A Study on the Feasibility of Electron-based Accelerator Driven Systems for Nuclear Waste Transmutation

Abstract

Nuclear waste transmutation is an important option for the development of advanced fuel cycle and effective nuclear waste management. The electron accelerator driven system (ADS) was investigated in the study for nuclear waste transmutation as an alternative to proton based ADS. Target design and optimization was carried out to obtain maximum neutron generation. Subcritical core design based on single and multiple targets was investigated. System performance between electron-based ADS and proton-based ADS was compared in terms of neutron generation rate, transmutation efficiency and power generation. It was determined that the electron-based target was capable of providing high neutron flux, small target geometry size, small scale subcritical core, and low radiation damage. Multiple target design in the electron-driven ADS was also explored to flatten power distribution in the ADS subcritical core. Regarding transmutation, the power peaking factors in both the electron- and proton- ADS increase ~ 10% during the burnup period of 700 days. Thermal power in proton ADS is higher than that of electron ADS by a factor ~ 20. The transmutation effectiveness of preliminary electron-based ADS is smaller by a factor of 11 compared to preliminary proton-based ADS. Proton ADS has higher radiation damage to target materials and surrounding materials. The capital cost for electron-based and proton-based accelerator facility is fairly comparable with the cost of proton-based facilities being slightly higher by a factor of 20%.

Comparing with the proton-driven ADS, the electron-driven ADS pros include small target size and small core scale, multiple target possibility for low PPF, low radiation damage to target surroundings, wide availability electron beam at ~100 MeV, and low capital cost of electron accelerator facility. There are also aspects against electron-driven ADS, including low efficiency of neutron generation rate, low transmutation efficiency, low thermal power, and electricity generation.