Chae Byung-gun
The author is the acting editor-in-chief at the JoongAng Ilbo.
The Korean government's success in securing a U.S. pledge to support the acquisition of nuclear-powered submarines is being hailed as a diplomatic triumph, but the celebration is premature. Korea has only taken its first step toward becoming a "nuclear submarine nation."
The process of acquiring nuclear submarines can be divided into two parts. The first is the "shell," or the hull and reactor. Korea, a major shipbuilding power, already builds its own conventional submarines but has yet to develop a fully functional reactor for submarine use. Unlike reactors that are fixed to the ground, submarine reactors must operate while constantly moving between bases, making them far more difficult to design and maintain. Still, experts say construction is not impossible, given the nation's decadeslong investment in nuclear power infrastructure and research.

Government and industry circles have turned their attention to small modular reactors (SMRs), which share technical similarities with submarine reactors. The power output needed for a Korean nuclear submarine - about 70 to 100 megawatts - coincidentally matches the capacity of the SMRs that the government is currently developing.
Yet technology may be less of a hurdle than politics. "It's unclear whether the U.S. government will allow Korea to take full charge of the project," said Yu Ji-hoon, a research fellow at the Korea Institute for Defense Analyses (KIDA). "Washington could impose conditions that ensure its control over [...] design or assembly." Both the U.S. executive branch and Congress have long imposed strict restrictions on the export of strategic or advanced weaponry, and nuclear submarines are no exception. Domestic construction could also mean higher costs. Kim Dong-yub, a professor at the University of North Korean Studies, notes that "the United States may appear to grant Korea's request but could, behind the scenes, demand something in return, such as additional investments in U.S. shipyards or higher defense cost-sharing."

The second obstacle is fuel. A nuclear submarine cannot operate without enriched uranium. This issue is even more sensitive than the reactor itself. The revised 2015 Korea-U.S. nuclear cooperation agreement - effective through 2035 - allows Korea to enrich uranium up to 20 percent with U.S. consultation but bans enrichment above that level. Seoul is reportedly considering importing uranium enriched to below 20 percent from the United States, but this requires addressing Article 13 of the agreement, which stipulates that nuclear materials "shall not be used for any military purpose." To move forward, Korea must either negotiate a revision or propose a way in which fuel for naval propulsion does not qualify as military use.
Even if the U.S. administration agrees, the plan would still need approval from Congress, where amending nuclear agreements has historically faced strong scrutiny. Each step may also bring new financial burdens. Experts believe the fuel that Korea aims to acquire will likely be the high-assay low-enriched uranium used in SMRs. "For Korea to ensure a stable supply, it may need to make large-scale investments to U.S. companies such as Centrus Energy to expand production capacity," said Ham Hyung-pil, the director of KIDA's Center for Security and Strategy.
Even if Korea completes a prototype reactor, imports fuel and successfully demonstrates the technology, its fleet could be rendered useless if Washington later decides to halt fuel exports or restrict enrichment. While Korea could, in theory, pursue its own uranium enrichment program or import nuclear fuel from Russia, such options are unrealistic both politically and strategically.
The entire program - from reactor production and hull construction to refueling and long-term operation - depends on maintaining a stable relationship with Washington. A former military officer who once tried to persu...

Ver todos los episodios