Electron linac based mixed-field transmutation of 129I

The goal of this work was to determine the feasibility of using electron linacs for transmutation of selective long-lived fission products (LLFPs), particularly 129I. We have designed a converter system that produces both photons and neutrons, thus creating a mixed radiation field. The strength of the field depends on electron beam energy and current, as well as the converter material and geometry. The converter was optimized to maximize transmutation rate of 129I via two channels: 129I(γ,n)128I and 129I(n,γ)130I. The optimum electron beam energy was found to be around 100 MeV. Computer simulations were benchmarked by experimental data on 133Cs (129I surrogate) photon-induced and neutron-induced transmutation rates. While further optimization of the system is necessary, we have demonstrated that accelerator-driven photonuclear reactions can be practical for 129I transmutation.