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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 883 records · Page 49
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Decommissioning of obsolete Nuclear Facilities in the UJV Rez, a. s. - 19027

UJV Rez, a. s. (further also UJV) is a leading institution in all areas of nuclear R and D in the Czech Republic and has had a dominant position in the nuclear program since it was established in 1955 as the Nuclear Research Institute Rez. The activities of UJV encompass nuclear physics, chemistry, nuclear power and many other topics. The main issues addressed at UJV in past decades have included research, development and services for NPPs, the fuel cycle and irradiation services for research and development in the industrial sector and medicine. UJV also manages most institutional radioactive wastes (RAW) produced in the Czech Republic (approx. 90 %). After more than 60 years of activities of the UJV in the nuclear field, there were obsolete nuclear facilities to be decommissioned. Decommissioning of nuclear facilities UJV is the only ongoing decommissioning project in the Czech Republic. Preparations for decommissioning began in 1996. Safety analysis report (SAR) was performed comprising the identification and characterization of potential sources of risk, potentially exposed receptors and exposure pathways, potential chemical compounds, radionuclides and media of concern. The results of the SAR enabled to determine the priorities of the decommissioning, the decommissioning the expenses and as well as project implementation. The decommissioning project was revised on the base of information obtained during decommissioning. The decommissioning was divided into two phases according to the level of risk and the financing limitations. The Ministry of Finance significantly financially contributed the decommissioning, although the UJV also contributed a considerable amount. Overall cost is close to the amount of Eur 27 million. Decommissioning started in 2003 and will be finished in 2018. Almost all facilities have already been successfully decommissioned. In the following table, the status of decommissioning of facilities is described. 1) Reloading site for RAW storage (Building 211/6): last item in progress 2003 - 2018; 2) Special Sewage System: decommissioned 2004 - 2005, reused; 3) Liquid RAW storage tanks (Building 211/3): decontaminated 2004 - 2013, reused; 4) Technology for RAW treatment (Building 241): decommissioned 2003 - 2011; 5) Contaminated equipment (Building 250): decommissioned 2003 - 2016; 6) Systems for storage of sealed sources (Building 261); decommissioned 2003 - 2005; 7) Decay tanks (Building 211/5); decommissioned 2003 - 2014, reused; 8) Old bituminating unit (Building 211/3); decommissioned 2004 - 2008; 9) Surface RAW storage site; decommissioned 2009 - 2014. Later, other unused decommissioning facilities, which were not included in the decommissioning project financed by the state, were included. These facilities are continuously decommissioned and financed from own resources of UJV. These facilities are like facilities already decommissioned: radiochemical laboratories, (including glove boxes), liquid RW storage tanks (including sewage systems), liquid RW treatment technology, hot cells, accumulated RW, etc. Realization started 2016 and expected duration is till 2026. Estimated budget is approximately Eur 17 million. The decommissioning of nuclear facilities in UJV is being carried out on the high level of radiation protection and up to now there was no extraordinary event or accident, although some challenges we were forced to address. (authors)

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

Ethanol Conversion over La 0.7 Sr 0.3 MnO 3–x (100): Autocatalysis, Adjacent O-Vacancies, Disproportionation, and Dehydrogenation

The mechanism for catalytic conversion of ethanol over La 0.7 Sr 0.3 MnO 3– x (100) surface to acetaldehyde and ethene was investigated. Pre-exposure temperature-programmed reaction (PE-TPR) experiments were performed in which ethanol was introduced to oxidized or reduced surfaces followed by heating. In particular, sequential PE-TPR experiments were conducted to incrementally and gradually reduce the surface. The products and their ratios were investigated as a function of surface reduction. The data show that acetaldehyde and ethene production is catalyzed with hydrogen abstraction and oxygen abstraction reactions occurring by intermediates in vacancies at various temperatures >400 K. Adsorption of acetaldehyde followed by a temperature-programmed reaction does not produce ethene, indicating that acetaldehyde is not an intermediate to ethene and that the hydrogen and oxygen abstraction from ethanol to ethene are decoupled steps. Further evidence for this mechanistic nuance was obtained using isotopically labeled ethanol (CD 3 CH 2 OH), which produces CD 3 CHO and CD 2 CH 2 . Additionally, the ratio of aldehyde production to alkene production increases with reduction, suggesting that aldehyde is produced from a disproportionation reaction between ethoxy species in adjacent O-vacancies, while ethene is produced from a dehydrogenation reaction with ethoxy species in vacancies without requiring adjacent O-vacancies. Counterintuitively, this finding indicates that the more oxygenated product (aldehyde vs ethene) is favored with more vacancies and that the net alcohol conversion is autocatalytic. Density functional theory calculations were able to find the previously unknown disproportionation pathway between ethoxies in adjacent O-vacancies, and kinetic Monte Carlo simulations support this interpretation by reproducing experimental selectivities. The activation energies for these pathways are estimated as 132 ± 10 kJ/mol for the disproportionation reaction (when occurring between ethoxies in adjacent vacancies) and as 148 ± 11 kJ/mol for the direct dehydrogenation reaction of an ethoxy in a vacancy. Based on these results, a mechanism with operative pathways based on elementary steps in O-vacancies is reported.

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

Physical Properties and Gas Hydrate at a Near-Seafloor Thrust Fault, Hikurangi Margin, New Zealand

The Papaku Fault Zone, drilled at International Ocean Discovery Program (IODP) Site U1518, is an active splay fault in the frontal accretionary wedge of the Hikurangi Margin. In logging-while-drilling data, the 33-m-thick fault zone exhibits mixed modes of deformation associated with a trend of downward decreasing density, P-wave velocity, and resistivity. Methane hydrate is observed from ~30 to 585 m below seafloor (mbsf), including within and surrounding the fault zone. Hydrate accumulations are vertically discontinuous and occur throughout the entire logged section at low to moderate saturation in silty and sandy centimeter-thick layers. In this paper, we argue that the hydrate distribution implies that the methane is not sourced from fluid flow along the fault but instead by local diffusion. This, combined with geophysical observations and geochemical measurements from Site U1518, suggests that the fault is not a focused migration pathway for deeply sourced fluids and that the near-seafloor Papaku Fault Zone has little to no active fluid flow.

58 GEOSCIENCES↗
DOE OSTI2024

Energy Efficiency Analysis and Grid Service Results for Commercial Buildings using the VOLTRON IoT Platform

In fiscal year 2021 (FY21), the Commercial Buildings Integration Program (CBI) within the Building Technologies Office (BTO), funded PNNL to conduct a field evaluation of the AIRCx and ILC using an Internet-of-Things (IoT) platform, VOLTTRON. The primary goal of the project is to show that software solutions deployed and delivered through an IoT-platform can identify energy efficiency opportunities and manage peak load (beyond the traditional demand response) in commercial buildings. There are also two secondary goals: 1) show that the energy efficiency solutions will result in identification of significant savings opportunities (10% to 30%) as well as energy cost reductions (10% to 15%) by managing the peak load in commercial buildings, and 2) show that an IoT-based software solution is more cost-effective compared to a manual process in meeting the Re-tuning/retro commissioning (RCx) mandates and there is a pathway for broader adoption of this approach. This report provides AIRCx and ILC results for two building located in District of Columbia managed by the energy service provider Intellimation.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Electrocatalytic Hydrogenation of Oxygenated Compounds in Aqueous Phase

Electrocatalytic hydrogenation is a fascinating strategy to hydrogenate biogenic compounds at ambient conditions by replacing the thermal and H2 inputs by cathodic potential. This work compares the performance of this approach (in aqueous phase at room temperature) for a variety of model oxygenated compounds reacted over a series of metals. The target functionalities were carbonyl groups, aromatic rings, and ether bonds. All metals explored (Pt, Rh, Pd, Cu) are active for the reduction of carbonyl compounds to alcohols. For instance, conversion rates of benzaldehyde increased as a function of metal as: Pt < Rh < Pd (Cu was tested at different conditions). In contrast, only Rh and Pt were found active for hydrogenation of aromatic rings (Rh was more active than Pt). Comparing among the target functionalities, carbonyl groups are more reactive than aromatic rings and ether bonds in phenolic compounds and di-aryl ethers on all explore metals. This carbonyl reactivity, however, is enabled by the aromaticity of the molecule. Hence, the reactivity trend of the examined molecules is: butyraldehyde < furfural < acetophenone < benzaldehyde. For phenolic compounds, phenol is more reactive than cresol and methoxy phenol. Thus, the presence of substituting groups at the functionality being converted (either carbonyl or aromatic ring) decreases conversion rates. Ether bonds are cleaved under electrocatalytic conditions, which opens two main pathways for the conversion of aryl ethers: hydrogenation of the aromatic ring and hydrogenolysis of the ether bonds, whereas hydrolysis occurs as a minor pathway. Electrocatalytic hydrogenation competes with the H2 evolution reaction at the conditions of the tests, therefore Faradaic efficiency (fraction of current utilized in hydrogenation) and hydrogenation rates are correlated. That is, within the potential range explored, increasing hydrogenation rates lead to higher Faradaic efficiencies. The slope of this correlation, however, depends on the potential and on the functionality being hydrogenated. Keywords: Hydrogenation, electrocatalysis, metal catalysis, aqueous phase hydrogenation, biomass conversion. Acknowledgements The authors would like to thank Yang Song, Prof. Johannes Lercher, and the group of Prof. Hubert A. Gasteiger at the Technische Universität München for advice and support. The authors are grateful to Donald M. Camaioni, Nirala Singh, and Juan Herranz for fruitful discussions. The research described in this paper is part of the Chemical Transformation Initiative at Pacific Northwest National Laboratory (PNNL), conducted under the Laboratory Directed Research and Development Program at PNNL, a multi-program national laboratory operated by Battelle for the U.S. Department of Energy.

Hydrogenation, electrocatalysis, metal catalysis, ↗
DOE OSTI2015

BiGG Models: A platform for integrating, standardizing and sharing genome-scale models

In this study, genome-scale metabolic models are mathematically structured knowledge bases that can be used to predict metabolic pathway usage and growth phenotypes. Furthermore, they can generate and test hypotheses when integrated with experimental data. To maximize the value of these models, centralized repositories of high-quality models must be established, models must adhere to established standards and model components must be linked to relevant databases. Tools for model visualization further enhance their utility. To meet these needs, we present BiGG Models (http://bigg.ucsd.edu), a completely redesigned Biochemical, Genetic and Genomic knowledge base. BiGG Models contains more than 75 high-quality, manually-curated genome-scale metabolic models. On the website, users can browse, search and visualize models. BiGG Models connects genome-scale models to genome annotations and external databases. Reaction and metabolite identifiers have been standardized across models to conform to community standards and enable rapid comparison across models. Furthermore, BiGG Models provides a comprehensive application programming interface for accessing BiGG Models with modeling and analysis tools. As a resource for highly curated, standardized and accessible models of metabolism, BiGG Models will facilitate diverse systems biology studies and support knowledge-based analysis of diverse experimental data.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Explosive Byproduct Gas Transport Through Sorptive Geomedia

Current underground nuclear explosion (UNE) detection strategies rely heavily on atmospheric noble gas sampling of radioxenon. However, discriminating nuclear weapons testing programs from civilian sources is difficult due to highly variable atmospheric radioxenon backgrounds and processes affecting subsurface transport of parent radionuclides. Here, we aim to study the transport of gases produced by subsurface explosions as novel stable signatures for underground nuclear explosion (UNE) monitoring. These gases may be produced in large quantities with distinct molecular ratios, which will be impacted by subsurface transport processes. To demonstrate how ratios of gases produced by explosions can change during transport in geomaterials, we conducted laboratory benchtop experiments on the transport of carbon dioxide (CO 2 ) and hydrogen (H 2 ) gases through variably saturated zeolitic tuff, which is abundant at the historic US testing site. We observed that zeolitic tuff sorbs substantial quantities of CO 2 while allowing H 2 to transport more freely, leading to changes in the molecular ratios of the two gases along the transport pathway. Gas uptake in the dry zeolitic tuff core was 72.3% for CO 2 , compared with 53.4% for xenon and 7.6% for H 2 . The presence of 20% water saturation disrupted the CO 2 sorption process, though to a lesser extent than observed for noble gases, with a 36.7% drop in xenon sorption compared with a 21.9% drop for CO 2 . These results represent the first observations of zeolite sorption altering explosive gas ratios during transport through geomedia relevant to nuclear proliferation monitoring.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Defect-Driven Redox Interplay on Anatase TiO 2 : Surface-Structure Dependent Activation for CO 2 Hydrogenation Catalysis

Titanium dioxide (TiO 2 ) is one of the most extensively studied oxides as an active catalyst or catalyst support, particularly in energy and environmental applications, but the atomistic mechanisms governing its dynamic response to reactive environments and their correlation to reactivity remain largely elusive. Using in situ environmental transmission electron microscopy (ETEM), synchrotron X-ray diffraction (XRD), ambient-pressure X-ray photoelectron spectroscopy (AP-XPS), temperature-programmed reduction (TPR), reactivity measurements, and theoretical modeling, we reveal the dynamic interplay between oxygen loss and replenishment of anatase TiO 2 under varying reactive conditions. Under H 2 exposure, anatase TiO 2 undergoes surface reduction via lattice oxygen loss, forming Ti 3 O 5 . In contrast, CO 2 exposure induces oxygen replenishment, reversing stoichiometry. In mixed H2/CO 2 environments, the reverse water–gas shift (RWGS) reaction proceeds selectively on stepped and high-indexed TiO 2 surfaces, whereas the thermodynamically stable TiO 2 (101) surface remains inactive and intact. Critically, H 2 pretreatment generates oxygen vacancies on TiO 2 (101), transforming it into an active Ti 3 O 5 or defect-rich surface that catalyzes RWGS. By correlating surface structure, defect dynamics, and gas-phase interactions, this work deciphers the competition between H 2 -driven reduction and CO 2 -driven oxidation pathways at the atomic scale. Furthermore, these insights establish defect engineering as a strategic lever to activate inert TiO 2 facets, advancing the design of adaptive catalysts for sustainable fuel synthesis technologies.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Laboratory Evaporation Testing Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream, LAW Off-Gas Condensate, from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of canistered glass waste forms. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to be within acceptable concentration ranges in the LAW glass. Diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task examines the impact of potential future disposition of this stream in the Hanford tank farms, and investigates auxiliary evaporation to enable another disposition path. Unless an auxiliary evaporator is used, returning the stream to the tank farms would require evaporation in the 242-A evaporator. This stream is expected to be unusual because it will be very high in corrosive species that are volatile in the melter (chloride, fluoride, sulfur), will have high ammonia, and will contain carryover particulates of glass-former chemicals. These species have potential to cause corrosion of tanks and equipment, precipitation of solids, release of ammonia gas vapors, and scale in the tank farm evaporator. Routing this stream to the tank farms does not permanently divert it from recycling into the WTP, only temporarily stores it prior to reprocessing. Testing is normally performed to demonstrate acceptable conditions and limits for these compounds in wastes sent to the tank farms. The primary parameter of this phase of the test program was measuring the formation of solids during evaporation in order to assess the compatibility of the stream with the evaporator and transfer and storage equipment. The origin of this LAW Off-Gas Condensate stream will be the liquids from the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP) from the LAW facility melter offgas system. The stream is expected to be a dilute salt solution with near neutral pH, and will likely contain some insoluble solids from melter carryover. The soluble components are expected to be mostly sodium and ammonium salts of nitrate, chloride, and fluoride. This stream has not been generated yet, and, thus, the composition will not be available until the WTP begins operation, but a simulant has been produced based on models, calculations, and comparison with pilot-scale tests. This report discusses results of evaporation testing of the simulant. Two conditions were tested, one with the simulant at near neutral pH, and a second at alkaline pH. The neutral pH test is comparable to the conditions in the Hanford Effluent Treatment Facility (ETF) evaporator, although that evaporator operates at near atmospheric pressure and tests were done under vacuum. For the alkaline test, the target pH was based on the tank farm corrosion control program requirements, and the test protocol and equipment was comparable to that used for routine evaluation of feed compatibility studies for the 242-A evaporator. One of the radionuclides that is volatile in the melter and expected to be in high concentration in this LAW Off-Gas Condensate stream is Technetium-99 (99Tc). Technetium will not be removed from the aqueous waste in the Hanford WTP, and will primarily end up immobilized in the LAW glass by repeated recycle of the off-gas condensate into the LAW melter. Other radionuclides that are also expected to be in appreciable concentrations in the LAW Off-Gas Condensate are 129I, 90Sr, 137Cs, and 241Am. The concentrations of these radionuclides in this stream will be much lower than in the LAW, but they will still be higher than limits for some of the other disposition pathways currently available. At this time, these scoping tests did not evaluate the partitioning of the radionuclides to the evaporator condensate, since ample data are available separately from other experience in the DOE complex. Results from the evaporation testing show that the neutral SBS simulant first forms turbidity at ~7.5X concentration, while the alkaline-adjusted simulant became turbid at ~3X concentration. The major solid in both cases was Kogarkoite, Na3FSO4. Sodium and lithium fluorides were also detected. Minimal solids were formed in the evaporator bottoms until a substantial fraction of liquid was removed, indicating that evaporation could minimize storage volume issues. Achievable concentration factors without significant insoluble solids were 17X at alkaline pH, and 23X at neutral pH. In both runs, significant ammonia carried over and was captured in the condenser with the water condensate. Results also indicate that with low insoluble solids formation in the initial testing at neutral pH, the use of Reverse Osmosis is a potential alternate method for concentrating the solution, although an evaluation is needed to identify equipment that can tolerate insoluble solids. Most of the ammonia remains in the evaporator bottoms during the neutral pH evaporation, but partitions to the condensate during alkaline evaporation. Disposition of both streams needs to consider the management of ammonia vapor and its release. Since this is an initial phase of testing, additional tasks related to evaporation methods are expected to be identified for development. These tasks likely include evaluation and testing of composition variability testing and evaluations, corrosion and erosion testing, slurry storage and immobilization investigations, and evaporator condensate disposition.

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

Safeguards Challenges and Safeguards Technology Needs Assessment for Leading Thorium Fuel Cycles

Several thorium fuel cycle variants are currently being actively pursued by the global nuclear energy community. These variants have short-, medium-, and long-term deployment pathways in a variety of reactor types, including thorium-fueled molten salt reactors. Those pathways in turn give rise to a variety of fuel designs, fuel cycle facilities, and nuclear material processing requirements. These emerging fuel cycles will impact the technical implementation of safeguards, and they already raise questions about the applicability of current verification technologies. To address this issue, research is being performed to produce a detailed safeguards technology road map. It will include a needs assessment of the detection research and development (R&D;) necessary to transition the current safeguards technology toolkit to meet the verification needs of thorium fuel cycles, and to formulate the scientific basis for building new instrumentation to fill any potential capability gaps. The purpose of this technology road map is to define and inform on the safeguards technology needs for thorium fuel cycles, reflecting only the leading candidate thorium fuel cycles prioritized based on implementation timescales and the current direction of international programs. This work provides a guide to the priorities for future directed R&D; needed to bring the technology readiness levels (TRLs) of safeguards detection solutions in line with the higher TRLs of the most promising thorium fuel cycles. Herein, a summary is presented of thorium fuel cycle options and activities currently under way worldwide, which provides the technical basis for the needs evaluation. The key synergies and differences between these fuel cycles and current conventional uranium- and plutonium-based fuel cycles will be discussed from a nuclear material accountancy and detection standpoint. Reactor inventory calculations, fuel cycle simulations, and conclusions from the safeguards technology needs assessment will be presented, together with plans for experimental validation.

Worrall, Louise G.↗
DOE OSTI2018

Means of Meeting Chapter 15 Requirements for a Small Modular Reactor Cooled by Lead-Bismuth

The mission of the Department of Energy Office of Nuclear Energy (DOE-NE) is to advance nuclear power as a resource capable of meeting the nation’s energy, environmental, and national security needs by resolving technical, cost, safety, proliferation resistance, and security barriers through Research, Development, and Demonstration (RD&D). To assist in accomplishing this, DOE-NE has established the Gateway for Accelerated Innovation in Nuclear (GAIN) to provide the nuclear community with access to the technical, regulatory, and financial support necessary to move innovative nuclear energy technologies toward commercialization. As part of this program, a GAIN Voucher was awarded to the Columbia Basin Consulting Group (CBCG) to develop for the Lead-Bismuth Reactor (LBR): (1) a means of meeting Chapter 15 requirements and (2) to perform an assessment against a gap analysis developed by the U.S. Nuclear Regulatory Commission (NRC) for Chapter 15. These two assessments will determine to what extent the LBR can adapt to or meet the Chapter 15 Accident Analysis requirements, and determine gaps that may still exist and what additional information is needed in order to close them. The CBCG LBR design is being developed with a high level of passive safety. It has the advantages of the classical liquid metal reactor, i.e. small size and passive safety, while having the additional advantage of a chemically inert coolant. The CBCG and the Pacific Northwest National Laboratory (PNNL) collaborated to develop an initial licensing pathway for the CBCG Lead-Bismuth conceptual reactor design. It was found that the reactor is well along the licensing pathway and is licensable although some additional design information is needed to establish a complete licensing basis. The missing information is identified in this report and it is noted that much of the missing information can be obtained from the Fast Flux Test Facility (FFTF), a DOE liquid metal test reactor. It was also found that the traditional Chapter 15 requirements for assessing the response of a reactor to possible accident sequences can be adapted to the LBR concept. The Chapter 15 review examined several classes of initiating events and accidents that are normally covered in Chapter 15: reactivity initiated events, reduction in heat removal events, local fuel failure events, and events initiated on the steam supply side. Although some design information is lacking at present, the LBR can be expected to respond as required by Chapter 15 requirements to almost all of the first three events. For events initiated on the steam side, design information is lacking and so conclusions cannot be reached at present. On the other hand, it should be quite possible to develop the design information for the steam supply side and the impact of events initiated on this side can be assessed in a subsequent study.

Wootan, David W.↗
DOE OSTI2018

Spatial and Spin Symmetry Breaking in Semidefinite-Programming-Based Hartree–Fock Theory

The Hartree–Fock problem was recently recast as a semidefinite optimization over the space of rank-constrained two-body reduced-density matrices (RDMs) [ Phys. Rev. A 2014, 89, 010502(R)]. This formulation of the problem transfers the nonconvexity of the Hartree–Fock energy functional to the rank constraint on the two-body RDM. We consider an equivalent optimization over the space of positive semidefinite one-electron RDMs (1-RDMs) that retains the nonconvexity of the Hartree–Fock energy expression. The optimized 1-RDM satisfies ensemble N-representability conditions, and ensemble spin-state conditions may be imposed as well. The spin-state conditions place additional linear and nonlinear constraints on the 1-RDM. We apply this RDM-based approach to several molecular systems and explore its spatial (point group) and spin (Ŝ 2 and Ŝ 3 ) symmetry breaking properties. When imposing Ŝ 2 and Ŝ 3 symmetry but relaxing point group symmetry, the procedure often locates spatial-symmetry-broken solutions that are difficult to identify using standard algorithms. For example, the RDM-based approach yields a smooth, spatial-symmetry-broken potential energy curve for the well-known Be–H 2 insertion pathway. We also demonstrate numerically that, upon relaxation of Ŝ 2 and Ŝ 3 symmetry constraints, the RDM-based approach is equivalent to real-valued generalized Hartree–Fock theory.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

There Are Safe Limits for Radioactivity - Does WIPP Need to Filter its Exhaust Air? - 17165

Pilot Plant (WIPP) underground repository resulted in the release of americium and plutonium (mostly {sup 241}Am) into the environment and contaminated portions of the repository, primarily along the ventilation path from the location of the incident. The WIPP uses a ventilation system to ensure that underground air is circulated through the repository and to ensure that air quality conditions are safe for the workers. Since the air in the repository exits to the surface through an exhaust shaft, this shaft is the sole potential pathway for airborne radioactivity release from the repository. During normal operations before the 2014 incident, exhaust air was released to the environment unfiltered, with an automatic switch to filtration when airborne radioactivity was detected immediately down-stream from the active waste disposal operation. However, since the radiation release event, the WIPP ventilation system has been, and will likely remain in what is called 'filtration mode,' (i.e., exhaust air is routed through a HEPA filter system). Redirection of the ventilation system through the HEPA (High Efficiency Particulate Air) filter system was necessary at the peak of the radiation release event to protect aboveground workers at the site and the public in the surrounding areas; however, it has hampered recovery efforts and has exacerbated the inherent safety issues of working underground. As a component of the Carlsbad Environmental Monitoring and Research Center's (CEMRC) WIPP environmental monitoring program, airborne radioactivity samples are collected daily in the exhaust shaft ventilation air as it reaches the surface, and before entering the HEPA filters. Since June 2014, airborne radiation levels entering the HEPA filters have averaged about 1% of a derived air concentration (DAC) for {sup 241}Am. An airborne radioactivity level of one DAC is equivalent to a potential worker internal dose exposure of 50 mSv per work year, if a worker were continuously exposed for a full work year (2000 hours). During Project Reach and throughout decontamination campaigns conducted in Panel 7 for several months in 2015, these unfiltered levels rose to 3-5% of a DAC, with a one week spike reaching almost one DAC in June 2015, during decontamination of the most heavily contaminated exhaust drift in Panel 7. Since that period, the unfiltered levels have never exceeded 2% of a DAC. Going forward, the question is, should WIPP resume unfiltered discharge of its underground ventilation air? Evaluation of more than two years of underground ventilation sampling data indicates that residual radioactivity levels in the underground no longer warrant HEPA filtration in order to meet either worker or environmental protection criteria. In terms of radiological risk at or in the vicinity of the WIPP site, the increased risk from resuming unfiltered ventilation is exceedingly small and would not result in a hypothetical dose to a member of the public in excess of the 100 micro Sv per year limit for periodic confirmatory sampling as required for operating repositories by the Environmental Protection Agency (40 CFR 191). In addition, the requirement for respiratory protection for workers underground exposed to 1-2% of a DAC is questionable, given the added industrial safety risk of heavy equipment operation while wearing respirators. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Discovery and Characterization of 2-Acylaminoimidazole Microsomal Prostaglandin E Synthase-1 Inhibitors

As part of a program aimed at the discovery of antinociceptive therapy for inflammatory conditions, a screening hit was found to inhibit microsomal prostaglandin E synthase-1 (mPGES-1) with an IC 50 of 17.4 μM. Structural information was used to improve enzyme potency by over 1000-fold. Addition of an appropriate substituent alleviated time-dependent cytochrome P450 3A4 (CYP3A4) inhibition. Further structure–activity relationship (SAR) studies led to 8, which had desirable potency (IC 50 = 12 nM in an ex vivo human whole blood (HWB) assay) and absorption, distribution, metabolism, and excretion (ADME) properties. Here, studies on the formulation of 8 identified 8·H 3 PO 4 as suitable for clinical development. Omission of a lipophilic portion of the compound led to 26, a readily orally bioavailable inhibitor with potency in HWB comparable to celecoxib. Furthermore, 26 was selective for mPGES-1 inhibition versus other mechanisms in the prostanoid pathway. These factors led to the selection of 26 as a second clinical candidate.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Niagara Falls Storage Site - Balance of plant investigation results - 15432

The Niagara Falls Storage Site (NFSS) is a 77.3-hectare (ha) (191-acre) property that is owned by the United States Government and located in the township of Lewiston, Niagara County, New York. The NFSS is part of the former Lake Ontario Ordnance Works (LOOW) that was used by the War Department beginning in 1942 for the production of trinitrotoluene (TNT). During the 1940's and 1950's, the Manhattan Engineer District and the Atomic Energy Commission brought various radioactive wastes and uranium processing byproducts (residues) resulting from our nation's atomic energy program to the LOOW for storage. Site operations caused soil, sediment, and groundwater contamination that lead to several remedial actions, which culminated in the construction of the Interim Waste Containment Structure (IWCS) on the NFSS. The U. S. Army Corps of Engineers (USACE)-Buffalo District is the lead Federal agency for Formerly Utilized Sites Remedial Action Program (FUSRAP) remediation of the NFSS. As the lead agency, USACE is conducting a remedial investigation/feasibility study (RI/FS) pursuant to the protocols set forth in the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). CERCLA activities at the NFSS have transitioned from the site RI activities to the FS evaluation of potential remediation alternatives. USACE recognizes the need to implement a focused CERCLA FS process and, therefore, has established three separate operable units (OUs) for NFSS: the IWCS OU, the Balance of Plant (BOP) OU [i.e., all on-site areas outside the boundary of the IWCS], and the Groundwater OU. This paper details recent investigations into the underground utilities, groundwater/soil contamination, and past storage of contaminated material on the Balance of Plant Operable Unit of the NFSS. Recent fieldwork activities have investigated areas of elevated groundwater contamination as well as an investigation to determine/eliminate any preferential pathway that historical underground utilities may have provided on-site in these areas. Additional areas of investigation included strategic placement of groundwater wells at locations of historic residue storage piles and intersections of various underground utilities (based on aerial photography and geophysical surveys). Several hundred locations across the site were investigated with a gamma walk-over survey, boring, surveying and sampling of soil-cores to aide in the delineation of soil contamination throughout the Balance of Plant Operable Unit. The series of investigations indicated multiple operational areas still have impacts above background conditions, risk-based concentrations, and promulgated maximum contaminant levels for multiple media in the Balance of Plant Operable Unit. The soil, groundwater, sediment, and utility sampling data show that 1) radionuclide impacts derived from ore-residue handling operations still exist, 2) impacts from other inorganic and organic compound exist in TNT manufacturing and support areas, and 3) contaminant transport from past source areas is minimal. The full compendium of site history and recent sampling data provides a well-defined conceptual site model that provides the necessary input data to prepare volumetric soil estimates for the Balance of Plant Operable Unit Feasibility Study. The scale of the NFSS and complexity of prior operations provide many remedial challenges. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Site-specific programming of the host epithelial transcriptome by the gut microbiota

The intestinal epithelium separates us from the microbiota but also interacts with it and thus affects host immune status and physiology. Previous studies investigated microbiota-induced responses in the gut using intact tissues or unfractionated epithelial cells, thereby limiting conclusions about regional differences in the epithelium. Here, we sought to investigate microbiota-induced transcriptional responses in specific fractions of intestinal epithelial cells. To this end, we used microarray analysis of laser capture microdissection (LCM)-harvested ileal and colonic tip and crypt epithelial fractions from germ-free and conventionally raised mice and from mice during the time course of colonization. We found that about 10% of the host’s transcriptome was microbially regulated, mainly including genes annotated with functions in immunity, cell proliferation, and metabolism. The microbial impact on host gene expression was highly site specific, as epithelial responses to the microbiota differed between cell fractions. Specific transcriptional regulators were enriched in each fraction. In general, the gut microbiota induced a more rapid response in the colon than in the ileum. Our study indicates that the microbiota engage different regulatory networks to alter host gene expression in a particular niche. Understanding host-microbiota interactions on a cellular level may facilitate signaling pathways that contribute to health and disease and thus provide new therapeutic strategies.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Systematic Process Intensification involving Zeotropic Distillation

Distillation is commonly used for separating homogeneous fluid mixtures. While it is based on a simple thermally driven vapor-liquid equilibrium phenomenon at the two-phase region, different variants of distillation systems exist. These include simple distillation, dividing wall columns, pressure swing distillation, thermally coupled distillation and reactive distillation. Complex separation may also involve multiple distillation in a sequence to achieve the desired products. These sequences can be constructed as direct sequence, indirect sequence or thermally coupled columns. Even when a sequence is fixed, each column in the sequence can have a plethora of design alternatives to consider. All these make the design and intensification of distillation systems a challenging task. The large number of plausible design alternatives increases the combinatorial complexity for screening. Although significant efforts have been made in the past, we still lack a method for systematic identification of novel pathways for process intensification of distillation system. This is due to the lack of a generalized representation of all plausible alternatives in a single modeling and optimization framework. In this work, we first present a general representation of thermally driven vapor-equilibrium phenomenon using abstract building blocks. Specifically, each tray in a distillation column is represented by a liquid block and a vapor block with a shared semi-restricted boundary representing the interface. The arrangement of these building blocks in a two-dimensional grid gives rise to all plausible variants of distillation systems. These systems range from simple distillation, dividing wall columns to task-integrated columns. This enables us to systematically identify both classic and out-of-the-box intensified designs at the column and flowsheet levels. The overall distillation-based separation process synthesis problem is formulated as a single mixed-integer nonlinear programming (MINLP) model. In conclusion, the proposed approach is applied to multi-component zeotropic systems to show the capability of identifying promising intensified alternatives.

42 ENGINEERING↗
DOE OSTI2022

A genome-wide association study of suicide attempts in the million veterans program identifies evidence of pan-ancestry and ancestry-specific risk loci

In this study, to identify pan-ancestry and ancestry-specific loci associated with attempting suicide among veterans, we conducted a genome-wide association study (GWAS) of suicide attempts within a large, multi-ancestry cohort of U.S. veterans enrolled in the Million Veterans Program (MVP). Cases were defined as veterans with a documented history of suicide attempts in the electronic health record (EHR; N = 14,089) and controls were defined as veterans with no documented history of suicidal thoughts or behaviors in the EHR ( N = 395,064). GWAS was performed separately in each ancestry group, controlling for sex, age and genetic substructure. Pan-ancestry risk loci were identified through meta-analysis and included two genome-wide significant loci on chromosomes 20 ( p = 3.64 × 10 -9 ) and 1 ( p = 3.69 × 10 -8 ). A strong pan-ancestry signal at the Dopamine Receptor D2 locus ( p = 1.77 × 10 -7 ) was also identified and subsequently replicated in a large, independent international civilian cohort ( p = 7.97 × 10 -4 ). Additionally, ancestry-specific genome-wide significant loci were also detected in African-Americans, European-Americans, Asian-Americans, and Hispanic-Americans. Pathway analyses suggested over-representation of many biological pathways with high clinical significance, including oxytocin signaling, glutamatergic synapse, cortisol synthesis and secretion, dopaminergic synapse, and circadian rhythm. These findings confirm that the genetic architecture underlying suicide attempt risk is complex and includes both pan-ancestry and ancestry-specific risk loci. Moreover, pathway analyses suggested many commonly impacted biological pathways that could inform development of improved therapeutics for suicide prevention.

60 APPLIED LIFE SCIENCES↗