Detecting low levels of transuranics with electron energy loss spectroscopy

With the second difference electron energy loss spectroscopy (EELS) technique, transuranic (TRU) and rare-earth (RE) elements have been detected at low concentration levels (< 200 ppm) in alteration phases formed during the laboratory corrosion of nuclear waste glass. Use of the high-energy M4,5 edges to detect TRU elements is the only method available to positively identify them because the weaker lower-energy N4,5 edges overlap with the more intense M4,5 edges of the trace levels of REs that may be present in the same alteration phases. The position and intensity of the M4,5 absorption edges of the TRU were confirmed with samples of transuranic contaminated soils and data from the literature. The M4 : M5 ratio for the actinide absorption edges was used, in combination with crystal chemical considerations to determine chemical state.