U.S. to Support South Korea’s Nuclear Submarine Program

The United States is now moving forward with a plan that would enable South Korea to build nuclear-powered attack submarines. This decision is described as a fundamental change to long standing U.S. policy on the spread of naval nuclear propulsion and a high-stakes political and technical undertaking for its allies.

The announcement emerged in public form in late October, when President Donald Trump said during the Asia-Pacific Economic Cooperation (APEC) meetings in Gyeongju that he had authorized South Korea to build a “nuclear-powered submarine”. He also repeated the same declaration on social media. U.S. and South Korean officials have subsequently published a fact sheet and held talks in mid-November. According to both governments, talks have initiated progress on the submarine issue between the two countries.

What the governments released so far is thin on technical detail but heavy on political consequence. A White House fact sheet said the United States had “given approval” for the Republic of Korea (ROK) to proceed with nuclear-propulsion submarines. It also described a large Korean investment in U.S. shipbuilding and other industrial sectors as part of a package that would accompany the security cooperation. South Korean President Lee Jae-myung told reporters the two countries had agreed to “move forward” on building nuclear-powered submarines.

South Korea’s request, and Washington’s response, focus on fuel and legal authorities as much as hull design. During talks on Oct. 29, President Lee asked President Trump to help Seoul in obtaining the nuclear fuel and fuel-cycle capabilities, like enrichment and spent-fuel reprocessing. He emphasized that this would be needed to operate compact naval reactors for conventionally armed SSNs (nuclear-powered attack submarines). Reuters has reported that Lee explicitly sought U.S. support for progress on enrichment and reprocessing, while Seoul emphasized that the submarines would not be nuclear-armed.

Allies and analysts said the move marks a precedent. Nuclear-propulsion technology for submarines has been tightly guarded; Washington has previously authorized transfers only to a small group of partners, and only under strict safeguards. Policy experts warned that sharing propulsion technology or fuel-cycle capabilities with Seoul would require changes to existing civilian nuclear-cooperation agreements and would reshape long-standing U.S. nonproliferation practice.

Practical and political hurdles for this deal are substantial. Building and operating SSNs demands specialized reactor design, a nuclear-safety culture, trained crews, radiological infrastructure and detailed industrial experience. U.S. officials and independent analysts have said that even with political approval, the program would likely require years of work and intense governance arrangements, and costs per boat could run into the billions.

The decision has immediate diplomatic reverberations across Northeast Asia. Beijing has warned that such a partnership risks “touching on the global non-proliferation regime and the stability of the Korean Peninsula,” according to the Chinese ambassador in Seoul, and analysts warned it could complicate Sino-U.S. relations and prompt defensive responses, including expanded Chinese submarine activity in nearby waters. Pyongyang has routinely denounced U.S.-ROK military cooperation and is expected to use the announcement for propaganda and justification for its own naval programs.

The announcement has already reshaped debate in capitals across the region: supporters call it a necessary modernization to deter growing threats; critics warn it risks an arms-race dynamic and erodes long-standing non-proliferation norms. The coming months of diplomacy and technical negotiation will determine whether the decision becomes a concrete program of capability development or a diplomatic milestone whose practical realization proves more complicated than its initial fanfare.

Web Resources on U.S. and South Korea’s Nuclear Submarine Deal

1. U.S. will allow South Korea to build nuclear-powered submarine
2. South Korea’s Lee asks Trump for fuel used by nuclear-powered submarines
3. US, South Korea to ‘move forward’ on building nuclear-powered submarines
4. Game Changer: Trump Approves South Korea’s Nuclear Submarine Ambition
5. AcademicBlock.com: Top 10 Strongest Navies in the World