South Korea has announced its plan to build a nuclear-powered submarine to counter the growing threats from its rivals in the region. The plan was announced by the Ministry of National Defense of the Republic of Korea.

Korea had reached a shared understanding with the United States to cooperate on the construction of conventionally armed, nuclear-powered submarines in November 2025. The two countries had agreed to closely consult on avenues to source fuel for the nuclear-powered submarines.

Therefore, Korea has established a policy foundation to pursue the acquisition of nuclear-powered submarines as a national-level project. It should be kept in mind that the nuclear-powered submarines that Seoul intends to build would not carry nuclear weapons.

South Korea’s nuclear-powered submarine program

“The objective of this project is to enhance operational endurance and survivability, thereby strengthening maritime security capabilities and achieving a higher level of deterrence, particularly in relation to the Democratic People’s Republic of Korea (DPRK),” reads a Ministry of National Defense document published on Tuesday.

In the document, Seoul makes it clear that there is no intention on its side to “possess or use” nuclear weapons. It has also agreed to ensure transparency and cooperate with the International Atomic Energy Agency (IAEA) in accordance with relevant international agreements.

The nuclear-powered submarine program will be called the ‘Chang Bogo N Project,’ which pays tribute to the country’s first submarine, the ROKS Chang Bogo.

Seoul believes that the nuclear-powered submarines will play a huge role in deterring the nuclear and missile threats from North Korea. It should be noted that North Korea had disclosed in 2025 that it is building a nuclear-powered strategic guided missile submarine.

Combined with its nuclear-capable land-based missiles, the nuclear-powered submarines could further enhance North Korea’s military prowess. Therefore, the US-South Korea alliance needs a similar platform to curb threats in the maritime domain, as Seoul claims.

Benefits of nuclear vessels

A nuclear-powered submarine comes with distinct advantages over conventional vessels. The nuclear propulsion allows them to conduct extended underwater surveillance missions without the exposure caused by surfacing.

Moreover, they can operate more stealthily and respond more quickly when a threat is detected. They serve as an important pillar of the underwater kill chain, responding to threats before they materialize.

Seoul says that its nuclear-powered vessels “will be equipped with precision strike capabilities capable of responding to DPRK (North Korea) nuclear threats.”

The document states that the submarine’s nuclear reactor will use low-enriched uranium, and that the system will be developed to allow long-cycle operation with minimal fuel replacement. To ensure stability in acquisition and maintenance, Seoul will build the vessels entirely within the country.

The plan is to launch the first vessel under the project in the mid-2030s, with operational deployment planned from the late 2030s onward. South Korea has a history of developing submarines, and it is currently bidding to supply KSS-III-class diesel-electric submarines to Canada.