Standing wave nuclear fission reactor and methods

A method comprising:

• locating a plurality of fissile nuclear fuel assemblies in a central core region of a reactor core of a nuclear fission reactor, each fissile nuclear fuel assembly including fissile nuclear fuel material;
• locating a first plurality of fertile nuclear fuel assemblies in a peripheral core region of the reactor core, the peripheral core region located radially outward from the central core region, each fertile nuclear fuel assembly of the first plurality of fertile nuclear fuel assemblies including fertile nuclear fuel material;
• operating the nuclear fission reactor to generate neutrons with the plurality of fissile nuclear fuel assemblies;
• based on the generated neutrons, breeding up the fertile nuclear fuel material of the first plurality of fertile nuclear fuel assemblies into fissile nuclear fuel material;
• and
• shuffling at least one of the fissile nuclear fuel assemblies and at least one of the first plurality of fertile nuclear fuel assemblies in a manner that establishes a standing wave of fissioning fissile nuclear fuel material.