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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Accelerated Basin De-Inventory Maximum Fissile Estimate

The Accelerated Basin De-inventory (ABD) program increases processing of Spent Nuclear Fuel (SNF) in H-Canyon to accelerate the closure of L Basin. The dissolved SNF will be dispositioned to Sludge Batches that will be processing in the Defense Waste Processing Facility and converted to glass. The fissile glass loading directly impacts the amount of glass canisters made. This memorandum provides an estimated maximum quantity of total fissile expected to be transferred to a Sludge Batch to support increasing the fissile glass loading and thus reducing the number of canisters created across the lifetime of the ABD mission.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Application of Process Chemical Modeling to Optimize Radioactive Waste Disposal at the Savannah River Site – 24242

The Liquid Waste Program (LWP) managed by Savannah River Mission Completion (SRMC) is responsible for the treatment and disposal of waste at the Savannah River Site (SRS). Radioactive waste at SRS is stored and processed at four key facilities – each with their respective functions to store, blend, grout, or vitrify waste. The tank farm, where waste is stored, consists primarily of legacy waste with new material incoming from the Accelerated Basin De-inventory program (ABD), which is managed by Savannah River Nuclear Solutions (SRNS). System planning is done by SRNS and SRMC to optimize ABD and LWP operations, respectively.

Georgiou, Andreas↗
DOE OSTI2020

NASNF Processing and Packaging Technical Study

The ABD program will require development of a strategy for the dispositioning the Non-Aluminum Spent Nuclear Fuel (NASNF), some of which will be very challenging to handle and dissolve as described in this report. Not all the NASNF is suitable for processing through the electrolytic dissolver. The strategy may involve dissolution of the majority of the NASNF inventory in the electrolytic dissolver combined with some other disposition alternative(s) for the fraction that is not suitable for electrolytic dissolution. This report highlights the risks and challenges associated with the baseline approach of using the electrolytic dissolver to process all of the NASNF. In addition, the characteristics of the NASNF and how those characteristics relate to the risks associated with electrolytically dissolving the specific fuel types.

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

Fine-tuned vs. natural supersymmetry: what does the string landscape predict?

A vast array of (metastable) vacuum solutions arise from string compactifications, each leading to different 4-d laws of physics. The space of these solutions, known as the string landscape, allows for an environmental solution to the cosmological constant problem. We examine the possibility of an environmental solution to the gauge hierarchy problem. We argue that the landscape favors softly broken supersymmetric models over particle physics models containing quadratic divergences, such as the Standard Model. We present a scheme for computing relative probabilities for supersymmetric models to emerge from the landscape. The probabilities are related to the likelihood that the derived value of the weak scale lies within the Agrawal et al. (ABDS) allowed window of values leading to atoms as we know them. This then favors natural SUSY models over unnatural (SUSY and other) models via a computable probability measure.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Increased Fissile Loading Flowsheet Review

A request was made by H-Canyon Process Engineering to assess the impact of blending dissolved, neutralized Spent Nuclear Fuel (SNF) with future sludge batches and their impact on downstream processing facilities including the Concentration, Storage and Transfer Facilities (CSTF), the Salt Waste Processing Facility (SWPF), the Defense Waste Processing Facility (DWPF), Saltstone, and the Effluent Treatment Facility (ETF). The purpose of this change is to accelerate the deinventory of SNF which is currently stored in the L-Area Disassembly Basin. The addition of SNF increases the mass of fissiles in each future sludge batch, due to their high enrichment. This high enrichment has the potential to complicate the programs to eliminate criticality events in the downstream processing facilities and will increase the number of canisters produced by DWPF because of the SNF mass increase. A separate report addressed the impacts to glass. The review and subsequent calculations were based on average predicted compositions of Accelerated Basin Deinventory (ABD) slurry, average compositions for predicted future sludge batches, average past salt batches and average past recycle batches to predict the feeds that will be processed in SWPF, DWPF, Saltstone, the 2H evaporator and ETF. Each of the processes was evaluated for potential issues.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2023

Mixing Study for the Modification of H-Canyon Tank 31 and 32 Recirculation Lines Via M-Star®

As a part of the Accelerated Basin De-Inventory (ABD) program Tanks 31 or 32 will be re-purposed to support increasing the number of annual Material Test Reactor (MTR) and High Flux Isotope Reactor (HFIR) dissolutions. The proposed plan will allow Tanks 31 or 32 to be used as the dissolver cold chemical solution makeup tank and storage tank. The dissolver cold chemicals are 50% nitric acid, process water, mercuric nitrate, and gadolinium nitrate. Tanks 31 and 32 are 9 ft. (outer diameter) x 36 ft, horizontal, and can hold approximately 56,000 liters (15,000 gallons) each. One full volume of Tanks 31 or 32 can support 4 HFIR 6.4D equivalent batches. Both tanks are equipped with liquid level instrumentation. Tank 31 is equipped with 1 pump used for transfer and recirculation while Tank 32 is equipped with two pumps, one for transfer and the other for recirculation. Each of the pumps is equipped with sample taps. The tanks do not have specific gravity instrumentation, an agitator, or a sampler. Piping modifications will also be performed to supply the tank with cold chemicals. The current dissolver chemical composition is 5.0 -8.5M HNO3 and ~0.2 g Gd/L. The recirculating pump connected to Tank 31 is rated for a flowrate 175 gpm while the pump connected to Tank 32 is rated for a flowrate 50 gpm.

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

Dissolution Flowsheet for Non-Aluminum Spent Nuclear Fuel Campaign 1

As part of the Accelerated Basin De-inventory (ABD) program, H Canyon plans to dissolve non-aluminum spent nuclear fuel (NASNF) in the 6.3D electrolytic dissolver. NASNF Campaign 1 plans to electrolytically dissolve 68 bundles of fuel assemblies from the Carolinas-Virginia Tube Reactor (CVTR), Heavy Water Components Test Reactor (HWCTR), and Experimental Boiling Water Reactor (EBWR). The fuel assemblies are intact Zircaloy or stainless steel (SS) clad UO 2 rods, tubes, and plates. The H Canyon electrolytic dissolver previously dissolved a variety of UO 2 core fuel types in SS, Zircaloy, Nichrome, or Incoloy cladding from 1969 to 1980. The objective of this study was to identify flowsheet conditions through literature review and laboratory experimentation to safely dissolve NASNF Campaign 1 bundles in the H Canyon electrolytic dissolver. Bench-scale electrolytic dissolution tests were performed to demonstrate a flowsheet for NASNF Campaign 1 bundles. The outer bundles are composed of SS or Al alloy, Al 6061-T6, and contain intact Zircaloy or SS clad UO 2 fuel assemblies. The key objectives of these tests were to determine bounding dissolver chemistries and the sparge requirement to ensure H 2 concentration remain less than 60 vol % of the lower flammability limit (LFL) during dissolution. The impact of HNO 3 concentration and the addition of fluoride on the dissolution efficiency of Zircaloy, 304L SS, Al 6061-T6, and Inconel 625 were examined. While SS, Al, and Inconel 625 readily dissolve utilizing electrolytic dissolution, Zircaloy disintegrated anodically; the surface of Zircaloy oxidized and the oxide layer spalled off and settled at the bottom of the dissolver as an insoluble material. The black flakes were identified as ZrO 2 and 85% of the Zr processed was converted to black ZrO 2 flakes when Zr was anodically disintegrated in 9.5 M HNO 3 .

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Rescue of Unique Liquid IP-2 Portable Tanks at Savannah River Site

Introduction • Savanah River Site procured six large IP-2 portable tanks capable of transporting liquids in 2003 to support layup of F Canyon at SRS. • Tanks are being rescued and recertified to support eventual disposition of up to 171,000 L of contaminated solvent solutions from H Canyon at SRS and to potentially transport Depleted Uranium solutions to support the ABD Program.

Fee, Nathaniel C. [Savannah River Nuclear Solution↗
DOE OSTI2025

Reference Fuel Development for Non-Aluminum Spent Nuclear Fuel Management

The Savannah River Site (SRS) L Area Facility provides for the safe receipt, storage, handling, and shipping of spent nuclear fuel (SNF) and has received more than 47,000 SNF assemblies since 1964. In order to consolidate receipt and storage analysis, L Area criticality safety has historically used several aluminum-clad “reference fuels” to establish bounding storage, handling, and cask loading limits and then applied a reactivity comparison approach to demonstrate that candidate fuels may be processed under the reference fuel limits. Currently, only aluminum-clad SNF from off-site research reactors are transferred on-site. The Accelerated Basin De-Inventory (ABD) program will begin the removal of bundled Non-Aluminum Spent Nuclear Fuel (NASNF) from the L Area disassembly basin for dissolution and disposition, which has driven the need for a non-aluminum reference fuel. This paper discusses the process and results of creating a new fictional homogenous NASNF highly enriched uranium reference fuel, “MITZ,” to be used in nuclear criticality safety evaluations for upcoming SNF disposition operations. Data demonstrating the relationship between neutron multiplication behavior and fuel spacing is generated for the new reference fuel MITZ as well as existing reference fuels representing several types of SNF assemblies.

Reference Fuel↗
DOE OSTI2025

Reference Fuel Development for Non-Aluminum Spent Nuclear Fuel Management

The Savannah River Site (SRS) L Area Facility provides for the safe receipt, storage, handling, and shipping of spent nuclear fuel (SNF) and has received more than 47,000 SNF assemblies since 1964. In order to consolidate receipt and storage analysis, L Area criticality safety has historically used several aluminum-clad “reference fuels” to establish bounding storage, handling, and cask loading limits and then applied a reactivity comparison approach to demonstrate that candidate fuels may be processed under the reference fuel limits. Currently, only aluminum-clad SNF from off-site research reactors are transferred on-site. The Accelerated Basin De-Inventory (ABD) program will begin the removal of bundled Non-Aluminum Spent Nuclear Fuel (NASNF) from the L Area disassembly basin for dissolution and disposition, which has driven the need for a non-aluminum reference fuel. This paper discusses the process and results of creating a new fictional homogenous NASNF highly enriched uranium reference fuel, “MITZ,” to be used in nuclear criticality safety evaluations for upcoming SNF disposition operations. Data demonstrating the relationship between neutron multiplication behavior and fuel spacing is generated for the new reference fuel MITZ as well as existing reference fuels representing several types of SNF assemblies.

Reference Fuel↗
DOE OSTI2021

Electrolytes Polymerization‐Induced Cathode‐Electrolyte‐Interphase for High Voltage Lithium‐Ion Batteries

Abstract Lithium‐ion batteries (LIBs) based on LiNi x Co y Mn 1‐x‐y O 2 (NCM) cathode materials have been widely commercialized, because of their high energy density, favorable rate performance, and relatively low cost. However, with increased Ni content to further increase their energy density, their cycling stability deteriorates dramatically and thus fails to meet the commercial application requirements. The artificial cathode‐electrolyte‐interphase (CEI) is a promising approach to solve this problem. Here, a robust CEI is fabricated through in situ polymerization of ethylene carbonate induced by aluminum isopropoxide (AIP). By adding 1 wt.% AIP in a commercial electrolyte, the capacity retention of LiNi 0.8 Co 0.1 Mn 0.1 O 2 ||Li cell at 1 C rate has been significantly increased from 80.8% to 97.8% with a highly reversible capacity of 176 mA h g −1 after 200 cycles. AIP can be also used as an additive during the slurry‐making process, enabling a reversible capacity of 170 mA h g −1 for LiCoO 2 after 200 cycles even at a high charge cut‐off voltage of 4.6 V. It is confirmed that the in situ formed CEI layer can prevent the cathodes from cracking and reduce the irreversible phase transformation.

Yang, Jixiang↗
DOE OSTI2024

Finding a common ground for RCM experiments. Part B: Benchmark study on ethanol ignition

Rapid compression machines (RCMs) are widely used to investigate gas phase reaction kinetics of various kind of fuels at application relevant conditions. In principle, the operation of an RCM is based on the idea of compressing a homogenous pre-mixed fuel-air mixture by a piston. Usually creviced pistons ensure a homogenous adiabatic core in the center of the reaction chamber which permits the assumption of an isentropic relation between the measured pressure and gas temperature. Despite the ideal core gas compression, non-ideal effects such as heat loss, differences in the compression behavior, and ultimately non-standardized design and operation of rapid compression machines lead to different experimental results in different facilities at nominally the same end of compression conditions. In this study ignition delay times of ethanol are investigated at four different conditions in five independent RCMs. As expected, the raw results of the different facilities indeed show notable differences at the same end of compression conditions. However, according to the adiabatic core hypothesis the agreement between kinetic simulations and experiments should be consistent for all facilities provided that the facility effects are correctly accounted for. To elaborate upon this hypothesis, a kinetic mechanism is optimized to reflect the experimental results of all facilities. In the end, the optimized mechanism predicts all experimental data within the expected uncertainty. This confirms the reliability of RCM experiments for kinetic investigations and the validity of the effective volume approach in simulating RCM data.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Influence of mineralogical and chemical compositions on alkali-silica-reaction of Tennessee limestones

The paper aims to identify potential correlations between mineralogical and chemical compositions of AAR reactive dolomitic limestone aggregates from Tennessee and their expansion on ASTM C1293 for quick evaluation of reactivity. The chemical compositions of 26 limestones, namely the silica content (SiO 2 ), showed a strong correlation with the expansion in the concrete prism test. The early and highly expansive limestones are characterized by a high clay/ mica content (>5%). The reactivity of Tennessee limestones is mainly caused by crypto/microcrystalline quartz, chert, and finely disseminated silica in carbonate and clay/mica matrices, and it can be reasonably evaluated using X-ray diffraction and chemical analysis coupled with petrographic examinations.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Development of high-early-strength fiber-reinforced self-compacting concrete

High-early-strength fiber-reinforced self-compacting concrete (FRSCC) is a practical material for the precast concrete industry to double its production capacity. In this study, we developed high-early-strength FRSCC mixtures that achieved a compressive and flexural strength of at least 24 MPa and 3.5 MPa, respectively, at 6 h, using commercially available components, typical mixing procedures, and air curing. A mix design process was developed based on the literature and experimental results. The effect of six different fiber reinforcements on the fresh and mechanical properties of concrete was analyzed. The cost limit was set at 523 USD/m 3 to make the concrete mix cost-effective.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Observation of large Rashba spin–orbit coupling at room temperature in compositionally engineered perovskite single crystals and application in high performance photodetectors

Indirect absorption extended below the direct transition edge and increase in carrier lifetime derived from Rashba spin–orbit coupling may advance the optoelectronic applications of metal halide perovskites. Spin-orbit coupling in halide perovskites is due to the presence of heavy elements in their structure. However, when these materials lack an inversion symmetry, for example by the application of strain, spin–orbit coupling becomes odd in the electron’s momentum giving rise to a splitting in the electronic energy bands. Here we report on the observation of a large Rashba splitting of 117 meV at room temperature, as predicted by relativistic first-principles calculations, in halide perovskite single crystals through a facile compositional engineering approach. Partial substitution of organic cations by rubidium in single crystals induces significant indirect absorption and dual peak photoluminescence as a result of a large Rashba splitting. We measured circularly polarized photoluminescence and magneto-photoluminescence in perovskite films printed by single crystals as well as magneto-electroluminescence and magneto-photocurrent in spin-LEDs based on perovskite single crystals. They indicated significant spin-momentum locking due to the large Rashba effect. A hybrid perovskite single crystal photodetector achieved record figures of merit, including detectivity of more than 1.3 × 10 18 Jones which represents a three orders of magnitude improvement compared to the to date record. Furthermore, these findings show that facile compositional engineering of perovskite single crystals holds great promise for further advancing the optoelectronic properties of existing materials.

36 MATERIALS SCIENCE↗