Determination of critical trace impurities in “uranium silicide dispersed in aluminium” nuclear fuel by inductively coupled plasma mass spectrometry (ICP-MS)

The quality assurance (QA) of nuclear materials is one of the most important aspects of chemical quality control (CQC) program for safe operation of nuclear reactors. The characterization of trace impurities in the starting materials and fabricated products is one of the stepping stones in the overall QA process. Depending on the reactor design and operational conditions, these trace impurities have different specification limits in nuclear materials. Reports of analytical methodologies for their precise and accurate quantification are limited in literature and “uranium silicide dispersed in aluminium” (U3Si2-Al) is no exception. U3Si2-Al is one of the most important nuclear fuels for the conversion of research and test reactors employing highly enriched uranium to the one employing low enriched uranium. A novel three step matrix separation procedure has been developed in this work for quantification of seven critical trace impurities viz., B, Cd, Hf, Eu, Sm, Gd and Dy in U3Si2-Al by inductively coupled plasma mass spectrometry (ICP-MS). The matrix elements Si and Al have been separated by offline pretreatment of the sample whereas U has been separated online before nebulizing the sample into ICP-MS. The online nebulization assisted solvent extraction of U by a stationary extractant phase has reduced the liquid waste generation drastically. The validation of the proposed analytical methodology has been done by spike addition and recovery studies in three real U3Si2-Al samples. The analyte recoveries are ≥ 95%. The relative standard deviations (RSDs) on the determined quantities have been observed within 8%.