Selecting suitable software
It was recognised early in the project that to accurately address the inspection problem three-dimensional design tools would be essential. The Zetec UltraVision 3D ultrasonic software package was selected for the design and verification of the methodology. This tool allows the user to input the critical flaws in different parts of the nozzle joint and select the most suitable beams from a phased array probe to detect them. This was validated experimentally during the project and shown to be a viable route for designing the inspection techniques.
TWI evaluated the generic methodology using the two prototype systems from Olympus and Phoenix/M2M, using a different TWI-developed procedure for each. The ENIQ approach of identifying the essential parameters was followed to provide a capability statement for inspection of the nozzle joints. TWI specified two specimens containing flaws for this assessment, which were fabricated by Sonaspection.
Hands-on testing and validation
Qualified PAUT Level 2 operators followed the procedures and reported on the specimens, providing an independent assessment of the systems’ capability and performance. This exercise was also a valuable way to identify practical issues which could then be reported back to the suppliers to help them develop their inspection products.
TWI compared the experimental findings with simulations created using the CIVA software package to build a technical justification for the use of PAUT for inspection of nozzle joints. This document is important to ensure that end-users can rely on the inspection results and also, crucially, be aware of the method’s limitations, so it can be effectively and confidently used in industry.
TWI completed the project by sectioning one of the specimens to verify the presence of the flaws and additional indications found by the inspection. The second specimen was retained to aid technology transfer activities and for demonstrations to TWI Members. The specimen is also being used for training of operators and TWI is presently working on developing bespoke training programmes for TWI Members who wish to implement PAUT of their nozzle joints.