South Korea’s Nuclear Submarine Ambitions: What You Need to Know About the SSN Development Plan

[Green Economy News = Choi Seong, Reporter]

On May 20, documents the Ministry of National Defense submitted to Rep. Kang Dae-sik, a member of the National Defense Committee, show the Navy recently filed a formal requirements request for nuclear-powered submarines with the Joint Chiefs of Staff.

The Republic of Korea Navy’s long-standing ambition—the acquisition of a Korean-designed nuclear-powered attack submarine (SSN), a move that could reshape maritime defense—has taken its first official step. Military authorities have opened formal administrative procedures to pursue construction, and the government plans to publish a detailed development roadmap later this month.

The Defense Acquisition Program Administration and the Joint Chiefs of Staff said the Navy formally submitted a requirements package calling for the construction of at least four Korean-style nuclear-powered submarines with a displacement of 5,000 metric tons or more. The JCS is expected to make a requirements decision this month, and the government plans to unveil a Basic Plan for Nuclear Submarine Development at month’s end. The plan will outline a construction timeline, estimated budget, and a comprehensive nonproliferation stance designed to address international concerns.

The program is intended to establish an independent, all-domain naval nuclear deterrent with effectively unlimited submerged endurance in response to North Korea’s increasingly covert SLBM and nuclear-submarine developments. Defense Minister Ahn Gyu-baek said officials are also reviewing separate legislation—a Special Law on Nuclear Submarines—to set up a military nuclear governance framework.

The Navy’s formal request brings nuclear-submarine acquisition back into the legal and institutional fold for the first time in more than 20 years, since Project 362 was quietly pursued and later shelved in 2003. Seoul’s military has already demonstrated world-class diesel-submarine construction and underwater SLBM-launch capability with the Dosan Ahn Chang-ho class (about 3,000 metric tons), and rapid advances in domestic small modular reactor (SMR) technology have created a technical foundation for a submarine nuclear propulsion system. Once deployed, an SSN can operate submerged at high speed for months before refueling is required.

Significant diplomatic and economic hurdles remain, however, including securing nuclear fuel, revising the ROK‑U.S. nuclear cooperation agreement, and potential U.S. pressure to have some or all hulls built at American shipyards.

\”Many practical issues still need careful review,\” said Choi Ki-il, chair of the Military Studies Department at Sangji University. \”Given that the KF-21 program took roughly 25 years, this effort will likely take at least 10 to 20 years. Still, taking the first official step carries significant symbolic weight.\”