[en] Whereas temperature measurements had an increasing importance in the control of nuclear power reactors, the authors studied new measurement systems perfectly adapted to requirements associated with nuclear reactors. More specifically and initially, these measurements aimed at ensuring thermal safety for the core and fuel bars. The author presents the measurement amplifier operation principle, the different devices and circuits, amplifier characteristics, and diverter characteristics. He describes the whole operation, comments various operational aspects, discusses the influence of room temperature on precision, and briefly reports tests performed within a pile