INSTRUMENT FOR MEASURING BURNUP DISTRIBUTION OF IRRADIATED FUEL ASSEMBLY OF NUCLEAR REACTOR

摘要

PURPOSE:To easily calibrate the sensitivity of radiation detectors and to exactly measure the distribution of burnup by housing the plural radiation detectors at equal intervals axially into a detector housing container and sliding the container at every housing interval of the radiation detectors in an instrument body. CONSTITUTION:The detector housing container 7 is disposed slidably in the axial direction of the instrument body 9 having approximately the same length as the axial length of a fuel assembly and the plural radiation detectors 3, 5 are housed at the equal intervals axially into said container. A housing container driving part 11 is slid relative to the body 9 at every housing interval of the plural detectors 3, 5. Measurements are carried out at least twice, i.e., in a certain axial position at the side face of the irradiated fuel assembly 13 of a nuclear reactor and the position where the container 7 is slid by the housing interval of the detectors 3, 5 therefrom. The calibration of the sensitivity of the detectors 3, 5 is thereby easily executed and the distribution of the burnup is exactly measured.