As the first anniversary of the ROK–U.S. Joint Fact Sheet singed in November 2025 approaches, Seoul and Washington should demonstrate concrete progress in implementing their commitments. The United States approved South Korea’s construction of nuclear-powered submarines and pledged close cooperation on the requirements for the program, including avenues to source fuel. Those political commitments must now be translated into clear timelines and clearly assigned responsibilities. Securing a shipyard alone will not deliver a nuclear-powered submarine. Fuel specifications and supply arrangements must be established to align reactor design and testing, submarine construction and entry into service. Delays in fuel cooperation could lead to design changes, higher costs and uncertainty for companies considering investment. Diplomatic negotiations and domestic development must not become trapped in a cycle in which each waits for decisions from the other. There has been some progress. In December 2025, the two countries’ foreign affairs officials agreed on the need to move promptly toward