| 摘要 |
PURPOSE:To measure non-destructively the uranium dioxide content in a nuclear fuel rod by measuring the wall thickness of a cladding pipe then measuring the AC magnetization rate of the fuel rod thereby eliminating substantially the measurement error occurring in a ferromagnetic inclusion and cladding pipe. CONSTITUTION:The nuclear fuel rod 11 is first passed in water in a water tank 12 and the wall thickness of the cladding pipe is measured by an ultrasonic wall thickness gage 14 having an ultrasonic probe 13. The rod 11 is electromagnetically coupled to one coil 4 out of a pair of the coil 4, 5 which are complementarily connected in the directions of negating the induced voltages each other in the AC magnetic field of the coil 3 and the unbalance voltage induced in the coil 4 is taken out as the measurement output. The basic wave component is detected by a phase locked amplifier 7 from the measured output and the high-frequency component is detected by a high-frequency component detector 8. The measurement error occuring in the ferromagnetic mixture is substantially removed from the detected basic wave component value by the correction with the detected high-frequency component value and the measurement error occurring in the cladding pipe is substantially removed by the correction with the measured wall thickness value. |
