Jennifer Matzel | 18-ERD-016
Stable isotope compositions of nuclear materials can provide additional signatures of nuclear material production processes that offer a fuller, more accurate picture of potential proliferative activities at a nuclear facility. In this project, we analyzed the stable isotope compositions of nuclear materials of known provenance and production history to establish the ability to interpret isotope signatures at three stages of the nuclear fuel cycle: (1) conversion to uranium oxide; (2) uranium enrichment; and (3) plutonium production in a reactor. Our research was motivated by observations of apparent stable isotope signatures in nuclear materials that lack a known provenance, where attempts to establish a working understanding of these signatures were frustrated by a lack of knowledge about the production history of the material. Our work found that calcination is the critical step in defining the oxygen isotope signature of uranium oxides and forms the basis of a global model to predict the probable location of origin of uranium dioxide fuel pellets. The research also characterized the degree of molybdenum isotope variation at the start of the uranium fuel cycle and demonstrated that large, mass-dependent variations in molybdenum isotopes of highly enriched uranium oxides are likely related to the enrichment process that produced them. Finally, the research developed new tools to characterize reactor operating parameters from stable fission product measurement in spent fuel or stable activation products in reactor structural components that maximize information return from small samples with as little handling as possible. These new stable isotope signatures can provide indicators of historic or ongoing proliferation activities and can contribute to analysis of the method or sophistication of different nuclear material production pathways.
This work provides new tools to detect and characterize the production of nuclear materials at multiple points in the nuclear fuel cycle, offering a fuller, more accurate picture of potential proliferative activities at a nuclear facility. The development of unique isotopic signatures of nuclear proliferation, coupled with state-of-the-art analytical methods, are foundational capabilities of Lawrence Livermore National Laboratory's forensic science mission and the Laboratory's nuclear, chemical and isotopic science and technology core competency. The work also supports Livermore's nuclear threat reduction mission to prevent and detect state and non-state actors' acquisition of weapons-useable nuclear material, technology, and expertise. These new stable isotope signatures can provide indicators of historic or ongoing proliferation activities and can contribute to analysis of the method or sophistication of different nuclear material production pathways. As such, the work advances the mission of NNSA's Office of Defense Nuclear Nonproliferation to develop ways to detect and characterize foreign nuclear fuel cycle and weapons development activities and to provide the technical means to monitor and verify compliance with nuclear weapons materials reduction agreements.
Publications, Presentations, and Patents
Matzel, J. 2018. "Oxygen isotope compositions of uranium oxide by NanoSIMS." Nuclear Forensics User's Group Meeting, Aldermaston, UK, September 2018. LLNL-PRES-757797
Rolison, J. M., 2018. "Molybdenum isotope composition of nuclear materials: Methodology and results from uranium ore concentrates." Eleventh International Conference on Methods and Applications of Radioanalytical Chemistry, Kailua-Kona, HI, April 2018. LLNL-POST-748543
Rolison, J. M., et al. 2019. "Molybdenum isotope compositions of uranium ore concentrates by double spike MC-ICP-MS." Applied Geochemistry 103:97-105. doi:10.1016/j.apgeochem.2019.03.001. LLNL-JRNL-758218
Savina, M., et al. 2019. "Spent nuclear fuel analysis by resonance ionization mass spectrometry." 29th Goldschmidt Conference, Barcelona, Spain, August 2019. LLNL-PRES-791401
Singleton, M., et al. 2019. "Variation of oxygen isotopes in uranium oxide fuel pellets." National Meeting of the American Chemical Society, Orlando, FL, April 2019. LLNL-PRES-771053
Trappitsch, R., M. R. Savina, and B. H. Isselhardt. 2018. "Resonance ionization of titanium: high useful yield and new autoionizing states." Journal of Analytical Atomic Spectrometry 33 (11):1962-1969. doi:10.1039/c8ja00269j. LLNL-JRNL-756574
Weisman, I., et at. 2019. "Oxygen isotopes in uranium oxides measured by NanoSIMS: Refining a technique for nuclear forensics." National Meeting of the American Chemical Society, Orlando, FL, April 2019. LLNL-PRES-770545