Application of HRGS for forensic characterization of uranium oxides, pure uranium metals and uranium alloys.

A nondestructive iterative method for uranium-bearing material characterization with HRGS developed earlier in Burdeinyi et al. (2020) is applied to determine matrix densities, uranium mass fraction and uranium isotope masses of uranium ore, UO and UO powders, fuel elements in the form of UO microspheres, uranium metal and uranium alloys. It is shown that UO powders with uranium mass fraction of about 84% can be distinguished from the powders of UO with uranium mass fraction of about 87%; uranium products in the form of liquid or loose powder with matrix density of 0.5-2.0g/cm can be distinguished from uranium products in the form of compacted fuel elements with matrix density of 6.0-10.0g/cm and from pure metal uranium and uranium alloys with matrix density of 14.0-19.0g/cm. In fuel microspheres based on UO the uranium mass fraction 88.02% measured by HRGS is consistent, within the measurement uncertainties, with the results of isotope dilution mass spectrometry 87.76±0.64% and also is confirmed by X-ray diffraction technique. The uranium mass fraction of the uranium ore estimated as 0.08% by HRGS is consistent, within the measurement uncertainties, with the value 0.09±0.01% determined with WDXRF. Densities of two different uranium metal samples, estimated as 18.42g/cm and 19.33g/cm by HRGS are consistent with values 18.24±0.55g/cm and 18.86±0.59g/cm, respectively, obtained by the gas pycnometry technique.