In a meeting on "Civilian Nuclear Energy in an Unstable, Carbon-Constrained World," sponsored by the Nonproliferation Policy Education Center (NPEC) on November 5, 2007, at the Carnegie Corporation, Carnegie Senior Associate Sharon Squassoni mapped out three different futures for nuclear energy expansion worldwide. With maps on reactor capacities, uranium enrichment, and spent fuel reprocessing from 2007 to 2050 (see attached slide presentation and appendix for more detailed data), Squassoni concluded that the proliferation consequences of a significant (2-3x current capacity) nuclear energy expansion could be serious. However, goals are unlikely to be met for structural reasons. Even in the absence of a significant expansion, the world could have many more "new" nuclear states, in regions of considerable proliferation concern.