The need to test difficult to access, thick section steel components for weld defects and in-service corrosion that may lead to pressure vessel/component failure in the nuclear power generation industry requires the application of high sensitivity ultrasonic testing (UT) techniques. However the transducers that generate the beams of ultrasound do not operate well in radioactive environments and their response quickly deteriorates such that they are rendered of little use for defect detection/monitoring. This project will research the construction and testing of novel, radiation resilient, ultrasonic transducers manufactured from exotic materials and a variety of probe assembly techniques. The goal is to provide the nuclear industry with a reliable UT solution for prolonged in-service inspection and permanent monitoring. Two scenarios are envisaged: (a) elevated temperature, high radiation inspection close to the nuclear reactor (b) low radiation - inspection of nuclear waste containers stored at bespoke sites over very long periods. Our objective is to develop a series of prototype ultrasonic probes designed to suit the specific in-service inspection needs.