French developments in the ultrasonic examination of pressure vessels

In 1985, 34 Pressurized Water Reactors (PWRs) were already in service in France and 21 were being constructed. The manufacturer (Framatome) and the owner (Electricité de France, EDF) have consequently gained great experience in the ultrasonic examination of the various components and particularly of the reactor vessel. The development work initiated concerns: • —the improvement of the knowledge of methods used; • —the beginning of automation in fabrication control; • —the continuation of the technical implementation of the signal and image processing. At the fabrication stage, work was carried out to demonstrate the total adequacy of those examinations required by the RCCM Code. In addition, Framatome is developing the automation of ultrasonic inspection in shop. Inservice inspection of the vessel is carried out with ‘MIS’ inspection equipment. Data analysis is improved by special software allowing the performance of different types of UT indications to be presented. Diffraction echoes from focused probes are used to size underclad defects on reactor nozzles.