2002 Volume 1 Issue 2 Pages 209-219
With a view to utilizing in post-irradiation examination (PIE) of fuel assemblies the powerful technique of nondestructive X-ray computed tomography (X-ray CT scanning) widely used in medical practice, the technique was further developed and successfully applied to a spent fuel assembly irradiated to 59 GWd/t in the JOYO experimental FBR.
The effect of gamma rays emitted from the spent fuel was mitigated by the use of pulsed high-energy X-ray source, which contributed to obtaining clear cross sectional images, from which a 3-dimensional image could be derived.
Application of the technique thus developed should permit enhancing the resolution of measurements and simplifying fuel PIE. Defect size was measured within an error of ±0.3mm, and differences in density distinguished down to ±4% in a material of density -8g/cm3 density.
With such accuracy, non-destructive PIE could well come to replace destructive method in many instances, to enhance efficiency and reduce radioactive waste. The technique could further be applied to the analysis of overall fuel assembly behavior, such as bundle-duct interaction and central void distribution affected by irradiation temperature.
