Mexico said it will work with the United States and Canada to convert its high-enriched uranium reactor, removing the materials that could potentially be used for bomb-making. The agreement is being announced Tuesday at the 47-country Nuclear Security Summit hosted by US President Barack Obama to refocus world attention on the dangers of nuclear materials falling into the hands of terrorists. The move is a step toward Mexico's conversion to a reactor that operates on low-enriched uranium, which is far less likely to be made into a weapon.