Abstract: A nuclear power plant controlling system is provided in which the thermal limit can be brought close to the full limit of operation restrictions by automatic control. The system includes a thermal limit monitor, including a receiver configured to receive a first signal, a prospective time deriving unit configured to derive a prospective time for the first signal to arrive at the full limit, a judging unit configured to judge a remaining time to the prospective time, a compensating unit configured to compensate the first signal based on a second signal, a first transmitter configured to transmit a first instruction to vary a rate factor of the first and second signals by synchronizing the compensation, and a second transmitter configured to transmit a second instruction to hold the first or second signal after arriving at the full limit or at a threshold that is just before the full limit.

Abstract: Provide the technique for controlling nuclear power plant in which the thermal limit can be brought close to the full limit of operation restrictions by the automatic control, using the simple information outputted shorter cycle than that of the thermal limit.