This paper describes the development of radiation and temperature tolerant electronics capable of functioning inside an operating nuclear reactor vessel. The technology will enable every fuel assembly in a commercial reactor to be instrumented with self-powered neutron detectors (SPND) at different axial locations. Thermocouples for measuring the reactor coolant temperature may also be installed in every fuel assembly, as will an associated vacuum microelectronic (VME) wireless transmitter to continuously broadcast the signals from the SPND and/or thermocouples to a single receiving antenna inside the reactor vessel that will route the signal out of the reactor vessel. The successful development of this technology would enable key operating parameters of every fuel assembly in a commercial reactor core to be continuously monitored. The increase in reactor power distribution measurement density relative to existing densities, where roughly one-third of the fuel assemblies are instrumented, will significantly reduce the uncertainty in the measured core peaking factors. Reducing the uncertainty in the measured core peaking factors will allow the core operating power levels to be increased. This result will, in turn, allow the reactor to generate more electrical power from the same amount of fuel, operate at the same electrical output power level for longer periods before refueling with the same amount of fuel, or generate the same amount of electricity from less fuel.