METHOD FOR ULTRASOUND SHADOW TESTING OF EMPTINESS OF COMPENSATOR OF CORE OF DISPERSION- TYPE FUEL ELEMENTS Russian patent published in 1999 - IPC

FIELD: ultrasound flaw detection, in particular, for testing fuel elements of nuclear reactors. SUBSTANCE: method involves movement of fuel element along its axis, sounding it in cross-section plane, choosing delay and duration of first gate pulse as equal to delay and duration of first half-wave of signal which has passed through core. This half-wave is detected by means of second gate pulse which delay is equal to delay of first half-wave of signal which has passed through plug, and duration is restricted by arrival of second half-wave of signal which has passed fuel element in any position. In addition method involves comparison of position of detected half-wave to position of first gate pulse. Core beginning is detected by end of transient process from mismatch to match of first half-wave and first gate pulse. End of core is detected by start of transient process from match to mismatch. Flaw is detected in cases if first half wave raises in fuel element piece from start to end of core. EFFECT: possibility to control emptiness of dispersion-type fuel element along complete core length. 4 dwg