[1A5] Eddy current array developments for remote deployment on the ITER project
R Wasif
Innerspec Technologies, UK
The inspection of welds and components for nuclear applications can be more challenging due to extreme levels of radiation and temperature. Innerspec Technologies UK Ltd (ITUK) has undertaken a development project in collaboration with the UK Atomic Energy Authority (UKAEA) to develop non-destructive testing (NDT) procedures for inspecting the remotely welded joints within the ITER facility. Initially, a feasibility study was carried out to identify the most suitable NDT technique. Eddy current array (ECA), phased array ultrasonics and guided wave electromagnetic acoustic transducers (EMATs) were considered as candidate solutions and, following the feasibility study, ECA was selected to be taken forward for further development.
Subsequently, dedicated high- and low-frequency array probes have been developed and tested to detect and size the surface and buried defects, employing encoder and calibration curves. The research has also been extended to characterise defects such as tungsten inclusions using the phase angle. To avoid damage to the electronics in extreme environments, ECA probe coils were separated from the excitation and data acquisition unit with 60 m coaxial coils to achieve a high signal-to-noise ratio. The results revealed that the ECA technique can successfully be deployed remotely for the detection and sizing of defects down to 3 mm in extreme environments.
Subsequently, dedicated high- and low-frequency array probes have been developed and tested to detect and size the surface and buried defects, employing encoder and calibration curves. The research has also been extended to characterise defects such as tungsten inclusions using the phase angle. To avoid damage to the electronics in extreme environments, ECA probe coils were separated from the excitation and data acquisition unit with 60 m coaxial coils to achieve a high signal-to-noise ratio. The results revealed that the ECA technique can successfully be deployed remotely for the detection and sizing of defects down to 3 mm in extreme environments.
