Trump announces US will share nuclear submarine technology with South Korea

US President Donald Trump announced that his administration will share nuclear propulsion technologies with South Korea, allowing the South Korean navy to build at least one nuclear-powered submarine.

Trump made this significant announcement one day after finalizing an agreement that involves South Korea investing $350 billion in the US economy.

The US had previously shared its nuclear propulsion technology only with the United Kingdom and, more recently, with Australia under the 2021 AUKUS agreement. This pact involves the two nations assisting Australia in constructing a new class of nuclear-powered submarines.

The sensitive technology had been kept a closely guarded secret for decades, but China’s growing military power in the region has prompted allies to seek more advanced weaponry from the US.

In a social media post, Trump stated that the submarine would be built at the Hanwha Philly Shipyard, a commercial shipyard acquired by a South Korean company in 2024.

As a purely commercial facility, the shipyard is not currently equipped to handle nuclear material or construct military vessels.

“As President Trump and President Lee make shipbuilding a central element of the US-Korea alliance, Hanwha is ready to support this alliance with its advanced shipbuilding capabilities,” said Alex Wong, Hanwha’s chief of strategy, in a statement.

“Through Hanwha Philly Shipyard and other investments and partnerships, a revitalized American shipbuilding industry will benefit US workers, enhance the prosperity of both the US and Korea, and strengthen our nations’ shared security,” Wong added.

The agreement and the surprising choice of construction site raise questions about the timeline and cost required to upgrade the facility and train a skilled workforce for such a highly specialized and precise task.

Huntington Ingalls Industries, the American company responsible for building nuclear-powered submarines, is facing delays of two to three years in the construction of Virginia-class nuclear submarines and 18 to 24 months for the first vessel of the new Columbia-class.

The delays are attributed to supply chain issues and difficulties in hiring enough workers for the demanding and hazardous tasks of shipbuilding. Both issues will impact the addition of another submarine to an already packed construction schedule and overextended supply chain.

In a Truth Social post, Trump said, “Our military alliance is stronger than ever, and for that reason, I have given them approval to build nuclear-powered submarines instead of the old-fashioned and much less agile diesel-engine submarines they currently have.”

Trump’s decision came a day after South Korean President Lee Jae-myung asked him to grant Seoul access to the fuel necessary to operate nuclear submarines.

Lee stated that South Korea’s diesel-powered vessels cannot effectively track North Korean and Chinese submarines due to navigational limitations.

“If the fuel supply is permitted, we can build several submarines equipped with conventional weapons using our own technology to defend the waters around the Korean Peninsula, which will ultimately reduce the burden on US forces,” Lee told Trump, according to South Korea’s Yonhap agency.

US-South Korea cooperation on nuclear energy, which includes the sale of US reactor technology, requires Seoul to obtain US approval for enriching or reprocessing nuclear fuel derived from US-provided technology or materials.

According to POLITICO, South Korea’s pursuit of nuclear submarine capability reflects Seoul’s concern over China’s growing military presence in the Indo-Pacific region and the increasing threat from North Korea.