Recent developments in ultrasonic probes working up to 180 deg C for the inspection of the Superphenix fast breeder reactor

The main and safety vessels of SUPERPHENIX were designed to allow In-Service-Inspections. The remote controlled device MIR was developed for this purpose. The ultrasonic examination has required the development of all new focused transducers fitted with severe operating conditions prevailing in the intervessels interval: nitrogen gas at 1800C. We give a list of problems to be resolved and technological solutions which were found. Measurements of acoustical properties on actual probes are compared with theoretical values. We produce some examples obtained in actual conditions which show the detection of reference reflectors located in welds at various depth, with various disalignements against focus beam. Inspite of the severe environment and the perturbations caused by the austenitic welds, the I.S.I of SPX1 using high temperatures transducers is possible with a good spatial resolution and signal to noise ratio