Display device for reactor core power distribution

The device of the present invention can recognize the state of distribution for a reactor core power in detail. That is, in a reactor core map, a function is provided for optionally setting the upper limit and the lower limit for the stepwise display of the value for thermal power of each fuel. Then, display levels having predetermined number of steps and thermal power ranges for each of the levels are determined based on the predetermined upper and lower values. The display level of the thermal power of each fuel is judged by the thermal power range, and each kind of display patterns is determined by the color and the letter corresponding to the display level of the thermal power, to display a reactor core map. With such a constitution, an operator can optionally determine the appropriate upper and lower values in accordance with the state of the thermal power upon stepwise display for the thermal power by the reactor core map. Accordingly, it is possible to determine the state of power distribution and peak position easily and accurately. (I.S.)