Evaluation of proliferation resistance of plutonium based on spontaneous fission neutron emission rate

The proliferation resistance of plutonium can be enhanced by isotopic denaturing and one of the features of Pu isotopic denaturing is increasing of the spontaneous fission neutron emission rate. A high spontaneous fission neutron emission rate causes “predetonation” in a nuclear explosive device, and it makes the designing and building of a nuclear explosive device more complicated. In this paper, the enhancement of Pu proliferation resistance by isotopic denaturing was evaluated based on spontaneous fission neutron emission rate using a simple nuclear explosive device model. The feature of spontaneous fission neutron was evaluated with probabilistic approach, and a new Pu categorization which makes enable to categorize plutonium by its isotopic compositions was proposed based on the evaluation results. The Pu categorization was applied to an evaluation of the proliferation resistance of plutonium produced in LWRs and FBRs using the evaluation function, “Attractiveness” for two types of plutonium; plutonium produced in typical LWRs and FBRs, and denatured plutonium produced by transmutation of MAs.

► Pu proliferation resistance was evaluated based on spontaneous fission neutron.
► A new Pu categorization based on spontaneous fission neutron was proposed.
► The Pu categorization was applied to an evaluation using “Attractiveness” function.
► Proliferation resistances of plutonium produced in LWRs and FBRs were evaluated.