Development of uranium and plutonium based nuclear weapons—what impacts the choice of fissile material route?

This paper examines the underlying reasons why states have chosen to pursue a particular fissile material route in their nuclear weapons development. This analysis is conducted using case studies that describe historical developments and events, alongside an evaluation of their impact on the choice of fissile material route. Key areas of interest include the role of uranium resources, the visibility or covert nature of nuclear weapons activities, international relations, military delivery systems, and measures imposed by the export controls and nuclear safeguards regimes. The results of the work show that although uranium resources play a role, they impact the route in only one case. Insight into whether or not the nuclear weapon program is conducted openly or covertly does not seem to have impacted the selected fissile material route much, and the same can be said about the military delivery systems. In contrast, international relations, both in terms of government-to-government relations and proliferation networks, appear as far more important. The impact of export control and safeguards measures is shown to depend heavily on the context of international relations and the unique circumstances of each case.