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At least 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

An Overview of Potential Future Aviation Energy Carriers

Global jet fuel demand is projected to grow to 165 billion gallons by 2050 and there is growing interest in the aviation industry to understand the capabilities of alternative energy carriers. This report considers several potential energy carriers, reviewing their production potential, operational considerations, and economic implications to inform potential next steps in aeronautics research. The following energy carriers (i.e., fuels) were evaluated in this study for future use in aviation: sustainable aviation fuel (SAF) - both biomass-based and power-to-liquids (PtL) - based SAF - cryogenic hydrogen (LH 2 ) - also known as liquid hydrogen - liquefied natural gas (LNG), liquefied ethane (LE), and Jet X. The barriers and opportunities for the evaluated energy carriers vary. SAF is a commercially available drop-in fuel compatible with existing aircraft and infrastructure. SAF is limited by both higher prices and slow commercialization of multiple pathways using different feedstocks necessary to significantly grow supply. Cryogenic fuels, in contrast, have very different thermal, physical, and chemical properties than SAF and Jet A, requiring the construction of new airport storage and dispensing infrastructure and the design of new aircraft energy systems capable of mitigating heat transfer and boil-off. Cryogenic fuels offer an opportunity to diversify aviation fuel carriers from domestic energy relevant for both energy security and resilience. This means cryogenic fuels are more of a longer-term solution for aircraft but are worth exploring for potential future cost savings and emissions benefits. Jet X refers to non-drop-in liquid hydrocarbon fuels in the early stages of investigation seeking favorable properties. There are substantial barriers to non-drop-in liquid aviation fuels that are not compatible with existing aircraft and fuel infrastructure.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2020

Implementation of the Glycolate Destruction Process with Sodium Permanganate in the Defense Waste Processing Facility (DWPF) - 20141

The Savannah River Site (SRS) seeks to replace formic acid with glycolic acid as a chemical reductant in the Defense Waste Processing Facility (DWPF), where borosilicate glass is mixed with high-level radioactive waste, melted at high temperatures, then poured into stainless steel canisters for safe storage. Prior research and development have demonstrated the feasibility and advantages of the new nitric-glycolic acid flowsheet over the current nitric-formic acid flowsheet to chemically adjust the radioactive sludge slurry waste in the Sludge Receipt and Adjustment Tank (SRAT) prior to vitrification. Use of glycolic acid reduces hydrogen and ammonia generation during the reduction process, thus reducing flammability hazards and purge requirements in the DWPF processing vessels. In addition, glycolic acid will support the new Salt Waste Processing Facility (SWPF) by allowing for receipt of higher volumes of waste due to reduction of flammable gases, increased boil-up rates in the vessels, and easing the processing of future sludge batches containing high levels of mercury. However, during DWPF operations, trace amounts of glycolate are anticipated to be entrained in the recycle stream and sent to the Concentration, Storage, and Transfer Facilities (CSTF) via the Recycle Collection Tank (RCT). The RCT receives condensate from the Slurry Mix Evaporator Condensate Tank (SMECT) and Off-gas Condensate Tank (OGCT) that may contain unreacted glycolate. A literature review found the potential for hydrogen generation due to thermolysis of glycolate in caustic CSTF conditions. Savannah River National Laboratory (SRNL) conducted several tests on simulant and radioactive waste from various tanks at SRS and confirmed that glycolate added to waste at concentrations of approximately 1000 mg/L and higher generates hydrogen through thermolysis. There are potential operating scenarios in the future where glycolate concentration could exceed 1000 mg/L in the 2H Evaporator Drop Tank, the highest accumulation point for DWPF organics received via recycle. These findings presented a need to develop another process to mitigate the impact of glycolic acid to the CSTF. Several DWPF compatible options were evaluated for their ability to destroy glycolate in the DWPF recycle stream under various processing conditions, thereby mitigating its introduction to the CSTF. Downselection testing identified sodium permanganate as the most promising and simplest option to oxidize glycolate. It has been demonstrated to be effective in various RCT simulant compositions, operating temperatures, oxidant addition rates, solution pH, and initial glycolate concentrations. A feasibility study identified existing tanks within the facility that could be used for receiving and storing the commercially available sodium permanganate, as well as feeding it to the RCT for processing. The use of existing equipment as well as the ability to purchase the pre-mixed chemical reduces implementation and operational complexity. The downstream impacts of the sodium permanganate reaction were also evaluated and demonstrated to have minimal impact on other chemical species present in the RCT and CSTF, as well as on the materials of construction of the RCT and CSTF vessels and associated piping and instrumentation. Future work is in progress to validate the glycolate destruction process with testing in actual radioactive RCT waste before implementation in DWPF. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRSDate not supplied

A Heritage BioSensor for Lunar Biology Experiments

Introduction: Automated biological experiments on small spacecraft missions have gained prominence over the past decade due to their simplicity, accessibility, and small mass, volume, and power needs. Most recently, the BioSensor microfluidic CubeSat payload aboard BioSentinel used an automated microfluidic cell culture system to study the effects of environmental stressors like deep space radiation and microgravity on yeast growth and metabolism. BioSentinel’s successor, the Lunar Explorer Instrument for space biology Applications (LEIA), will study the effects of lunar gravity and radiation using an improved version of the BioSensor microfluidic platform. The BioSensor payload has great adaptability to host a diverse range of biological experiments with single- and multi-celled organisms in both crewed and uncrewed missions, making it a compelling candidate for future space biology studies in a lunar surface environment. BioSensor Instrumentation on BioSentinel: The first spaceflight mission with the BioSensor, BioSentinel’s biology experiments occurred at three locations -- deep space, ISS and ground. The payload contained 18 microfluidic cards, each featuring 16 growth wells (a total of 288 growth wells). Each well was loaded before launch with desiccated yeast. In space, liquid culture medium (nutrients) was automatically introduced to batches of wells at a time to initiate a series of biology experiments. Temperature was maintained by thin film heaters on both sides of each card. Each well was equipped with three LEDs emitting at 570 nm, 630 nm, and 850 nm, paired with photodetectors to measure cell concentration and the alamarBlue (metabolic indicator dye) color transition from blue to pink. Phenotypic parameters like cell viability, metabolic rate, and generation time can be derived from these measurements. The sequence and timing of fluid fills, optical measurements, and thermal control were stored onboard, but could be updated asynchronously via ground communication. LEIA: LEIA is slated for launch no earlier than 2026 on a CLPS lander. BioSentinel’s BioSensor has been modified for use in LEIA. These improvements include: (a) storage for multiple culture medium types, (b) additional LED color (465 nm) for a new biological assay for antioxidant (carotenoid) production, (c) housing modifications for later biology load before launch, (d) improved isolation between electronic and fluidic components, and (e) improved humidity control for prolonged organism viability in case of post-load launch delay. Future Prospects: The consistent and successful demonstration of complex fluidics platforms alongside reliable instrument operations in a space environment is poised to create strong momentum for BioSensor-based biological experiment payloads. Planned future developments with the BioSensor include extending compatibility to a broader range of organisms and assays. Preliminary work has already demonstrated successful growth of Arabidopsis seedlings in fluidic cards. With a few modifications to the optical assembly, the setup could easily measure photosynthetic traits in plants and cyanobacteria. The addition of fluorescence measurements and generation of novel luminescent assays will elevate BioSensor’s functionality further. Beyond the BioSensor’s potential uses on free-flyer missions, ISS and Gateway, and CLPS landers, deploying the BioSensor to the lunar surface or in an artificial habitat on crewed missions could enable pioneering research on both how life responds to lunar conditions and future bioproduction capabilities making the BioSensor an indispensable tool for future space biology research.

Chinmayee Govinda Raj↗
NASA NTRS2011

Liquid Methane Conditioning Capabilities Developed at the NASA Glenn Research Center's Small Multi- Purpose Research Facility (SMiRF) for Accelerated Lunar Surface Storage Thermal Testing

Glenn Research Center s Creek Road Cryogenic Complex, Small Multi-Purpose Research Facility (SMiRF) recently completed validation / checkout testing of a new liquid methane delivery system and liquid methane (LCH4) conditioning system. Facility checkout validation was conducted in preparation for a series of passive thermal control technology tests planned at SMiRF in FY10 using a flight-like propellant tank at simulated thermal environments from 140 to 350K. These tests will validate models and provide high quality data to support consideration of LCH4/LO2 propellant combination option for a lunar or planetary ascent stage.An infrastructure has been put in place which will support testing of large amounts of liquid methane at SMiRF. Extensive modifications were made to the test facility s existing liquid hydrogen system for compatibility with liquid methane. Also, a new liquid methane fluid conditioning system will enable liquid methane to be quickly densified (sub-cooled below normal boiling point) and to be quickly reheated to saturation conditions between 92 and 140 K. Fluid temperatures can be quickly adjusted to compress the overall test duration. A detailed trade study was conducted to determine an appropriate technique to liquid conditioning with regard to the SMiRF facility s existing infrastructure. In addition, a completely new roadable dewar has been procured for transportation and temporary storage of liquid methane. A new spherical, flight-representative tank has also been fabricated for integration into the vacuum chamber at SMiRF. The addition of this system to SMiRF marks the first time a large-scale liquid methane propellant test capability has been realized at Glenn.This work supports the Cryogenic Fluid Management Project being conducted under the auspices of the Exploration Technology Development Program, providing focused cryogenic fluid management technology efforts to support NASA s future robotic or human exploration missions.

Bamberger, Helmut H.↗
NASA NTRS2020

On Orbit Flight Testing of the Roll-Out Solar Array

The Roll-Out Solar Array (ROSA) is an innovative, lightweight solar array with a flexible substrate that makes use of the stored strain energy in its composite structural members to provide deployment without the use of motors while still packaging efficiently. The ROSA flight experiment was launched to the International Space Station (ISS)on June 3rd, 2017 as a part of the eleventh SpaceX commercial resupply mission. After two weeks of storage, ROSA was extracted from the Dragon spacecraft, deployed, and put through a week of tests to verify its structural characteristics as well as the performance of photovoltaics. The structural dynamics experiments included active excitation of out-of-plane bending modes, and a study of the thermal-structural interaction of the structure during day-night transitions. Data was gathered from a small number of accelerometers located at key points on the solar array and from cameras observing numerous photogrammetry targets spread out over the structure and the photovoltaic blanket. The goal in this effort was to better understand the performance of ROSA and to improve modeling efforts for future designs of similar solar arrays. Of particular interest are the first few system modes and mode shapes of the array, the amount of structural damping present, and degree of structural-thermal interaction seen during eclipse exit.

ROSA↗
NASA NTRSDate not supplied

Water Shelf Life for Long-Duration Rodent Research Missions

The National Aeronautics and Space Administration Rodent Research Project habitat is a highly-specialized rodent husbandry caging system that enables mice to be flown to the International Space Station for a variety of bioscience studies in the unique microgravity and radiation environment. The habitat accommodates an internal water supply box containing four water access points and two one liter flexible plastic sterile blood bags for storage. Two access points are provided on each side of the habitat, which accommodates five animals per side. Due to the nature of operations on the Space Station – including limited fluid handling – water cannot be changed out weekly as in ground-based vivariums. Water is added to the system a maximum of eighteen months prior to being provided to rodents. The dependable provision of high-quality drinking water is essential for both the welfare of rodents and the scientific integrity of the studies in which they are involved. The robust, multi-stage water preparation process involves the autoclave sterilization of deionized water, the addition of iodine to minimize biofilms, and filtration through a sterile filter to ensure removal of bacteria and other contaminants. The water is then loaded into the sterile blood bags as part of the automated delivery system. A water storage test determined that the shelf life of this water in the habitat could be increased up to four years from a previous eighteen months. This facilitates the ability to pre-position habitats on Station as well as demonstrates that the habitat’s water system can be utilized on future long-duration and deep space missions involving rodents.

Tyler Marsh↗
DOE OSTI2020

Markets and Economics for Thermal Power Extraction from Nuclear Power Plants Aiding the Decarbonization of Industrial Processes

This report analyzes the domestic industrial heat markets which may be plausible for using heat extracted from existing LWRs, contributing to the decarbonization of industry. It conceptualizes ideas for a future energy park centered around an LWR with various participating synergistic industries with extensive heat and material integrations with the LWR. It also presents comparison calculations for energy storage options and the levelized cost of heat from an LWR versus the levelized cost of heat from a conventional natural gas boiler and shows under what circumstances heat from LWRs is competitive with and beats natural gas.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2024

Hydropower Supply Chain Gap Analysis

In 2022, DOE conducted supply chain "deep dives" for renewable energy technologies, including hydropower (Uria-Martinez, Hydropower Industry Supply Chain Deep Dive Assessment 2022). The deep dive identified several challenges in the current hydropower supply chain. In addition, Nguyen et. al (2022) conducted an analogous deep-dive assessment on large (> 100-MW) power transformers (LPTs), a critical component of hydropower installations, and concluded that the LPTs as well as several upstream components and materials also have domestic supply chain challenges. These deep dives were the initial high-level assessments of these supply chains and were focused on identifying the biggest issues. Both recommended further investigation. In the two years since the deep dives were published, the Water Power Technologies Office (WPTO) has focused on improving our understanding of the hydropower supply chain and developing strategies for addressing these challenges. Because the challenges outlined above are most acute for large hydropower systems, most of the report and specifically, this report concentrates on the larger > 100-MW hydropower systems. Early in 2023, DOE's Secretary of Energy asked the Water Power Technologies Office (WPTO) to engage the hydropower community and seek input on strategies to secure and encourage domestic manufacturing. WPTO has established three focus areas for engagement: 1) Define the market for planned rehabilitations and new construction of the domestic fleet, 2) Provide insights for policies, incentives, loan programs, and technology investments to encourage domestic content, and 3) Define the existing and required domestic hydropower manufacturing capabilities and workforce. This report summarizes these efforts and complements the earlier work by further exploring the identified challenges and identifying potential actions to address these challenges. Furthermore, we conducted a detailed gap analysis of the domestic hydropower supply chain, down to the component level. From this analysis, we then make specific, actionable recommendations for closing these gaps. Section 2 of the report summarizes recent (i.e., since 2021) legislation impacting hydropower deployment and/or its supply chain. It then describes the efforts of WPTO to assess and improve the hydropower supply chain since the publication of the deep-dive assessments. In Section 3, the report updates the earlier supply chain and market studies, identifying specific capabilities by company and location. Section 4 outlines the hydropower demand signal for both new builds due to clean energy goals as well as refurbishments and upgrading of the current domestic fleet. Section 5 is a detailed gap analysis while Section 6 provides actionable recommendations for closing the gaps. Section 7 concludes the report by linking the recommendations to the identified gaps and discusses future efforts.

13 HYDRO ENERGY↗
DOE OSTI2022

Leaf water potential measurements using the pressure chamber: Synthetic testing of assumptions towards best practices for precision and accuracy

Leaf water potential (ψ leaf ), typically measured using the pressure chamber, is the most important metric of plant water status, providing high theoretical value and information content for multiple applications in quantifying critical physiological processes including drought responses. Pressure chamber measurements of ψ leaf (ψ leafPC ) are most typical, yet, the practical complexity of the technique and of the underlying theory has led to ambiguous understanding of the conditions to optimize measurements. Consequently, specific techniques and precautions diversified across the global research community, raising questions of reliability and repeatability. Here, we surveyed specific methods of ψ leafPC from multiple laboratories, and synthesized experiments testing common assumptions and practices in ψ leafPC for diverse species: (i) the need for equilibration of previously transpiring leaves; (ii) leaf storage before measurement; (iii) the equilibration of ψ leaf for leaves on bagged branches of a range of dehydration; (iv) the equilibration of ψ leaf across the lamina for bagged leaves, and the accuracy of measuring leaves with artificially ‘elongated petioles’; (v) the need in ψ leaf measurements for bagging leaves and high humidity within the chamber; (vi) the need to avoid liquid water on leaf surfaces; (vii) the use of ‘pulse’ pressurization versus gradual pressurization; and (viii) variation among experimenters in ψ leafPC determination. Based on our findings we provide a best practice protocol to maximise accuracy, and provide recommendations for ongoing species-specific tests of important assumptions in future studies.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Investigation of hydrometeorological influences on reservoir releases using explainable machine learning methods

Long short-term memory (LSTM) networks have demonstrated successful applications in accurately and efficiently predicting reservoir releases from hydrometeorological drivers including reservoir storage, inflow, precipitation, and temperature. However, due to its black-box nature and lack of process-based implementation, we are unsure whether LSTM makes good predictions for the right reasons. In this work, we use an explainable machine learning (ML) method, called SHapley Additive exPlanations (SHAP), to evaluate the variable importance and variable-wise temporal importance in the LSTM model prediction. In application to 30 reservoirs over the Upper Colorado River Basin, United States, we show that LSTM can accurately predict the reservoir releases with NSE ≥ 0.69 for all the considered reservoirs despite of their diverse storage sizes, functionality, elevations, etc. Additionally, SHAP indicates that storage and inflow are more influential than precipitation and temperature. Moreover, the storage and inflow show a relatively long-term influence on the release up to 7 days and this influence decreases as the lag time increases for most reservoirs. These findings from SHAP are consistent with our physical understanding. However, in a few reservoirs, SHAP gives some temporal importances that are difficult to interpret from a hydrological point of view, probably because of its ignorance of the variable interactions. SHAP is a useful tool for black-box ML model explanations, but the hydrological processes inferred from its results should be interpreted cautiously. More investigations of SHAP and its applications in hydrological modeling is needed and will be pursued in our future study.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1989

Mars surface-based factory: Computer control of a water treatment system to support a space colony on Mars

In a continued effort to design a surface-based factory on Mars for the production of oxygen and water, the Design Group at Prairie View A&M University made a preliminary study of the surface and atmospheric composition on Mars and determined the mass densities of the various gases in the martian atmosphere. Based on the initial studies, the design group determined oxygen and water to be the two products that could be produced economically under the martian conditions. Studies were also made on present production techniques to obtain water and oxygen. Analyses were made to evaluate the current methods of production that were adaptable to the martian conditions. The detailed report was contained in an Interim Report submitted to NASA/USRA in Aug. of 1986. Even though the initial effort was the production of oxygen and water, we found it necessary to produce some diluted gases that can be mixed with oxygen to constitute 'breathable' air. In Phase 2--Task 1A, the Prairie View A&M University team completed the conceptual design of a breathable-air manufacturing system, a means of drilling for underground water, and storage of water for future use. The design objective of the team for the 1987-1988 academic year was the conceptual design of an integrated system for the supply of quality water for biological consumption, farming, and residential and industrial use. The design has also been completed. Phase 2--Task 1C is the present task for the Prairie View Design Team. This is a continuation of the previous task, and the continuation of this effort is the investigation into the extraction of water from beneath the surface and an alternative method of extraction from ice formations on the surface of Mars if accessible. In addition to investigation of water extraction, a system for computer control of extraction and treatment was developed with emphasis on fully automated control with robotic repair and maintenance. It is expected that oxygen- and water-producing plants on Mars will be limited in the amount of human control that will be available to operate large and/or isolated plants. Therefore, it is imperative that computers be integrated into plant operation with the capability to maintain life support systems and analyze and replace defective parts or systems with no human interface.

Brice, R.↗
DOE OSTI2025

Assessing the Economic Value of Underground Thermal Storage for Hybrid Geothermal Power

Solutions are needed to address resource adequacy in the electric power system for highly decarbonized systems. The storage duration, the length of time a storage device can provide continuous output at its rated capacity, must be sufficient to receive full credit toward resource adequacy. Longer peaks and high fractions of variable renewable generation have increased the required duration to potentially seasonal durations. Underground Thermal Energy Storage (UTES) can be adapted to a hybrid storage power plant or heating and cooling applications to satisfy the need for long-duration storage. In this study, we use the Renewable Energy Deployment System (ReEDS) capacity expansion model to evaluate the increase in value for an enhanced geothermal system (EGS) resources by adding UTES. In modeled scenarios, using geothermal without storage as a baseline we compare the increase in economic value for plants with a range of storage characteristics. The added value of a hybrid storage plant changes depending on assumptions including the length of storage duration, efficiency, and ability to charge storage from the grid during periods of low energy prices. Relating proposed characteristics for geothermal UTES hybrids to the modeled economic value provides insight into economically viable costs for developing UTES as well as what combination of technology characteristics and future energy and policy assumptions drive significant value increases.

capacity expansion model↗
DOE OSTI2026

Thermal Reservoir Networks for Modularly Expandable Thermal Microgrids

The Department of Defense (DoD) faces the substantial challenge of cost-effectively retrofitting one to two installations per month, each comprising approximately 1,000 buildings, to improve resilience, reduce energy consumption, and enhance energy supply security. Achieving these objectives requires optimal system selection and effective risk mitigation during system integration. To address this need, we introduce Platform-Based Design (PBD), a structured, hierarchical methodology adapted from other industrial sectors to the domain of energy system retrofits. We demonstrate the effectiveness of PBD through a techno-economic feasibility study comparing geothermal-coupled thermal energy networks (TENs) with conventional energy systems for heating, cooling, and powering 17 buildings at Joint Base Andrews (JBA) in Maryland. Our analysis illustrates that the PBD approach enables rigorous, data-driven, sequential decision making, resulting in a family of Pareto-optimal systems, among which the TEN emerged as the most promising solution. The selected TEN design integrates geothermal borefields, heat recovery heat pumps, photovoltaic (PV) arrays, and battery storage. Compared to the baseline system – gas heating combined with air-source chillers – the proposed TEN reduces annual imported energy by 74% and peak electricity demand by 45%, achieves a levelized cost of energy of $\$0.210$/kWh, and substantially enhances resilience. Life-cycle costs increase by approximately 6%, and initial investment costs are about 2.5 times higher than the baseline. However, if central plant infrastructure, district loops, and utility-scale PV and battery systems are privately funded and operated, the initial investment would fall below the baseline system cost. Critical to achieving these significant performance improvements were detailed nonlinear dynamic simulations coupling geothermal heat transfer, energy system operation, and realistic feedback control logic. These simulations identified essential design modifications and control strategy refinements that substantially reduced energy use, peak demand, and compressor shortcycling, thereby improving durability and reliability—issues that would have been significantly more expensive to resolve during operation. Additionally, the verification step highlighted sensitivities to key design parameters that could reduce initial investment by approximately $\$2$ million and reduce annual life-cycle costs more than $\$300,000$. We recommend adopting the PBD methodology for future feasibility studies and TEN pilot projects to gain valuable operational experience. Furthermore, we recommend that DoD invest in transferring and scaling the PBD methodology to other installations. This entails developing standardized computational frameworks and component libraries as well as training industry in conducting PBD. Such investments would enable rapid, robust, reliable, and cost-effective retrofits, supporting DoD’s ambitious energy system modernization goals.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Automated Parameterized CFD Simulations of Phase-Change Material Embedded Heat Exchangers

Thermal storage can be implemented using Phase-Change Materials (PCM), which absorb significant latent heat with a relatively small temperature change. PCM phase-change processes are transient and are driven by thermal diffusion and natural convection – the latter, especially for melting process. Modeling and simulation of PCM heat exchangers is typically computationally intensive due to the relative complex time-dependent underlying physics. This paper presents a study investigating a single straight tube with circular transverse fins in the vertical orientation, using PCM’s with 37oC nominal melting temperature, leveraging automated parametric CFD simulations. The computational domain is reduced to 2D axisymmetric for a segment of the HX comprising a region in between two fins with constant wall temperature as boundary condition. This approach allows for faster evaluations of the transient thermal characteristics for a given design space of interest. Correlations and reduced order models (ROM’s) are developed. Results indicate that the ROM’s reproduce the CFD simulations with high accuracy for designs from the training data set, however, designs from cross-validation and test sets do not always have good agreement. The limited number of designs in the training set is a possible cause for the lack of robustness of the ROM’s and thus additional training designs will be added in future work. The ROM’s solve the simulations on average 500,000 times faster than CFD.

25 ENERGY STORAGE↗
DOE OSTI2023

The evaluation of aluminum and iron metal oxide settling behaviors for Hanford insoluble solids waste preprocessing

The Hanford site is currently one of the largest and most expensive cleanup sites for hazardous, radioactive waste. Over 20% of the waste found at the Hanford site is in the form of a high activity sludge. The insoluble solids in the sludge will need to be concentrated prior to vitrification in the high-level waste (HLW) melter. This will minimize the amount of liquid that will be evaporated during the melting process and expedite the melter processing rate. One proposed option for concentrating the insoluble solids is gravity settling in the storage tanks. Metal oxide compounds containing aluminum and iron make up the majority of the insoluble solids in the sludge, therefore understanding the behavior of these compounds in various tank waste matrices can facilitate sludge pretreatment options. A study of non-radioactive slurry solutions containing Al(OH) 3 (gibbsite), AlO(OH) (boehmite), and Fe 2 O 3 (iron (III) oxide) was conducted to determine the time dependent interface behavior and settling rates of these compounds. Variations in solids loading and sodium concentration were evaluated to represent waste processing conditions and the results of these settling studies were compared with prior tank waste settling tests. Information gathered from these studies can be used to inform future decisions on sludge treatment processes of the insoluble solids processed at the Hanford site.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Germplasm cryopreservation of macroalgae for aquaculture breeding and natural resource conservation: A review

The expansion of the global macroalgal aquaculture and climate change creates the need for germplasm preservation of valuable aquaculture strains and maintenance of natural biodiversity. Compared to the large number of studies in fish and shellfish species, relative few studies have been conducted on the macroalgal germplasm cryopreservation. The first cryopreservation of macroalgae to –75 °C was reported on Neopyropia tenera (formerly called Porphyra tenera) in 1964. To date, a total of 34 studies reported germplasm cryopreservation in 33 species, including Chlorophyta (7 species), Ochrophyta (14 species), and Rhodophyta (12 species). Here, the goal of this review was to summarize the published studies on macroalgal germplasm cryopreservation, compare the reported protocols for the cryopreservation process, and identify the factors affecting post-thaw viability. Overall, macroalgal germplasm cryopreservation included haploid or diploid thalli, spores, and gametes. Cryotubes (1.5-ml or 2-ml) have been widely used to package germplasm samples for cooling and storage in most studies, and the 0.5-ml straws and 5-ml cryotubes have been used in several studies. Two approaches (programmable controlled cooling and vitrification) were employed for macroalgal germplasm cryopreservation. A two-step programmable controlled cooling (e.g., from initial culture temperature to a frozen temperature, such as –40 °C, and then directly plunging into liquid nitrogen at –196 °C) was determined to be an effective cooling strategy. Vitrification, a super rapid cooling for a sample to form non-crystalline amorphous solid, was applied on macroalgal germplasm cryopreservation with sample encapsulation and dehydration. Survival of post-thaw samples varied significantly in different studies. Based on research updates, recommendations are made for future research. It is expected that this review can serve as a foundation for future germplasm banking of macroalgae for aquaculture and biodiversity preservation.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Direct Imaging of the Structural and Morphological Evolution of Epitaxial LiCoO 2 Films during Charge and Overcharge

The capacity decay of layered cathodes in high-voltage applications underscores the need to utilize accurate and precise techniques to understand the underlying mechanisms. Here, we use well-defined epitaxial LiCoO 2 (LCO) films on SrRuO 3 /SrTiO 3 (SRO/STO) with controlled orientations and defect structures along with in situ electrochemical atomic force microscopy to probe the structural and morphological evolutions during the charge and overcharge processes. We quantitatively show the morphological changes in both the reversible delithiation regime and the irreversible over-delithiation regime and correlate the overall electrochemical behaviors to atomic scale defect evolutions in the films. Further, we also observe a significantly lower charging capacity for LCO/SRO/STO(111) compared to that of LCO/SRO/STO(001) films of the same thickness, which is ascribed to different types of atomic scale defects formed during the film growth process. Our high- resolution scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) studies reveal that the antiphase boundaries in LCO/SRO/STO(111) act as viable channels for Li migration but are more susceptible to irreversible phase transitions, which then block subsequent Li diffusion. The failure mechanisms developed here may provide insight into the design of future cathode materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗