U.S. and Vietnamese officials have signed contracts to start converting the Dalat research reactor in Vietnam to burn low-enriched uranium rather than highly enriched uranium, the Energy Department's National Nuclear Security Administration announced today. Highly enriched uranium can be used for nuclear weapons, and U.S. officials, participating in NNSA's Global Threat Reduction Initiative, have been working in recent years with several nations to limit the use of the fissile material in reactors across the globe. Low-enriched uranium cannot be used...