Inspection robot cracks the code

Ageing nuclear reactors could be made safer with a non-destructive-testing inspection robot that better detects structural damage.

This is the hope of a European consortium that is working on NozzleInspect, a £1.3m project to provide a better method for detecting cracks in the nozzle welds of a nuclear plant.

At the moment, cracks in the component are detected using ultrasonic scanners that carry a number of different probes. These probes have to be calibrated separately by an operator who is at risk of being exposed to radiation during installation. Providing one half of the UK contribution to the project, The Welding Institute (TWI) will be designing a single phased-array probe that, it claims, will be safer, cheaper and more accurate than existing systems by reducing calibration time.

Project leader Dimos Liaptsis said that the device could remove the need for human intervention in the future. He added, however, that, while the technology is already proven, several challenges remain in developing the system for nuclear inspection.

‘One difficulty is that the curvature and weld profile of a nozzle is constantly changing,’ said Liaptsis. ‘We are currently working on altering the angles of the inspection in real time, depending on where in the nozzle we are.’

The TWI team is developing a navigation system that will map the profile of the nozzle ahead of the probe. It will then recalculate the delayed time in relation to the probe in order to steer the ultrasonic beam at specific angles.

The consortium is currently working on the system specifications and hopes to produce a prototype device by 2011.