Annual Report 2009/2010 - JUWEL - Forschungszentrum Jülich

Experimental details
The corrosion experiments of UAl x -Al fuel elements have been carried out in glass
autoclaves which contain the salt brine of definite composition. In order to simulate the
corrosion of the iron waste package FeCl 2 4H 2 O has additionally been added. The
experiments were carried out at 90°C and under an atmosphere being free of carbon dioxide
and oxygen. The autoclaves are shown in Fig. 20.
Fig. 20: Experimental setup of the corrosion experiments of unirradiated UAl x -Al fuel
elements: Left: Schematic autoclave setup. Right: Experimental autoclave setup.
After the termination of the corrosion experiments the solids were pre-treated with
isopropanol and then dried. As subsequent procedure the solids were subjected to the grain
size separation. This was done by sieving and by the application of the Atterberg method in
order to gain fractions > 63 μm, 2 – 63 μm, and < 2 μm. More details about the technical
setup and the sample pre-treatment is given elsewhere [2].
Before the XRD analysis these different grain size fractions of the secondary phases were
afterwards intimately mixed with an internal zincite standard of known weight in order to
assess the amount of each crystalline phase and the amorphous content as well by the
Rietveld method [3].
For the XRD measurements it has to be assured that the samples were under an inert
atmosphere while they were exposed to the X-rays. This was realized by the application of a
climate chamber which is shown in Fig. 21.
The dedicated atmosphere was established by an inert gas flow of Nitrogen through the
climate chamber. For the XRD measurements Cu K radiation ( 1
The gained intensity was generally registered by a NaI scintillation point detector on the one
of intensity within long term measurements was important. To account for the iron
fluorescence or any other parasitic radiation like Cu K a graphite monochromator or a nickel
foil filter was applied for their suppression.
For the accurate determination of the crystalline and amorphous phase content the particle
dimensions of the different grain size fractions have to be measured precisely [4]. Therefore
isopropanol suspensions of each fraction were subjected to supersonic treatment for
homogenisation reasons and afterwards prepared for REM analysis. With image analysis
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