Validation of reference materials for uranium radiochronometry in the frame of nuclear forensic investigations
Not Available
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
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Thorium, uranium and rare earth elements content in lanthanide concentrate (LC) and water leach purification (WLP) residue of Lynas advanced materials plant (LAMP)
Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMP and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) and 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) and 29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of {sup 232}Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted.
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
Effectiveness of mineral soil to adsorb the natural occurring radioactive material (norm), uranium and thorium
A study has been performed on U-soil and Th-soil adsorption of three types of soil collected from Selangor State of Malaysia which are Saujana Putra, Bukit Changgang and Jenderam Hilir. In this study, natural radionuclide (U and Th) soil adsorption based on batch experiments with various initial concentrations of the radionuclide elements were carried out. Parameters that were set constant include pH at 5;amount of soil used was 5 g each, contact time was 24 hour and different initial concentration for each solution of U and Th which is 5 mg/L, 10 mg/L, 15 mg/L, 20 mg/L, 25 mg/L and 40 mg/L were used. The K{sub d} values for each type of soil were determined in this batch experiments which was based on US-EPA method, in order to estimate adsorption capacity of the soil.The K{sub d} values of Th found higher than Kd values of U for all of the soil samples, and the highest was found on the soil collected from Bukit Changgang. The soil clay content was one of factors to influence the adsorption of both U and Th from dilute initial solution. The U-soil and Th-soil adsorption process for all the soil samples studied are generally obeying unimolecular layer Langmuir isotherm model. From Langmuir isotherm, the maximum adsorption capacity for U was 0.393mg/g and for Th was 1.53 mg/g for the soil that was taken from Bukit Changgang. From the study, it suggested that the soil from Bukit Changgang applicable as potential enhanced barrier for site disposing waste containing U and Th.
54 ENVIRONMENTAL SCIENCES↗
Hybrid functional study of α-uranium
We have used the hybrid density functionals to study the structural and electronic properties of alpha-U. The fraction of exact Hartree Folk exchange used is varied from 0.0 to 0.6. The equilibrium volume is found to be underestimated and bulk modulus overestimated with HSE as compared to both calculated by PBE and the experimental values. Electronic bands below the Fermi level are found to shift to lower energy with respect to PBE electronic bands which itself gives the bands shifted to lower energies as compared to UPS experiments.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Thermodynamic Studies to Support Extraction of Uranium from Seawater
This milestone report summarizes the data obtained in FY15 on the major task of quantifying the binding strength of amidoxime-related ligands. Thermodynamic studies of the interaction between U(VI) and amidoxime ligand HL III were studied to quantify the binding ability of U(VI) with amidoxime-related ligands and help to select grafting/reaction conditions so that higher yield of preferred amidoxime-related ligands is obtained. Besides the thermodynamic task, structural studies on vanadium complexation with amidoxime ligand were conducted to help understand the extremely strong sorption of vanadium on poly(amidoxime) sorbents. Data processing and summarization of the vanadium system are in progress and will be included in the next milestone report.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Evaluation of Uranium-235 Measurement Techniques
Monolithic U-Mo fuel plates are rolled to final fuel element form from the original cast ingot, and thus any inhomogeneities in 235 U distribution present in the cast ingot are maintained, and potentially exaggerated, in the final fuel foil. The tolerance for inhomogeneities in the 235 U concentration in the final fuel element foil is very low. A near-real-time, nondestructive technique to evaluate the 235 U distribution in the cast ingot is required in order to provide feedback to the casting process. Based on the technical analysis herein, gamma spectroscopy has been recommended to provide a near-real-time measure of the 235 U distribution in U-Mo cast plates.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Hydrochlorination of Uranium Dioxide in a Molten Salt Mixture- Phase 2: Sparged Benchtop Reaction Vessel Experiment
In 2023, Metatomic® Inc., a South Carolina based company, was awarded a Gateway for Advanced Innovation in Nuclear (GAIN) research voucher for a proposed series of experiments aimed at demonstrating the viability of a spent nuclear fuel (SNF) recycling process patented by Metatomic Inc. For the GAIN voucher, Metatomic Inc. selected Savannah River National Laboratory (SRNL) as a partner in executing the proposed proof-of-concept experiments. This report outlines the proof-of-concept experiments performed by SRNL for Metatomic Inc. during Phase 2 (of 2) experimentation. Though Phase 1 provided evidence of successful hydrochlorination, Phase 2 highlighted the nuances and challenges associated with scaling the reaction. The target UCl 4 species generated by the hydrochlorination of UO 2 generates water, which consumes UCl 4 . Compared to the single datapoint obtained at the end of the Phase 1 experiments, data collected at multiple timepoints during Phase 2 experiments indicated a presumed maximum percent conversion of 23% for this system that is likely influenced by water generation. Engineering improvements might be able to increase the percent conversion, but not likely to the degree needed for successful implementation of the technology. Moisture also presents an issue for the Hastelloy C276 reaction vessel. Eventually, corrosion will compromise the integrity of the reaction vessel, and the corrosion products could potentially affect the hydrochlorination chemistry. The presence of corrosion products, which were not produced in the Phase 1 alumina crucible, can and have created challenges when analyzing samples.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Health Risk Assessment Associated with Abandoned Copper and Uranium Mine Tailings
This study aims to investigate the dose rate and pollution level of Ciudanovita, Lisava, Anina, and Moldova Noua mining tailing dumps. In order to accomplish this, soil samples were collected according to LUCAS 2009/2012, in the summer of 2017. To start with, these samples were measured in situ for dose rate and revealed some interesting aspects, following this, they were investigated in the laboratory using different physico-chemical methods for more complex data. Therefore, two techniques have been used for structural investigation that revealed some particularities in terms of morphology, color and shape (optical microscopy, scanning electron microscopy) and, two for chemical composition (Fourier transform infrared spectroscopy and inductive coupled plasma mass spectrometry), which provided the qualitative confirmation of chemical groups involved in soil composition along with the heavy and radioactive metals presence (i.e. Pb, U, Cu, Cr, Cd, Ni, Zn, and Mn), expressed also by contamination factor.
54 ENVIRONMENTAL SCIENCES↗
Zirconium Matrix Alloys for Uranium-Intensive Dispersion Fuel Compositions
No abstract prepared.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Choice of Fine Packing for Rectification of Uranium Hexafluoride
Coefficients are proposed for the Bain–Hougen equation for calculating the limit velocity of vapor in a column filled with fine packing for the rectification of metal hexafluorides and their mixtures. It is shown that a simple method of comparing different packings in terms of the kinetic and hydrodynamic parameters is possible by using the effective throughput per unit volume of the packing, equivalent to one transfer unit.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Modelling and Optimization of Uranium (VI) Ions Adsorption Onto Nano-ZnO/Chitosan Bio-composite Beads with Response Surface Methodology (RSM)
Nano-ZnO-chitosan bio-composite beads were prepared for the sorption of UO{sub 2}{sup 2+} from aqueous media. The resulting nano-ZnO/CTS bio-composite beads were characterized by TEM, XRD etc. The sorption of UO{sub 2}{sup 2+} by bio-composite beads was optimized using RSM. The correlation between four variables was modelled and studied. According to RSM data, correlation coefficients (R{sup 2} = 0.99) and probability F-values (F = 2.24 × 10{sup − 10}) show that the model fits the experimental data well. Adsorption capacity for nano-ZnO/CTS bio-composite beads was obtained at 148.7 mg/g under optimum conditions. The results indicate that nano-ZnO/CTS bio-composite beads are appropriate for the adsorption of UO{sub 2}{sup 2+} ions from aqueous media. Also, the suitability of adsorption values to adsorption isotherms was researched and thermodynamic data were calculated.
77 NANOSCIENCE AND NANOTECHNOLOGY↗
Irradiation and isolation of fission products from uranium metal–organic frameworks
Typical fission product formation experiments utilize metal or oxide target materials that must be dissolved prior to product separation. In this study, we report here a novel study using metal–organic frameworks for recovery of fission products into acidic media. We further show that the frameworks are largely preserved, such that this bulk target material could be retained for additional irradiations or characterizations. Through this approach, fission products can be separated from the actinide-based metal–organic framework using 0.01 M HNO 3 without the need to dissolve the framework itself, reducing the amount of acidic waste. Extraction yields of four frameworks with varying pore sizes are compared. In conclusion, the results suggest that it may be possible to use porous frameworks as target materials for the extraction of select fission products.
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
An interlaboratory collaboration to determine consensus 231 Pa/ 235 U model ages of a uranium certified reference material for nuclear forensics
Application of the 231 Pa/ 235 U radiochronometer for nuclear forensic investigations is challenged by a lack of certified reference materials with 231 Pa/ 235 U model purification dates. The Japan Atomic Energy Agency, Los Alamos National Laboratory, and Lawrence Livermore National Laboratory completed an interlaboratory study measuring 231 Pa/ 235 U model ages of New Brunswick Laboratory CRM U100. Results from independent laboratories were combined to calculate a consensus 231 Pa/ 235 U model purification date for CRM U100 of March 26, 1959 ± 237 days. This 231 Pa/ 235 U consensus date for CRM U100 may be used by the nuclear forensic community for quality control of 231 Pa/ 235 U radiochronometry measurements of unknown materials.
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
International cooperation in age-dating uranium standards for nuclear forensics using the 231 Pa/ 235 U radiochronometer
During 2017–2018 Los Alamos National Laboratory, Lawrence Livermore National Laboratory and the China Institute of Atomic Energy collaborated in an interlaboratory 231 Pa/ 235 U radiochronometry exercise. The laboratories used different analytical methods to obtain a consensus model purification date for CRM U010 of December 28, 1958 ± 198 days and for CRM U850 of May 20, 1958 ± 363 days. These results agree with previously reported model dates using the 230 Th/ 234 U radiochronometer as well as the production histories of these materials. The concordance of interlaboratory data here confirms the ability of laboratories to make reproducible radiochronometry measurements using distinct analytical approaches.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Recovery of stable isotope taggants along a wet production pathway of uranium dioxide
Stable isotope taggants added to nuclear materials could be utilized as diagnostic nuclear forensics signatures; however, intentionally adding taggants is a relatively new and untested concept with respect to the nuclear fuel cycle. Here, in this study, we added trace amounts of stable Mo and W isotope taggants to starting materials used to synthesize UO 2 along a wet synthesis pathway. Successful incorporation and recovery of the Mo and W taggants was achieved in the UO 2 product and all its precursors. This study demonstrates the efficacy of stable isotope tagging along a wet UO 2 production pathway.
Nuclear forensics↗
Microbial communities biostimulated by ethanol during uranium (VI) bioremediation in contaminated sediment as shown by stable isotope probing
Stable isotope probing (SIP) was used to identify microbes stimulated by ethanol addition in microcosms containing two sediments collected from the bioremediation test zone at the US Department of Energy Oak Ridge site, TN, USA. One sample was highly bioreduced with ethanol while another was less reduced. Microcosms with the respective sediments were amended with 13C labeled ethanol and incubated for 7 days for SIP. Ethanol was rapidly converted to acetate within 24 h accompanied with the reduction of nitrate and sulfate. The accumulation of acetate persisted beyond the 7 d period. Aqueous U did not decline in the microcosm with the reduced sediment due to desorption of U but continuously declined in the less reduced sample. Microbial growth and concomitant 13 C-DNA production was detected when ethanol was exhausted and abundant acetate had accumulated in both microcosms. This coincided with U(VI) reduction in the less reduced sample. 13 C originating from ethanol was ultimately utilized for growth, either directly or indirectly, by the dominant microbial community members within 7 days of incubation. The microbial community was comprised predominantly of known denitrifiers, sulfate-reducing bacteria and iron (III) reducing bacteria including Desulfovibrio, Sphingomonas, Ferribacterium, Rhodanobacter, Geothrix, Thiobacillus and others, including the known U(VI)-reducing bacteria Acidovorax, Anaeromyxobacter, Desulfovibrio, Geobacter and Desulfosporosinus . As a result, the findings suggest that ethanol biostimulates the U(VI)-reducing microbial community by first serving as an electron donor for nitrate, sulfate, iron (III) and U(VI) reduction, and acetate which then functions as electron donor for U(VI) reduction and carbon source for microbial growth.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Refining the site conceptual model at a former uranium mill site in Riverton, Wyoming, USA
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54 ENVIRONMENTAL SCIENCES↗