FLAW INSPECTION METHOD FOR MAIN PIPELINES USING RADIOACTIVE TRACERS Russian patent published in 2000 - IPC

FIELD: in-service nondestructive flaw inspections. SUBSTANCE: method involves organizing process section inside pipeline separated from its main space with its external wall being that of pipeline; filling pipeline with process medium; marking process medium with radioactive tracer substance; displacing process section along pipeline part under inspection; rinsing pipeline wall, and displacing tracing substance detector at the same time recording radiation level and distance covered; data obtained is used to locate flaws, if any. Process section is organized so as to provide annular cavity to receive process medium and is displaced at speed equal to 1.0-50% of that of medium handled by pump; pipeline wall is rinsed by means of handled medium which is transferred through process section along inner wall of annular cavity. Radioactive isotopes of inert gases krypton-85 and/or xenon-133 are used for marking process medium. EFFECT: improved environmental friendliness of method without impairing pipeline carrying capacity. 8 cl, 2 dwg