Winning global support to phase out the civilian use of highly enriched uranium (HEU) has been one of the seminal achievements of the Nuclear Security Summit (NSS)process that President Barack Obama started four years ago.

For decades, the United States has sought to secure and minimize the worldwide use of this dangerous material. Important US-led efforts such as the Global Threat Reduction Initiative have successfully eliminated civilian HEU in more than two dozen countries, removing enough material to build 200 nuclear weapons. However, broader international efforts have been too often hampered by a lack of multilateral support.