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. Rim Kap-soo, government representative leading the 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, sources with knowledge of the matter said. It marks the first known meeting between the allies since Korea launched earlier this month a team responsible for negotiations with the U.S. on its pursuit of uranium enrichment and spent fuel reprocessing for peaceful use. 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,