| 摘要 |
PURPOSE: To discriminate a failure fuel rod, a fuel rod dislocated from a fixed position or nonarrangement of a fuel rod particularly in a reconstituted fuel bundle by using the characteristic of an interferential scattered ultrasonic wave. CONSTITUTION: A fuel channel to surround a bundle can easily pass an ultrasonic wave. This ultrasonic wave enters a square lattice of a bar when there is no object of hindering and disturbing a scattering process. Such a disturbing object happens to be composed of radioactive gas coming out as bubbles from the cracked bar, and this locally disturbs an acoustic impedance, and disturbs at least a part of the scattering process. When swelling or the other deformation is caused in the bar having leakage, its contributory quantity to a wave of an inteference wave is reduced. Therefore, information on completeness of fuel is obtained at a site by the analysis of an interference pattern in an opposite side channel surface. Therefore, a means to screen, that is, to select a reconstituted fuel bundle on a quality can be obtained. |
