Hanwha Philly Shipyard in Pennsylvania. (Hanwha Group)
Hanwha Philly Shipyard in Pennsylvania. (Hanwha Group)

South Korea would face multiple legal and diplomatic challenges in pursuing nuclear-powered submarines, including the need for both a dedicated agreement with the US on the military use of nuclear energy and stringent safeguards commitments with the International Atomic Energy Agency, according to a think tank report released Monday.

The report by the Asan Institute for Policy Studies assessed the required steps following forward-looking language included in the joint fact sheet issued after South Korean President Lee Jae Myung and US President Donald Trump's October summit.

The Seoul-based think tank noted that while the document signaled Washington’s positive stance toward Seoul’s pursuit of nuclear-powered submarines, “significant difficulties” remain — including final approval from the US government and Congress, as well as consent from the IAEA.

A key sticking point is the IAEA’s concern over the potential diversion of naval nuclear materials for weapons use. The report said the agency is highly likely to demand “a robust monitoring and inspection regime” before allowing any exemption.

Australia’s experience under the AUKUS security partnership — which has involved four years of ongoing negotiations on specific safeguards arrangements with the IAEA — underscores the complexity, the report noted.

Under the Nuclear Non-Proliferation Treaty, non-nuclear-weapon states are bound by comprehensive safeguard agreements prohibiting the diversion of nuclear materials into weapons. Article 14 of the agreement provides a limited exemption allowing for naval reactor fuel, but only if accompanied by detailed arrangements ensuring compliance with nonproliferation obligations.

“South Korea would also need to negotiate such implementation arrangements with the IAEA, likely mirroring the complicated and lengthy process faced by Australia,” the report said.

The report further highlights hurdles under US domestic law, which strictly separates the “peaceful use” and “military use” of nuclear energy. To procure naval nuclear fuel from the US, Seoul would have to conclude a separate bilateral agreement covering military applications.

This was hinted at during a recent US visit by South Korea's National Security Office Director Wi Sung-lac. Following talks with US Secretary of State and National Security Adviser Marco Rubio and US Energy Secretary Chris Wright, Wi said the two sides “shared the view that a separate agreement is necessary and agreed to pursue it.”

Congressional approval will be decisive for any such agreement, the report stressed. It warned that if US Democrats — typically firmer on nonproliferation issues than Republicans — regain control after next year’s US midterm elections, securing congressional support “may become even more challenging” for Seoul.

The report argued that South Korea must actively frame its nuclear-submarine ambitions as enhancing not only maritime security but also deterrence against North Korean provocations and strategic stability in the Indo-Pacific region — directly benefiting US regional security objectives.

It also recommended that Seoul consider sourcing “high-assay low-enriched uranium” (HALEU) instead of highly enriched uranium exceeding 90-percent enrichment, which is weapons-usable, even if that reduces reactor efficiency.

“Using HALEU could help alleviate US and international concerns regarding proliferation risks,” the report said, adding that Seoul should be prepared to accept “transparent institutional mechanisms,” including possible IAEA snap inspections of nuclear-related facilities.


mkjung@heraldcorp.com