Target/blanket design for LANL's accelerator transmutation of waste

The Los Alamos accelerator transmutation concept is directed at the problems associated with high-level wastes stored at several US Department of Energy sites. A more advanced long-term effort is investigating the potential of an accelerator-driven system to produce fission energy with a minimal nuclear waste stream. Both concepts employ a high-energy (1,600-MeV), high-current (25- to 60-mA) proton accelerator as the driver. The protons are directed onto a spallation target to produce neutrons, which are then moderated in the surrounding blanket. Because of the intense flux of neutrons generated, low-cross-section fission products such as {sup 99}Tc are easily transmuted, and higher actinide waste such as {sup 237}Np can be transmuted with a simple two-step capture/fission process. Also, very dilute mixtures are used, reducing the potential for criticality and power excursions. A layout for the target/blanket design is depicted. The most serious design challenges are associated with the flowing Pb-Bi target. Research is required to verify the thermal-hydraulic design and determine compatible container materials that can withstand the neutron environment.