The design concept of a subcritical advanced burner reactor (SABR) is described. SABR is fueled with transuranics (TRUs) discharged from thermal reactors cast into a TRU-Zr metal fuel pin and is cooled with sodium. The reactor operates subcritical to achieve a deep-burn four-batch fuel cycle that fissions 25% of the TRU in an 8.2-yr residence time, limited by radiation damage accumulation (200 displacements per atom) in the oxygen dispersion strengthened clad and structure. The annual TRU fission rate in SABR [3000 MW(thermal)] is comparable to the annual TRU discharge of three to five 1000-MW(electric) light water reactors, depending on the plant capacity factor of SABR. A tokamak D-T fusion neutron source based on physics and technology that will be demonstrated in ITER supports the subcritical operation.