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For Korea's ambitious nuclear submarine project, it's full steam ahead

Published: 31 Oct. 2025, 16:01

A concept image of an Australian nuclear attack submarine, which Australia will build with British design and American technical assistance as part of the Aukus project. [SCREEN CAPTURE]

The Korean government is moving forward with plans to develop and build nuclear-powered submarines — a project widely regarded as the most ambitious weapons acquisition effort in the country’s history.

Officials are reviewing the creation of an inter-agency task force under the Office for Government Policy Coordination to oversee the multibillion-dollar program, according to government sources on Friday. The Defense Ministry alone is deemed unlikely to manage such an expansive project.

The task force would include the Ministry of National Defense, the Ministry of Foreign Affairs, the Ministry of Economy and Finance, the Ministry of Trade, Industry and Energy, and the Ministry of Science and ICT, given the scale and technical complexity of the initiative.

The military reportedly plans to build at least four nuclear-powered submarines with a displacement of over 5,000 tons by the mid-2030s.

The program presents several significant challenges, including the design of large submarines, the development of small modular reactors and revisions to the Korea-U.S. nuclear cooperation agreement to secure enriched uranium fuel. Close coordination among relevant agencies will be essential.

Each nuclear submarine is expected to cost more than 3 trillion won ($2.1 billion) to build. With plans to procure between four and six vessels, total construction costs alone could range from 12 trillion to 18 trillion won. Including development costs, the full budget is projected to exceed 20 trillion won, surpassing the 16.5 trillion won for the KF-21 fighter jet program.

The U.S. Navy's Los Angeles-class nuclear-powered submarine USS Alexandria is seen arriving at the Busan Naval Operations Base in Busan on Feb. 10. Commissioned in 1991, the Alexandria, measuring 110 meters long and 10 meters wide, entered Busan to load supplies and provide crew rest, marking the submarine's first port call in Korea. [NEWS1]

Compared to conventional diesel-electric submarines, nuclear-powered submarines offer significantly superior operational capabilities. While diesel submarines can remain submerged for only a few weeks at most, nuclear-powered submarines can operate underwater for several months thanks to onboard reactors. They are also roughly three times faster, allowing for greater evasive maneuverability if detected.

Only six countries currently operate nuclear-powered submarines: the United States, Russia, China, the United Kingdom, France and India.

Australia is also aiming to join the club with U.S. technological support by around 2030. If Korea succeeds in its plan, it will become the eighth country in the world to possess nuclear-powered submarines.

Discussions on acquiring nuclear submarines in Korea date back to the first North Korean nuclear crisis during the Kim Young-sam administration. The Roh Moo-hyun administration in 2003 attempted a secret program to build 4,000-ton submarines, but the plan was scrapped after it was exposed by local media. A similar push during the Moon Jae-in administration also failed due to U.S. opposition.

That dynamic shifted following the Korea-U.S. summit held in Gyeongju on Wednesday, where President Lee Jae Myung reportedly requested U.S. support for nuclear fuel supply, and U.S. President Donald Trump agreed — raising the possibility that Korea’s decades-long ambition to develop nuclear submarines could finally be realized.

This article was originally written in Korean and translated by a bilingual reporter with the help of generative AI tools. It was then edited by a native English-speaking editor. All AI-assisted translations are reviewed and refined by our newsroom.
BY JEONG JAE-HONG [[email protected]]