System for monitoring a state of a nuclear reactor core

A system 120 for monitoring a state of a reactor core 140 in a nuclear reactor 100 may include an internal monitoring device 120 located inside the reactor core, the internal monitoring device including one or more internal sensor arrays 122 configured to take measurements of conditions of the reactor core 140 at different vertical regions within the reactor core to generate internal measurement data; an external monitoring device 130 located in the reactor structure outside the reactor core 140, the external monitoring device 130 including one or more external sensor arrays 132 configured to take measurements of conditions of the reactor core 140 at positions outside the reactor core 140 corresponding the plurality of different vertical regions within the reactor core to generate external measurement data, and a transmitter configured to wirelessly transmit the external measurement data; and a receiver station 170 configured to determine a state of the reactor core 140 based on the external and internal measurement data.