The monograph discusses the physical foundations of a new method of doping semiconductors, the basic element of which is nuclear reactions that occur in the volume of a semiconductor under the influence of fast charged particles, neutrons, high-energy gamma radiation, as well as the inevitably occurring side effects - the formation of radiation defects, the kinetics of their accumulation and annealing. Detailed data are presented on the technology of uniform irradiation of bulk ingots with neutrons depending on the specific design of the nuclear reactor, the medium and modes of annealing of radiation defects, the requirements for the starting material, and the electrophysical properties of doped silicon crystals are considered. The sources of radioactive contamination of the ingots during the irradiation process and the technological methods of their deactivation to a safe level are analyzed.The monograph is designed for scientists and production personnel interested in the problems of solid state radiation physics and radiation materials science of semiconductors and devices based on them, as well as graduate students and students of relevant specialties.