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Kayzar-Boggs, Theresa Marie

Publications and source records attributed to Kayzar-Boggs, Theresa Marie.

8 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Updated uranium reference material 231 Pa/ 235 U consensus model ages for nuclear forensics

Radiochronometry provides the model age of nuclear materials, which is useful for understanding the production history of materials found outside of regulatory control. Certified reference materials (CRMs) are important for radiochronometry to increase confidence in measurement quality; however, the absence of 231 Pa/ 235 U CRMs necessitates that nuclear forensic laboratories measure the 231 Pa/ 235 U model ages of preexisting uranium reference materials. Here, in this work, new consensus 231 Pa/ 235 U model ages are reported from three nuclear forensic laboratories for three reference materials using current analytical methods. These updated consensus values can be used for quality control of 231 Pa/ 235 U model age measurements.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2023

Plutonium Age Dating Interlaboratory Comparison Overview - Project Design, Sample Preparation, and Results [Slides]

Project Design – How do you validate measured Pu model age? There are no certified reference materials (CRMs) that are certified for Pu model age or purification dates. There are no Am isotopic CRMs - IRMM 0243 243 Am spike has 241 Am impurity that can be used; Community working toward "consensus ages." This project executed and evaluated results from a Pu age dating interlaboratory comparison with six IAEA NWAL participant laboratories. It also ran the first quality control evaluation of single-picogram to sub-picogram scale interlaboratory 241 Am assay measurements from cotton swipe matrices. Results are promising, with a majority of 241 Am/ 241 Pu model age results agree to within 1 to 4 years. The calculated 241 Am assay results show interlaboratory variability, expanded percent uncertainties on calculated consensus 241 Am concentrations were: PuAge-S1 = 3.1 %, PuAge-S2 = 23 %, and PuAge-S3 = 26 %. Data can be used to investigate laboratory methods and improve precision and accuracy of 241 Pu and 241 Am assay for future campaigns.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2023

Results from a controlled depleted uranium metal casting experiment designed to investigate nuclear Forensic Radiochronometry Signatures

The accurate interpretation of uranium metal 230 Th/ 234 U and 231 Pa/ 235 U radiochronometry model ages requires an understanding of how uranium parent nuclides and decay progeny ( 230 Th and 231 Pa) behave during uranium metal casting. In order to directly measure the spatial distribution of 230 Th and 231 Pa in uranium metal before and after vacuum induction melting (VIM), Los Alamos National Laboratory identified uranium metal feedstock, characterized the metal feedstock, conducted a controlled casting experiment of an approximately 120 kg uranium metal rod, and characterized the cast metal. Herein this study presents radiochronometry results and quantified 230 Th and 231 Pa VIM separation factors from bulk uranium.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2023

A chromatography chemistry for purifying $\mathrm{Pa}$ from $\mathrm{U-Nb}$ metal alloys

Here we present a chromatography chemistry for purifying protactinium from uranium metal alloys containing weight-percent concentrations of niobium. Niobium is precipitated in 9 M HCl without the co-precipitation of Pa as demonstrated by gamma-ray spectrometry. Protactinium is further purified using Bio-Rad™ anion resin AG® 1-X8 and 9 M HCl + 0.0128 M HF. A Pa/Nb separation factor of 85,000 and a 90% Pa recovery is demonstrated, which is amenable to 231 Pa concentration determination by isotope dilution and 231 Pa/ 235 U model age calculation for nuclear forensics.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2022

A new TEVA-DGA chromatography procedure to separate Pu, Am, and Np from bulk U materials

Trace actinides present within uranium (U) material are diagnostic signatures of U processing history. For example, the emplacement of U material within the high neutron-flux environment of a nuclear reactor can cause neutron capture of U to form 241-plutonium ( 241 Pu). Plutonium-241 then decays to progeny isotopes 241-americium ( 241 Am) and 237-neptunium ( 237 Np); therefore, the presence and relative abundances of these trace actinides is indicative of the material’s production history and intended employment (Mayer et al., 2013). During a pre-detonation nuclear forensics investigation, measurement of trace actinide 241 Pu, 241 Am, and 237 Np concentrations by an analytical laboratory may be requested. However, chemically purifying these elements from bulk U is a challenging and involved procedure requiring several sequential chromatography columns across 4+ days. To expedite Pu-Am-Np separation from bulk U material, and to improve the yield recovery of these elements, this DHS Postdoc Fellowship has worked to create a new chromatography separation chemistry.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2021

US-DOE and Republic of South Africa Uranium Benchmarking: Results From Los Alamos National Laboratory (Study Report)

This report details work performed at Los Alamos National Laboratory (LANL) in support of an interlaboratory uranium (U) benchmarking collaboration between LANL, Lawrence Livermore National Laboratory (LLNL), and South African Nuclear Energy Corporation (Necsa). The goal of this interlaboratory benchmarking exercise is to compare analytical methods and data obtained on uranium reference materials CUP-2 and New Brunswick Laboratory (NBL) certified reference material (CRM) 124-2. The LANL commitments for this project include performing microwave digestion of fresh CUP-2 and CRM 124-2 powders, measuring the U isotope composition of CUP-2 and CRM 124-2 by both single-collector and multi-collector inductively coupled plasma mass spectrometry (SC-ICP-MS and MC-ICP-MS, respectively), and determining trace-element abundances in CUP-2 and CRM 124-2 by inductively coupled plasma mass spectrometry (ICP-MS). This report details the methods employed by LANL in support of these objectives and presents the data obtained during this collaborative exercise.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗