Ultrasonic monitoring of the VVER-1000 FA form change

A procedure has been developed to determine the geometrical parameters of fuel assemblies (FA) by an ultrasonic pulse-echo technique used for all types light-water reactor FAs. The measurement is achieved through pairwise installation transducers opposite FA spacer grid faces at a distance not more than half transducer acoustic field near-region length such that axes are parallel each other. advantages presented it enables monitoring any modifications, including VVER with different number grids. paper presents mathematical model path in acoustics approximation and its verification results. was computational experimental studies test technique, engineering formulas have calculate errors transducer-measured surface. code simulate form change can be design new systems. VVER-1000 introduced units 1 2 Temelin NPP, Czech Republic, TVSA-T monitoring. successful use proposed makes possible recommend inspection benches other NPPs.