Even though conceptually UT of end closure welds was demonstrated on a variety of laboratory prototypes by some organisations in the past including NFC, systematic collection and analysis of this large amount of data has revealed many new angles. Some of the typical cases of interest are discussed in the paper.

This knowledge base is being utilised in the design, development and fabrication of a UT Test system with three immersion probes and which can be positioned at 120 deg thereby taking care of any variation in defect profile which is generally about 45 deg has been developed. A fourth probe is also provided to scan from plug end, which conclusively tells whether the signal is because of non-fusion or geometry of the weld. The job is rotated at low speed to avoid damage to the fuel inside. The design features incorporate facility for both backward and forward integration.