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A strategy for vitrification product assurance and control with X-ray fluorescence spectrometry (PACX)

Conference ·
OSTI ID:210227
 [1]
  1. Clemson Univ., SC (United States)

A product control strategy is proposed for the vitrification of low-level and/or mixed waste. This strategy is called Product Assurance and Control with X-ray fluorescence spectrometry (PACX). The strategy utilizes sequential wavelength dispersive x-ray fluorescence spectrometry and standardless fundamental parameters calculations to analyze both the melter feed and the glassy products. The melter feed is sampled prior to addition to the melt tank and then melted and cast into samples which should closely resemble the product from the vitrification process itself. The resulting sample disks are then analyzed by x-ray fluorescence spectrometry. All elements with atomic numbers down to sodium can be determined directly and then either boron or lithium can be determined by difference from the mass balance. The XRF intensities are converted into oxide compositions with the use of a novel standardless fundamental parameters program. Previous work has shown that there is an excellent correlation between the XRF results and the results from conventional wet chemical analyses, but the XRF results can be obtained within two to three hours of sampling. If compositional control limits for durability are available, the product acceptability can be determined prior to the batch being introduced into the melter. The durability could also be estimated from a model, if available, which predicts product durability from composition. If the predicted durability is estimated to be too low, the model can then be used to determine additives which will raise the durability of the final product to within acceptable limits. The additives can then be incorporated into the batch prior to addition into the melter. A similar XRF analysis can be carried out on the glass product from the melter which can then be used to predict and thus assure product acceptance.

OSTI ID:
210227
Report Number(s):
CONF-9509139--
Country of Publication:
United States
Language:
English