U.S.-Korean nuclear energy cooperation is conducted under a “123 agreement” required by Section 123 of the Atomic Energy Act of 1954. The current agreement was signed in 1973 and will expire on March 19, 2014. A new 123 agreement does not require congressional approval, but it must lie before Congress for 90 days of continuous session before going into effect.

As with most U.S. 123 agreements, the existing U.S.-Korean agreement requires U.S. consent for any reprocessing or enrichment activities related to U.S.-supplied materials and technology. Korea is requesting that the new 123 agreement include U.S. advance consent for future Korean civilian reprocessing and enrichment activities. The United States has opposed the idea, on grounds of general nonproliferation policy and the complications that such activities might pose for other security issues on the Korean peninsula. To comply with the 90-day congressional review requirement, a new agreement probably would need to have been submitted to Congress by spring 2013. Any lapse in the agreement could affect exports of U.S. nuclear materials and reactor components to Korea, potentially affecting ongoing construction of the UAE project.

With time running out to address the fundamental U.S. and Korean differences over reprocessing, the two countries announced on April 24, 2013, that they would extend the existing agreement by two years to allow for additional negotiations. Legislation to authorize the two-year extension was introduced by Representative Royce on June 20, 2013 (H.R. 2449).