pointing to their potential role in securing sea lanes and their broader impact on the defense, nuclear energy and shipbuilding industries.
The U.S. Congress is also taking a closer look. The Senate Armed Services Committee has called for an assessment of how South Korea’s nuclear-powered submarine program could affect Indo-Pacific security, proliferation risks, costs and the scope of future bilateral cooperation.