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Experts warn that acquiring nuclear submarines from the U.S. is a 'distant goal'

Published: 30 Oct. 2025, 17:48 Updated: 30 Oct. 2025, 17:53

The USS Alexandria (SSN-757), a Los Angeles-class nuclear-powered U.S. submarine weighing 6,900 tons, arrives in Busan on Feb. 10. [SONG BONG-GEUN]

GYEONGJU, North Gyeongsang — Momentum is building around Korea’s bid to acquire nuclear-powered submarines after U.S. President Donald Trump said on Thursday that the United States had approved the plan.

The announcement came just one day after President Lee Jae Myung publicly requested nuclear fuel supply during a summit with Trump in Gyeongju, North Gyeongsang. Within hours, the Korean presidential office announced that the two leaders had “reached a shared understanding.”

But major legal, diplomatic and technical hurdles remain. Experts note that verbal assurances alone do not equate to an executable plan.

Nuclear fuel supply and related technology transfers are tied to international nonproliferation treaties. Negotiations would also require separate bilateral agreements and legal changes, which have yet to be initiated.

The yet-to-be-unveiled Korea-U. S. joint fact sheet is expected to mention nuclear-powered submarines, according to government sources. They said it will likely emphasize continued discussions rather than explicitly confirm construction approval like Trump claimed.

“Korea must review the legal procedures for acquiring nuclear-powered submarines,” National Security Adviser Wi Sung-lac said during a briefing on Wednesday. “The existing Korea-U.S. nuclear agreement excludes military purposes, so we must make adjustments to complete the process.”

The current agreement — titled “Agreement for Cooperation Concerning Peaceful Uses of Nuclear Energy” — includes Article 13, which prohibits explosive or military applications. This clause sharply limits how Korea can use U.S. nuclear technology.

For that reason, many experts argue that the type of submarine discussed by the two leaders — one designed to track enemy subs — would not be permissible under the current agreement.

President Lee Jae Myung, right, presents U.S. President Donald Trump with the Grand Order of Mugunghwa and a model of the Cheonmachong gold crown at the Gyeongju National Museum in Gyeongju, North Gyeongsang on Oct. 29. [YONHAP]

Park Ro-byug, Korea’s former ambassador to Russia and a former chief negotiator for Korea-U.S. nuclear accords, said the issue falls under a legally gray area.

“While the nuclear-powered submarine under discussion is unrelated to nuclear weapons or explosives and could arguably be an extension of peaceful use, it appears to fall outside the scope of the current agreement,” Park said. “It will likely require a new, separate agreement.”

Observers have pointed to the Australia-United Kingdom-United States (Aukus) pact as a possible model.

Aukus, signed in 2021 under the Biden administration, allows Australia to receive nuclear technology and materials from the United States and Britain to build at least eight nuclear-powered submarines.

China has sharply criticized Aukus, calling the transfer of nuclear materials to a nonnuclear state a “clear violation” of the Nuclear Non-Proliferation Treaty.

Currently, only the five recognized nuclear powers — the United States, Britain, France, Russia and China — and nonsignatory India operate nuclear-powered submarines.

The Korea-U.S. talks could raise regional tensions and possibly accelerate arms ambitions in Japan or Taiwan, analysts warn.

Nonproliferation advocates in Washington may also resist the plan. Some types of nuclear fuel would require congressional approval before they could be exported.

Lee Byong-cheol, a professor at Kyungnam University's Institute for Far Eastern Studies, warned that the fuel type could determine diplomatic risk.

“Using highly enriched uranium carries significant nonproliferation and diplomatic risks,” Lee said. “We need a reactor that uses either low-enriched uranium or high-assay low-enriched uranium. That means Korea must address not only U.S. cooperation but also compliance with International Atomic Energy Agency safeguards.

U.S. President Donald Trump speaks with reporters aboard Air Force One shortly after taking off from Busan on Oct. 30. [AP/YONHAP]

“We must also carefully review export controls, technology transfer approvals, cooperation with the Nuclear Suppliers Group, responses from neighboring countries, including China, and domestic social acceptance.”

Choe Won-gi, a professor at the Korea National Diplomatic Academy, said Trump’s approval carries political weight but should not be mistaken for a final green light.

“It has major symbolic value for Korea’s diplomatic strategy,” Choi said. “But actually building and operating a nuclear-powered submarine would require treaties, legislation, long-term budgets, operational skill and significant military infrastructure. It’s a distant goal.”

Public support for nuclear armament in Korea — though strong — could also complicate the submarine plan. The U.S. Department of Energy still designates Korea as a “sensitive country” for nuclear energy security, which could add restrictions.

“Passing a special law might resolve procedural hurdles,” said Jo Bee-yun, a research fellow at the Sejong Institute. “But we still don’t know if Trump meant approval to build in the United States or how much technology U.S. companies are actually willing to share.

“Korea should emphasize the need for nuclear-powered submarines capable of long-duration submersion to secure a survivable second-strike capability, as well as address the growing regional security threats from China and others, to more effectively persuade the United States and the international community.”

This article was originally written in Korean and translated by a bilingual reporter with the help of generative AI tools. It was then edited by a native English-speaking editor. All AI-assisted translations are reviewed and refined by our newsroom.
BY PARK HYUN-JU [[email protected]]