A system for controlling a nuclear power plant including at least one nuclear reactor, the system comprising: - a set of sensors (12A, 12B, 12C) and actuators (14A, 14B, 14C) associated with the nuclear reactor(s); - a plurality of electronic control units (16A, 16B, 16C), each control unit (16A, 16B, 16C) being configured to perform at least one action from among acquiring a value measured by a corresponding sensor (12A, 12B, 12C) and controlling an actuator (14A, 14B, 14C), the control units (16A, 16B, 16C) and/or the sensors (12A, 12B, 12C) and/or actuators (14A, 14B, 14C) being according to several different nuclear safety classes, each control unit (16A, 16B, 16C), each sensor (12A, 12B, 12C) and/or each actuators (14A, 14B, 14C) being according to a respective nuclear safety class; and - an electronic device for managing the display of data on at least one display screen, the data being associated with the control units (16A, 16B, 16C), the electronic device being connected to the plurality of control units (16A, 16B, 16C) and comprising: - a set of electronic module(s) (26A, 26B, 26C) for creating overlay(s) (28A, 28B, 28C), the set being configured to create several separate overlays (28A, 28B, 28C), each overlay (28A, 28B, 28C) containing information to be displayed for a respective safety class, associated with one or several control units (16A, 16B, 16C) according to said safety class, the created overlays (28A, 28B, 28C) are separated from one safety class to the next, the electronic device comprises at least one module for creating overlay(s) (26A, 26B, 26C) for each respective safety class, the overlay creation modules (26A, 26B, 26C) being separated from one safety class to the next, the data from a sensor (12A, 12B, 12C) or actuator (14A, 14B, 14C) according to a safety class being transmitted to a control unit (16A, 16B, 16C) according to said safety class, then to the electronic module (26A, 26B, 26C) according to the said safety class, and - an electronic generating module according to the highest safety class from among the different safety classes, configured to generate at least one data page to be displayed, each page being obtained by superimposing a plurality of separate overlays (28A, 28B, 28C), the generating module is configured to generate each page by superimposing an overlay (28A, 28B) associated with a higher safety class on top of an overlay (28B, 28C) associated with a lower safety class, to favor the information from the higher safety class in case of conflict during the superposition of the overlays (28A, 28B, 28C). - a set of sensors (12A, 12B, 12C) and actuators (14A, 14B, 14C) associated with the nuclear reactor(s); - a plurality of electronic control units (16A, 16B, 16C), each control unit (16A, 16B, 16C) being configured to perform at least one action from among acquiring a value measured by a corresponding sensor (12A, 12B, 12C) and controlling an actuator (14A, 14B, 14C), the control units (16A, 16B, 16C) and/or the sensors (12A, 12B, 12C) and/or actuators (14A, 14B, 14C) being according to several different nuclear safety classes, each control unit (16A, 16B, 16C), each sensor (12A, 12B, 12C) and/or each actuators (14A, 14B, 14C) being according to a respective nuclear safety class; and - an electronic device for managing the display of data on at least one display screen, the data being associated with the control units (16A, 16B, 16C), the electronic device being connected to the plurality of control units (16A, 16B, 16C) and comprising: - a set of electronic module(s) (26A, 26B, 26C) for creating overlay(s) (28A, 28B, 28C), the set being configured to create several separate overlays (28A, 28B, 28C), each overlay (28A, 28B, 28C) containing information to be displayed for a respective safety class, associated with one or several control units (16A, 16B, 16C) according to said safety class, the created overlays (28A, 28B, 28C) are separated from one safety class to the next, the electronic device comprises at least one module for creating overlay(s) (26A, 26B, 26C) for each respective safety class, the overlay creation modules (26A, 26B, 26C) being separated from one safety class to the next, the data from a sensor (12A, 12B, 12C) or actuator (14A, 14B, 14C) according to a safety class being transmitted to a control unit (16A, 16B, 16C) according to said safety class, then to the electronic module (26A, 26B, 26C) according to the said safety class, and - an electronic generating module according to the highest safety class from among the different safety classes, configured to generate at least one data page to be displayed, each page being obtained by superimposing a plurality of separate overlays (28A, 28B, 28C), the generating module is configured to generate each page by superimposing an overlay (28A, 28B) associated with a higher safety class on top of an overlay (28B, 28C) associated with a lower safety class, to favor the information from the higher safety class in case of conflict during the superposition of the overlays (28A, 28B, 28C).