A device for monitoring a nuclear reactor, the device comprising: a case formed of a rigid material, the case including a shielding layer configured to insulate an internal portion of the device from external heat and radiation, the shielding layer includes at least one of uranium, tungsten, lead, and sintered nanoparticles; a coupling unit configured to adhere the case to a surface location of a nuclear reactor; a sensing unit configured to generate environmental measurements by measuring environmental conditions in a vicinity of the device; a data processing unit configured to generate measurement data by processing the environmental measurements; a transmitter configured to transmit the measurement data externally from the device as radio waves; and a power unit configured to power the device independently of a power source external to the device; a movement measurement unit configured to generate movement measurements by measuring movement conditions of the monitoring device, the movement conditions including at least one of speed and acceleration; a controller, the controller configured to: determine whether normal operating conditions or off-normal operating conditions exist in the nuclear reactor based on at least one of the environmental measurements and the movement measurements, and control, based on the determined condition, an operation mode of at least one of the sensing unit, the data processing unit and the transmitter, wherein: in the normal operating conditions, at least one of the sensing unit, the data processing unit and the transmitter is operated intermittently; in the off-normal operating conditions, at least one of the sensing unit, the data processing unit and the transmitter is operated continuously; wherein the data processing unit, the power unit, the sensing unit, the transmitter and the controller are inside the case. a case formed of a rigid material, the case including a shielding layer configured to insulate an internal portion of the device from external heat and radiation, the shielding layer includes at least one of uranium, tungsten, lead, and sintered nanoparticles; a coupling unit configured to adhere the case to a surface location of a nuclear reactor; a sensing unit configured to generate environmental measurements by measuring environmental conditions in a vicinity of the device; a data processing unit configured to generate measurement data by processing the environmental measurements; a transmitter configured to transmit the measurement data externally from the device as radio waves; and a power unit configured to power the device independently of a power source external to the device; a movement measurement unit configured to generate movement measurements by measuring movement conditions of the monitoring device, the movement conditions including at least one of speed and acceleration; a controller, the controller configured to: determine whether normal operating conditions or off-normal operating conditions exist in the nuclear reactor based on at least one of the environmental measurements and the movement measurements, and control, based on the determined condition, an operation mode of at least one of the sensing unit, the data processing unit and the transmitter, wherein: in the normal operating conditions, at least one of the sensing unit, the data processing unit and the transmitter is operated intermittently; in the off-normal operating conditions, at least one of the sensing unit, the data processing unit and the transmitter is operated continuously; wherein the data processing unit, the power unit, the sensing unit, the transmitter and the controller are inside the case. determine whether normal operating conditions or off-normal operating conditions exist in the nuclear reactor based on at least one of the environmental measurements and the movement measurements, and control, based on the determined condition, an operation mode of at least one of the sensing unit, the data processing unit and the transmitter, wherein: in the normal operating conditions, at least one of the sensing unit, the data processing unit and the transmitter is operated intermittently; in the off-normal operating conditions, at least one of the sensing unit, the data processing unit and the transmitter is operated continuously; wherein the data processing unit, the power unit, the sensing unit, the transmitter and the controller are inside the case. in the normal operating conditions, at least one of the sensing unit, the data processing unit and the transmitter is operated intermittently; in the off-normal operating conditions, at least one of the sensing unit, the data processing unit and the transmitter is operated continuously; wherein the data processing unit, the power unit, the sensing unit, the transmitter and the controller are inside the case.