Mechanized Dye Penetrant of Valve connection welds

Landaeus, M.; DEKRA Industrial AB; Sweden

Landaeus, M.; DEKRA Industrial AB; Sweden
Fohlin, N.; DEKRA Industrial AB; Sweden
Hallqvist, T.; DEKRA Industrial AB; Sweden

ID: ECNDT-0160-2018

There are often inspection challenges regarding attenuation, geometry or limitation due to obstacle of testing valve connection welds in nuclear power plants. This can also be the case of other components in certain material not suitable for UT and requirements to inspect the media surface. There are also high doses in these areas that makes a efficient mechanized system necessary. DEKRA has developed a system using qualified mechanized Dye Penetrant technique. The manipulator, named Bläckfisken, uses special arms with rails to apply the DPI tool to the inspection area. The manipulator follows a predefined trajectory that is unique for each valve. New valve trajectories can be generated and tested offline in the control software.
The NDT system is currently in use for periodic in-service inspection at Forsmark 3 BWR. The system is qualified by the Swedish Qualification Body and fulfilling the demands in Sweden and ENIQ. The arms is developed to fit into many different valve types and manage very small valve openings and long distances from the mounting of the manipulator to the weld. There are many challenges regarding DPI technique with small spray nozzles and small camera systems working around obstacles etc. This new generation of manipulators is also prepared for full inner surface DPI inspection of the pipe surface.