13th March 2018
Aroldo Claus is an NDT data analyst level 3 at Nucleoeléctrica, CIVA user in Argentina.
What is your day to day job today?
Taking into account the fact that the main job of our department is to perform in service inspections (ISI) of the nuclear power plants ATUCHA 1 and 2 (PHWR) and Embalse (CANDU), working for the Gerencia de Servicios para Centrales (GSPC, Service Management for Power Plants) of Nucleoélectrica Argentina SA (NA-SA); the day to day in my job as ultrasonic data analyst can be resumed as follows:
When in service inspections are performed, I analyze the data given by the UT robotic team that mainly inspects welding of the primary circuit. Many times I rely on the CIVA models.
Then, the other part of the year, when preparing the in service inspections of the mentioned plants, I take care of preparation work, revision and actualization of inspection techniques.
How did you discover NDT simulation?
This is a very interesting question for me, since my first approach to NDT modeling, we could say, was very lateral. In 2000, at the beginning of my career in NDT, I was working in the seamless pipe factory of Tenaris Siderca for the Universidad Tecnológica Nacional Facultad Regional Delta (National Technological University Delta Regional Faculty), as training and certification assistant according to ISO 9712 of NDT operators. On that date, in the R&D center of that factory, they already used CIVA (Version 8), and they were dictating CIVA training in an office next to ours. That's how I discovered CIVA.
What convinced you to use CIVA?
First, the need to incorporate to the GSPC an NDT modeling tool that not only provides ray tracing, but also the interaction between the elastic wave and the material and its defects.
Secondly, the large number of validations and publications that the CEA has made, as well as some studies of the EPRI.
Finally, the NDT operator-oriented approach of this tool is very important, facilitating its usability with respect to general purpose tools of Finite Element Analysis (FEA).
For which kind of applications do you use it the most?
For the verification of existing trials and procedures. For example, the modelling of the beam of probes, the verification of coverage, the comparison between codes of application (ASME XI vs KTA 3201.4, ASME V vs CSA N285, etc.).
For the development of new inspection procedures. Definition and modelling of transducers, calibration blocks, verification blocks. Comparison of the new procedure vs the previous one before some witness reflectors.
To help for the validations of inspections according to the ENIQ (this is a work that is just beginning to be carried out).
I understood that you use the UT, ET and GWT modules in CIVA. Do you perform in practice other kinds of inspections?
Our department also uses the following methods for the different inspections required in the NPP:
- Penetrant testing
- Magnetic flux leakage
- Industrial Radiography (Gamma and X)
- Vacuum or leak test
- Magnetic particles
- Visual inspection
What is the main problematic you are facing that could be solved thanks to simulation?
I would like to name two among many others:
The modeling of the inspection of dissimilar welds in a component of conical external geometry and containing in the inner part thermal sleeves, using TRL transducers (in a PHWR reactor). This is a manual conventional ultrasound inspection A-SCAN. The signals that are presented to the operator on the screen when using TRL transducers are not very easy to discriminate, therefore the modeling of this inspection was performed in order to help the operators. On the other hand, very soon, this inspection will be updated to Dual Matrix Phased Array Probes with mechanized scan coding. Prior to the update, the modeling was carried out in order to determine the best solution.
Within the framework of the life extension project of the Embalse nuclear power plant during the replacement of all the reactor feeders, in team with Mauro Mattioli and GSPC staff, we designed the phased array encoded ultrasound inspection to replace the RX inspection requested by ASME III of the final welds of the feeders, as allowed by the CODE CASE 659-2 and the subsequent modeling of its validation.
The most notable of this project, apart from the validation, was the design of the inspection for the detection of discontinuities perpendicular to the weld seam, with access only from one side of the weld (Weld cap without stirring, in a CANDU reactor).