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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

ZAM Modeling Study to Support the Tank Closure Cesium Removal (TCCR) 1A Unit

Currently at the Savannah River Site (SRS), the Tank Closure Cesium Removal (TCCR) is an “at-tank” process designed to remove cesium from aqueous tank waste. Cesium will be removed by ion exchange using the engineered IONSIV® R9120 form of Crystalline Silicotitanate (CST) media. The current TCCR design has two columns online in a lead-lag configuration to optimize media usage and achieve the target decontamination. Once the lead column is saturated with cesium, it will be removed from service, the lag column will rotate into the lead position, and a new column with fresh ion-exchange media will be placed into the lag position. The TCCR process for cesium removal from Tank 10H is detailed in X-SOW-H- 00002. Demonstration of the system began in early calendar year 2019 with two batches of salt solution generated by dissolving saltcake in Tank 10H, followed by processing of these batches through the TCCR system. A third TCCR Tank 10H dissolved saltcake batch is scheduled for processing soon. Upon completion of the demonstration with Tank 10H dissolved saltcake, Tank 9H salt solution will be transferred to Tank 10H and subsequently processed through the TCCR unit with new CST media (referred to as R9120-B 30x60) added to new IX columns. The TCCR processing campaign of Tank 9H salt solution is referred to as TCCR-1A .

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Hydraulic Properties of Grout Monoliths Containing Organic Ion Exchange Resin - 18369

The Waste Treatment and Immobilization Plant (WTP) at Hanford is being constructed to treat 56 million gallons of radioactive waste currently stored in underground tanks at the Hanford site. Operation of the WTP will generate several solid secondary waste (SSW) streams including spent spherical resorcinol formaldehyde cation exchange resin (IXr). The current plan for safe disposal of IXr is solidification in cementitious material (CM) typically comprised of cement, fly ash and blast furnace slag. Three CM formulations were tested to stabilize IXr for long-term land disposal. Two IXr loading rates, 0.1 and 0.3 v/v IXr:grout were used with the three CM formulations to prepare simulated waste form monoliths for hydraulic property testing. Following curing, the monoliths were removed from molds and tested to determine saturated hydraulic conductivity (K{sub sat}) and water retention properties. K{sub sat} was measured using a standard flexible permeameter method ASTM D-5084-10. A constant vapor pressure (CVP) method was used to determine van Genuchten parameters for desorption moisture retention curves for each of the SSW grout formulations. For the CVP method, vacuum saturated, intact wafers approximately 1.25 cm thick were placed above a saturated salt solution inside a sealed container for equilibration. Each saturated salt solution has an associated vapor pressure related to relative humidity in the container. Visual examination and three-dimensional x-ray micro computed tomography (μCT) indicated that the IXr was uniformly distributed in the cured waste form. Saturated hydraulic conductivity was within the range previously reported by Flach et al. in a study of the hydraulic properties of 98 pastes and grouts. The solidification of IXr in CM resulted in a waste form with water retention properties similar to cementitious pastes. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Characterization of the LAWB99-series and ORLEC-series Glasses

In this report, the Savannah River National Laboratory provides chemical analysis results for a series of simulated low activity waste (LAW) glass compositions. These data will be used in the development of improved sulfur solubility models for LAW glass. A procedure developed at the Pacific Northwest National Laboratory for producing sulfur saturated melts (SSMs) was used to fabricate the glasses characterized in this report. This method includes triplicate melting steps with excess sodium sulfate, followed by grinding and washing to remove unincorporated sulfur salts. The wash solutions were also analyzed as part of this study.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Results for the January 2022 Semiannual Tank 50 Salt Solution Sample

In this Technical Report, the chemical and radionuclide contaminant results from the January 2022 Semiannual sample of Tank 50 salt solution are presented in tabulated form. The information from this characterization will be used by Savannah River Mission Completion (SRMC) for the transfer of aqueous waste from Tank 50 to the Saltstone Production Facility (SPF), where the waste will be treated and disposed in the Saltstone Disposal Facility. This Technical Report compares results, where applicable, to SPF Waste Acceptance Criteria (WAC) LIMITS and TARGETS that were established at the time the Tank 50 sample was obtained. The chemical and radionuclide contaminant results from the characterization of the January 2022 semiannual sampling of Tank 50 were requested by SRMC personnel via a Task Technical Request (TTR) and details of the testing are presented in the Savannah River National Laboratory (SRNL) Task Technical and Quality Assurance Plan (TTQAP). This Technical Report is part of Deliverable 2 relating to Task 1 from the SRMC request. Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals per Task 2 from the RMC request, will be obtained semiannually for the January 2022 and July 2022 Tank 50 samples.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Results for the July 2022 Semiannual Tank 50 Salt Solution Sample

In this Technical Report, the chemical and radionuclide contaminant results from the July 2022 Semiannual sample of Tank 50 salt solution are presented in tabulated form. The information from this characterization will be used by Savannah River Mission Completion (SRMC) for the transfer of aqueous waste from Tank 50 to the Saltstone Production Facility (SPF), where the waste will be treated and disposed in the Saltstone Disposal Facility. This Technical Report compares results, where applicable, to SPF Waste Acceptance Criteria (WAC) LIMITS and TARGETS that were established at the time the Tank 50 sample was obtained. The chemical and radionuclide contaminant results from the characterization of the July 2022 semiannual sampling of Tank 50 were requested by SRMC personnel via a Task Technical Request (TTR) and details of the testing are presented in the Savannah River National Laboratory (SRNL) Task Technical and Quality Assurance Plan (TTQAP). This Technical Report is part of Deliverable 2 relating to Task 1 from the SRMC request. Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals per Task 2 from the SRMC request, will be obtained semiannually for the January 2022 and July 2022 Tank 50 samples.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

Synthesizing Highly Crystalline Graphite Powder from Bulk Polyethylene Waste for Lithium-Ion Battery Anodes

Upcycling plastic waste into graphite can potentially be used, in conjunction with other methods, to manage existing waste materials and diversify graphite supply chains. However, synthesizing large quantities of crystalline graphite powder from plastic waste, particularly polyethylene (PE), remains a challenge because PE decomposes into light gases during thermal processing, and simple methods do not exist at any appreciable size scale to address this challenge. In this work, a method is developed for air processing bulk forms of PE waste to create a stable carbon char that does not readily decompose during high-temperature processing. This method employs solid additives in the form of salts, which are combined with the PE melt during air processing to increase the effective surface area of the melt and improve the oxygen-driven chemistry that stabilizes the PE for high-temperature processing. After removing the solid salt additives from the PE-derived char, it is converted into a highly crystalline bulk graphite powder using a Fe-based low-temperature (<1500 °C) catalytic process. The PE-derived graphite powder showed excellent electrochemical performance as an anode material for lithium-ion batteries (LIBs) with a capacity of up to 302 mAh/g at 0.5 discharge/charge cycles per hour (0.5 C) and capacity retention of 100% after 415 cycles.

Huynh, Ngoc Tien↗
DOE OSTI2023

Results for the January 2023 Semiannual Tank 50 Salt Solution Sample

In this Technical Report, the chemical and radionuclide contaminant results from the January 2023 Semiannual sample of Tank 50 salt solution are presented in tabulated form. The information from this characterization will be used by Savannah River Mission Completion (SRMC) for the transfer of aqueous waste from Tank 50 to the Saltstone Production Facility (SPF), where the waste will be treated and disposed in the Saltstone Disposal Facility. This Technical Report compares results, where applicable, to SPF Waste Acceptance Criteria (WAC) LIMITS and TARGETS that were established at the time the Tank 50 sample was obtained.1 The chemical and radionuclide contaminant results from the characterization of the January 2023 semiannual sampling of Tank 50 were requested by SRMC personnel via a Task Technical Request (TTR)2 and details of the testing are presented in the Savannah River National Laboratory (SRNL) Task Technical and Quality Assurance Plan (TTQAP).3 This Technical Report is part of Deliverable 2 relating to Task 1 from the SRMC request.2 Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals per Task 2 from the SRMC request will be obtained semiannually for the January 2023 and July 2023 Tank 50 samples.

Crawford, Charles L.↗
DOE OSTI2022

Nuclear Waste Attributes of SMRs Scheduled for Near-Term Deployment

The purpose of this study is to evaluate the nuclear waste attributes of Small Modular Reactors (SMRs) scheduled for deployment within this decade using available data and established nuclear waste metrics, with the results compared to a reference large Pressurized Water Reactor (PWR). The current fleet of commercial nuclear reactors in the U.S. is composed of 92 large Light Water Reactors (LWR) with an average electricity generating capacity of over 1,000 MWe each. These large LWRs built on-site in massive construction projects have been the mainstay of the industry for the last 50 years. However, new construction soon is expected to include several designs of smaller reactors primarily fabricated in factories and installed in the field in modules. Some of these SMRs will also be LWRs, while some will use other coolants such as liquid metals, molten salts or gases, and different types of fuels. The technologies and economics of SMRs have been the focus of many studies, but there has been only minimal information published on the amount of nuclear waste different types of SMRs are expected to generate and no reports focused on near-term-deployable designs. In this study, the nuclear waste attributes of three small reactors scheduled for near-term-deployment, VOYGR TM (from NuScale Power), Natrium TM ab (from TerraPower), and Xe-100 (from X-energy), were assessed by comparing nuclear waste metrics with those of a reference large Pressurized Water Reactor (PWR).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Synthesis of americium trichloride via chlorination of americium oxide using zirconium tetrachloride in LiCl-KCl molten salt

To better inform electrorefining operations of used nuclear fuel, a fundamental understanding of the electrochemical properties of each actinide in the molten salt electrolyte is needed. Access to actinide chlorides is thus required to support measurement of these properties. In this work, we synthesized americium trichloride through a novel pathway comprising chlorination of Am2O3 with ZrCl4 in a LiCl-KCl molten salt at 500 degrees C. The formation of AmCl3 was confirmed by cyclic voltammetry and gamma spectroscopy. This chlorination method does not produce mixed hazardous-radioactive waste and the byproduct, ZrO2, is not electrochemically active and does not affect the actinide electrodeposition reaction.

actinide chloride synthesis↗
DOE OSTI2019

Soil sealing by algae: An alternative to plastic pond liners for outdoor algal cultivation

Commercial production of algal biofuels is currently limited by high capital costs, particularly costs of synthetic pond liners that minimize seepage of cultivation fluids, salts, and nutrients into the subsurface beneath outdoor algae cultivation facilities. Even some profitable nutraceutical companies bear the high costs of pond liners. However, studies of animal waste holding ponds and aquaculture facilities have shown that underlying soils can effectively “self-seal”, potentially eliminating the need for plastic liners. Here, we explored the potential for self-sealing with algae to provide an alternative to synthetic pond liners in unlined algae cultivation ponds. Laboratory-scale soil column experiments were used to investigate soil clogging by algae, a topic rarely discussed in the literature. Columns composed of fine sand, loamy sand, and loam soil displayed reductions in saturated hydraulic conductivity of the entire soil column of up to two orders of magnitude in response to infiltration by the alga Scenedesmus dimorphus suspended in algal culture nutrient solution at a density of 5 × 10 8 cells L –1 . Scanning electron microscope imaging showed a dense algal layer on the surface of each soil column, thickly coating mineral grains with algal material and filling pore spaces. The algal coating was absent in samples at >3 cm depth in the soil columns, and measurements of chlorophyll content also confirmed that algal cells were mostly confined to the soil surface. In this study, the application of an algal suspension contributed significantly to soil sealing. In conclusion, this new application of biological sealing technology should be studied further to determine its utility and durability as an alternative to plastic liners, perhaps in conjunction with soil compaction to achieve hydraulic conductivities beneath algal production ponds that are protective of groundwater quality.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Long-term Prediction of Spent Fuel Storage Canisters - Issues and Approaches - 18112

The considerations involved in aging management of stainless steel canisters used in dry cask storage of spent fuel are discussed in this paper in a probabilistic framework. The two important modes of degradation in the long-term performance of the casks are localized corrosion and stress corrosion cracking initiating from the external surface. These degradation modes are determined by the evolution of the electrochemical behavior and the strain rate of the stainless steel. Laboratory data suggest that Type 304L/316L stainless steels should suffer from localized corrosion and SCC under salt deposits. However, field inspection of the canisters has not indicated extensive pitting or stress corrosion cracking. This discrepancy can be understood in terms of the joint probabilities of various factors that must come together to cause these failure modes. A Bayesian network approach is suggested as the framework for modeling the probability of failure of canisters and long-term management of aging. The gaps in knowledge to conduct a Bayesian network analysis are discussed. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Crystalline Disposal R&D at LBNL: FY20 Progress Report

Within the Spent Fuel & Waste Science and Technology (SFWST) Program, research work continues further with the goal to better understand long-term performance of disposal systems in three main geologic rock types: clay/shale, salt, and crystalline rock. This report documents LBNL’s research activities related to investigations of crystalline host rock according to the scope of two work packages: SF-20LB01030207 “Crystalline International Collaborations – LBNL,” and SF-20LB01030203 “Crystalline Disposal R&D – LBNL.” These research activities correspond are related to key Features, Events, and Processes (FEPs), ranked in importance from medium to high, as listed in Table 7 of the Used Fuel Disposition Campaign Disposal Research and Development Roadmap (FCR&D-USED-2011-000065 REV0) (Nutt, 2011). Specifically, these research activities address FEP 2.2.01, Excavation Disturbed Zone (EZD). The results of these research activities provide important insights into understanding and predicting flow and transport processes that could occur in low-permeability crystalline rocks, in which fractures might serve as main conduits for fluid flow and radionuclide transport. The evolution of the EDZ during the excavation of the tunnel as well as the evolution of microcrack growth within the EDZ after the emplacement of backfill are critical for predicting the long- term behavior of the EDZ. A number of factors including stress, temperature, water activity, capillary pressure, chemistry, and mineralogy can affect the rock evolution, which require advanced experimental tools to study it.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2019

Ceramic Waste Form Process for Immobilizing Iodine in Glass-Bonded Iodosodalite

A modified glass-bonded sodalite ceramic waste (CWF) form approach was used to fabricate ACWF-NaI or ACWF-AgI iodosodalite [i.e., Na 8 (AlSiO 4 ) 6 I 2 ] waste forms by occluding either NaI or AgI, respectively, into zeolite 4A at elevated temperatures, adding an NBS-4 glass binder, and firing at 925°C. The phase purity of ACWF-NaI was 82.6 mass% Na 8 (AlSiO 4 ) 6 I 2 (with amorphous remainder) while the ACWF-AgI only had 25.9 mass% Na 8 (AlSiO 4 ) 6 I 2 , despite the iodine being added as AgI; the remainder phases for ACWF-AgI included NaAlSiO 4 (15.1 mass%), AgI (4.5 mass%), and Ag 0 (0.2 mass%). This study shows that, starting from two different iodine salts, that the CWF process could be used for immobilization.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Microbial communities for valorizing biomass using the carboxylate platform to produce volatile fatty acids: A review

The carboxylate platform employs a diverse microbial consortium of anaerobes in which the methanogens are inhibited. Nearly all biomass components are digested to a mixture of C1-C8 monocarboxylic acids and their corresponding salts. The methane-arrested anaerobic digestion proceeds readily without needing to sterilize biomass or equipment. It accepts a wide range of feedstocks (e.g., agricultural residues, municipal solid waste, sewage sludge, animal manure, food waste, algae, and energy crops), and produces high product yields. This review highlights several important aspects of the platform, including its thermodynamic underpinnings, influences of inoculum source and operating conditions on product formation, and downstream chemical processes that convert the carboxylates to hydrocarbon fuels and oxygenated chemicals. Furthermore, this review further establishes the carboxylate platform as a viable and economical route to industrial biomass utilization.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

The Role of the Organic Solvent Polarity in Isolating Uranyl Peroxide Capsule Fragments

Uranyl peroxide capsules are a fascinating class of polyoxometalates (POMs), discovered only in the 21st century. Understanding the reactivity between peroxide, alkali cations, and uranyl in alkaline solutions is important in nuclear science disciplines including mineralogy, nuclear energy, and legacy nuclear wastes. In this work, we have developed a general procedure to isolate different fragments of the uranyl-peroxide POM capsules, using organic solvents to partially remove K + salts from crude solids of the monomer building block UO 2 (O 2 ) 3 4– (K–U 1 ), leading to stabilization of these reactive fragments. Higher polarity organic solvents remove more K + salts from the crude solid, owed to higher solubility, resulting in more extensive linking of uranyl peroxide building units. By this strategy we have isolated and structurally characterized a dimer K 6 [(UO 2 ) 2 (O 2 ) 4 (OH) 2 ]·7H 2 O (K–U 2 ) and a hexamer face frequently observed in the capsules, K 12 [(UO 2 ) 6 (O 2 ) 9 (OH) 6 ]$·x$H 2 O(K–U 6 ). Comparing experimental and computed Raman spectra shows that these intermediates crystallize by a solid-to-solid transformation, via polymerization of the monomer building block. By small-angle X-ray scattering (SAXS), we track the conversion of the fragments to POM capsules; the reaction rate increases from K–U 1 (days) < K–U 2 (hours) < K–U 6 (instantaneous). This study provides a general synthetic procedure to isolate metastable uranyl peroxide oligomers and control the oligomerization, which will be later applied to systems with the heavier alkalis that are even less stable.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
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 OSTI2018

Thermodynamic Properties of Rare Earth Chlorides in Molten Salts: A Novel Approach to Experimental Electrochemistry of Molten Salts

The thermodynamic and electrochemical properties of rare earth chlorides in molten salt solutions are of interest from the standpoint of both pyrochemical processing of spent nuclear fuel and for the development of Generation IV nuclear reactors. Knowledge of key properties like activity coefficients and phase diagrams will accelerate the development of safe reliable carbon free energy. In this work, three conduits of research have been pursued and reported within the larger theme of minimization of waste in spent fuel reprocessing and associated technology development. The activity coefficient of rare earth chlorides has been investigated using ground breaking theory and experimental approach. Furthermore, an ionic size dependent activity coefficient model is presented. This book also contains research into quaternary phase diagrams for LiCl-KCl-CsCl-RECl3 molten salt systems. This book should prove an excellent introduction to anyone pursuing a career in experimental high temperature electrochemistry and molten salt chemistry.

Bagri, Prashant↗
DOE OSTI2019

Carbon polyaniline capacitive deionization electrodes with stable cycle life

Electrode materials for capacitive deionization (CDI), an energy efficient method for desalination, were developed in this work. Waste-tire derived carbon (TC) coated with polyaniline was used to form a carbon polymer composite (CPC). CPC was used as an electrode in CDI configurations to determine the salt adsorption capability of the material. Chemical treatment of TC with KOH led to an enhancement in surface area to 952 m 2 /g and microporosity in the sub-2-nm range. This unique microstructure is considered to be beneficial for effective ion uptake in CDI applications. The capacitance of the electrodes was further enhanced through surface coating with polyaniline, resulting in a specific capacitance of 168.2 F/g. In batch cell testing with 1.2 V applied potential, the salt adsorption capacity (SAC), measured in mg of salt adsorbed per gram of active material, in a 1500–1700 ppm KCl solution was measured at 14.2 mg/g. Scale-up of the process with ionic-membrane-assisted CDI (MCDI) led to improvement in SAC at 18.9 mg/g. Further, cycling tests revealed that the electrodes had comparable or better longevity compared to other CDI materials, retaining >92.8% charging capacity after 300 cycles. In conclusion, high adsorption capacities for other salts such as LiCl, NaCl, MgCl 2 and CaCl 2 have been found.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗