IN-CORE NUCLEAR INSTRUMENTATION DETECTOR AGGREGATE AND REACTOR OUTPUT MONITORING DEVICE

PROBLEM TO BE SOLVED: To provide a reactor output monitoring device capable of always monitoring a three-dimensional neutron flux distribution in a reactor. SOLUTION: A fixed type neutron detector, a mobile type neutron detector, and a gamma thermo detector are arranged in the axial direction in this detector aggregate. The fixed type neutron detector can be complemented by the gamma thermo detector, to thereby facilitate monitoring of the three-dimensional reactor output distribution. The gamma thermo detector can be easily calibrated by the mobile type neutron detector, to thereby dispense with a calibration heater.