August 2025 – President Lee Jae Myung and President Donald Trump hold their first bilateral White House summit, laying the groundwork for deeper Korea‑U.S. nuclear cooperation; Lee says “we will keep the Korea‑U.S. alliance at the core of our foreign policy” [2].

October 2025 – At a Gyeongju summit, President Trump signals approval for Seoul’s nuclear‑powered submarine program and endorses civil uranium enrichment and spent‑fuel reprocessing; he states “we approve Seoul’s plan for nuclear‑powered attack submarines” [16].

Nov 13 2025 – A joint fact sheet released after the summits details U.S. support for South Korea’s civil uranium enrichment, spent‑fuel reprocessing, and nuclear‑submarine development; the sheet notes “the United States backs the process toward civil uranium enrichment and spent fuel reprocessing” [1].

Dec 1 2025 – South Korea and the United States agree to launch sectoral working groups to implement summit commitments on nuclear submarines and civilian nuclear fuel‑cycle projects; officials say “we will swiftly establish sectoral working groups” [25].

Dec 1 2025 – Seoul’s foreign ministry urges Washington to begin civil uranium enrichment and spent‑fuel reprocessing talks, emphasizing the need for transparent cooperation; the ministry declares “we call on Washington to promptly begin discussions” [27].

Dec 1 2025 – Both sides set a timeline for the first working‑group meetings, targeting a start within three months; a spokesperson notes “we will convene the first meetings within the next three months” [28].

Dec 2 2025 – Seoul reaffirms full adherence to the Nuclear Non‑Proliferation Treaty while advancing its nuclear‑powered submarine program; a senior official affirms “we fully uphold our obligations under the NPT” [22].

Dec 3 2025 – President Trump publicly approves South Korea’s nuclear‑powered, conventionally‑armed submarine program, calling the alliance “stronger than ever”; he says “the alliance is stronger than ever” [21].

Dec 3 2025 – First Vice Foreign Minister Park Yoon‑joo meets U.S. think‑tank leaders, stressing Korea’s non‑proliferation record; he remarks “South Korea adheres to the Non‑Proliferation Treaty” [20].

Dec 7 2025 – The presidential office creates task forces for nuclear submarines, uranium enrichment, and defense‑cost sharing to support upcoming negotiations; officials state “we will draw a road map for consultations” [19].

Dec 10 2025 – Vice Foreign Minister Kim Jina arrives in Washington to press for rapid U.S. action on civil uranium enrichment and spent‑fuel reprocessing, saying “Korea is ready and asks the U.S. to assign a counterpart” [18].

Dec 15 2025 – National Security Adviser Wi Sung‑lac plans to discuss nuclear‑powered submarines with U.S. officials and notes three task forces are ready; he says “we have formed three task forces to prepare consultations” [17].

Dec 16 2025 – Wi meets U.S. Secretary of State Marco Rubio, citing Australia’s Section 91 exception as a model for a separate bilateral submarine‑fuel agreement; he remarks “Australia obtained an exception under Section 91, and we may seek a similar arrangement” [15].

Dec 16 2025 – U.S. Energy Secretary Chris Wright meets Wi in Washington, reaffirming U.S. backing for civil uranium enrichment, spent‑fuel reprocessing, and nuclear‑powered submarines; Wright says “we will explore a separate bilateral deal to obtain a Section 91 exception” [14].

Dec 17 2025 – Wi and Wright discuss implementation steps, confirming U.S. support for a civil nuclear fuel‑cycle subject to legal requirements; Wright notes “the United States supports a process that will lead to civil uranium enrichment” [14].

Dec 18 2025 – South Korea’s defense ministry announces plans to negotiate with the United States for nuclear‑submarine fuel, targeting completion of talks within two years; a senior official says “we aim to complete the negotiations within two years” [12].

Dec 18 2025 – Security adviser Wi reports progress in accelerating implementation of summit agreements, pledging faster follow‑up; he states “we have made progress and will expedite follow‑up measures” [11].

Dec 19 2025 – Foreign Minister Cho Hyun says Seoul will arrange President Lee Jae Myung’s state visit to China in early 2026 to stabilize ties; he declares “we will arrange the president’s state visit to China in the early part of next year” [9].

Dec 21 2025 – Wi announces simultaneous working‑level talks on uranium enrichment, spent‑fuel reprocessing, and nuclear submarines to start in the new year; he says “we will launch multiple working‑level discussions at once” [8].

Dec 24 2025 – The United States and South Korea agree to pursue a stand‑alone nuclear‑submarine cooperation pact, with a U.S. delegation slated to visit Korea early 2026; a spokesperson notes “we will pursue a stand‑alone agreement on cooperation for nuclear‑powered submarines” [6].

Dec 24 2025 – Seoul states it will use low‑enriched uranium below 20 % for submarine fuel and will not consider highly enriched uranium; the ministry confirms “we will secure low‑enriched uranium below 20 % and HEU is not under consideration” [6].

Jan 9 2026 – South Korea forms an interagency consultative team, chaired by Rim Kap‑soo, to prepare first‑round negotiations to revise the 123 Agreement for standing approval of enrichment and reprocessing; the team says “we will hold director‑general level meetings and working‑level consultations in phases” [3].

Jan 13 2026 – Lee Jae Myung’s administration pushes the alliance forward, highlighting U.S. approval of nuclear‑powered submarines and civilian nuclear aims amid broader security modernization; a senior official notes “Seoul’s push to acquire nuclear‑powered submarines receives approval from Trump” [2].

Feb 4 2026 – Foreign Minister Cho Hyun meets U.S. Energy Secretary Chris Wright in Washington, reaffirming urgency to advance civil uranium enrichment, spent‑fuel reprocessing, and nuclear‑submarine collaboration, and pledging swift concrete steps; Cho states “we share a clear understanding that rapid, concrete steps are needed” [1].

Future milestones – Early 2026: U.S. working‑level delegation visits Seoul for stand‑alone submarine‑pact talks [6]; early 2026: First round of civil uranium enrichment and spent‑fuel reprocessing negotiations commence [3]; 2026: President Lee’s state visit to China scheduled for early 2026 [9]; November 2026: Defense chiefs meeting to assess second stage of OPCON transfer [12]; by 2030: South Korea aims to retake wartime operational control from the United States [12].