Speaker
Description
Introduction
An exercise for emergency situations was held in the Austrian Agency for Health and Food Safety in cooperation with the federal state Carinthia. The Exercise was funded by the Federal Ministry of Sustainability and Tourism. Therefore 21 soil samples, 19 ground vegetation samples and 6 sediment samples were collected. During former emergency exercises samples were only measured by gamma spectrometry. This time 10 samples were selected after the gamma measurements to perform an exercise with radiochemical sample preparation for Sr-90, Am-241 and Plutoniumisotopes. These samples were analysed using a rapid method and afterwards by using a method for monitoring measurements.
The goals of these exercises are first to establish sample preparation methods and analyses which can be performed at once after an emergency situation with all the equipment and software needed at hand. Second to train the people which have to perform those analyses so that they can perform them “blindfolded” and third to determine the activity concentrations now present in these samples with the monitoring measurements.
Material and Methods
Internal standards were added to 4 of the 10 samples before the sample preparation. The results of the monitoring measurements were used to evaluate the results of the rapid determination. Therefore ashing, leaching and adding of the internal standards to the sample was conducted and afterwards two subsamples were created – one for the monitoring and one for the rapid determination.
The separation of the analytes for the rapid determination was conducted with Sr-Spec Resin and DGA Resin. Sr-90 was measured with Liquid Scintillation Counting and the chemical recovery was measured by Sr-86 and Sr-88 with ICP-MS. Am-241 and the Plutonium isotopes were measured with alpha spectrometry and Pu-239 was measured with ICP-MS.
During the analyte separation for monitoring, an ion exchange chromatography and in soil samples TEWA resin was used in addition to the other resins.
Results and Discussion
12 samples can be analysed within 48 hours even by one person. If two people are conducting the separations 12 samples can be analysed within 24 hours (ashing and digestion not included). The results of the samples with internal standard addition were in consistence with the calculated value. Furthermore the results of the rapid methods were in agreement with the monitoring determination. Within two soil samples Pu-239/240 and Am-241 could be determined with the rapid method although no internal standard was added. The activity concentration of sample 7 was 1.78 ± 0.12 Bq/kg for Pu-239/240, 0.049 ± 0.012 Bq/kg for Pu-238 and 0.744 ± 0.074 Bq/kg for Am-241. The activity concentration of sample 8 was 1.54 ± 0.09 Bq/kg for Pu-230/240, 0.0364 ± 0.0062 Bq/kg for Pu-238 and 0.573 ± 0.046 for Am-241. Thus the rapid determination can be successfully used to determine samples with elevated activity concentrations compared to the current values.
