The commitments made in Washington in 2010 are : Following the summit in Washington in 2010 six new countries ( Azerbaijan , Denmark , Gabon , Hungary , Lithuania and Romania ) and one new international organisation ( Interpol ) were invited by South Korea to join the NSS . Fifty-three countries attended the second summit in Seoul in 2012 , which built on the goals that had been identified in Washington . New ambitions were added to the Washington Work Plan : the participants recognised the need to increase synergy between nuclear safety and security and better protect radiological sources from theft and misuse . Radiological sources may not be usable for a nuclear weapon , but they are well suited for making a ‘ dirty bomb ’ , which can release radiation and cause social upheaval
second summit in Seoul in 2012
2012 Nuclear Security Summit
Nuclear Security Summit