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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 1,531 records · Page 85
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

URS/WTP's Future Leader Program and AECOM's Early Career Professional Technology Exchange - 17239

URS Energy and Construction, Inc. (URS), a subsidiary of AECOM, is the Bechtel National, Inc. (BNI) teaming subcontractor on the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Project. Recently, the WTP Project has begun a transition toward facility turnover and commissioning. With that transition came the hiring of staff for the startup and commissioning workforce. With many of these individuals being Early Career Professionals (ECPs), URS recognized a need to create and implement a workforce development program to give these professionals the skills to thrive in a professional environment and provide a sense of community to improve talent retention. The result of this recognition of need was the creation of URS/WTP Future Leaders. This paper will share the successes and lessons learned related to founding the URS/WTP Future Leaders. This includes establishing programs such as the Continuous Learning Workshops, Rotational Program, and implementing a mentor program. In addition, establishing a budget and obtaining support from Human Resources will be discussed. By March 2017, the ECP program will have been in effect for approximately two years. As a separate effort, many of AECOM's major waste remediation contractors have started having Early Career Professional Technology Exchanges (ECP TE) in an effort to create collaboration between sites and to establish industry contacts that will continue to be a resource for years to come. Washington River Protection Solutions, LLC; URS/WTP; Savannah River Remediation, LLC; and Nuclear Waste Partnership, LLC have conducted ECP TE, with each site hosting an event. For these events, each participant prepares a presentation and answers questions on the presentation topic. This allows ECPs to practice presentation skills, develop skills in answering questions from their peers and management, and be the expert in the room on a particular topic. Tours of the onsite facilities also are given as a way for ECPs to gain a broader understanding of the waste remediation industry and the challenges that other sites are facing. Accomplishments, lessons learned, and future plans for ECP TE will be discussed. The ECP TE events allow AECOM, as the parent company, to provide a unique learning opportunity to the next generation of engineers within the DOE nuclear field and to ensure the safe operations of these nuclear sites for years to come. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Robotic Solutions for Remote Access and Retrieval of High-Level Radioactive Waste - 19544

This paper describes the ongoing development of robotic solutions for accessing and retrieving high-level radioactive waste from underground storage bins as part of the Calcine Retrieval Project at the INL Site. The waste is in the form of a solid powder, referred to as calcine, stored in a set of stainless steel bins within an underground concrete vault. Due to the radiation field produced by the calcine, all operations must be performed remotely. The Calcine Retrieval Project is currently carrying out proof-of-concept testing of methods for the various stages of calcine retrieval. The bins were designed with no means for access, so retrieval operations will require welding access riser pipes to the bins, followed by cutting through the bin walls from within the risers. These tasks are complicated by the fact that four of the risers must be placed off center on a domed surface, resulting in a weld joint that is curved and tilted relative to the riser axis. The Access Riser Connection robot is being developed to perform these operations using interchangeable welding and plasma cutting attachments. The majority of the calcine will be removed using a vacuum system and pneumatically transferred to storage. This system is not described in this paper. However, the bins contain several internal features that are expected to retain calcine, most notably circumferential stiffening rings on the walls and radial ribs on the floors. One of the solutions being developed for the task of retrieving this residual calcine is a vacuum crawler, a wheeled robot using vacuum to adhere to the interior walls of the bins. The vacuum crawler would use a separate vacuum system to remove residual calcine or would use compressed air to move calcine to a location from which it can be retrieved more easily. While comparable welding and wall-climbing robots have been developed before, this particular application has several constraints that are not satisfied by existing systems. For this reason, both the access riser welder and the vacuum crawler, although still under development, may be of interest to other projects faced with similar constraints. (author)

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

Development and application of FPGA-based logic controller - 357

The control systems of nuclear power plants contain many components which are becoming obsolete at an increasing rate. Nowadays maintenance for analog-based protection systems may be difficult as analog parts become obsolete or hard to obtain. Various studies have been conducted to address this control system hardware obsolescence issue. Those control systems of nuclear power plants have been replaced with modern digital control systems such as the programmable logic controller (PLC) and the distributed control system (DCS). The central processing unit (CPU)- based platforms such as the PLC and the DCS require an operating system (OS) and application software, and thus they might result in a common-cause failure when a problem occurs in the operating system or application software. The field programmable gate array (FPGA) is highlighted as an alternative to the conventional protection or control systems. This paper presents the development of an FPGA-based logic controller (FLC) and a diverse protection system (DPS) with the FLC platform. Protection functions for the DPS were implemented in FPGAs without any CPU or OS. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2024

Disinfection system with high throughput and low power requirements

Devices, methods and techniques are disclosed to perform high confidence sterilization of indoor air with low power requirements. In one example aspect, a sterilization device includes a power source, an energy storage coupled to the power source and configured to store electric charges, a set of electrodes arranged in a specified geometry to have a fixed characteristic impedance, and a switch positioned between the energy storage and the set of electrodes. The switch is configured to operate to establish a pulsed electric field on the set of electrodes.

Sampayan, Stephen↗
DOE OSTI2026

Broad frequency tuning of a Nb$_{3}$Sn superconducting microwave cavity for dark matter searches

We demonstrate a novel broad-frequency tuning mechanism for superconducting microwave cavities designed for dark matter searches. Using a Nb$_3$Sn-coated cigar-shaped cavity operating at approximately 9 GHz, we achieve continuous frequency tuning exceeding 1 GHz by mechanically separating the two cavity halves: a "tuning-by-opening" technique. Finite-element method simulations predict that radiative losses do not degrade the quality factor even for large openings, as a closed cavity with an intrinsic quality factor of $10^7$ maintains this value for apertures up to 9 mm, corresponding to a tuning range from 9.0 to 7.5 GHz. Experimental validation using both copper ring spacers and a continuous sliding mechanism confirms $Q_0$ values exceeding the dark matter quality factor across the entire explored frequency range, despite mechanical imperfections and film non-uniformities. This tuning approach avoids inserting elements into the resonant volume, making it particularly suitable for high-Q superconducting cavities in axion haloscope experiments and readily applicable to REBCO-based implementations capable of operating in multi-tesla magnetic fields.

Maiello, D. [Padua U.; INFN, Padua] (ORCID:0009000↗
DOE OSTI2014

PV Reliability Operations and Maintenance (PVROM) Database Initiative: 2014 Project Report

To fill a major knowledge gap, Sandia National Laboratories (SNL) and the Electric Power Research Institute (EPRI) are jointly engaged in a multi-year research effort, supported by the Department of Energy’s SunShot Program, to examine real-world photovoltaic (PV) plant reliability and performance. Findings and analyses, derived from field data documented in the PV Reliability Operations Maintenance (PVROM) database tool as well as from convened workshops and working group discussions, are intended to inform industry best practices around the optimal operations and maintenance (O&M) of solar PV assets. To improve upon and evolve existing solar PV O&M approaches, this report: 1. Provides perspective on the concept of PV “system” reliability and how it can inform plant design, operations, and maintenance decisions that produce better long-term outcomes; 2. Describes the PVROM data collection tool, its technical capabilities, and results generated from database content in 2014; 3. Presents ongoing research efforts that are meant to drive the solar industry toward PV O&M best practice protocols and standards; and 4. Reflects on future areas of inquiry that can help better forecast plant health (e.g., system component availability, component wear out, etc.) and associated lifecycle costs. Ultimately, this report adds to the knowledge base of improving PV system O&M activities by discussing data collection and analysis techniques that can be used to better understand and enhance the reliability, availability, and performance of a photovoltaic system.

14 SOLAR ENERGY↗
DOE OSTI2024

D2NO: Efficient handling of heterogeneous input function spaces with distributed deep neural operators

Neural operators have been applied in various scientific fields, such as solving parametric partial differential equations, dynamical systems with control, and inverse problems. However, challenges arise when dealing with input functions that exhibit heterogeneous properties, requiring multiple sensors to handle functions with minimal regularity. To address this issue, discretization-invariant neural operators have been used, allowing the sampling of diverse input functions with different sensor locations. However, existing frameworks still require an equal number of sensors for all functions. We propose a novel distributed approach to further relax the discretization requirements and solve the heterogeneous dataset challenges. Our method involves partitioning the input function space and processing individual input functions using independent and separate neural networks. A centralized neural network is used to handle shared information across all output functions. This distributed methodology reduces the number of gradient descent back-propagation steps, improving efficiency while maintaining accuracy. Here, we demonstrate that the corresponding neural network is a universal approximator of continuous nonlinear operators and present three numerical examples to validate its performance.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2026

Assessing plasma face component thermal response to rotating 3D magnetic fields for SPARC tokamak

Thermal response simulations of plasma-facing components (PFCs) in the SPARC tokamak, performed with the HEAT code, show that three-dimensional (3D) heat loads resulting from stationary n=1 perturbations require highly radiative scenarios, with up to 95% of the power crossing the separatrix (P SOL ) being radiated, to maintain PFC temperatures within acceptable operational limits, whereas the application of slowly rotating 3D fields substantially reduces the thermal loads. The HEAT module, developed to predict heat loads from non-axisymmetric plasmas, is extended to model time-dependent heat flux patterns generated by rotating 3D fields, and a comprehensive thermal analysis is performed on PFCs subjected to both the maximum and minimum power loads, as well as to rotating heat flux distributions, to evaluate the temperature evolution for varying perturbation amplitudes and rotation frequencies. The extension of this analysis to 3D fields with toroidal mode number n=2 shows that this configuration leads to weaker localized heat flux peaks relative to the n=1 case, enabling safe operation with less than 80% of the power radiated when static 3D fields of low amplitude are applied, while using slowly rotating fields at higher amplitudes. These results indicate that n=2 perturbations are generally less detrimental to divertor power exhaust, emphasizing the strong dependence of divertor power exhaust on the characteristics of the applied 3D fields.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2017

Astrometric Calibration and Performance of the Dark Energy Camera

We characterize the ability of the Dark Energy Camera (DECam) to perform relative astrometry across its 500 Mpix, 3 $deg^2$ science field of view, and across 4 years of operation. This is done using internal comparisons of $~ 4 x 10^7$ measurements of high-S/N stellar images obtained in repeat visits to fields of moderate stellar density, with the telescope dithered to move the sources around the array. An empirical astrometric model includes terms for: optical distortions; stray electric fields in the CCD detectors; chromatic terms in the instrumental and atmospheric optics; shifts in CCD relative positions of up to $\approx 10 \mu m$ when the DECam temperature cycles; and low-order distortions to each exposure from changes in atmospheric refraction and telescope alignment. Errors in this astrometric model are dominated by stochastic variations with typical amplitudes of 10-30 mas (in a 30 s exposure) and $5^{\prime}-10^{\prime}$ arcmin coherence length, plausibly attributed to Kolmogorov-spectrum atmospheric turbulence. The size of these atmospheric distortions is not closely related to the seeing. Given an astrometric reference catalog at density $\approx 0.7$ $arcmin^{-2}$, e.g. from Gaia, the typical atmospheric distortions can be interpolated to $\approx$ 7 mas RMS accuracy (for 30 s exposures) with $1^{\prime}$ arcmin coherence length for residual errors. Remaining detectable error contributors are 2-4 mas RMS from unmodelled stray electric fields in the devices, and another 2-4 mas RMS from focal plane shifts between camera thermal cycles. Thus the astrometric solution for a single DECam exposure is accurate to 3-6 mas ( $\approx$ 0.02 pixels, or $\approx$ 300 nm) on the focal plane, plus the stochastic atmospheric distortion.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

An Efficient Annual-Performance Model of a Geothermal Network for Improved System Design, Operation, and Control: Preprint

Geothermal district energy systems (DES), and specifically geothermal networks, provide a viable solution for decarbonizing residential and commercial heating and cooling loads. District energy systems of all kinds enable a thermal resource with a relatively high capital cost (such as a geothermal borehole field) to be shared among a large number of users. While district heating and cooling has been studied for many years, geothermal networks, fifth generation DES that utilize water-source heat pumps and an ambient temperature loop to meet heating and cooling loads, have not been implemented extensively and thus require additional technical and economic optimization to obtain maximum benefits. This paper presents a newly developed reduced-order model that captures the flow of energy within the network, including the commercial and residential users' electrical usage, at an hourly rate over a year. The model includes building loads, heat pumps, borehole fields, and auxiliary heat/cool input, all connected with an ambient-temperature thermal loop model. In the model, operational control is possible for the borehole fields, circulation pump, and auxiliary system. For a given system, the model can output the complete state parameters for each component, the thermal loop, and the collective system, such as flow rate over time, average thermal loop temperature over time, and total electricity usage. The model can also be used to optimize the system control for maximizing system efficiency or minimizing system operational cost. For example, one initial assessment of the borehole controller for an example system showed that a controller with on/off operation of the borehole field reduces annual electrical usage by 33%, compared with continuous operation mode. Hence, the model can assist in optimizing a given system's operation to get the most value out of a geothermal network installation. Future work will consider the model's application to a demonstration project, including the model validation against operational data and system operation optimization.

ambient-temperature loop↗
DOE OSTI2025

Operator origin of anomalous dimensions in de Sitter space

The late-time limit of the power spectrum for heavy (principal series) fields in de Sitter (dS) space yields a series of polynomial terms with complex scaling dimensions. Such scaling behavior is expected to result from an associated operator with a complex dimension. In a free theory, these complex dimensions are known to match the constraints imposed by unitarity on the space of states. Yet, perturbative corrections to the scaling behavior of operators are naively inconsistent with unitary evolution of the quantum fields in dS space. This paper demonstrates how to compute one-loop corrections to the scaling dimensions that appear in the two-point function from the field theory description in terms of local operators. We first show how to evaluate these anomalous dimensions using Mellin space, which has the feature that it naturally accommodates a scaleless regulator. We then explore the consequences for the soft de Sitter effective theory (SdSET) description that emerges in the long wavelength limit. Carefully matching between the UV and SdSET descriptions requires the introduction of novel nondynamical “operators” in the effective theory. This is not only necessary to reproduce results extracted from the Källén-Lehmann representation (that use the space of unitary states directly), but it is also required by general arguments that invoke positivity. Published by the American Physical Society 2025

Cohen, Timothy↗
DOE OSTI2023

Magneto-optical measurement of magnetic field and electrical current on a short pulse high energy pulsed power accelerator

We describe a direct magneto-optical approach to measuring the magnetic field driven by a narrow pulse width (<10 ns), 20 kA electrical current flow in the transmission line of a high energy pulsed power accelerator. The magnetic field and electrical current are among the most important operating parameters in a pulsed power accelerator and are critical to understanding the properties of the radiation output. However, accurately measuring these fields and electrical currents using conventional pulsed power diagnostics is difficult due to the strength of ionizing radiation and electromagnetic interference. Our approach uses a fiber coupled laser beam with a rare earth element sensing crystal sensor that is highly resistant to electromagnetic interference and does not require external calibration. Here, we focus on device theory, operating parameters, results from an experiment on a high energy pulsed power accelerator, and comparison to a conventional electrical current shunt sensor.

42 ENGINEERING↗
DOE OSTI2020

Challenges and Opportunities in Magnetospheric Space Weather Prediction

Abstract Space Weather is the study of the dynamics of the coupled Solar‐Terrestrial environment, as these dynamics impact technological systems and human activity. This paper reviews a selection of the advances, challenges, and new opportunities for magnetospheric space weather, and while the focus is on specific phenomena, many other aspects of space weather will have similar challenges and needs. As a scientific field with direct applications, the field of space weather is partly driven by imperatives from both policy and operations. We provide an introduction to some of the context in which the field exists and discuss how this might shape future developments and norms within the space weather enterprise. We briefly examine benchmarking, as a policy and operationally driven activity, as it provides immediate societal relevance and an opportunity to stretch scientific understanding. As numerical space weather prediction now becomes routine, and exascale computing is in the near future, we identify challenges relating to computational expense and big data, capturing and accounting for uncertainties, and specification of boundary conditions. Here, as with the observations supporting numerical space weather prediction, the key challenge lies in extending the lead time of predictions. We also discuss the role of data, particularly in regard to model validation and empirical modeling. Due to the growing societal impact of space weather, we also examine the relationships between space weather and its terrestrial counterpart and look at the importance of continuous evaluation, monitoring progress in predictive capability, and communication with researchers, forecasters, and end users.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

Transuranic Waste Facility: Evaluation of Material-at-Risk Limits

The purpose of this analysis was to provide an evaluation and justification of the differences in the safety-basis parameters of Area G and the proposed TRU Waste Facility (TWF) in response to a request from the Los Alamos Field Office. Many of the differences in safety parameters stem from physical attributes such as facility location, size, and updated safety-basis requirements, etc. However, the primary safety-basis parameter that LANL and the Los Alamos Field Office can control for the proposed TWF is the required MAR limit. Based on the following analysis, LANL has proposed to reduce the overall facility MAR from 30,000 PE Ci to 21,400 PE Ci, and the waste storage buildings from 4,550 PE Ci to 3,200 PE Ci. The recommendation balances program requirements, operational considerations, facility construction cost, and container costs. To implement the reduced MAR strategy above, the Los Alamos Field Office and LANL will need to work with WIPP to ensure two characterization/shipment campaigns are scheduled each year. The analysis in this document included a review of historical trends and potential future scenarios in activity for enduring waste containers to define the expected normal operating range. The first part of the MAR analysis resulted in a newly defined range of activity of 10.5-18.0 PE Ci per DE2= expected for the design life of the new TWF. However, for accident scenario analysis, containers will use the WIPP WAC limits because there are no other individual container controls. Specifically, accident scenarios involving less than the building MAR will use the 80-PE Ci WIPP-WAC limit for drums. The accident analyses are intended to bound the potential impacts, and are not intended to be based on normal operational ranges. The Field Office also requested that LANL evaluate a potential reduction of the waste storage building MAR Limit by a factor of two to three. LANL used the newly defined MAR range of 10.5-18.0 PE Ci/DE to define upper and lower MAR boundary requirements using three containerization scenarios. The result of the analysis showed that the most probable scenario of future operations that balances costs, drum packaging efficiency, and shipment efficiency will routinely require the use of one-third to two-thirds of the MAR limit for each building. This result, paired with scenarios that could potentially provide short-term MAR increases, demonstrates that the MAR cannot be reduced by a factor as large as two to three, but can be reduced from 4,550 PE Ci to 3,200 PE Ci for waste storage buildings (a reduction of 30%). The TWF PDSA submittal contained combustibility values for enduring waste that appeared relatively large compared to Area G. The analysis provided the basis for the initial combustibility values established in the PDSA. Although the recent data provided combustibility values that were much lower than the PDSA assumptions (27% versus 80% in PDSA), the analysis shows that there is variability in combustible loading over time. For safety-basis accident scenarios, the material composition distribution for waste containers will be included in the MAR requirement by assuming all waste is combustible instead of applying a control for combustible loading. For operations and programs, it is better to assume 100% combustibles and maintain flexibility for waste generator containerization rather than to maintain a requirement for administrative controls of combustible loading. Controlling MAR through administrative controls is difficult for both the generator and waste management operations.

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

Beyond a = c : gravitational couplings to matter and the stress tensor OPE

We derive constraints on the operator product expansion of two stress tensors in conformal field theories (CFTs), both generic and holographic. We point out that in large N CFTs with a large gap to single-trace higher spin operators, the stress tensor sector is not only universal, but isolated: that is, < TTO > = 0 , where O ≠ T is a single-trace primary. We show that this follows from a suppression of < TTO > by powers of the higher spin gap, Δ gap , dual to the bulk mass scale of higher spin particles, and explain why < TTO > is a more sensitive probe of Δ gap than a – c in 4d CFTs. This result implies that, on the level of cubic couplings, the existence of a consistent truncation to Einstein gravity is a direct consequence of the absence of higher spins. By proving similar behavior for other couplings < TO 1 O 2 > where O i have spin s i ≤ 2, we are led to propose that 1/Δ gap is the CFT “dual” of an AdS derivative in a classical action. These results are derived by imposing unitarity on mixed systems of spinning four-point functions in the Regge limit. Using the same method, but without imposing a large gap, we derive new inequalities on these three-point couplings that are valid in any CFT. These are generalizations of the Hofman-Maldacena conformal collider bounds. By combining the collider bound on TT couplings to spin-2 operators with analyticity properties of CFT data, we argue that all three tensor structures of < TTT > in the free-field basis are nonzero in interacting CFTs.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Quantum mechanical expansion of variance of a particle in a weakly non-uniform electric and magnetic field

We have solved the Heisenberg equation of motion for the time evolution of the position and momentum operators for a non-relativistic spinless charged particle in the presence of a weakly non-uniform electric and magnetic field. It is shown that the drift velocity operator obtained in this study agrees with the classical counterpart, and that, using the time dependent operators, the variances in position and momentum grow with time. The expansion rate of variance in position and momentum are dependent on the magnetic gradient scale length, however, independent of the electric gradient scale length. In the presence of a weakly non-uniform electric and magnetic field, the theoretical expansion rates of variance expansion are in good agreement with the numerical analysis. It is analytically shown that the variance in position reaches the square of the interparticle separation, which is the characteristic time much shorter than the proton collision time of plasma fusion. After this time, the wavefunctions of the neighboring particles would overlap, as a result, the conventional classical analysis may lose its validity. The broad distribution of individual particle in space means that their Coulomb interactions with other particles become weaker than that expected in classical mechanics.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Bootstrapping quantum extremal surfaces. Part I. The area operator

Quantum extremal surfaces are central to the connection between quantum information theory and quantum gravity and they have played a prominent role in the recent progress on the information paradox. We initiate a program to systematically link these surfaces to the microscopic data of the dual conformal field theory, namely the scaling dimensions of local operators and their OPE coefficients. We consider CFT states obtained by acting on the vacuum with single-trace operators, which are dual to one-particle states of the bulk theory. Focusing on AdS 3 /CFT 2 , we compute the CFT entanglement entropy to second order in the large c expansion where quantum extremality becomes important and match it to the expectation value of the bulk area operator. We show that to this order, the Virasoro identity block contributes solely to the area operator.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Assessment of field-induced quantum confinement in heterogate germanium electron–hole bilayer tunnel field-effect transistor

The analysis of quantum mechanical confinement in recent germanium electron–hole bilayer tunnel field-effect transistors has been shown to substantially affect the band-to-band tunneling (BTBT) mechanism between electron and hole inversion layers that constitutes the operating principle of these devices. The vertical electric field that appears across the intrinsic semiconductor to give rise to the bilayer configuration makes the formerly continuous conduction and valence bands become a discrete set of energy subbands, therefore increasing the effective bandgap close to the gates and reducing the BTBT probabilities. In this letter, we present a simulation approach that shows how the inclusion of quantum confinement and the subsequent modification of the band profile results in the appearance of lateral tunneling to the underlap regions that greatly degrades the subthreshold swing of these devices. To overcome this drawback imposed by confinement, we propose an heterogate configuration that proves to suppress this parasitic tunneling and enhances the device performance.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗