As described above, heterogeneous reflector configurations may be used in which different reflector materials are in different reflector channels. For example, in an embodiment some reflector channels may be filled with lead while other channels may be filed with a different material such as zirconium, steel, iron, graphite, beryllium, tungsten carbide, lead-bismuth, or graphite. By filling different channels with different materials (e.g., lead in a first channel and graphite in a second), different material compositions (e.g., lead in a first channel and lead-bismuth in a second), and/or different composition ratios (e.g., lead-bismuth eutectic (44.5% lead/55.5% bismuth) in a first channel and a 37% lead/63% bismuth lead-bismuth composition in a second), the reflection characteristics of the molten nuclear fuel salt reactor may be tailored to obtain desired effects. One illustrative embodiment is filling reflector channels closest to the reactor core with graphite and reflector channels further away from the reactor core with lead, lead-bismuth, or alternating between the two. For example, with reference to