Patent Number: 
Section: claims

1. A nuclear fission fuel structure for propagating a nuclear fission deflagration wave, the nuclear fission fuel structure comprising:a plurality of non-contiguous segments of previously-burned nuclear fission fuel material inserted into a core of a nuclear fission deflagration wave reactor; anda nuclear fission igniter module disposed in the core of the nuclear fission deflagration wave reactor to initiate a propagating nuclear fission deflagration wave in the previously-burned nuclear fission fuel material, the nuclear fission igniter module including a source of protons and an intermediate material configured to receive the protons from the source of protons and further configured to provide fast-fission neutrons to the previously-burned nuclear fission fuel material. 2. The nuclear fission fuel structure of claim 1, wherein the intermediate material provides the fast-fission neutrons by a process chosen from electro-fission of elements and photo-fission of elements. 3. The nuclear fission fuel structure of claim 1, wherein the source of protons includes a linear particle accelerator.