Investigation of Backscatter X-Ray Imaging Techniques for Uranium Dioxide Fuel Rods

Radiography by Selective Detection (RSD), a was investigated for its ability to determine the presence and types of defects in a UO2 fuel rod surrounded by zirconium cladding. Images created using a Monte Carlo model compared favorably with actual X-ray backscatter images from mock fuel rods. A fuel rod was modeled as a rectangular parallelepiped with zirconium cladding, and pencil beam X-ray sources of 160 kVp (79 keV avg) and 480 kVp (218 keV avg) were generated using the Monte Carlo N Particle Transport Code to attempt to image void and palladium (Pd) defects in the interior and on the surface of the fuel pellet. It was found that the 160 kVp spectrum was unable to detect the presence of interior defects, whereas the 480 kVp spectrum detected them with both the standard and the RSD backscatter methods, though the RSD method was very inefficient. It was also found that both energy spectra were able to detect void and Pd defects on the surface using both imaging methods. Additionally, two mock fuel rods were imaged using a backscatter X-ray imaging system, one consisting of hafnium pellets in a Zircaloy-4 cladding and the other consisting of steel pellets in a Zircalloy-4 cladding which was thenencased in a steel cladding (a double encapsulation configuration employed in irradiation and experiments). It was foundthat the system was capable of detecting individual HfO2 pellets in a Zircaloy-4 cladding and may be capable of detectingindividual steel pellets in the double-encapsulated sample. It is expected that the system would also be capable of detecting individual UO2 pellets in a Zircaloy-4 cladding, though no UO2 fuel rod was available for imaging.

References
1. Weinberg, M. The Quantum Theory of Fields, 1995. 2. Blinder, S.M. Klein-Nishina Formula for Photon-Electron Scattering. Web: Wolfram Demonstration Project website, July 20, 2010. 3. Addicott, Benjamin T. Characterization and Optimization of Radiography by Selective Detection Backscatter X-Ray Imaging Modality. Thesis. University of Florida, 2006. Web: University of Florida website, at “Scatter X-ray Imaging” 4. Shedlock, Daniel. X-Ray Backscatter Imaging for Radiography by Selective Detection and Snapshot: Evolution, Development, and Optimization. Diss. University of Florida, 2007. Web: University of Florida website, at “Scatter X-ray Imaging.” 5. XMuDat: Photon Attenuation Data on PC. Report. International Atomic Energy Agency, Aug. 1998. Web: IAEA website, July 22, 2010. 6. Oldenberg. Modern Physics For Engineers. McGraw-Hill, NY, 1966. 7. IAEA. Computational Analysis of the Behaviour of Nuclear Fuel Under Steady State, Transient and Accident Conditions. Rep. No. 1578, International Atomic Energy Agency, Dec. 2007. Web: IAEA website, July 15, 2010. 8. Brashier, Raymond W. Method of Inspecting the Quality of Nuclear Fuel Rod Ends. Westinghouse Electric Corp., assignee, Patent 4994232, Feb. 19, 1991. 9. Groeschel, F. “Neutron Radiography of Irradiated Fuel Rod Segments at the SINQ: Loading, Transfer and Irradiation Concept,” Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 424.1, 215–20 1999. Web: ScienceDirect, July 15, 2010. 10. Briesmeister J.F. Ed. MCNP—A General Monte CarloN-Particle Transport Code. LANL Report LA-13709-M, Los Alamos National Laboratory, Los Alamos, NM, 2000. 11. Image J. NIH. Web: . 12. Nucsafe. Web: .
Metrics
Usage Shares
Total Views
9 Page Views
Total Shares
0 Tweets
9
0 PDF Downloads
0
0 Facebook Shares
Total Usage
9