USING SYNCHROTRON LIGHT TO FOLLOW CORROSION IN SIMULATED INTERMEDIATE LEVEL WASTE PACKAGES

摘要

High energy x-rays provide an excellent means of characterising the heterogeneous nature of materials, allowing undestructive and in-situ observation of processes occurring below the surface. The high energy x-ray source of beamline ID11 at the European Synchrotron Radiation Facility (ESRF) has been used to characterise a number of aspects of the cement-aluminium system as a simulation for studying the reactions which occur during encapsulation of Intermediate Level Waste (ILW). Diffraction Contrast Tomography (DCT), a metallurgical characterisation technique has been used to map the grain structure of the aluminium metal before its confinement in cement. X-ray diffraction computed tomography (XRD-CT) has been employed to follow the reactions occurring between the cement and aluminium wire after curing, providing a 2D slice through the sample and allowing the spatial location of each chemical phase present to be identified. This was done alongside Phase Contrast Tomography (PCT) to give a full 3D volume of the sample. The purpose of combining these techniques was to provide a means of identifying the extent of corrosion, the reaction products present and their spatial locality within the sample volume. These types of result spread over an extended time period aim to describe the condition of the simulated waste packets so as to provide a proxy for anticipating the condition and evolution of real stored waste.