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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Evaluation of OpenAI Codex for HPC Parallel Programming Models Kernel Generation

We evaluate AI-assisted generative capabilities on fundamental numerical kernels in high-performance computing (HPC), including AXPY, GEMV, GEMM, SpMV, Jacobi Stencil, and CG. We test the generated kernel codes for a variety of language-supported programming models, including (1) C++ (e.g., OpenMP [including offload], OpenACC, Kokkos, SyCL, CUDA, and HIP), (2) Fortran (e.g., OpenMP [including offload] and OpenACC), (3) Python (e.g., numpy, Numba, cuPy, and pyCUDA), and (4) Julia (e.g., Threads, CUDA.jl, AMDGPU.jl, and KernelAbstractions.jl). We use the GitHub Copilot capabilities powered by the GPT-based OpenAI Codex available in Visual Studio Code as of April 2023 to generate a vast amount of implementations given simple + + prompt variants. To quantify and compare the results, we propose a proficiency metric around the initial 10 suggestions given for each prompt. Results suggest that the OpenAI Codex outputs for C++ correlate with the adoption and maturity of programming models. For example, OpenMP and CUDA score really high, whereas HIP is still lacking. We found that prompts from either a targeted language such as Fortran or the more general purpose Python can benefit from adding code keywords, while Julia prompts perform acceptably well for its mature programming models (e.g., Threads and CUDA.jl). We expect for these benchmarks to provide a point of reference for each programming model's community. Overall, understanding the convergence of large language models, AI, and HPC is crucial due to its rapidly evolving nature and how it is redefining human-computer interactions.

Godoy, William↗
DOE OSTI2020

FPDetect: Efficient Reasoning About Stencil Programs Using Selective Direct Evaluation

We present FPDetect, a low-overhead approach for detecting logical errors and soft errors affecting stencil computations without generating false positives. We develop an offline analysis that tightly estimates the number of floating-point bits preserved across stencil applications. This estimate rigorously bounds the values expected in the data space of the computation. Violations of this bound can be attributed with certainty to errors. FPDetect helps synthesize error detectors customized for user-specified levels of accuracy and coverage. FPDetect also enables overhead reduction techniques based on deploying these detectors coarsely in space and time. Experimental evaluations demonstrate the practicality of our approach.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

Performance Evaluation of Different Parallel Programming Models in SCALE-Shift Sequences for Criticality and Shielding Applications [Abstract]

The SCALE code system has been widely used for nuclear criticality safety, reactor physics, radiation shielding, source term generation, and inventory analyses by researchers, industry, and regulatory bodies. Although limited support for shared- and distributed-memory parallel processing was introduced via C++ threading, OpenMP, and MPI, a hybrid parallel programming model with both distributed- and shared-memory parallelism has not been fully supported in the SCALE code system.

Nuclear Criticality Safety Program (NCSP)↗
DOE OSTI2024

Evaluations for Nuclear Criticality Safety Program 12 C, 139 La, minor actinides, 235 U [Slides]

For light nuclei, preliminary work extends the evaluation from 6.5 MeV to ~ 10 MeV. For 139 La, the team delivered full evaluation in fast region to ORNL, including covariances. For sup>235 U, RPI data simulations, the team performed simulations and showed some improvement for neutrons below 5 MeV. Some of the changes needed for more improvement might not be supported by the current format. Some of the changes above 12 MeV to account for the angular distribution of preequilibrium neutrons require a change in the PFNS evaluation procedure.

235U re-evaluation↗
DOE OSTI2026

Evaluation Toolkit for Technical Assistance Programs

Across the United States, every home, business, industry, and government depends on abundant, reliable, and affordable electricity. Energy stakeholders have many options to improve how energy is generated, distributed, and used, but choosing the right path can be complex and challenging. To support more informed decision-making about local electricity systems, the U.S. Department of Energy (DOE) and its national laboratories provide customized technical assistance (TA) through several different programs. These TA programs are designed to support a wide range of stakeholders with a variety of needs. Technical assistance may include brief consultations with subject-matter experts, in-depth technical modeling and analysis, stakeholder engagement, and peer-to-peer exchange. Delivering effective TA is an iterative process that requires evaluation and adaptation. A comprehensive and robust evaluation framework provides the structure needed to ensure that TA programs and practitioners remain effective, responsive to industry trends, and aligned with local needs. This toolkit provides a framework—including a clear, structured process—that TA program staff can adapt to their program's goals to evaluate success.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2018

Instrumentation for Hanford Direct-Feed Low-Activity Waste Real-Time, In-Line Process Monitoring - 18339

The direct-feed low-activity waste (DFLAW) process will utilize facilities in the Hanford tank farms to stage tank waste feed, a new facility to pretreat the tank waste feed, and facilities in the Hanford Waste Treatment and Immobilization Plant (WTP) to immobilize the low-activity waste (LAW) and disposition effluents from the vitrification process. Process sampling is used extensively throughout the DFLAW process to qualify waste feeds, control the process, and demonstrate compliance with regulatory and contractual commitments. The U.S. Department of Energy's Office of River Protection (ORP) has started a program to evaluate the potential benefits of replacing some sample collection requirements with realtime, in-line monitoring (RTIM). The program will identify, develop, and evaluate technologies that can reduce the number of samples required for WTP operation. Potential benefits of RTIM include elimination of process holds for sample analysis, a reduction in worker exposure to radiation and chemical hazards, decreased secondary waste volume, reducing the cost for sample collection and analysis, an improvement in product quality, and timely indication of process anomalies. In order to incorporate RTIM, the process control strategy for the overall process, as well as each unit operation, was reviewed and revisions to the strategies proposed. The following items were identified for incorporation of RTIM: - Real-time material balance calculations linked to the process control system; - Use of RTIM instruments to validate the material balance for selected analytes; - Anion analysis for determination of selected semi-volatile species (e.g., chlorine, sulfur, and fluorine) in the recycle stream. Based on the proposed process control strategy, a preliminary list of potential analytical equipment was developed. This was followed by a preliminary survey of instrument technologies currently on the market building on surveys performed for ORP, literature reviews, vendor web sites, and subject matter experts from the Savannah River National Laboratory and other U.S. Department of Energy national laboratories. Each technology was evaluated for measurement capability, operations and maintenance requirements, space requirements, and potential for application as process control instrumentation. The instrument technologies were chosen based on the following criteria: - Ability to perform analyses needed; - Potential to be used or adapted for use as process control instruments; - Potential to be adapted to size and operational constraints of standard WTP sample cabinets; - Operational and maintenance requirements. (authors)

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

Evaluating Performance Portability of Accelerator Programming Models using SPEC ACCEL 1.2 Benchmarks

As heterogeneous architectures are becoming mainstream for HPC systems, application programmers are looking for programming model implementations that offer both performance and portability across platforms. Two directive-based programming models for accelerator programming that aim at doing this are OpenMP 4/4.5 and OpenACC. Many users want to know the difference between these two programming models, the state of their implementations, how to use them, and evaluate how suitable they are for their applications.The Standard Performance Evaluation Corporation (SPEC) ACCEL benchmarks, developed by the SPEC High Performance Group (HPG), recently released SPEC ACCEL 1.2 benchmark suite to help the evaluation of OpenCL, OpenMP 4.5 and OpenACC on different platforms. Inthis paper we present our preliminary results that evaluates OpenMP4.5 and OpenACC on a variety of accelerator-based systems: POWER9with NVIDIA V100 GPUs (Summit), Intel Xeon Phi 7230 (Percival), and AMD Bulldozer Opteron with NVIDIA K20x (Titan). Comparing these benchmarks on different systems gives us insight into the support for OpenMP and OpenACC and their execution times provide insights about their quality of implementations provided by different vendors. We also compare best of OpenMP and OpenACC to see if a particular programming model favors a particular type of benchmark kernel.

Boehm, Swen↗
DOE OSTI2021

Security Self-Assessment Toolkit for Nuclear Materials Facilities: Focus on Insider Threat Mitigation

Theft or sabotage of weapons-usable nuclear materials is a global concern. To minimize this threat, establishing and maintaining an effective nuclear security regime is required to protect against criminal or other negligent acts. Use of a formalized insider threat mitigation program is one such security measure. Individuals who have or held authorized access to an organization's critical assets, such as nuclear materials, are considered "insiders." Insider threats, or insider adversaries, are motivated individuals who possess access, authority, and knowledge to conduct a malicious act or facilitate that of an external party. To thwart insider threats (both intentional and unintentional), organizations can formalize an enterprise-wide approach to identify and mitigate the unique risks presented by insiders. This report provides an approach to evaluate an insider threat mitigation program at facilities with nuclear materials. Formal program evaluations serve many purposes and can be designed using several different methods and techniques. This report presents a self-assessment approach to program evaluation whereby an organization can assess its strengths, identify key gaps, and set priorities for ongoing improvement efforts to mitigate insider threats. Results of the self-assessment can provide critical information to contribute to the continuous improvement of an organization’s insider threat mitigation program within eight specific domain areas.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2017

Reducing the small-heart effect in pediatric gated myocardial perfusion single-photon emission computed tomography

Background: We compared two reconstruction algorisms and two cardiac functional evaluation software programs in terms of their accuracy for estimating ejection fraction (EF) of small hearts (SH). Methods: The study group consisted of 66 pediatric patients. Data were reconstructed using a filtered back projection (FBP) method without the resolution correction (RC) and an iterative method based on an ordered subset expectation maximization (OSEM) algorithm with the RC. EF was evaluated using two software programs of quantitative gated single-photon emission computed tomography (SPECT) (QGS) and cardioREPO. We compared the EF of gated myocardial perfusion SPECT to echocardiographic measurement (Echo). Results: Forty-eight of 66 patients had an end-systolic volume < 20 mL which was used as the criterion for being included in the SH group, and the SH effect led to an overestimation of EF. While significant differences were observed between Echo (66.9 ± 5.0%) and QGS-FBP without RC (76.9 ± 8.4%, P < .0001), QGS-OSEM with RC (76.6 ± 8.6%, P < .0001), and cardioREPO-FBP without RC (72.1 ± 10.0%, P = .0011), no significant difference was observed between Echo and cardioREPO-OSEM with RC (67.4 ± 6.1%) in SH group. Conclusions: In pediatric gated myocardial perfusion SPECT, the SH effect can be significantly reduced when an OSEM algorithm is used with RC in combination with the specific cardioREPO algorithm.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

DOE Grand Junction Office Marks 75 Years of Contribution to the Nation's Defense Program - 18380

On July 26, 2016, the former US Department of Energy (DOE) Grand Junction Office was listed on the National Register of Historic Places in recognition of its important, historic roles in the Manhattan Project and the Cold War. The work done from Grand Junction, Colorado, was an important component of the nation's defense program; however, because of the classified nature of the work, little of this history was originally available to the public. In 1943, the privately-owned site that later became the Grand Junction Office was purchased by the US government for the Colorado Area Office for the US Army Corps of Engineers Manhattan Engineer District (MED). The Colorado Area Office's mission was to procure and process uranium as part of a nationwide effort to build an atomic bomb. This race to build a bomb ahead of Nazi Germany became known as the Manhattan Project. Approximately 14% of the uranium obtained for the Manhattan Project was from Colorado Plateau ore-the largest source of domestic uranium ore known at the time. Uranium extracted from vanadium mill tailings was concentrated into uranium oxide, or 'yellowcake,' and shipped by rail to a facility in Tonawanda, New York, for further refinement. At the conclusion of World War II, the military MED mission ended, and the Grand Junction site became the principal US Atomic Energy Commission (AEC) office for acquiring and exploring for domestic uranium. The Colorado Raw Materials Office's primary objective was to increase the stockpile of fissionable material as rapidly as possible. To do that, AEC incentivized private industry and invited individual prospectors to locate uranium ores on public lands of the Colorado Plateau. Seemingly overnight, the small city of Grand Junction was transformed into a booming, modern metropolis and the national center of uranium exploration. Program operations in Grand Junction later included those of the National Uranium Resource Evaluation (NURE) program, the Uranium Mill Tailings Radiation Control Act (UMTRCA), vicinity properties cleanup, decontamination and decommissioning, and long-term surveillance and maintenance of legacy sites. In 2001, DOE transferred most of the original Grand Junction 55.7-acre site to the Riverview Technology Corporation, a business-development nonprofit sponsored by Mesa County and the City of Grand Junction. The US Department of Energy Office of Legacy Management continues to operate from leased facilities onsite. The Office of Legacy Management will host the 2018 Long-Term Stewardship Conference in Grand Junction on August 20-23. Conference attendees are invited to participate in a special 75. anniversary celebration at the Grand Junction Office where they will have the opportunity to learn more about the office's historic past, its ongoing and expanding work, and its goals of informing future generations. (authors)

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

MCC On Boarding Section J-2 (Exhibit H) Quality Assurance Requirements [Slides]

Upon MATOC Award, SUBCONTRACTOR shall submit a Quality Assurance Program for evaluation in accordance with subcontract technical and quality requirements. This may be the Subcontractors corporate QA program. Acceptance by Triad of the SUBCONTRACTORS Quality Assurance Program (QAP), as prescribed in Exhibit H, QC-01A and 01B, allows the SUBCONTRACTOR to execute this contract using their approved QAP. SUBCONTRACTORS QAP as approved by CONTRACTOR must meet the applicable requirements of DOE Order 414.1D (see next slide) and must address flow down of the quality requirements to lower tier subcontractors. Triad acceptance of SUBCONTRACTOR’s QAP approval is required prior to Notice to Proceed with on-site work. A Project Specific QA plan may on rare occasions be required for a specific task

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗
DOE OSTI2022

140,142 Ce Neutron Cross Section Resolved Resonance Region Evaluation [Abstract]

A resolved resonance region evaluation of 140,142 Ce has been carried out by Oak Ridge National Laboratory. Requested by the US Nuclear Criticality Safety Program, this evaluation is based on recent high-resolution transmission and capture high-resolution measurements of nat Ce and 142 Ce conducted at JRC-GEEL at the Geel Linear Accelerator facility, as well as recently measured thermal constants available from the EXFOR database. Starting from the resonance parameters from the ENDF/B-VIII.0 library and following a preliminary R-matrix analysis, an updated set of resonance parameters and corresponding covariance information was derived by the fit of these experimental datasets using the Reich-Moore approximation of the R-matrix theory as implemented in the SAMMY code system. The resolved resonance region upper energy limit for 140 Ce was kept at 200 keV while the 142 Ce resonance region was extended from 13 to 26 keV. This new evaluation was found to be in good agreement not only with several integral quantities of interest to the reactor physics community, but also with the stellar Maxwellian-averaged cross section.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

R-matrix Resolved Resonance Region Evaluation of 140,142 Ce

Oak Ridge National Laboratory completed the resolved resonance region (RRR) evaluation of the two most abundant cerium isotopes, 140 Ce (88.45%) and 142 Ce (11.11%), as requested by the US Nuclear Criticality Safety Program. These evaluations are based on recent high-resolution transmission and capture measurements performed on nat Ce and highly enriched 142 Ce samples at the JRC-Geel Linear Accelerator facility, as well as measured thermal constants available from the EXFOR database. Starting from the resonance parameters of the ENDF/B-VIII.0 library followed by a preliminary R-matrix analysis, an updated set of resonance parameters and corresponding covariance information were derived by fitting these measured data using the Reich–Moore approximation of the R -matrix theory, as implemented in the SAMMY code system. The 140 Ce RRR upper energy limit was kept at 200 keV, whereas the 142 Ce resonance region was extended from 13 to 26 keV. Updated statistical properties were obtained for the new evaluations and compared to those derived from the ENDF/B-VIII.0 nuclear data library. The new evaluation work improved some of the discrepancies found in previous work, such as the capture resonance integral and stellar Maxwellian-averaged cross sections. These integral quantities were mainly derived from the fit of the latest measured data, especially the neutron capture yield data for 142 Ce isotope.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Driving Affordable Energy Through Utility Program Design

The presentation is aimed to teach participants about achieving affordable energy through utility program design. Learning objectives include: identify key utility program characteristics that support affordability and consumer choice; apply best practices in outreach, eligibility, and evaluation to improve program design; and evaluate strategies for aligning program design with customer needs and regulatory goals.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2019

PROGRESS ON 140,142CE NEUTRON CROSS SECTION RESOLVED RESONANCE REGION EVALUATIONS

Oak Ridge National Laboratory is working on completing the resonance parameter evaluation of 140,142Ce in the neutron energy range up to 200 keV. Performed with the support of the US Nuclear Criticality Safety Program, this evaluation aims to generate high-fidelity cerium cross-section and covariance data. A point-wise representation of the cross sections derived from the resonance parameters will provide improved calculations of self-shielding factors for nuclear criticality safety applications and additional evaluation support for continuous-energy radiation transport methodologies. The evaluation procedure uses the Reich Moore approximation of the R-matrix theory implemented in the SAMMY code system to fit resonance parameters to high-resolution transmission and neutron capture measurements of natCe performed in 2016 by the JRC-GEEL instrument scientists at the Geel Linear Accelerator facility as well as other experimental data sets on both natural and highly-enriched cerium samples available in the experimental library EXFOR. In the analyzed energy range this work aims to improve and extend the resolved resonance region present in the latest US nuclear data library ENDF/B-VIII.0 for 140,142Ce isotopes. This paper will present the preliminary results of the R-matrix analysis based on recently measured natCe transmission data.

Chapman, Chris↗
DOE OSTI2019

Abradable Sealing Materials for Emerging IGCC-Based Turbine Systems (Final Report)

Reducing the gap between rotating and stationary parts in gas turbine engines, and mitigating gas leakage via these paths, can significantly increase the performance and attendant efficiency. One approach to reducing such gaps is to deploy abradable coatings on the stationary shroud components as seals, to reduce the blade-tip clearances under operational conditions. Abradable coatings must be able to withstand high temperature oxidation, thermal cycling, and erosion, while providing optimal controlled abrasion and associated shape retention. Existing abradable seals utilized in power generation turbines have generally been optimized for use with natural gas-fired systems; however, preliminary testing of syngas and high-hydrogen-content (HHC) fired turbines has shown that the stability of hot-section materials (and presumably abradable sealing materials) may be substantially altered due to characteristic changes in the combustion by-products (partial pressures of water vapor, etc.) as well as characteristic impurities and particulate matter entrained in the fuel. The primary focus of this research program has been to develop a mechanistic understanding of how the altered combustion environments modify the thermo-mechanical stability and performance of the sealing materials, including the requisite abradable sealing behavior. A key component of the research program carried out has been an exploration of mechanisms underpinning observed degradation processes, and an assessment of connections to the combustion environments and characteristic non-combustible constituents. The ultimate goal of the project has been to advance the goals of the Advanced Turbine Program by developing materials design protocols leading to turbine hot-section components with improved resistance to service lifetime degradation under advanced fuels exposures. This research program has evaluated the performance and degradation of ceramic abradable seals used in the high-temperature turbine sections of gas turbine engines. The focus has been two-fold: (1) to understand performance of such materials in relation to the turbines operating on coal-derived syngas and high hydrogen content (HHC) fuels, ultimately seeking an improved understanding of factors that control performance and durability of abradable seal materials for these combustion environments (and play into materials design protocols); and (2) to evaluate the potential of alternative materials as abradable seals for the higher temperatures expected with IGCC and HHC fueled turbine systems. In particular, we carried out an initial assessment of multi-layered systems of existing abradable seal materials (YSZ) and other ceramics. The research program also investigated several classes of abradable coatings under simulated exposures to syngas-based combustion environments, evaluating the relevant wear behavior, hardness, stability under cyclic oxidation, and general thermo-mechanical behavior. The research also attempted to develop alternatives to carrying out full-scale combustion-based abradability test rig exposures to evaluate materials system performance. The research has been focused on correlating the measured thermo-mechanical behavior, and controlled abrasive wear, with the intrinsic properties of the multilayer coatings and processing-controlled microstructural features that have shown attractive machinability characteristics based on weak interfacial bonding between the constituent phases at elevate temperatures (while maintaining thermochemical stability). This program has resulted in an improved mechanistic understanding of factors governing performance of high temperature abradable seals, and degradation mechanisms unique to IGCC-based power generation turbine systems and the realization of coal-derived syngas and HHC-based combustion environments – ultimately with the goal of developing a knowledge base upon which the design of coatings that retain optimal sealing characteristics and are more resistant to the observed wear/attack mechanisms, important aspects of advancing the goals of the DOE Advanced Turbine Program.

36 MATERIALS SCIENCE↗
DOE OSTI2025

LLM Benchmarking with LLaMA2: Evaluating Code Development Performance Across Multiple Programming Languages

The rapid evolution of large language models (LLMs) has opened new possibilities for automating various tasks in software development. This paper evaluates the capabilities of the LLaMA 2-70B model in automating these tasks for scientific applications written in commonly used programming languages. Using representative test problems, we assess the model's capacity to generate code, documentation, and unit tests, as well as its ability to translate existing code between commonly used programming languages. Our comprehensive analysis evaluates the compilation, runtime behavior, and correctness of the generated and translated code. Additionally, we assess the quality of automatically generated code, documentation, and unit tests. Here, our results indicate that while LLaMA 2-70B frequently generates syntactically correct and functional code for simpler numerical tasks, it encounters substantial difficulties with more complex, parallelized, or distributed computations, requiring considerable manual corrections. We identify key limitations and suggest areas for future improvements to better leverage AI-driven automation in scientific computing workflows.

97 MATHEMATICS AND COMPUTING↗