Development of an Underwater Radiography Inspection System for Inspection of Flexible Risers
An EU collaboration between EU companies and research organisations, known as FlexiRiserTest, has been working to produce an underwater radiography inspection prototype system suitable for the inspection of flexible risers. It is believed to be the first time ever that a marinised digital radiograph flat panel detector for underwater inspection has been reported.
Usually, film or phosphor plates are used in underwater radiography, but after exposure to radiation it is necessary for such radiographic media to be returned topside for development and processing. A digital detector does not need to be removed in-between individual exposures, a task that would normally be extremely time consuming and costly when operating in a subsea environment.
The developed marinised digital detector can rapidly produce digital radiographic images of the riser and relay the results via an umbilical to the topside computer. The partners have also developed a robot crawler to facilitate the underwater radiographic inspection system deployment.
The inspection technology has been tested to 20 meters water depth, but the partners in the project are confident that much greater depths would be possible with some further development.
The work is as a result of a 2 year European Framework 6 part funded project shared between nine organisations. The project's elected exploitation manager, CIT, was also involved in developing the technology. CIT is now setting up an NDT inspection team comprising project partners CIT, TSC and EuroNDT with the aim of carrying out sea trials to test the technology. The team will specialise in conducting underwater inspection tasks for underwater man made structures including umbilical, pipes and flexible risers.
