Will Korea’s Nuclear Hopes Be Realized? Rising Expectations for Korea-U.S. Nuclear Agreement Revision [Digging Energy]

Trump’s Approval of Nuclear-Powered Submarines Spurs Action
Korea-U.S. Nuclear Agreement Now on the Agenda
Reduced Burden of Radioactive Waste Management
Momentum for Securing Full-Cycle Nuclear Fuel Technology

President Lee Jae-myung is guiding U.S. President Donald Trump to his seat after commemorative photo session for the Korea-U.S. summit at Gyeongju National Museum, Gyeongbuk, on October 29, 2025. Photo by Presidential Office Press Photographers Group, Yonhap News Agency

On the 30th, with U.S. President Donald Trump’s sudden approval of South Korea’s construction of nuclear-powered submarines, there is growing attention on the revision of the Korea-U.S. Nuclear Cooperation Agreement and subsequent discussions.

President Donald Trump, who is currently visiting South Korea, stated on the social media platform Truth Social, “The Korea-U.S. military alliance is stronger than ever,” and added, “Based on that, I have approved South Korea to build nuclear-powered submarines instead of the outdated and less maneuverable diesel submarines it currently possesses.”

This is in response to President Lee Jaemyung’s request during the Korea-U.S. summit held the previous day, in which he said, “It would be appreciated if you could make a decisive move to allow us to receive fuel for nuclear-powered submarines.”

Enriched uranium is required to build nuclear-powered submarines. According to the Korea-U.S. Nuclear Cooperation Agreement signed in 2015, South Korea may only enrich uranium to below 20% with written consultation from the United States, but so far, the U.S. has never granted South Korea permission to enrich uranium. As a result, revision or advancement of the existing agreement is needed.

The Korea-U.S. summit also included discussions on the nuclear cooperation agreement as an agenda item. Wi Sunglak, Director of the National Security Office, explained in a press briefing immediately after the summit on the 29th, “Through previous consultations, there is a mutual understanding regarding the direction of the nuclear cooperation agreement.”

Foreign Minister Cho Hyun also stated in a media interview on the 23rd, “We strongly requested the ability to enrich uranium and reprocess spent nuclear fuel, and that request was accepted.” Therefore, it is expected that the upcoming “fact sheet” summarizing the details of the Korea-U.S. summit will include content related to the nuclear cooperation agreement.

South Korea’s Enrichment and Reprocessing Authority Likely to Expand

The Korea-U.S. Nuclear Cooperation Agreement signed in 2015 is valid for 20 years and will expire in 2035. Since there are still 10 years left, the current discussions are reportedly focused not on a full revision, but on broadly recognizing South Korea’s rights to enrichment and reprocessing within the existing framework of the agreement.

South Korea aims to secure reprocessing and enrichment technology at a level similar to Japan. Japan has obtained a “comprehensive prior consent” from the United States, which allows it to enrich uranium to below 20% and to reprocess spent fuel.

South Korea is jointly researching pyroprocessing (a dry process) reprocessing technology with the United States for research purposes only. When spent nuclear fuel is reprocessed via pyroprocessing, nuclear materials such as plutonium, uranium-235, and uranium-238 are extracted in a mixed state, which reduces the risk of nuclear proliferation. However, the United States is still reportedly concerned about the proliferation risks associated with pyroprocessing.

Unlike South Korea, Japan reprocesses spent nuclear fuel using a wet chemical process, which allows for the extraction of pure plutonium.

Pyroprocessing involves four stages: pretreatment, electroreduction, electrorefining, and electrowinning. Of these, South Korea is only permitted to independently conduct research up to the pretreatment and electroreduction stages. Research beyond these stages must be conducted jointly with the United States. It is expected that the scope of these activities will be expanded in the follow-up discussions on the Korea-U.S. Nuclear Cooperation Agreement.

If the authority to reprocess spent nuclear fuel is expanded, the burden of managing radioactive waste, which is currently at capacity, can be significantly reduced. According to Korea Hydro & Nuclear Power, spent fuel storage at Hanbit Nuclear Power Plant will reach capacity in 2030, followed by Hanul in 2031 and Kori in 2032.

Reprocessing spent nuclear fuel can theoretically reduce the volume of waste by up to one-tenth. Technically, the reprocessed materials can also be used again as fuel for nuclear power plants.

Professor Jeong Dongwook of Chung-Ang University’s Department of Energy Systems Engineering said, “If the authority to reprocess spent nuclear fuel is expanded, the extracted materials can be reused as nuclear fuel, and the burden of managing radioactive waste can be alleviated. However, it will take a long time to develop processes that can be commercially implemented outside of laboratory settings.”

“Securing Full Nuclear Fuel Cycle Technology... Strengthening Korea-U.S. Trust”

If the authority to enrich uranium is expanded, it would be significant in that South Korea could localize uranium enrichment technology, which is currently entirely dependent on foreign sources.

Currently, Korea Hydro & Nuclear Power imports uranium ore for use in domestic nuclear power plants, which is then enriched by companies in France, Russia, and the United States, and brought back in the form of “yellowcake” (uranium-235 enriched to about 5%). This enriched uranium is then processed by Korea Nuclear Fuel to be loaded into nuclear reactors.

Professor Moon Joohyun of Dankook University’s Department of Energy Engineering explained, “As nuclear power plants have expanded recently, demand for uranium has increased and the market has become unstable. If South Korea can enrich uranium domestically, it will be able to establish a stable fuel supply system.” If South Korea secures its own uranium enrichment technology, it will also be able to produce HALEU, a next-generation nuclear fuel used in sodium-cooled fast reactors and other advanced reactors.

Professor Jeong Dongwook said, “If South Korea’s authority for enrichment and reprocessing is expanded, it will demonstrate to the world that Korea-U.S. trust is strong. It is also significant in that South Korea can secure the full nuclear fuel cycle technology, which has been lacking until now.”