The United States, after many years of languishing on the sidelines, is now taking a leading role in attempting to control nuclear proliferation into the hands of the bad guys (i.e. terrorists and/or rogue states). Hillary Clinton signed an agreement this week with Argentina that allows for the installation of radiation-detection equipment and "associated infrastructure" at the Port of Buenos Aires. For the State Department's explanation of what this program is about, see this official link.
The Megaports Initiative was begun in 2003. Closely associated with it is the National Lab system. See this brief link.
According to Clinton, 30 ports around the world are now included in the initiative, with others in Asia, Latin America and the Caribbean, the Middle East, Europe, and Africa in the works.