Using CID for internals visual inspection and measurement

Solid state sensors for video camera applications, notably the CCD (charge coupled device), tend to be much more compact than conventional tubes and therefore offer advantages in remote viewing applications. A major drawback in the nuclear context, however, is their low tolerance to radiation. Recently, however, Electricite de France and the French company Image Technologie have been working on a solid state vision system using CID (Charge injection device) technology, which is radiation resistant up to 105 gamma absorbed dose. The particular application is inspection and measurement of clearances in PWR core guide tubes. The system promises to save outage time by combining metrology with visual inspection - effectively two tools in one. Clearance measurements are made via the screen on the operator's computerized control system using an electronic grid system. Images can then be stored on magnetic tape. The CID camera is located at the lower end of a system of linked rods. The rods connect to a special head at the upper end, which provides fine height adjustment of the tool assembly. (author)