Figure of Merit Analysis of Proliferation Resistant Plutonium and Uranium

Proliferation resistance is a key component for developing nuclear materials that reduce the threat of nuclear weapons proliferation. Increased proliferation resistance of a material may lead to relaxed international safeguards on the material saving valuable International Atomic Energy Agency resources that can be used elsewhere. Previously, the proliferation resistance of the plutonium and uranium vectors in this study have been evaluated based purely on the alpha decay heat of 238Pu and 232U. These vectors consisted of elevated concentrations of 238Pu and 232U which increases the heat generation of the material and thus makes it less attractive for weapons purposes. However, the scope of that analysis only included a particular simple fission nuclear weapon design. In order to broaden the scope of the proliferation resistance analysis, this study utilizes a Figure of Merit based equation derived by Charles G. Bathke. This equation relates the material’s attractiveness to the bare critical mass, decay heat, dose rate, and (for less technologically advanced states) the spontaneous fission neutron generation rate. In the case of the plutonium vector, the material attractiveness remain constant for the most part as the decay heat decreases slowly over time. However, in the case of the uranium vector, the material attractiveness rapidly decreases over time. As 232U decays, not only does the decay heat rapidly increase, but also the dose rate increases as a result of the build-up of one of its daughters (208Tl), which emits an energetic gamma ray. Understanding the attractiveness of these vectors in a broader scope will better quantify their proliferation reisstance.