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At least 721 records · Page 40

Chloride capture using a C–H hydrogen bonding cage

Tight binding and high selectivity are hallmarks of biomolecular recognition. Achieving these behaviors with synthetic receptors has usually been associated with OH and NH hydrogen bonding. Contrary to this conventional wisdom, we designed a chloride-selective receptor in the form of a cryptand-like cage using only CH hydrogen bonding. Crystallography demonstrated chloride stabilized by six short 2.7-Å hydrogen bonds originating from the cage’s six 1,2,3-triazoles. Atto-molar affinity (10 17 M –1 ) was determined using liquid- liquid extractions of chloride from water into nonpolar dichloromethane solvents. Controls verified the additional role of triazoles in rigidifying the 3D structure to effect recognition affinity and selectivity: Cl – > Br – > NO 3 – > I – . This cage reflects anti-Hofmeister salt extraction and preliminary corrosion inhibition.

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Analysis of Dust Samples Collected from an Inland ISFSI Site (Site A)

In September of 2020, dust samples were collected from the surface of spent nuclear fuel (SNF) dry storage canisters during an inspection at an inland Independent Spent Fuel Storage Installation. The purpose of the sampling was to assess the composition and abundance of the soluble salts present on the canister surface, information which provides a metric for potential corrosion risks. The samples were delivered to Sandia National laboratories for analysis. At Sandia, the soluble salts were leached from the dust and quantified by ion chromatography. In addition, subsamples of the dust were taken for scanning electron microscope analysis to determine the texture and mineralogy of the dust and salts. The results of those analyses are presented in this report.

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Analysis of Dust Samples Collected from a Near-Marine East Coast ISFSI Site ("Site C")

In June of 2022, dust samples were collected from the surface of an in-service spent nuclear fuel dry storage canister during an inspection at an Independent Spent Fuel Storage Installation. The site is anonymous but is a near-marine or brackish water east coast location referred to here as "Site C". The purpose of the sampling was to assess the composition and abundance of the soluble salts present on the canister surface, information that provides a metric for potential corrosion risks. Following collection, the samples were delivered to Sandia National Laboratories for analysis. At Sandia, the soluble salts were leached from the dust and quantified by ion chromatography. In addition, subsamples of the dust were taken for scanning electron microscopy to determine the particle sizes, morphology, and mineralogy of the dust and salts. The results of those analyses are presented in this report.

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Melter Tests to Define LAW Halide Concentrations, Phase 2

The present work represents the second of two phases to address the formation of secondary sulfate phases while processing high waste loading LAW formulations with elevated halide, chromium, and phosphate feed concentrations over a wide range of LAW waste types, including those with high potassium concentrations. The Test Plan for the present work outlines a series of tests designed to assess the formation of secondary phases over a range of sulfur and halide concentrations for two LAW streams and associated glass formulations as well as crucible testing to identify additives that have the potential to suppress the formation of secondary phases for wastes with high chlorine contents. The combined results from both phases of testing and from previous tests with these LAW waste streams will be used as inputs to future work to develop concentration limits for these components in the LAW glass property composition models and to support the modification and updating of the current WTP LAW glass formulation algorithm.

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Analysis of the Gas Core Actinide Transmutation Reactor (GCATR)

Design power plant studies were carried out for two applications of the plasma core reactor: (1) As a breeder reactor, (2) As a reactor able to transmute actinides effectively. In addition to the above applications the reactor produced electrical power with a high efficiency. A reactor subsystem was designed for each of the two applications. For the breeder reactor, neutronics calculations were carried out for a U-233 plasma core with a molten salt breeding blanket. A reactor was designed with a low critical mass (less than a few hundred kilograms U-233) and a breeding ratio of 1.01. The plasma core actinide transmutation reactor was designed to transmute the nuclear waste from conventional LWR's. The spent fuel is reprocessed during which 100% of Np, Am, Cm, and higher actinides are separated from the other components. These actinides are then manufactured as oxides into zirconium clad fuel rods and charged as fuel assemblies in the reflector region of the plasma core actinide transmutation reactor. In the equilibrium cycle, about 7% of the actinides are directly fissioned away, while about 31% are removed by reprocessing.

Clement, J. D.↗

A Summary of the Department of Energy’s Advanced Demonstration and Test Reactor Options Study

An assessment of advanced reactor technology options was conducted to provide a sound comparative technical context for future decisions by the U.S. Department of Energy (DOE) concerning these technologies. Strategic objectives were established that span a wide variety of important missions, and advanced reactor technology needs were identified based on recent DOE and international studies. A broad team of stakeholders from industry, academia, and government was assembled to develop a comprehensive set of goals, criteria, and metrics to evaluate advanced irradiation test and demonstration reactor concepts. Point designs of a select number of concepts were commissioned to provide a deeper technical basis for evaluation. The technology options were compared on the bases of technical readiness and the ability to meet the different strategic objectives. Using the study's evaluation criteria and metrics, an independent group of experts from industry, universities, and national laboratories scored each of the point designs. Pathways to deployment for concepts of varying technical maturities were estimated for the different demonstration systems with regard to cost, schedule, and possible licensing approaches. This study also presents the trade-offs that exist among the different irradiation test reactor options in terms of the ability to conduct irradiations in support of advanced reactor research and development and to serve potential secondary missions. The main findings of the study indicate the following: (1) for industrial process heat supply, a high-temperature gas-cooled reactor is the best choice because of the high outlet temperature of the reactor and its strong passive and inherent safety characteristics; (2) for resource utilization and waste management, a sodium-cooled fast reactor (SFR) is best because of the use of a fast flux to destroy actinides; (3) to realize the advantages of a promising but less-mature technology, a fluoride salt-cooled high-temperature reactor and a lead-cooled fast reactor fare about the same; (4) for fulfilling the needs of a materials test reactor, a SFR is considered best because of its ability to produce high fast flux, incorporate test loops, and provide additional large volumes for testing.

Advanced reactors↗

On Temperature Limits for the Outer Surface of a Container in a Disposal Facility - 20313

The temperature in a disposal facility for high-level radioactive waste (HLRW) is an issue for safety. When the recommencement of the search for and selection of a site for a disposal facility for HLRW in Germany was stipulated by the Site Selection Act (StandAG 2017) in 2017, a precautionary temperature limit of 100 deg. C on the outer surface of the containers with high-level radioactive waste in the disposal facility section was set. This precautionary temperature limit shall be applied in preliminary safety analyses provided that the 'maximum physically possible temperatures' in the respective host rocks have not yet been determined due to pending research. Therefore, this issue is addressed and discussed in this paper, contributing to 'pending research' by a review of the literature. This paper briefly discusses a few examples of thermohydraulic, mechanical, chemical and biological processes in a disposal facility, because temperature limits are derived based on safety impacts regarding THMCB-processes. The temperature-dependent processes have been extracted from databases for features, events and processes (FEP-databases). Furthermore, it is discussed if the feasibility to retrieve and recover HLRW is hampered at high temperatures. A design temperature concerning single components of a disposal facility for the preservation of their features can be derived when a safety concept is established. However, the interactions of all relevant processes in a disposal concept must be considered to determine a specific temperature limit for the outer surface of the containers. Therefore, applicable temperature limits may vary for particular safety and disposal concepts in the following host rocks: rock salt, clay stone and crystalline rock. Technical solutions for retrieval and design options for recovery seem to be viable up to temperatures of 200 deg. C with different, sometimes severe, downsides according to expert judgement. Temperature limits regarding the outer surface of the containers can be derived specifically for each safety concept and design of the disposal facility in a host rock. General temperature limits without reference to specific safety concepts or the particular design of the disposal facility may narrow down the possibilities for optimisation of the disposal facility and could adversely affect the site selection process in finding the best suitable site. (authors)

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Simulations of Criticality Control Overpack Container Compaction at the Waste Isolation Pilot Plant

Criticality Control Overpack (CCO) containers are being considered for the disposal of defense-related nuclear waste at the Waste Isolation Pilot Plant (WIPP). At WIPP, these containers would be placed in underground disposal rooms, which will naturally close and compact the containers closer to one another over several centuries. This report details simulations to predict the final container configuration as an input to nuclear criticality assessments. Each container was discretely modeled, including the plywood and stainless steel pipe inside the 55-gallon drum, in order to capture its complex mechanical behavior. Although these high-fidelity simulations were computationally intensive, several different material models were considered in an attempt to reasonably bound the horizontal and vertical compaction percentages. When exceptionally strong materials were used for the containers, the horizontal and vertical closure respectively stabilized at 43:9 % and 93:7 %. At the other extreme, when the containers completely degraded and the clay seams between the salt layers were glued, the horizontal and vertical closure reached respective final values of 48:6 % and 100 %.

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Identification and Mitigation of Inhibitory Substances Contained in High-Salinity Crude Glycerol Generated from Biodiesel Production for Polyhydroxyalkanoate Synthesis by Haloferax mediterranei

High-salinity crude glycerol generated from biodiesel production poses significant challenges to microbial valorization due to inhibitory ingredients that severely limit microbial growth. This study identified and mitigated inhibitory substances contained in high-salinity glycerol sludge to enable its conversion to polyhydroxyalkanoates (PHAs) by the extreme halophilic archaeon Haloferax mediterranei. The long-chain fatty acids (LCFAs) were consistently identified as the primary inhibitors by liquid chromatography−mass spectrometry, Fourier transform infrared spectroscopy, and ultraviolet−visible spectroscopy. Acid precipitation at pH 2 efficiently removed these LCFAs, substantially reducing the required feedstock dilution from 23 to 3 times, improving PHA titer by 40%. Furthermore, this dilution reduction also increased the feedstock salinity utilization, achieving a 46% reduction in external salt supplementation for H. mediterranei growth. In contrast, overliming and arrested anaerobic digestion were confirmed to be ineffective in inhibitor removal. This study provides deep insights into inhibitor chemistry and presents acid precipitation as an effective pretreatment strategy for waste valorization of highsalinity crude glycerol.

LC-MS↗

Small Reactors in Microgrids: Technology Modeling and Selection (Net-Zero Microgrid Program Project Report)

This report demonstrates the capabilities of the net-zero microgrid (NZM) Xendee platform for modeling an SR module with electricity, heat extraction and thermal storage in microgrids configurations. The model effectively captures the most important technical and economic considerations for SR technology specific analysis: cost and operational characteristics of SR technology and financial costs and incentives. The model can analyze multiple scenarios to establish metrics for cost-competitive and zero-carbon microgrids connected to the grid or completely isolated. The model is fully integrated within the Xendee platform for modeling and analysis of clean energy microgrids with storage and generation from renewable energy sources. The model captures the capabilities, constraints, and nuances of SR by incorporating parameters related to plant economics, design efficiency and performance, plant operation and component and fuel lifespan. The cost and operational parameters modeled in the SR module are specific to the technology selected for integration in the microgrid. Cost parameters recognize advanced nuclear technology for modular production and installation based on economies of scale from factory manufacture and related commissioning, and cost reduction through technology maturation—first-of-a-kind (FOAK) and nth-of-a-Kind (NOAK). The cost parameters include installation, operations and maintenance (O&M), fuel refueling cycle, and reactor life. Installation cost reflects economies of scale due to unit sizing at scale and colocation. O&M economies of scale for both fixed- and variable-cost fuel life-cycle costs are incurred at every refueling interval, with separate front- and back-end fuel costs, as well as waste-handling and disposition costs. This report investigates key characteristics of different SR technologies suitable for microgrid applications, including design principles, sizing, coolant properties, temperature ratings, fuel structures, and life-cycle considerations. This also includes fuel technologies applicable to these SR systems, alongside strategies for nuclear-waste and spent-fuel management and approaches to address safety, security, and proliferation challenges. Four primary groups of SR technologies are examined: water-cooled, liquid-metal-cooled, high-temperature gas-cooled, and molten-salt-cooled systems. In this report, an initial guideline for technology selection is established, aligning the characteristics of the technologies with the requirements of microgrids. The selection of technology in a microgrid is influenced by various factors, including financial capacity, location and accessibility, demand type and characteristics, reliability and resilience requirements, area constraints, and the lifespan of the microgrid. The types of electrical and non-electrical applications within the microgrid also play a significant role in technology selection. The characteristics of SRs, such as their smaller size, modularity, transportability, long refueling interval, improved safety features, ability to operate in autonomous or semi-autonomous mode, and provision of high-grade heat, are particularly appealing for microgrids. Furthermore, a list of considerations for implementing SRs in microgrids is outlined. The SR model is created to be continuously improved with the acquisition of actual data on investment and operational costs, experience with supply chains, production at scale, and field deployments. In the near term, performance data on applications in microgrids will become available from lessons learned from laboratory tests, such as those planned for the Microreactor Applications Research Validation and Evaluation Project (MARVEL), led by Idaho National Laboratory (INL). The SR model incorporates scenario data and known SR design specifications, enabling technoeconomic analysis for SR deployment in microgrids. It specifically considers the distinctive attributes of SRs as generators in technoeconomic studies. SRs can be modeled and analyzed with generation from renewable-energy sources, energy storage, and flexible loads over a range of functionality and applications. This offers a comprehensive tool for feasibility studies, scenario development, and sensitivity analysis for “what-if” consideration of any range of assumptions about SRs in microgrids and other aggregations of distributed-energy resources, including virtual power plants.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Electrochemical and Thermodynamic Properties of U in LiCl-KCl-UCl{sub 3} salt system

Pyro-processing technology has been considered and examined by several countries as a promising method for the recovery and recycle of uranium and actinide elements from used nuclear fuel. One of the key processes in pyro-processing is an electro-refiner (ER) where the metallic fission products are loaded into an anode basket and dissolved into lithium-potassium chloride (LiCl-KCl) eutectic salt at 773 K. Many researchers have been exploring the fundamental characterizations of U in LiCl-KCl system by using various electrochemical methods, resulting in several reported values of diffusion coefficient, apparent standard potential, and activity coefficient of U in the salt system. In addition, several researchers measured kinetic parameter of U (exchange current density, i{sub 0}) by using Tafel and linear polarization (LP) methods. Despite available data sets on this ternary salt system, there are discrepancies due to different experimental conditions, design, size of the cell, and measurement techniques. In addition, the i{sub 0} for U/U{sup 3+} reaction has only been measured since 2009; therefore, only few data sets are available to date although the i{sub 0} is critical for the development of dynamic ER model. The value of i{sub 0} is a kinetic characteristic in an ideal equilibrium state; therefore, it is very challenging to be measured by experiments. The authors have estimated the values of i{sub 0} via Tafel and linear polarization methods (LP); however, these methods are lack of maintaining electrode surface area during the measurements. In addition, some data are not following the trends from other literature studies due to its difficulties of the measurement. Therefore, further experimental determinations have to be accomplished to understand the i{sub 0} kinetics and the database for the i{sub 0} of U/U{sup 3+} couple in LiCl-KCl eutectic salt needs to be established systematically. In the present study, an experimental setup was designed and used in a consistent manner to build a meaningful database for U in LiCl-KCl system. LiCl-KCl-UCl{sub 3} salt was prepared at different concentrations and temperatures ranging from 0.5 wt% to 4 wt% and 723 K to 798 K, respectively. Then, CV, open circuit potential (OCP), and electrochemical impedance spectroscopy (EIS) were performed to understand the electrochemical, thermodynamic, and kinetic properties of U. Specially, i{sub 0} values have not been measured via EIS method; therefore, this study provides a good chance to confirm the i{sub 0} values with the new technique.

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Exploring the Nature of f-Element Soft Donor Interactions Using Electronically Tunable Azolate Ionic Liquids

This project was undertaken to advance the understanding of how f-elements interact with moderately soft donors, a heavily investigated yet open question which is of prime importance in spent nuclear fuel processing and fundamental inorganic chemistry. During the course of the project, based on exciting results, a stretch goal was developed to study the hydrolysis products of transuranic actinide metals, a somewhat understudied field even with its significance in nuclear fuel cycle and impacts in environmental chemistry. The stretch goal was to take our serendipitous discovery of an easy route to isolation of crystalline multinuclear ƒ-element hydrolysis products, and apply it to gaining a mechanistic understanding of Pu(III/IV) colloid formation. The simplicity of our techniques should lend themselves to the remote handling required for study of many transuranic elements. We developed several methodologies using azolium azolate chemistry to overcome ƒ-element hydrolysis problems that prohibit the isolation of ƒ-element soft donor complexes and to build a crystallographic library of ƒ-element N-donor complexes as a means to understand the fundamental differences between actinide and lanthanide interactions with moderately soft donor ligands. Our next major endeavor will be to transfer this chemistry from 4ƒ elements to transuranic elements, particularly in the study of hydrolysis of Pu(III/IV). While our work is fundamental in nature, applications of the knowledge we are generating should be felt in such diverse fields as catalysis, separations in general, nuclear waste remediation specifically, and many other applications in f-element magnetic and luminescent properties. The potential ramifications of the consistent and robust formation of hydrolysis controlled hexanuclear lanthanide structures are enormous, with future uses being catalyst formation, higher-nuclearity structure synthesis using our hexanuclear motif as a fundamental building block, Pu waste remediation, separations, and many other potential applications resulting from characteristic magnetic and luminescent properties of lanthanide polynuclear structures. Three synthetic methodologies (direct mixing with variable stoichiometries, use of volatile solvent, metathesis) were developed starting with 7 acidic and 6 basic azoles to obtain ionic liquids suitable for f-element coordination. Proton transfer by acidic/basic azole combination led to suitable low melting salts and two cocrystals. Acid/base reaction of azoles with soft-donor permanent cations of ([X 4444 ][OH] (where [X 4444 ] + = tetrabutylammonium [N 4444 ] + or tetrabutylphosphonium [P 4444 ] + ) with weakly acidic azoles including imidazole, 1,2,3-triazole, 1,2,4-triazole, 5-aminotetrazole, 4,5-dicyanoimidazole, and 2-amino-4,5-dicyanoimidazole) revealed several suitable low-melting salts. Metathesis reactions of Na(azolate) were conducted by first using weakly acidic azoles including 4,5-dicyanoimidazole, 2-amino-4,5-dicyanoimidazole, 5-aminotetrazole, and 1,2,4-triazole to form sodium or lithium salts using group(I) hydroxides in methanolic solutions. The best results were obtained by reacting the basic and acidic azoles directly in 1:1 or 3:1 ratios at elevated temperatures. Twenty-two azole mixtures were identified which are either low melting solids or room temperature liquids. Each of the low melting solids was confirmed to be a new solid phase, each of which is being further characterized. The liquids and solids are anticipated to be ILs, eutectics, or partially ionized systems, all of which will be suitable for the dissolution of f-element salts. Five new synthetic methodologies were developed to finding suitable crystallization conditions for f-element complexation with the goal of finding simple one pot reaction syntheses and crystallization strategies that could be used under the demanding conditions of transuranic chemistries. These synthetic methods yield many new crystalline phases which were studied by single crystal X-ray diffraction.

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Experimental determination of solubilities of magnesium borates: Solubility constants of boracite [Mg 3 B 7 O 13 Cl(cr)] and aksaite [MgB 6 O 7 (OH) 6 ·2H 2 O(cr)]

In this work, solubility measurements regarding boracite [Mg 3 B 7 O 13 Cl(cr)] and aksaite [MgB 6 O 7 (OH) 6 ·2H 2 O(cr)] from the direction of supersaturation were conducted at 22.5 ± 0.5 °C. The equilibrium constant (log 10 K 0 ) for boracite in terms of the following reaction, Mg 3 B 7 O 13 Cl(cr) + 15H 2 O(l) ⇌ 3Mg 2+ + 7B(OH) 4 – + Cl – + 2H + is determined as -29.49 ± 0.39 (2σ) in this study. The equilibrium constant for aksaite according to the following reaction, MgB 6 O 7 (OH) 6 •2H 2 O(cr) + 9H 2 O(l) ⇌ Mg 2+ + 6B(OH) 4 – + 4H + is determined as -44.41 ± 0.41 (2σ) in this work. This work recommends a set of thermodynamic properties for aksaite at 25 °C and 1 bar as follows: ΔH$0\atop{f}$ =-6063.70 ± 4.85 kJ·mol -1 , ΔG =-5492.55 ± 2.32 kJ·mol -1 , and S 0 = 344.62 ± 1.85 J·mol -1 ·K -1 . Among them, ΔG$0\atop{f}$ is derived from the equilibrium constant for aksaite determined by this study; ΔH$0\atop{f}$ is from the literature, determined by calorimetry; and S 0 is computed in the present work from ΔG$0\atop{f}$ and ΔH$0\atop{f}$. This investigation also recommends a set of thermodynamic properties for boracite at 25 °C and 1 bar as follows: ΔH$0\atop{f}$ =-6575.02 ± 2.25 kJ·mol -1 , ΔG$0\atop{f}$ =-6178.35 ± 2.25 kJ·mol -1 , and S 0 = 253.6 ± 0.5 J·mol -1 ·K -1 . Among them, ΔG$0\atop{f}$ is derived from the equilibrium constant for boracite determined by this study; S 0 is from the literature, determined by calorimetry; and ΔH$0\atop{f}$ is computed in this work from ΔG$0\atop{f}$ and S 0 . The thermodynamic properties determined in this study can find applications in many fields. For instance, in the field of material science, boracite has many useful properties including ferroelectric and ferroelastic properties. The equilibrium constant of boracite determined in this work will provide guidance for economic synthesis of boracite in an aqueous medium. Similarly, in the field of nuclear waste management, iodide boracite [Mg 3 B 7 O 13 I(cr)] is proposed as a waste form for radioactive 129 I. Therefore, the solubility constant for chloride boracite [Mg 3 B 7 O 13 Cl(cr)] will provide the guidance for the performance of iodide boracite in geological repositories. Boracite/aksaite themselves in geological repositories in salt formations may be solubility-controlling phase(s) for borate. Finally, solubility constants of boracite and aksaite will enable researchers to predict borate concentrations in equilibrium with boracite/aksaite in salt formations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Develop Recovery Systems for Separations of Salts from Process Streams for use in Advanced Life Support System

The main objectives of this project were the development of a four-compartment electrolytic cell using high selective membranes to remove nitrate from crop residue leachate and convert it to nitric acid, and the development of an six compartment electrodialysis cell to remove selectively sodium from urine wastes. The recovery of both plant inedible biomass and human wastes nutrients to sustain a biomass production system are important aspects in the development of a controlled ecological life support system (CELSS) to provide the basic human needs required for life support during long term space missions. A four-compartment electrolytic cell has been proposed to remove selectively nitrate from crop residue and to convert it to nitric acid, which is actually used in the NASA-KSC Controlled Ecological Life Support System to control the pH of the aerobic bioreactors and biomass production chamber. Human activities in a closed system require large amount of air, water and minerals to sustain life and also generate wastes. Before using human wastes as nutrients, these must be treated to reduce organic content and to remove some minerals which have adverse effects on plant growth. Of all the minerals present in human urine, sodium chloride (NACl) is the only one that can not be used as nutrient for most plants. Human activities also requires sodium chloride as part of the diet. Therefore, technology to remove and recover sodium chloride from wastes is highly desirable. A six-compartment electrodialysis cell using high selective membranes has been proposed to remove and recover NaCl from human urine.

Colon, Guillermo↗

Transforming CO 2 to Porous Carbon as a High-Performing Sodium-Ion Battery Anode via Electrochemical Reduction in Molten Carbonates

The prevalence of sodium over lithium prompts exploration of sodium-ion batteries (SIBs) as a viable alternative to lithium-ion batteries (LIBs). Hard carbon has emerged as a promising anode material for SIBs, yet its synthesis poses sustainability challenges and emits pollutants. Here, in this study, we introduce CO 2 -derived porous carbon (graphitic and amorphous) as an anode for SIBs via electrochemical reduction of CO 2 in a molten eutectic carbonate salt at a lower temperature that yields materials with controlled microstructure, morphology, and porosity conducive to energy storage. Our CO 2 -derived carbon demonstrates remarkable specific capacity, superior rate capability, and stable cycling performance as a SIB anode. This innovative strategy harnesses waste CO 2 toward advancing SIB energy technology.

CO2-derived carbon↗

Laser-Induced Breakdown Spectroscopy for Contamination Detection in Concrete on Nuclear Facilities - 18296

Laser-Induced Breakdown Spectroscopy (LIBS) provides a real-time analytical technique for determining the elemental composition of a sample. This work was carried out to determine the suitability of the method for contamination detection in concrete. Cement paste samples were cast, containing simulant radionuclide contaminant salts of Co and Ni at 0.1 wt% inclusion. LIBS was then carried out on the samples, and contaminated samples compared to an uncontaminated ordinary portland cement (OPC) reference. A ratio of normalised peak intensities was used to determine differences in spectra between the samples. Where differences between sample and reference spectra were discovered, the National Institute of Standards and Technology spectral lines database was consulted, the identity of the contaminants could be confirmed, and Co and Ni were both identified at less than 0.1 wt% inclusion. (authors)

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