A means of transmuting key long-lived nuclear wastes, primarily the minor actinides (neptunium, americium, and curium) and iodine, using a hybrid proton accelerator and subcritical lattice, is proposed. By partitioning the components of the light water reactor (LWR) spent fuel and by transmuting key elements, such as the plutonium, the minor actinides, and a few of the long-lived fission products, some of the most significant challenges in building a waste repository can be substantially reduced. The proposed machine, based on the described PHOENIX Concept, would transmute the minor actinides and the iodine produced by 75 LWRs and would generate usable electricity (beyond that required to run the large accelerator) of 850 MW(electric).