| Popis: |
To analyse highly diluted samples of nuclear reprocessing plants outside hot cells, and to minimize the risks of radiation on operators and materials, a multielement determination method with low detection limits is required. Total Reflection X-Ray Fluorescence Analysis (TXRF) combines these demands with the advantages of simplicity of sample preparation, the need for only small amounts of sample and the circumstance of yielding a minimum amount of additional (active) waste. This method was therefore assessed as to its possible application in the analytical procedures of nuclear reprocessing plants. For this purpose a TXRF-spectrometer was installed partially in a glove box. New instrumental developments were required for sealing the cryostat and the cable connections of the high voltage supply of the X-ray tubes. The application to simulated medium and highly active waste solutions and processing streams containing uranium and thorium shows good results for the determination of U and a large number of elements, e.g. Cs, Ba, Ru, Rh, Pd, Te, Sb, without any preceding separation. However, relatively large amounts of iron (in medium active waste MAW) and uranium, at a ratio of about 50: 1 and higher, should be separated because of coincidence of U L-lines and K-lines of the fission product elements (Rb up to Pd). The accurate determination of lanthanide L-lines in highly active waste (HAW) was not possible without separation. The results of the inactive measurements using simulated solutions permit it to extend investigations to active samples in order to proof the capability of TXRF in the analysis of real-life solutions of nuclear reprocessing plants. |
