In addition, there was agreement to create a "nuclear security contact group" of senior officials that will meet later in the year, said Page Stoutland, vice president for scientific and technical affairs of the Nuclear Threat Initiative.
MISSED OPPORTUNITIES
"I think the summit has solid progress but also some missed opportunities," Bunn said.
The summit unveiled action plans for each of the five main international organizations and initiatives working to secure nuclear and radiological materials.
These organizations and initiatives include the IAEA, the United Nations, INTERPOL, Global Initiative to Combat Nuclear Terrorism, and Global Partnership Against the Spread of Weapons and Materials of Mass Destruction.
"I think there is a missed opportunity to do more to strengthen international nuclear security institutions because they will have to take up the slack that we are not meeting at the summit any more," Bunn said.
"Action plans really only strengthened those groupings very modestly."
In Luongo's view, another disappointment is that the summit did not set important, big long term goals for the next decade that countries could take action to meet in the absence of the summit process.
ACTIONS BEYOND 2016 NSS
For all the progress or missed opportunities, the end of the summit ushers in an era where individual country should continue their efforts to lock down their nuclear materials and secure nuclear facilities.
"Continuing the work within the five international organizations and the creation of a nuclear security contact group is a good start. It is important, however, that mechanisms be developed for the longer term,"Stoutland said.
According to the NTI, many countries do not yet have all the security measures in place. For example, nearly half of the countries do not require cyber security at nuclear facilities.
Meanwhile, at the moment, there are no globally agreed standards for effectively securing nuclear materials.
"We need to move on that direction, and we need fast global efforts to secure radiological sources that can be used in a dirty bomb. The risk can be reduced using very simple, low cost security measures," Bunn said.
In the post-summit era, Bunn said, the world needs to do whatever they can with all the available tools. "One of the key tools is bilateral cooperation. So I was happy to see the U.S. and China issue a joint statement on strengthening their nuclear security bilateral cooperation."
Meanwhile, there is a lot to be done to try to rebuild cooperation between the United States and Russia, he added.
According to Fissile Materials Working Group, Russia and the United States have well over two-thirds of all weapons-usable nuclear materials in the world.
More efforts are needed to ensure the IAEA gets reliable funding that allows it to actually plan and prioritize its activity, which means the funding is coming more from regular budget and less from voluntary contributions from member states, Bunn added.