POWER SURVEILLANCE DEVICE FOR NUCLEAR FURNACE

PROBLEM TO BE SOLVED: To improve safety and operation rate by accurate surveillance of the output change of a nuclear furnace which is hardly detected with conventional APRM signals. SOLUTION: A device includes a plurality of neutron flux measuring means 13 arranged in a furnace core 12 of a nuclear furnace, a process control computer 19 to estimate the output condition of the furnace core in accordance with neutron flux detection signals measured by the neutron flux measuring means 13, a monitor signal counter 25 provided with a filter to extract the features of the change of detection signals in accordance with the neutron flux detection signals and a stability monitor 26 to evaluate the stability of the furnace core from a value for the neutron flux detection signals to which required filtering is applied in the monitor signal counter 25. The monitor signal counter 25 filters the neutron flux detection signals with a weight coefficient corresponding to the basic mode distribution and the high-order mode distribution of a neutron flux in the condition of the furnace core of the nuclear furnace to generate monitor signals and the stability monitor 26 estimates and evaluates the stability of the furnace core 12 in accordance with the monitor signals obtained by filtering.