Laser-based systems for non-contact generation and detection of ultrasound are being investigated at the CEGB's Marchwood Engineering Laboratories for application to remote non-destructive inspection problems. These include the in-situ inspection of the graphite bricks that make up the cores of Advanced Gas-Cooled Reactors (AGR's). The propagation of laser-generated ultrasonic pulses in AGR graphite has been studied using a laboratory system incorporating a Q-switched ruby laser generator and Michelson interferometer detector