Techniques for the ultrasonic inspection of inner nozzle radius areas of L.R.W. pressure vessels

For the detection of sub cladding cracks in inner nozzle radius areas, several techniques exist, both for inspection from the inside as well as from the outside. Each of these techniques have their own merits and characteristics with regard to defect detection, manipulation and inspection time. The selection of the appropriate technique is often dominated by the particular circumstances such as type of reactor and accessibility, size and geometry of the nozzle and its radius, surface condition and existing hardware concepts for pre- and inservice examination. This paper includes an overview of the latest optimizations and improvements of various techniques. 8 refs