NederlandsRadiation & Environment - Tomography
NRG has extensive knowledge and expertice on the use of tomography. Tomography is a non-destructive investigation tool which has a history of more than 10 years within NRG and started with investigation of active nuclear fuel. Later, the focus shifted to complex materials investigations.
Use of Computer Tomography for Non Destructive Investigation
For more information, there is our brochure (pdf-file, 44 kb)
The advantage of tomography is the geometrical form-true reconstruction of objects, especially of regions that are difficult to reach with other techniques. Complex materials in the sense of complex geometry or complex composition are good candidates for investigation with tomography. Two-dimensional and full three-dimensional reconstruction methods are available in the 'Tomografica' reconstruction software package.
Cost efficiency is maximal for more expensive parts and objects.
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| Figure 1a: Piece of a welded tube | Figure 1b: Glasfibre reinforced resin sample |
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| Figure 1c: Slice of a ceramic blade | Figure 1d: Part of a damaged gasturbine blade |
Example of a tomography system
In the nuclear power plant of Dodewaard a tomography system was realised to investigate fuel rods and assemblies with emission tomography. This system is shown in the figure shown above.
Degradation Transform method
For this project a new mathematical method for simultaneous reconstruction of activity and density distribution of the fuel, called the Degradation Transform method, was developed by NRG. This method only needs one set of measurements. Formerly the fuel was assumed to be homogeneous in density. This is proven to be incorrect for fuel exposed to high temperatures. Now, from the same measurement, used for assessing the activity distribution, a reconstruction of the density can be made to show possible voids or cracks in the fuel.
Most measurements on fuel are 2-D tomographic measurements. Several methods for reconstruction were implemented, among them ART, MULART, ML/EM and the above mentioned Degradation Transform method. Most of them available in the tomografic software package 'TomoGrafica'.
Reporting
The results of a Tomography study are alway recorded in a document. You are free to use it for your internal or external communication. Smaller studies can be reported in a letter or a presentation
Our customers
Clients for our services are from national governmental organisations and various businesses.
NRG is also involved in European (research) projects related to the abovementioned topic. In this way clients have access to up-to-date knowledge from the international community.
Contact
Ing. B. Janssen NRG-RE, PO Box 9035, 6800 ET Arnhem, Netherlands tel: +31-263562997, fax: +31-264423635, b.janssen@nrg.eu