Scaling and Cost Tradeoffs for Atw: Preliminary Considerations

The use of accelerator-produced spallation neutrons to transmute actinide and long-lived fission-products portends a means to alleviate requirements for deepgeological disposal. The accelerator performance, targetblanket physics, chemical-processing requirements, and overall systems engineering are closely coupled in determining the economic incentives for the Accelerator Transmutation of Waste (ATW). Preliminary estimates of and insight into the economics of a net-power-producing ATW are provided by a simplified (analytic) cost-based systems model. Even for large-capacity systems, the accelerator dominates the economics and technology for the ATW cases examined. Since the accelerator represents an important (-50%) add-on cost to an ATW-based power plant, reducing the accelerator requirement by increasing the blanket neutron multiplication, increasing the thermalconversion efficiency, and reducing neutron leakage and parasitic absorption in the target-blanket assembly are main avenues for improving the economic prospects of an ATW that would be fuelled with low-reactivity, actinide “waste” generated by light-water fission reactors (LWRS). This route to improved systems has strong implications for the thermalhydraulic, neutronic, and chemical-processing designs of the ATW.