Use of an Infrared Spectroscopic Method
for Isotopic Analysis of Gaseous
Uranium Hexafluoride
K. Alicia Strange Fessler, Patrick E. O’Rourke, Nicholas F. DeRoller,
Darrell Simmons, and Steven M. Serkiz
Abstract A high performance infrared (HPIR) system was developed and demonstrated for the infrared absorption analysis of uranium-235 and uranium-238 isotopes
in uranium hexafluoride gas samples. The method takes advantage of the recent
commercial availability of quantum cascade lasers (QCL) and has required the use
of advanced statistical data analysis, as well as materials selection due to the chemical
reactivity of uranium hexafluoride gas. Sweeping the QCL over the spectral range and
sampling via a high-rate analog-to-digital converter provided 0.0005 cm
−1 spectral
resolution, allowing for high-precision measurements of the isotopic peak shift. A
data analysis method was developed using principal component analysis to predict the
isotope weight percent content of uranium-235. The HPIR precision, accuracy, and
error were evaluated for a wide range of isotopic ratio samples (0.287–93.7 weight
percent uranium-235), and the results were compared to the International Target
Values (ITVs) set forth by the International Atomic Energy Agency (IAEA) for
nondestructive and destructive analytical techniques used in safeguards verification
under the Treaty on the Non-proliferation of Nuclear Weapons. The method meets
or surpasses the IAEA ITVs for nondestructive analysis of samples with isotopic
content of depleted to highly enriched. The results also demonstrated the capability
of the HPIR system to correctly predict the uranium-235 weight percent content
of a mislabeled sample whose isotopic distribution was validated by mass spectroscopic measurements. The HPIR measurement is nondestructive and, thus, allows
for confirmatory analyses of the exact sample at a designated IAEA laboratory if
higher resolution or a certified analysis is needed.
K. A. S. Fessler (B) · P. E. O’Rourke · N. F. DeRoller
Savannah River National Laboratory, 301 Gateway Drive, Aiken, SC 29803, USA
e-mail: alicia.fessler@srnl.doe.gov
D. Simmons
Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37830, USA
S. M. Serkiz
Bechtel National Inc., 3000 Post Oak Boulevard, Houston, TX 77056, USA
Clemson University, Calhoun Drive, Clemson, SC 29634, USA
© The Minerals, Metals & Materials Society 2021
T. S. Srivatsan et al. (eds.), Metal-Matrix Composites, The Minerals, Metals
& Materials Series, https://doi.org/10.1007/978-3-030-65249-4_12
183
for Isotopic Analysis of Gaseous
Uranium Hexafluoride
K. Alicia Strange Fessler, Patrick E. O’Rourke, Nicholas F. DeRoller,
Darrell Simmons, and Steven M. Serkiz
Abstract A high performance infrared (HPIR) system was developed and demonstrated for the infrared absorption analysis of uranium-235 and uranium-238 isotopes
in uranium hexafluoride gas samples. The method takes advantage of the recent
commercial availability of quantum cascade lasers (QCL) and has required the use
of advanced statistical data analysis, as well as materials selection due to the chemical
reactivity of uranium hexafluoride gas. Sweeping the QCL over the spectral range and
sampling via a high-rate analog-to-digital converter provided 0.0005 cm
−1 spectral
resolution, allowing for high-precision measurements of the isotopic peak shift. A
data analysis method was developed using principal component analysis to predict the
isotope weight percent content of uranium-235. The HPIR precision, accuracy, and
error were evaluated for a wide range of isotopic ratio samples (0.287–93.7 weight
percent uranium-235), and the results were compared to the International Target
Values (ITVs) set forth by the International Atomic Energy Agency (IAEA) for
nondestructive and destructive analytical techniques used in safeguards verification
under the Treaty on the Non-proliferation of Nuclear Weapons. The method meets
or surpasses the IAEA ITVs for nondestructive analysis of samples with isotopic
content of depleted to highly enriched. The results also demonstrated the capability
of the HPIR system to correctly predict the uranium-235 weight percent content
of a mislabeled sample whose isotopic distribution was validated by mass spectroscopic measurements. The HPIR measurement is nondestructive and, thus, allows
for confirmatory analyses of the exact sample at a designated IAEA laboratory if
higher resolution or a certified analysis is needed.
K. A. S. Fessler (B) · P. E. O’Rourke · N. F. DeRoller
Savannah River National Laboratory, 301 Gateway Drive, Aiken, SC 29803, USA
e-mail: alicia.fessler@srnl.doe.gov
D. Simmons
Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37830, USA
S. M. Serkiz
Bechtel National Inc., 3000 Post Oak Boulevard, Houston, TX 77056, USA
Clemson University, Calhoun Drive, Clemson, SC 29634, USA
© The Minerals, Metals & Materials Society 2021
T. S. Srivatsan et al. (eds.), Metal-Matrix Composites, The Minerals, Metals
& Materials Series, https://doi.org/10.1007/978-3-030-65249-4_12
183