The inspection of Fast Breeder Test Reactor ( PBTR) fuel pin end plug welds by X-ray radiography presents certain problems in detecting extremely small defects in the weld zone because of the special geometry of the components. The use of a defect standard in addition to the conventional image quality indicators has been explored. Characterisation of the radiographs of standard defects and evaluation of typical defects from weld radiographs have been carried out using a scanning microdensitometer.