Rapid Separation of Photofissioned Uranium Products via a Single-Pass Multiplexed Chromatographic Fission Product Separation System
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07 ISOTOPE AND RADIATION SOURCES↗
Engineering topics
Carney, Kevin
Publications and source records attributed to Carney, Kevin.
A composite position independent monitor of reactor fuel irradiation using Pu, Cs, and Ba isotope ratios
When post-irradiation materials from the nuclear fuel cycle are released to the environment, certain isotopes of actinides and fission products carry signatures of irradiation history that can potentially aid a nuclear forensic investigation into the material's provenance. In this study, combinations of Pu, Cs, and Ba isotope ratios that produce position (in the reactor core) independent monitors of irradiation history in spent light water reactor fuel are identified and explored. These position independent monitors (PIMs) are modeled for various irradiation scenarios using automated depletion codes as well as ordinary differential equation solutions to approximate nuclear physics models. Experimental validation was performed using irradiated low enriched uranium oxide fuel from a light water reactor, which was sampled at 8 axial positions from a single rod. Plutonium, barium and cesium were chemically separated and isotope ratio measurements of the separated solutions were made by quadrupole and multi-collector inductively coupled mass spectrometry (Cs and Pu, respectively) and thermal ionization mass spectrometry (Ba). The effect of axial variations in neutron fluence and energy spectrum are evident in the measured isotope ratios. Furthermore, two versions of a combined Pu and Cs based PIM are developed. A linear PIM model, which can be used to solve for irradiation time is found to work well for natural U fuel with <10% 240 Pu and known or short cooling times. A non-linear PIM model, which cannot be solved explicitly for irradiation time without additional information, can nonetheless still group samples by irradiation history, including high burnup LEU fuel with unknown cooling time. 137 Ba/ 138 Ba is also observed to act as a position independent monitor; it is nearly single valued across the sampled fuel rod, indicating that samples sharing an irradiation history (same irradiation time and cooling time) in a reactor despite experiencing different neutron fluxes will have a common 137 Ba/ 138 Ba ratio. Modeling of this Ba PIM shows it increases monotonically with irradiation and cooling time, and a confirmatory first order analytical solution is also presented.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Quantification of 85 Rb, 136 Ce, 142 Nd and 150 Nd Enriched Isotope Standards
Enriched isotope standards are required for routine nuclear fuel burnup and other radiochemical analyses. In 2017 Idaho National Laboratory (INL) generated isotope standard solutions containing enriched 85 Rb, 136 Ce, 142 Nd, and 150 Nd. Oxide and chloride forms of each enriched isotope were obtained from the Oak Ridge Isotope Production program, dissolved, and quantified by isotope dilution-multi collector mass spectrometry. Quantification of the isotope solutions was performed independently by two separate laboratories at INL: the Analytical Laboratory (AL) at the Material and Fuels Complex (MFC) and the Ultra-trace Analytical Laboratory (UAL) in Idaho Falls. Concentration measurement results for all solutions and 142 Nd isotope ratio values reported by both laboratories are in quantitative agreement with each other, while isotope ratio values reported for 150 Nd are observed to have an apparent ~0.8% bias between the results of each laboratory. Data for 85 Rb/ 87 Rb isotope ratio values for UAL TIMS measurements and AL MC-ICP-MS measurements are in quantitative agreement with each other, while those of UAL MC-ICP-MS are observed to be much higher due to the existence of unidentified polyatomic interferences in the 84-88 m/z range for this instrument. Concentration and isotope ratio values for these isotope tracer solutions, along with detailed description of the analytical and data analysis methods utilized, are reported herein.
07 ISOTOPE AND RADIATION SOURCES↗
RADIOLOGICAL SEALED SOURCE LIBRARY: A NUCLEAR FORENSICS TOOL
If a terrorist were to obtain and possibly detonate a device that contained radiological material, radiological forensic analysis of the material and source capsule could provide law enforcement with valuable clues about the origin of the radiological material; this information could then provide further leads on where the material and sealed source was obtained, and the loss of control point. This information could potentially be utilized for attribution and prosecution. Analyses of nuclear forensic signatures for radiological materials are generally understood to include isotopic ratios, trace element concentrations, the time since irradiation or purification, and morphology. Radiological forensic signatures for sealed sources provide additional information that leverages information on the physical design and chemical composition of the source capsule and containers, physical markings indicative of an owner or manufacturer. Argonne National Laboratory (Argonne), in collaboration with Idaho National Laboratory (INL), has been working since 2003 to understand signatures that could be used to identify specific source manufacturers. These signatures include the materials from which the capsule is constructed, dimensions, weld details, elemental composition, and isotopic abundances of the radioactive material. These signatures have been compiled in a library known as the Argonne/INL Radiological Sealed Source Library. Data collected for the library has included open-source information from vendor catalogs and web pages; discussions with source manufacturers and touring of production facilities (both protected through non-disclosure agreements); technical publications; and government registries such as the U.S. Nuclear Regulatory Commission’s Sealed Source and Device Registry.
National Nuclear Forensics Library↗