Patent ID: 7104127

Claim:
A nondestructive method for determining a defective cladding of a nuclear fuel rod from the presence of a liquid in the fuel rod, comprising the steps of: (a) providing a tube to be inspected, wherein the tube comprises an outer surface and an internal surface; (b) arranging a wave emitter close to a side of the tube to be inspected for discharging an inspection wave obliquely incident to a first position on the outer surface by a predefined tilt angle and subsequently progressing to come into contact with the internal surface at a second position thereon; (c) arranging a receiving device at another side of the tube with respect to the wave emitter for receiving the inspection wave passing through the tube; (d) making an evaluation to determine whether the passing-through inspection wave can only be detected by the receiving device while the same is being arranged at a specific position at another side of the tube with respect to the wave emitter; if so, it represents that there is no liquid existed inside the tube under the level indicated by the second position; (e) making an evaluation to determine whether the passing-through inspection wave can be detected by the receiving device while the same is being arranged at two different positions both at another side of the tube with respect to the wave emitter; if so, it represents that there is liquid existed inside the tube at the level indicated by the second position.