World leaders arrive at the 2016 Nuclear Security Summit (NSS) in Washington, D.C. with a large helping of food for thought. While a little of it, particularly in the wake of the good news of Iran coming in from out of the nuclear freezer in January this year, looks quite tasty (as an appetizer at least), the other morsels on the menu do not appear so palatable, perhaps even indigestible.

Uppermost in leaders’ minds, particularly in the wake of the Brussels attacks and other atrocities committed by the so-called Islamic State, must be the fear of terrorists getting hold of nuclear weapons or the materials to make them.

One of the nightmare scenarios which keeps security experts awake at night is terrorists somehow obtaining nuclear warheads and delivering them to large population centers (such as New York) by sea. In addition, if just one warhead (from whatever source) got into ISIL’s hands it would clearly represent a security threat of almost unimaginably terrible proportions.

So while the Islamic State is not directly on the agenda for the NSS, it and other extremist threats are, however, likely to be in the backs of people’s minds as they enter the negotiating chamber, and may well be of concern to Presidents Obama and Xi as they meet for bilateral discussions on the fringes of the Summit. Taking measures to prevent the smuggling of materials and blueprints for making nuclear weapons by unauthorized agents and actors must be high on their agenda.

How to prevent uncontrolled nuclear proliferation in states which are less stable or which are viewed by the international community as beyond the pale obviously also represents an area of major concern. Finding ways to police these states is, as ever, an issue of concern for those present at the Summit, and one which requires the careful and patient attention of all concerned.

Of course, one problem less this year is the question of Iran, which was brought to a successful conclusion in January, in large part due to China’s intervention on the question of the Arak heavy water reactor, which it has offered to redesign so that it will be unable to produce weapons grade plutonium. China therefore proved, muchto some observers’ surprise, to be a key player in bringing Iran in from out of the cold, and Beijing has thus gone a considerable distance towards proving its credentials as a responsible actor on the world stage in terms of nuclear security.

China’s highly successful behind-the-scenes activity on this and other issues relating to international security will do much in the long-term to dispel general criticisms by observers in the West that China is not behaving as a responsible stakeholder on the world stage.

But in the short-term there is the vexed question of what this Summit can be expected to achieve in terms of the passing of concrete measures.

Russia’s absence from the negotiations is clearly likely to be a major obstacle to progress given its status as a major nuclear power. Nevertheless, there is much that can be achieved by discussion among the remaining participants, particularly in addressing how to establish and enforce counter-terrorism measures relating to preventing the unauthorized use of existing nuclear materials. This could be achieved, for instance, by improving nuclear security regulations and monitoring.

Thus, given the landmark agreement that was reached with regard to Iran, and China’s clear intention to cooperate more closely with the US on nuclear proliferation, there is every reason to be hopeful that this Summit can deliver some more positive steps in the right direction, even if progress towards outright solutions on the level of the Iran deal may prove elusive at this stage.

Jeremy Garlick is lecturer in international relations at the Jan Masaryk Centre for International Studies, University of Economics in Prague.

The opinions expressed here are those of the writer and don't represent views of China Daily website.