Report

Institute for Future Strategy, Seoul National University — U.S.–Korea Nuclear Cooperation Agreement Task Force
“A Foundational Study for the Advanced Revision of the U.S.–Korea Nuclear Cooperation Agreement”

This report summarizes the findings of the Task Force on the U.S.–Korea Nuclear Cooperation Agreement (123 Agreement) at the Institute for Future Strategy (IFS), Seoul National University. It analyzes the historical evolution and main contents of the Agreement signed in 1956, focusing especially on the structure and implementation of the 2015 revision. The study aims to use the 2035 expiration as a strategic opportunity to enhance Korea’s technological autonomy and international standing by proposing advanced directions and policy strategies for revision. Despite Korea’s world-class nuclear technology, the current agreement still requires prior U.S. consent for sensitive activities such as spent fuel reprocessing and uranium enrichment. The report examines the resulting constraints on technological sovereignty and energy security in depth.

The 123 Agreement is a framework the United States has signed with allied countries as part of its non-proliferation policy, maintaining control over the peaceful use of nuclear materials and technology through a prior-consent system for sensitive activities. Korea’s 1974 revision enabled the introduction of commercial nuclear power plants, but also formalized prohibitions on enrichment and reprocessing, restricting autonomous technological use. The 2015 revision marked partial progress by introducing long-term consent for R&D on pyroprocessing and enrichment, establishing a high-level bilateral commission to ensure flexible implementation, and expanding cooperation in spent fuel management and nuclear exports. However, long-term consent for commercial use remains excluded, and the principle of prior written approval continues to limit Korea’s technological autonomy and equal footing in negotiations.

The report emphasizes that current international dynamics are not merely external variables in managing the Agreement, but decisive structural factors shaping the rationale and direction for its revision. Global changes—such as the renewed focus on nuclear energy amid climate challenges, restructuring of supply chains, energy geopolitics, strategic competition among the U.S., China, and Russia, and evolving non-proliferation norms—highlight the need for Korea’s proactive response. Following the war in Ukraine, reliance on Russian uranium enrichment has emerged as a risk, prompting the United States and its allies to diversify nuclear fuel supply chains. Korea, therefore, must also review policies for securing independent enrichment capabilities and fuel self-sufficiency.

Korea now possesses world-class nuclear reactor technologies, including APR1400, SMART, and SMR, and has achieved notable progress in spent fuel management and pyroprocessing R&D. However, technical demonstration remains incomplete, and additional technological and legal safeguards are needed to meet international transparency standards. The report suggests that in future revision discussions, Korea should secure technological autonomy and negotiation parity by building a verified technical base for long-term consent, improving international acceptability through AI-based non-proliferation technologies, strengthening the U.S.–Korea strategic technology alliance through cooperation in exports, SMR co-development, and patent sharing, continuously monitoring global policy changes, and enhancing inter-ministerial coordination through improved domestic legal and institutional frameworks.

In conclusion, the report views the 2035 revision not as a routine renewal, but as a turning point for Korea’s nuclear technology independence and emergence as a global strategic leader. It calls for an integrated response across government, industry, and academia to achieve three strategic goals simultaneously: securing technological sovereignty, ensuring energy supply stability, and strengthening Korea’s status as a responsible actor within the global non-proliferation order.

Keywords:
U.S.–Korea Nuclear Cooperation Agreement, 123 Agreement, nuclear technology autonomy, spent fuel reprocessing, pyroprocessing, uranium enrichment, non-proliferation, energy security, SMR, strategic technology alliance, nuclear fuel supply chain, technological sovereignty