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DOE OSTI2022

Mercury and Radiocesium Accumulation and Associations With Sublethal Endpoints in the Florida Green Watersnake ( Nerodia floridana )

Mercury (Hg) and radiocesium ( 137 Cs) are well-known environmental contaminants with the potential to impact the health of humans and wildlife. Snakes have several characteristics conducive to studying environmental contamination but have rarely been included in the monitoring of polluted sites. We investigated the bioaccumulation of Hg and 137 Cs and associations with sublethal effects (standard metabolic rate [SMR] and hemoparasite infections) in Florida green watersnakes (Nerodia floridana). We captured 78 snakes from three former nuclear cooling reservoirs on the US Department of Energy's Savannah River Site in South Carolina (USA). For captured snakes, we (1) determined whole-body 137 Cs, (2) quantified total Hg (THg) using snake tail clips, (3) conducted hemoparasite counts, and (4) measured the SMR. We used multiple regression models to determine associations among snake body size, capture location, sex, tail THg, whole-body 137 Cs, Hepatozoon spp. prevalence and parasitemia, and SMR. Average whole-body 137 Cs (0.23 ± 0.08 Becquerels [Bq]/g; range: 0.00–1.02 Bq/g) was correlated with snake body size and differed significantly by capture site (Pond B: 0.67 ± 0.05 Bq/g; Par Pond: 0.10 ± 0.02 Bq/g; Pond 2: 0.03 ± 0.02 Bq/g). Tail THg (0.33 ± 0.03 mg/kg dry wt; range: 0.16–2.10 mg/kg) was significantly correlated with snake body size but did not differ by capture site. We found no clear relationship between SMR and contaminant burdens. However, models indicated that the prevalence of Hepatozoon spp. in snakes was inversely related to increasing whole-body 137 Cs burdens. Our results indicate the bioaccumulation of Hg and 137 Cs in N. floridana and further demonstrate the utility of aquatic snakes as bioindicators. Furthermore, our results also suggest a decrease in Hepatozoon spp. prevalence related to increased burdens of 137 Cs. Although the results are intriguing, further research is needed to understand the dynamics between 137 Cs and Hepatozoon spp. infections in semiaquatic snakes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2019

Synthesis of β-Cyclodextrin Immobilized Starch and Its Application for the Removal of Dyestuff from Waste-Water

A natural polymeric adsorbent, β-cyclodextrin immobilized starch (CS-βCD) was prepared by introducing host functional molecule β-cyclodextrin (β-CD) onto starch in presence of citric acid. The immobilization conditions were optimized to: m CA:m CS = 1:2, reaction time of 2 h and reaction temperature at 120 °C, by varying the input levels of the reactant, CS-βCD with a series of immobilization ratio (IR) and carboxyl content (CC) could be obtained. The FT-IR and {sup 13}C-NMR analysis indicated the β-CD molecules have been immobilized onto starch via the formation of ester linkages. The XRD and SEM analysis showed CS-βCD had more looser structure and more irregular surface compared with native starch. The GPC analysis showed CS-βCD had a reduced molecular weight but a more complicated molecular configuration. The adsorbing capacities of CS-βCD to three cationic dyes (methylene blue, methyl purple and basic fuchsin) were significantly improved compared with native starch, diatomite and zeolite. The adsorption behaviors of CS-βCD to the three dyes had high fitting degrees to both Langmuir and Freundlich models (R{sup 2} > 0.98). The decolourization ratio of CS-βCD to the mixed dyestuff waste-water had reached 88.75%, which was much higher than other absorbents. The results indicated the CS-βCD would become a high-efficiency dyestuff adsorbent, and would have a promising application in the industrial dyestuff waste-water treatment.

36 MATERIALS SCIENCE↗

DOE OSTI2017

High-performance formamidinium-based perovskite solar cells via microstructure-mediated δ-to-α phase transformation

The δ → α phase transformation is a crucial step in the solution-growth process of formamidinium-based lead triiodide (FAPbI 3 ) hybrid organic–inorganic perovskite (HOIP) thin films for perovskite solar cells (PSCs). Because the addition of cesium (Cs) stabilizes the α phase of FAPbI 3 -based HOIPs, here our research focuses on FAPbI 3 (Cs) thin films. We show that having a large grain size in the δ-FAPbI 3 (Cs) non-perovskite intermediate films is essential for the growth of high-quality α-FAPbI 3 (Cs) HOIP thin films. Here grain coarsening and phase transformation occur simultaneously during the thermal annealing step. A large starting grain size in the δ-FAPbI 3 (Cs) thin films suppresses grain coarsening, precluding the formation of voids at the final α-FAPbI 3 (Cs)–substrate interfaces. PSCs based on the interface void-free α-FAPbI 3 (Cs) HOIP thin films are much more efficient and stable in the ambient atmosphere. This interesting finding inspired us to develop a simple room-temperature aging method for preparing coarse-grained δ-FAPbI 3 (Cs) intermediate films, which are subsequently converted to coarse-grained, high-quality α-FAPbI 3 (Cs) HOIP thin films. As a result, this study highlights the importance of microstructure meditation in the processing of formamidinium-based PSCs.

14 SOLAR ENERGY↗

DOE OSTI2025

Stabilization of Preternatural Barium Oxidation States as an Unexpected Byproduct of β-Decay: Discovery of a New Halide Semiconductor Alloy

137 Cs has a wide range of roles in the nuclear industry. The solid material, safely encapsulated in CsCl as 137 CsCl, is stored as fission product waste from nuclear power production and legacy waste from nuclear weapons production; it has also served as a radiation source in food and sewage irradiators as well as medical devices. However, because of the solubility of the chloride salt and the relatively high specific activity of 137 Cs, damaged or broken capsules can lead to severe radiological accidents. Safe capsule design and material recycling are complicated by the unclear structural evolution during β-decay, which remains ambiguous due to the differing oxidation states of Cs (1+) and Ba (2+). Here, in this study, we use first-principles calculations to investigate the evolving structure–property relationships of Cs 1–x Ba x Cl during β-decay. Despite the well-established 2+ formal oxidation state of alkali-earth metals, we find that Ba 1+ can be stabilized in the form of a mixed-valence alloy at low concentrations. Specifically, we identify three regimes for the β-decay of 137 Cs into CsCl: Ba-doped CsCl (Ba ≤ 14%), wherein Ba has the expected 2+ oxidation state; Cs–Ba–Cl alloys, where Ba has a mix of the usual Ba 2+ and highly unusual Ba 1+ oxidation state in the form of a quasi-disordered mixed-valence alloy (Ba = 25%); and phase separation into a CsCl + BaCl 2 + Ba (m) mechanical mixture, where Ba reverts to its expected 2+ oxidation state (Ba > 25%). Surprisingly, the Cs 0.75 Ba 0.25 Cl mixed-valence alloy is a narrow indirect band gap semiconductor (1.05 eV) despite the insulating nature of both CsCl and BaCl 2 . It also exhibits strongly excitonic polarized optical properties, has glass-like ultralow thermal conductivity (directional average of 0.21 W/mK at 300 K), and shows greater resistance to deformation under both tensile and volumetric strengths compared with the original CsCl structure (e.g., shear and Young’s modulus of 9.04 and 31.62 GPa, respectively). These findings imply that transmutation of 137 Cs leads to highly unusual chemical bonding that stabilizes Ba 1+ in local regions of the quasi-disordered Cs 0.25 Ba 0.75 Cl, resulting in anomalous physical properties. Moreover, this discovery provides valuable insight for safe nuclear waste capsule design, which can aid in preventing environmental or human exposure to radioactive materials.

Fuhr, Addis S. [Oak Ridge National Laboratory (ORN↗

DOE OSTI2020

Revisiting heat treatment and surface activation of GaAs photocathodes: In situ studies using scanning tunneling microscopy and photoelectron spectroscopy

The lifetime of GaAs photocathodes in polarized electron guns is limited due to the delicate activation layer. An atomically clean and smooth GaAs surface is needed to deposit a robust activation layer, such as Cs 2 Te, with longer lifetime compared to traditional (Cs,O) activation. A previous experiment with Cs 2 Te activation on GaAs used heat cleaning temperatures around 400°C to avoid an increase in surface roughness [Bae et al., Appl. Phys. Lett. 112, 154101 (2018)]. Furthermore, high-temperature heat cleaning around 580°C, which results in a relatively contamination-free surface, could be one possible way to improve quantum efficiency. However, one should be cautious about surface roughness degradation during high-temperature heat cleaning. In this paper, we report results of surface roughness measurements on native, heat cleaned, and (Cs,O) activated GaAs photocathodes under vacuum. The results, measured by ultrahigh vacuum scanning tunneling microscopy, show that the surface roughness improves as the heat cleaning temperature is increased, by at least a factor of three for 580°C heat cleaning, compared to the native sample. Activation with (Cs,O) is shown to increase surface roughness by a factor of four compared to a 580°C heat cleaned sample. This confirms that high-temperature heat cleaning can be useful for depositing good quality robust activation layers on GaAs. Additionally, we also report chemical analysis for each step of preparation for p-doped GaAs photocathodes using X-ray photoelectron spectroscopy (XPS), angle-resolved XPS, and ultraviolet photoelectron spectroscopy. Our results indicate that the (Cs,O) activation layer forms a sandwich structure consists of Cs and oxygen. We found no formation of any specific compound such as Cs 2 O or Cs 11 O 3 .

43 PARTICLE ACCELERATORS↗

DOE OSTI2016

Metallographic autopsies of full-scale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN: III. The importance of strand surface roughness in long twist pitch conductors

As part of the ITER conductor qualification process, 3 m long Cable-in-Conduit Conductors (CICCs) were tested at the SULTAN facility under conditions simulating ITER operation so as to establish the current sharing temperature, T cs , as a function of multiple full Lorentz force loading cycles. After a comprehensive evaluation of both the Toroidal Field (TF) and the Central Solenoid (CS) conductors, it was found that T cs degradation was common in long twist pitch TF conductors while short twist pitch CS conductors showed some T cs increase. However, one kind of TF conductors containing superconducting strand fabricated by the Bochvar Institute of Inorganic Materials (VNIINM) avoided T cs degradation despite having long twist pitch. In our earlier metallographic autopsies of long and short twist pitch CS conductors, we observed a substantially greater transverse strand movement under Lorentz force loading for long twist pitch conductors, while short twist pitch conductors had negligible transverse movement. With help from the literature, we concluded that the transverse movement was not the source of T cs degradation but rather an increase of the compressive strain in the Nb 3 Sn filaments possibly induced by longitudinal movement of the wires. Like all TF conductors this TF VNIINM conductor showed large transverse motions under Lorentz force loading, but Tcs actually increased, as in all short twist pitch CS conductors. We here propose that the high surface roughness of the VNIINM strand may be responsible for the suppression of the compressive strain enhancement (characteristic of long twist pitch conductors). Furthermore, it appears that increasing strand surface roughness could improve the performance of long twist pitch CICCs.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2024

Cooled Spray Technology for Particulate Reduction in a Heavy-Duty Engine

Cooled spray (CS) technology passively reduces particulate matter (PM) emissions from diesel engines compared to non-CS-equipped diesel engines. CS inserts are mounted near the injector nozzle and control mixing so that the fuel and air can premix while limiting combustion near fuel-rich zones, thereby reducing the formation of particulate matter. CS components contain no moving parts and could be installed as a retrofit or built into new engines. However, CS technology is early in its development, and further investigations are needed to understand the overall performance implications and practicality of the technology. In this paper, we investigate several important aspects of CS, providing a clearer picture of some challenges and potential benefits of CS. Two alignment techniques are used to characterize measurement ease and bias, namely, an optical alignment and spray-plug impact alignment. While the optical technique facilitates alignment more easily, a bias was measured between the optical and spray-plug techniques, suggesting the optical technique may have insufficient accuracy without additional corrections. We also evaluate the engine performance of a well-aligned and poorly aligned CS insert, compared to the baseline configuration. The poorly aligned insert shows slower combustion than the baseline and mixed overall performance. However, the well-aligned insert shows faster combustion than the baseline and PM emission reduction at most operating conditions, with some conditions showing PM reduction up to 80%. Furthermore, the results of this paper highlight the alignment challenges of CS technology as well as the potential PM reduction benefit of the technology.

33 ADVANCED PROPULSION SYSTEMS↗

DOE OSTI2019

Impact of Crystalline Silicotitanate Particle Size on Cesium Removal Efficiency

Washington River Protection Solutions is working on a Tank-Side Cesium Removal (TSCR) system to remove Cs from Hanford tank waste supernate. Removal of 137 Cs from tank waste supernate by TSCR results in a low-activity waste (LAW) form that can be fed directly to the Hanford Waste Treatment and Immobilization Plant (WTP) LAW vitrification facility, where the supernate can be vitrified into a glass form. Crystalline silicotitanate (CST) ion exchange media, manufactured by Honeywell UOP, LLC (product IONSIV TM R9140-B), was selected for use as the ion exchange media to remove Cs at TSCR. The particle size used in testing is expected to impact the kinetic performance of the ion exchange media. Therefore, two single-column systems were tested with CST Lot 2002009604. One column contained <25 mesh sieve cut fraction and the other column contained <35 mesh sieve cut fraction. Flowrate through both test systems was adjusted to match the CST contact time expected for the full-scale operation, i.e., matched bed volumes per hour (BV/h) at 1.83 BV/h. The feed was processed downflow through the columns until ~1000 BVs of feed were processed. The waste acceptance criteria (WAC) limit for the WTP LAW vitrification facility is <3.18E-5 Ci 137 Cs per mole Na. For a tank waste containing 156 µCi/mL 137 Cs and 5.6 M Na, up to 0.114% of the influent 137 Cs concentration may be delivered to the WTP (based on 137 Cs content in AP-107 tank waste); this required a Cs decontamination factor of 876. The WAC limit was used as one of the relevant process parameters, along with the 50% breakthrough point, Cs loading per gram of CST, and the mass transfer zone.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2024

Assessing Suitable Geologic Carbon Storage Sites Across Utah

Utah has a wealth of potential geological reservoirs for carbon dioxide storage (CS) and a long history of geologic research resulting in an abundance of available subsurface data to evaluate CS potential. Reservoirs may include sandstone, carbonate, and basalt; these rock types are plentiful in Utah’s subsurface and the complex Phanerozoic history throughout the state requires evaluating each geologic region individually for promising reservoir-seal pairs for CO2 storage. Classifying Utah by geologic provinces (or “geo-regions”) allows for customized thinking about suitable CS reservoir and seal distribution, CO2 point sources, land use, and existing infrastructure. Preliminary results from this study highlight the geologic CS potential across 15 geo-regions. Four regions stand out as having high CS potential: the Uinta Basin, San Rafael Swell, Paradox Basin, and the southern Basin and Range Province. The Uinta Basin and San Rafael Swell geo-regions are well suited for CS and have several projects ongoing to evaluate Cretaceous Frontier and Naturita Formations, Jurassic Navajo Sandstone and Entrada Sandstone, and Permian Weber Sandstone reservoir units that lie beneath robust sealing units like the ~5000-ft-thick Mancos Shale and Carmel Formation. Reservoirs such as the Navajo and Weber Sandstones have been demonstrated to be suitable reservoirs through a long history of oil and gas exploration in Utah. New areas of interest include the southern Basin and Range in southwest Utah, where the Jurassic Navajo Sandstone is overlain by the sealing Carmel Formation at suitable depths (>3000 ft), and has good porosities based on outcrop analogue data. Just to the north (e.g., central Basin and Range), legacy wells and 2D seismic data show possible salt and subsurface basalt flows that may provide additional possible CS reservoirs and seals. This geo-region also has the advantage of being coupled with geothermal energy resources that may be used to power burgeoning direct air capture technologies. In the Paradox Basin of southeastern Utah, the Leadville Limestone is a potential storage reservoir beneath the thick (4000–5000 ft), salt-bearing Pennsylvanian Paradox Formation. Although the northern and western parts of Utah offer CS potential, these areas typically contain less infrastructure and subsurface penetrations, creating geologic uncertainty associated with subsurface seals and reservoirs due to a lack of data. Overall, this statewide assessment and ranking is the first step to aid in evaluating CS potential across Utah and provides a foundation for future research in the most favorable locations.

58 GEOSCIENCES↗

DOE OSTI2024

On the connection between least squares, regularization, and classical shadows

Classical shadows (CS) offer a resource-efficient means to estimate quantum observables, circumventing the need for exhaustive state tomography. Here, we clarify and explore the connection between CS techniques and least squares (LS) and regularized least squares (RLS) methods commonly used in machine learning and data analysis. By formal identification of LS and RLS ``shadows'' completely analogous to those in CS---namely, point estimators calculated from the empirical frequencies of single measurements---we show that both RLS and CS can be viewed as regularizers for the underdetermined regime, replacing the pseudoinverse with invertible alternatives. Through numerical simulations, we evaluate RLS and CS from three distinct angles: the tradeoff in bias and variance, mismatch between the expected and actual measurement distributions, and the interplay between the number of measurements and number of shots per measurement. Compared to CS, RLS attains lower variance at the expense of bias, is robust to distribution mismatch, and is more sensitive to the number of shots for a fixed number of state copies---differences that can be understood from the distinct approaches taken to regularization. Conceptually, our integration of LS, RLS, and CS under a unifying ``shadow'' umbrella aids in advancing the overall picture of CS techniques, while practically our results highlight the tradeoffs intrinsic to these measurement approaches, illuminating the circumstances under which either RLS or CS would be preferred, such as unverified randomness for the former or unbiased estimation for the latter.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2017

Bond Durability of Carbon-Microfiber-Reinforced Alkali-Activated High-Temperature Cement Adhering to Carbon Steel

The study aims at evaluating the bond durability of a carbon microfiber (CMF)-reinforced alkali-activating calcium aluminate cement (CAC)/fly ash F (FAF) blend cementitious material adhering to carbon steel (CS) under stresses induced by a 350°C heat-25°C water cooling cycle. This cementitious material/CS joint sample was originally prepared in an autoclave at 300°C under a pressure of 8.3 MPa. For comparison, two reference geothermal well cements, Class G modified with silica (G) and calciumaluminum phosphate (CaP), were employed as well reinforced with CMF. In the CAC/FAF blending cement systems, the CAC-derived cementitious reaction products preferentially adhered to CS surfaces, rather than that of FAF-related reaction products. CMF played a pivotal role in creating tough interfacial bond structure of cement layer adhering to CS. The bond toughness also was supported by the crystalline cementitious reaction products including sodalite, brownmillerite, and hedenbergite as major phases, and aragonite, boehmite, and garronite as minor ones. The brownmillerite as an interfacial reaction product between cement and CS promoted the chemical bonding of the cement to CS, while the other phases served in providing the attractive bonding of the cement to CS. The post-stress-test joint samples revealed the formation of additional brown-millerite, aragonite, and garronite, in particular brownmillerite as the major one. The combination of chemical bonding and self-advancing adherence behavior of the cement was essential for creating a better interfacial bond structure. A similar interfacial bond structure was observed with CaP. The crystalline phase composition of the autoclaved cement revealed apatite, zeolite, and ferrowyllieite as major reaction products, and aragonite and al-katoite as the minor ones. Ferrowyllieite was identified as cement/CS interfacial reaction product contributing to the chemical bond of cement, while the other phases aided in providing the attractive bond of cement. After a stress test, two phases, ferrowyllieite and aragonite, promoted the self-advancing adherence of cement to CS. However, the effectiveness of these phases in improving adherence performance of cement was less than that of CAC/FAF blend cement, reflecting the fact that the bond durability of CAC/FAF blend cement was far better than that of the CaP. In contrast, the autoclaved silica-modified G cement consisting of xonotlite, and 0.9 nm-to-bermorite and riversideite, with calcite as the crystalline reaction products, had no significant effect on improving the shear bond strength and the bond’s toughness. No interaction product with CS was found in the cement adhering to CS. After a stress test, the calcite phase acted only to promote the self-advancing adherence of cement, but its extent was minimal compared with that of the other cements, thereby resulting in poor bond durability.

15 GEOTHERMAL ENERGY↗

NASA NTRS2021

Going Beyond Hooked Participants: The Nibble- and-Drop Framework for Classifying Citizen Science Participation

Many citizen science (CS) programs aim to grow and sustain a pool of enthusiastic participants who consistently contribute their efforts to a specific scientific endeavor. Consequently, much research has explored CS participants’ motivations and their relationship to participant recruitment and retention. However, much of this research has focused on actively participating citizen scientists. If researchers want to elucidate the relationship between participant factors (such as demographics and motivations) and participant retention, it is necessary to develop a more comprehensive picture of the different degrees of participation in CS. This paper presents a framework for classifying participation throughout the participant’s engagement in a CS project/program. We suggest a CS participation model that captures the dynamic nature of participation across an arc of volunteering. Called the Nibble-and-Drop Framework, the model describes multiple exit points and stages of contribution typical of participation in a CS program. Applying the framework to the NASA GLOBE Observer (GO) CS program, we found that it captured the dynamics of participation in a global-scale, mobile, app-based, contributory style CS project. The framework guided our analysis of how different participant factors correlate with degrees of participation. We found that participants were motivated to initially participate because they wanted to contribute to NASA research and science. Participants who dropped out of the program at various points often initially engaged through specific collection events and did not feel the need to continue contributing beyond the event; other drop-outs doubted whether their contributions were meaningful, showing again the need to ensure that participants understand the value of their engagement in a CS project.

Heather Fischer↗

DOE OSTI2019

Understanding and Controlling Cesium Loading on Crystalline Silicotitanate - 19601

Savannah River Remediation (SRR) contracted with Westinghouse Electric Corporation (WEC), Columbia Energy and Environmental Services (CEES), to build and deliver a modular ion exchange process that will be used to remove radioactive cesium from dissolved salt solution contained in Tank 10 at the Savannah River Site (SRS). The resulting decontaminated salt solution will be sent to Tank 11 and then to Tank 50 for final disposition in grout at the Saltstone facility. At the end of processing, the loaded ion exchange (IX) columns are drained, rinsed, and dried. The IX columns are removed from the modular unit and stored at Interim Safe Storage (ISS). This ion exchange process is called the Tank Closure Cesium Removal (TCCR) system. The TCCR system consists of several unit operations and process monitoring capability housed within three modular units. The first modular unit contains the process control computer, the second modular unit contains the main process equipment (two prefilters, four IX columns, and resin trap (post filtration)), and the third modular unit is the ventilation system. The main unit operations of the TCCR system are filtration, ion exchange, and ventilation. The ion exchange media utilized is a form of inorganic Crystalline Silicotitanate (CST), IONSIV{sup TM} R9120-B supplied by UOP Honeywell. CST has a high selectivity for cesium (Cs) and has some affinity for other Group IA alkali metals on the periodic chart (hydrogen, lithium, sodium, potassium, rubidium, and francium). CST has also been shown to have affinity for strontium and actinides. Cesium loading on the CST is dependent on many factors including chemical composition (cations and anions), temperature, and pH of the salt solution. The actual amount of Cs loaded onto an IX column is dependent on the factors above along with the salt solution volume fed to the IX column. Because of CST's high selectivity for Cs, the Cs-137 equilibrium loading can contribute enough decay heat to result in an ion exchange column boiling event under no flow conditions in the IX column. The boiling event under no flow is a safety concern that must be prevented from occurring. To prevent boiling of the column under no flow conditions, the Cs-137 equilibrium loading must be determined and understood. Several methodologies were evaluated for performing the Cs-137 equilibrium loading determination for CST. After review of available research and development (R and D), batch equilibrium contact test data, and Zheng Anthony Miller (ZAM) model predictions for the salt solution chemistry in Tank 10, a methodology for determining the Cs-137 equilibrium loading on CST was selected. The methodology selected involves an in-tank batch equilibrium contact test performed in duplicate that considers additional corrections to account for anticipated operational evolutions. The in-tank batch equilibrium contact test utilizes ∼0.1 grams of CST secured in a slotted sample vial. The slotted sample vial design allows for salt solution to be in contact with the CST. The slotted sample vials containing the CST are submerged in Tank 10 and exposed to the salt solution for ten days. After ten days, the samples are retrieved and sent to the Savannah River National Laboratory (SRNL) for analysis of the Cs-137 equilibrium loading. Additional corrections are then made to the Cs-137 results to account for anticipated operational evolutions. Anticipated operational evolutions include external additions (water/caustic) to Tank 10 that result in a change to its chemical composition, tank temperature effects, departures from the laboratory testing (mixed vs. stagnant tank conditions), and IX column flushes. A description of the methodologies considered, feasibility of methodology deployment, and the down select process (benefits vs. risks) is discussed in this paper. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2022

Corrosion of Stainless and Carbon Steel in Aqueous Piperazine for CO2 Capture

Current obstacles that prevent commercial implementation of amine-scrubbing CO2 capture are the high costs. Reducing capital costs by appropriate selection of construction materials, which requires knowledge of material corrosion performance for the process, will improve the economic feasibility of this technology. Corrosion was evaluated in three pilot plant campaigns using aqueous piperazine with the Advanced Stripper (PZAS). 316L stainless steel (SS) experienced higher corrosion than 304 SS and 2205 duplex SS, and the corrosion rate showed strong dependence on the temperature. 304 and 2205 performed well at all locations and should be good construction materials for PZAS. Degraded PZ exacerbated 316L corrosion, and removal of PZ degradation products using a carbon adsorption bed significantly reduced corrosion. Carbon steel (CS) corrosion showed a weak temperature effect because the corrosion was more dependent on the protective siderite film. The protectiveness of the films was related to fluid velocity. Ni-based alloys corroded in PZ, and the rate increased with temperature. Corrosion of C1010 CS and SS (304, 316L, 430) was measured at absorber and water wash conditions on the bench-scale. Corrosion rate decreases with increasing PZ. 8 With more than 0.003 m PZ in solution, CS has acceptable corrosion performance. Corrosion of CS increases with increasing partial pressure of CO2, suggesting loading is another dominant parameter for carbon steel corrosion. Temperature has a less significant effect than PZ concentration and loading. CS corrosion increases with increasing flow velocity at both absorber and water wash conditions. SS had little corrosion at this lower temperature. Performance of siderite (FeCO3) protective films on CS was studied at representative stripper conditions on the bench-scale. Siderite films can deposit on the surface of CS in CO2-loaded PZ solution at temperatures >100 °C and protect CS from corrosion. The protection may fail in degraded PZ. Ethylenediamine (EDA) is one of the major contributors for the loss of film protectiveness or can be the surrogate for the effect of PZ degradation on siderite film protection. A link between protectiveness and the apparent density of siderite films was discovered. The apparent density of siderite films decreases with increasing flow velocity and decreasing CO2 loading, resulting in higher corrosion of CS.

Liu, Ching-Ting↗

DOE OSTI2020

Materials Data on Cs2PtC2(OF)4 by Materials Project

Cs2PtC2(OF)4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded to four O2- and eight F1- atoms to form distorted CsO4F8 cuboctahedra that share corners with two equivalent CsO4F8 cuboctahedra, a cornercorner with one PtO2F4 octahedra, faces with two equivalent CsO4F8 cuboctahedra, and faces with three PtO2F4 octahedra. The corner-sharing octahedral tilt angles are 17°. There are a spread of Cs–O bond distances ranging from 3.25–3.36 Å. There are a spread of Cs–F bond distances ranging from 3.13–3.28 Å. In the second Cs1+ site, Cs1+ is bonded in a 11-coordinate geometry to four O2- and seven F1- atoms. There are a spread of Cs–O bond distances ranging from 3.19–3.41 Å. There are a spread of Cs–F bond distances ranging from 3.11–3.29 Å. In the third Cs1+ site, Cs1+ is bonded to four O2- and eight F1- atoms to form distorted CsO4F8 cuboctahedra that share corners with two equivalent CsO4F8 cuboctahedra, a cornercorner with one PtO2F4 octahedra, faces with two equivalent CsO4F8 cuboctahedra, and faces with three PtO2F4 octahedra. The corner-sharing octahedral tilt angles are 16°. There are a spread of Cs–O bond distances ranging from 3.19–3.32 Å. There are a spread of Cs–F bond distances ranging from 3.16–3.33 Å. In the fourth Cs1+ site, Cs1+ is bonded in a 11-coordinate geometry to four O2- and seven F1- atoms. There are a spread of Cs–O bond distances ranging from 3.22–3.44 Å. There are a spread of Cs–F bond distances ranging from 3.12–3.32 Å. There are two inequivalent Pt2+ sites. In the first Pt2+ site, Pt2+ is bonded to two O2- and four F1- atoms to form PtO2F4 octahedra that share a cornercorner with one CsO4F8 cuboctahedra and faces with three CsO4F8 cuboctahedra. Both Pt–O bond lengths are 2.01 Å. There are a spread of Pt–F bond distances ranging from 1.97–2.01 Å. In the second Pt2+ site, Pt2+ is bonded to two O2- and four F1- atoms to form PtO2F4 octahedra that share a cornercorner with one CsO4F8 cuboctahedra and faces with three CsO4F8 cuboctahedra. There are one shorter (2.01 Å) and one longer (2.02 Å) Pt–O bond lengths. There are a spread of Pt–F bond distances ranging from 1.97–2.01 Å. There are four inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.23 Å) and one longer (1.32 Å) C–O bond length. In the second C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.22 Å) and one longer (1.33 Å) C–O bond length. In the third C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.23 Å) and one longer (1.32 Å) C–O bond length. In the fourth C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.22 Å) and one longer (1.33 Å) C–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cs1+, one Pt2+, and one C4+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to two Cs1+ and one C4+ atom. In the third O2- site, O2- is bonded in a distorted water-like geometry to two Cs1+, one Pt2+, and one C4+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cs1+, one Pt2+, and one C4+ atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to two Cs1+ and one C4+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to two Cs1+ and one C4+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cs1+, one Pt2+, and one C4+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to two Cs1+ and one C4+ atom. There are eight inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted single-bond geometry to four Cs1+ and one Pt2+ atom. In the second F1- site, F1- is bonded in a distorted single-bond geometry to four Cs1+ and one Pt2+ atom. In the third F1- site, F1- is bonded in a distorted single-bond geometry to four Cs1+ and one Pt2+ atom. In the fourth F1- site, F1- is bonded in a distorted single-bond geometry to four Cs1+ and one Pt2+ atom. In the fifth F1- site, F1- is bonded in a distorted single-bond geometry to three Cs1+ and one Pt2+ atom. In the sixth F1- site, F1- is bonded in a distorted single-bond geometry to four Cs1+ and one Pt2+ atom. In the seventh F1- site, F1- is bonded in a distorted single-bond geometry to three Cs1+ and one Pt2+ atom. In the eighth F1- site, F1- is bonded in a distorted single-bond geometry to four Cs1+ and one Pt2+ atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on CsSn by Materials Project

CsSn crystallizes in the tetragonal I4_1/acd space group. The structure is three-dimensional. there are two inequivalent Cs sites. In the first Cs site, Cs is bonded in a 6-coordinate geometry to six equivalent Sn atoms. There are a spread of Cs–Sn bond distances ranging from 4.06–4.21 Å. In the second Cs site, Cs is bonded in a 12-coordinate geometry to eight equivalent Sn atoms. There are a spread of Cs–Sn bond distances ranging from 4.09–4.19 Å. Sn is bonded in a 10-coordinate geometry to seven Cs and three equivalent Sn atoms. There are one shorter (2.99 Å) and two longer (3.00 Å) Sn–Sn bond lengths.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Cs4Li2(Si2O5)3 by Materials Project

Cs4Li2(Si2O5)3 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are eight inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to eight O2- atoms. There are a spread of Cs–O bond distances ranging from 3.08–3.61 Å. In the second Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Cs–O bond distances ranging from 3.12–3.67 Å. In the third Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Cs–O bond distances ranging from 3.19–3.75 Å. In the fourth Cs1+ site, Cs1+ is bonded in a 5-coordinate geometry to four O2- atoms. There are two shorter (3.12 Å) and two longer (3.20 Å) Cs–O bond lengths. In the fifth Cs1+ site, Cs1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Cs–O bond distances ranging from 3.20–3.42 Å. In the sixth Cs1+ site, Cs1+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Cs–O bond distances ranging from 3.17–3.66 Å. In the seventh Cs1+ site, Cs1+ is bonded in a 11-coordinate geometry to eleven O2- atoms. There are a spread of Cs–O bond distances ranging from 3.19–3.56 Å. In the eighth Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are two shorter (3.06 Å) and two longer (3.23 Å) Cs–O bond lengths. There are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.87 Å) and two longer (1.88 Å) Li–O bond length. In the second Li1+ site, Li1+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.87 Å) and two longer (1.88 Å) Li–O bond length. There are six inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.58–1.67 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.59 Å) and three longer (1.66 Å) Si–O bond length. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Cs1+ and two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to four Cs1+, one Li1+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cs1+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two Cs1+ and two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to four Cs1+, one Li1+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a distorted linear geometry to three Cs1+, one Li1+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Cs1+ and two Si4+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Cs1+ and two Si4+ atoms. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to two Cs1+ and two Si4+ atoms. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Cs1+ and two Si4+ atoms. In the eleventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Cs1+, one Li1+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a linear geometry to two Cs1+ and two equivalent Si4+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to three Cs1+, one Li1+, and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Cs1+, one Li1+, and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Cs1+ and two Si4+ atoms. In the sixteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Cs1+ and two equivalent Si4+ atoms. In the seventeenth O2- site, O2- is bonded in a distorted linear geometry to one Cs1+ and two equivalent Si4+ atoms. In the eighteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Cs1+ and two equivalent Si4+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Cs3Bi2 by Materials Project

Bi2Cs3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Cs sites. In the first Cs site, Cs is bonded in a 6-coordinate geometry to six equivalent Bi atoms. There are a spread of Cs–Bi bond distances ranging from 4.15–4.27 Å. In the second Cs site, Cs is bonded in a 6-coordinate geometry to six equivalent Bi atoms. There are a spread of Cs–Bi bond distances ranging from 3.95–4.30 Å. Bi is bonded in a 10-coordinate geometry to nine Cs and one Bi atom. The Bi–Bi bond length is 2.99 Å.

36 MATERIALS SCIENCE↗