Separation of thorium from uranium in support of particle reference material production

• Published in: Journal of radioanalytical and nuclear chemistry Vol. 331; no. 12; pp. 5237 - 5240
• Main Authors: Beck, Chelsie L., Arnold, Ean S., Warzecha, Evan J., Koh, Katherine, Stene, Riane E., Pope, Timothy R., Henson, Neil J., Vogt, Stephan K., Wellons, Matthew S., Barrett, Christopher A.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.12.2022; Springer; Springer Nature B.V
• Subjects: Chemistry; Chemistry and Materials Science; Diagnostic Radiology; Hadrons; Heavy Ions; Inorganic Chemistry; Nuclear Chemistry; Nuclear nonproliferation; Nuclear Physics; Physical Chemistry; Reference materials; Separation; Thorium; Thorium isotopes; Uranium; Separation of actinides; Age-dating; Extraction resins
• ISSN: 0236-5731; 1588-2780
• DOI: 10.1007/s10967-022-08539-z

This work investigated the utility of UTEVA and TEVA extraction resins for the separation of Th from U. The 230 Th/ 234 U radiochronometer is one “fingerprint” of nuclear material used to verify a State’s compliance with non-proliferation treaties or bi-lateral agreements. Reference materials with suitable particle densities, geometries, compositions and well-documented purification dates are continually needed. Legacy uranium inventories can be used as feedstock to produce younger reference materials, if the U and Th are quantitatively separated to reset the age of the material and allow new model ages to be developed by adding known quantities of 230 Th (e.g. SRM4325). High recoveries, > 90% of U were achieved using UTEVA but ~ 0.5% of Th remained with the U. The TEVA double stack showed quantitative recoveries of U and removal of Th below ICP-MS detection limits.