Seoul: South Korea's top negotiator for nuclear cooperation with the United States visited Washington last week, as the two sides are expected to soon initiate talks on allowing Seoul to obtain uranium enrichment and spent fuel reprocessing capabilities, diplomatic sources said Monday.

According to Yonhap News Agency, Rim Kap-soo, the government representative leading the South Korean task force on the matter, made the undisclosed trip and met with Christopher Yeaw, assistant secretary of state for arms control and nonproliferation at the State Department, and other officials from the Department of Energy. This visit marks the first known meeting between the allies since South Korea launched a team responsible for negotiations with the U.S. on its pursuit of uranium enrichment and spent fuel reprocessing for peaceful use.

South Korea is seeking to amend its bilateral nuclear energy pact with the U.S. to obtain standing prior approval for low-level uranium enrichment and spent fuel reprocessing, aiming to secure a stable fuel supply for commercial nuclear power plants. Under the existing 123 Agreement, South Korea may enrich uranium only to below 20 percent with written U.S. consent. Reprocessing spent fuel also requires U.S. approval, meaning Seoul cannot carry out these activities independently.

During the trip, Rim proposed launching the negotiations at an early date and the U.S. reportedly agreed, saying "the sooner the better," sources said. With Rim's visit, the two sides are expected to start the talks in the coming weeks, with a U.S. delegation widely anticipated to come to Seoul for the first round of negotiations. The U.S. side, however, is reportedly yet to designate its chief negotiator for the talks.

Washington has given Seoul the green light to pursue these efforts following the October summit talks between President Lee Jae Myung and U.S. President Donald Trump, a commitment that has been outlined in a joint summit agreement. As part of efforts to implement the summit agreements, the allies are also said to be in talks to arrange a visit to Seoul by a key official from the White House National Security Council.