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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Correlated Statistical Uncertainties in Coded-Aperture Imaging

In nuclear security applications, coded-aperture imagers provide the opportu- nity for a wealth of information regarding the attributes of both the radioac- tive and non-radioactive components of the objects being imaged. However, for optimum benefit to the community, spatial attributes need to be deter- mined in a quantitative and statistically meaningful manner. To address the deficiency of quantifiable errors in coded-aperture imaging, we present uncer- tainty matrices containing covariance terms between image pixels for MURA mask patterns. We calculated these correlated uncertainties as functions of variation in mask rank, mask pattern over-sampling, and whether or not anti- mask data are included. Utilizing simulated point source data, we found that correlations (and inverse correlations) arose when two or more image pixels were summed. Furthermore, we found that the presence of correlations (and their inverses) was heightened by the process of over-sampling, while correla- tions were suppressed by the inclusion of anti-mask data and with increased mask rank. As an application of this result, we explore how statistics-based alarming in nuclear security is impacted.

Fleenor, Matthew C↗
DOE OSTI2026

CONTROL AND DATA ACQUISITION IN A CYBER-PHYSICAL MIDSTREAM TESTBED

This thesis presents the development of a laboratory-scale cyber–physical midstream pipeline testbed designed to address this gap and support research in industrial control systems security. The platform integrates pumps, valves, sensors, programmable logic controllers (PLCs), and a human–machine interface (HMI) to emulate the monitoring and control architecture of real pipeline operations. The physical process is implemented as a closed-loop liquid circulation system designed to replicate flow behavior characteristic of midstream pipeline infrastructure. The testbed enables real-time data acquisition of key process variables, including flow rate and pressure facilitating the generation of datasets representative of normal pipeline operation. A threat model encompassing common ICS attack vectors was developed, including sensor spoofing, command injection, false data injection, denial-of-service attacks, and relay manipulation. Multiple attack scenarios were implemented and evaluated to demonstrate how cyber intrusions targeting sensors, actuators, networks, and software propagate into measurable physical consequences in pipeline flow and pressure. The developed platform serves as a practical, cost-effective environment for experimentation, education, and future cybersecurity research in midstream pipeline systems.

42 ENGINEERING↗
DOE OSTI2016

A Few Thoughts on the E-Tunnel Discharge at Rainier Mesa, Nevada National Security Site

In reviewing the Quarterly Monitoring Reports assembled by Navarro for the Rainier Mesa E-Tunnel discharge for the past year (the “Navarro” data), Greg Raab of the Nevada Department of Environmental Proctection (NDEP) noticed a decreasing trend in the pH and was curious as to what was causing it. He noticed an upswing in the March 2016 data and speculated as to whether the trend would go up. Irene Farnham (Navarro) sent along the Navarro chemical and flow data from ETunnel, going back for some of the variables to 1997. Previously I was curious as to whether there was a trend in the discharge flow rates from E-Tunnel that corresponded to Greg Raab’s observations and comments about the decreasing trend in pH observed between 2015 and 2016. So, I plotted the two time series from the Navarro data over roughly the same time period that Greg looked at. There does not appear to be much of a correlation. (NB: The value of 7.1 for January 2016 differs from the value of ~6.55 in Greg’s data).

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2017

Nominal 30-M Cropland Extent Map of Continental Africa by Integrating Pixel-Based and Object-Based Algorithms Using Sentinel-2 and Landsat-8 Data on Google Earth Engine

A satellite-derived cropland extent map at high spatial resolution (30-m or better) is a must for food and water security analysis. Precise and accurate global cropland extent maps, indicating cropland and non-cropland areas, is a starting point to develop high-level products such as crop watering methods (irrigated or rainfed), cropping intensities (e.g., single, double, or continuous cropping), crop types, cropland fallows, as well as assessment of cropland productivity (productivity per unit of land), and crop water productivity (productivity per unit of water). Uncertainties associated with the cropland extent map have cascading effects on all higher-level cropland products. However, precise and accurate cropland extent maps at high spatial resolution over large areas (e.g., continents or the globe) are challenging to produce due to the small-holder dominant agricultural systems like those found in most of Africa and Asia. Cloud-based Geospatial computing platforms and multi-date, multi-sensor satellite image inventories on Google Earth Engine offer opportunities for mapping croplands with precision and accuracy over large areas that satisfy the requirements of broad range of applications. Such maps are expected to provide highly significant improvements compared to existing products, which tend to be coarser in resolution, and often fail to capture fragmented small-holder farms especially in regions with high dynamic change within and across years. To overcome these limitations, in this research we present an approach for cropland extent mapping at high spatial resolution (30-m or better) using the 10-day, 10 to 20-m, Sentinel-2 data in combination with 16-day, 30-m, Landsat-8 data on Google Earth Engine (GEE). First, nominal 30-m resolution satellite imagery composites were created from 36,924 scenes of Sentinel-2 and Landsat-8 images for the entire African continent in 2015-2016. These composites were generated using a median-mosaic of five bands (blue, green, red, near-infrared, NDVI) during each of the two periods (period 1: January-June 2016 and period 2: July-December 2015) plus a 30-m slope layer derived from the Shuttle Radar Topographic Mission (SRTM) elevation dataset. Second, we selected Cropland/Non-cropland training samples (sample size 9791) from various sources in GEE to create pixel-based classifications. As supervised classification algorithm, Random Forest (RF) was used as the primary classifier because of its efficiency, and when over-fitting issues of RF happened due to the noise of input training data, Support Vector Machine (SVM) was applied to compensate for such defects in specific areas. Third, the Recursive Hierarchical Segmentation (RHSeg) algorithm was employed to generate an object-oriented segmentation layer based on spectral and spatial properties from the same input data. This layer was merged with the pixel-based classification to improve segmentation accuracy. Accuracies of the merged 30-m crop extent product were computed using an error matrix approach in which 1754 independent validation samples were used. In addition, a comparison was performed with other available cropland maps as well as with LULC maps to show spatial similarity. Finally, the cropland area results derived from the map were compared with UN FAO statistics. The independent accuracy assessment showed a weighted overall accuracy of 94, with a producers accuracy of 85.9 (or omission error of 14.1), and users accuracy of 68.5 (commission error of 31.5) for the cropland class. The total net cropland area (TNCA) of Africa was estimated as 313 Mha for the nominal year 2015.

Cropland mapping; cropland areas; 30-m; Landsat-8;↗
DOE OSTI2012

A Framework for Federated Two-Factor Authentication Enabling Cost-Effective Secure Access to Distributed Cyberinfrastructure

As cyber attacks become increasingly sophisticated, the security measures used to mitigate the risks must also increase in sophistication. One time password (OTP) systems provide strong authentication because security credentials are not reusable, thus thwarting credential replay attacks. The credential changes regularly, making brute-force attacks significantly more difficult. In high performance computing, end users may require access to resources housed at several different service provider locations. The ability to share a strong token between multiple computing resources reduces cost and complexity. The National Science Foundation (NSF) Extreme Science and Engineering Discovery Environment (XSEDE) provides access to digital resources, including supercomputers, data resources, and software tools. XSEDE will offer centralized strong authentication for services amongst service providers that leverage their own user databases and security profiles. This work implements a scalable framework built on standards to provide federated secure access to distributed cyberinfrastructure.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2011

THE DARK MATTER DISTRIBUTION IN A383: EVIDENCE FOR A SHALLOW DENSITY CUSP FROM IMPROVED LENSING, STELLAR KINEMATIC, AND X-RAY DATA

We extend our analyses of the dark matter (DM) distribution in relaxed clusters to the case of A383, a luminous X-ray cluster at z = 0.189 with a dominant central galaxy and numerous strongly lensed features. Following our earlier papers, we combine strong and weak lensing constraints secured with Hubble Space Telescope and Subaru imaging with the radial profile of the stellar velocity dispersion of the central galaxy, essential for separating the baryonic mass distribution in the cluster core. Hydrostatic mass estimates from Chandra X-ray observations further constrain the solution. These combined data sets provide nearly continuous constraints extending from 2 kpc to 1.5 Mpc in radius, allowing stringent tests of results from recent numerical simulations. Two key improvements in our data and its analysis make this the most robust case yet for a shallow slope {beta} of the DM density profile {rho}{sub DM} {proportional_to} r {sup -}{beta} on small scales. First, following deep Keck spectroscopy, we have secured the stellar velocity dispersion profile to a radius of 26 kpc for the first time in a lensing cluster. Second, we improve our previous analysis by adopting a triaxial DM distribution and axisymmetric dynamical models. We demonstrate that in this remarkably well-constrained system, the logarithmic slope of the DM density at small radii is {beta} < 1.0 (95% confidence). An improved treatment of baryonic physics is necessary, but possibly insufficient, to reconcile our observations with the recent results of high-resolution simulations.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2011

DE-FG02-04ER25606 Identity Federation and Policy Management Guide: Final Report

The goal of this 3-year project was to facilitate a more productive dynamic matching between resource providers and resource consumers in Grid environments by explicitly specifying policies. There were broadly two problems being addressed by this project. First, there was a lack of an Open Grid Services Architecture (OGSA)-compliant mechanism for expressing, storing and retrieving user policies and Virtual Organization (VO) policies. Second, there was a lack of tools to resolve and enforce policies in the Open Services Grid Architecture. To address these problems, our overall approach in this project was to make all policies explicit (e.g., virtual organization policies, resource provider policies, resource consumer policies), thereby facilitating policy matching and policy negotiation. Policies defined on a per-user basis were created, held, and updated in MyPolMan, thereby providing a Grid user to centralize (where appropriate) and manage his/her policies. Organizationally, the corresponding service was VOPolMan, in which the policies of the Virtual Organization are expressed, managed, and dynamically consulted. Overall, we successfully defined, prototyped, and evaluated policy-based resource management and access control for OGSA-based Grids. This DOE project partially supported 17 peer-reviewed publications on a number of different topics: General security for Grids, credential management, Web services/OGSA/OGSI, policy-based grid authorization (for remote execution and for access to information), policy-directed Grid data movement/placement, policies for large-scale virtual organizations, and large-scale policy-aware grid architectures. In addition to supporting the PI, this project partially supported the training of 5 PhD students.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2011

Assessing Vulnerabilities, Risks, and Consequences of Damage to Critical Infrastructure

Since the publication of 'Critical Foundations: Protecting America's Infrastructure,' there has been a keen understanding of the complexity, interdependencies, and shared responsibility required to protect the nation's most critical assets that are essential to our way of life. The original 5 sectors defined in 1997 have grown to 18 Critical Infrastructures and Key Resources (CIKR), which are discussed in the 2009 National Infrastructure Protection Plan (NIPP) and its supporting sector-specific plans. The NIPP provides the structure for a national program dedicated to enhanced protection and resiliency of the nation's infrastructure. Lawrence Livermore National Laboratory (LLNL) provides in-depth, multi-disciplinary assessments of threat, vulnerability, and consequence across all 18 sectors at scales ranging from specific facilities to infrastructures spanning multi-state regions, such as the Oil and Natural Gas (ONG) sector. Like many of the CIKR sectors, the ONG sector is comprised of production, processing, distribution, and storage of highly valuable and potentially dangerous commodities. Furthermore, there are significant interdependencies with other sectors, including transportation, communication, finance, and government. Understanding the potentially devastating consequences and collateral damage resulting from a terrorist attack or natural event is an important element of LLNL's infrastructure security programs. Our work began in the energy sector in the late 1990s and quickly expanded other critical infrastructure sectors. We have performed over 600 physical assessments with a particular emphasis on those sectors that utilize, store, or ship potentially hazardous materials and for whom cyber security is important. The success of our approach is based on building awareness of vulnerabilities and risks and working directly with industry partners to collectively advance infrastructure protection. This approach consists of three phases: The Pre-Assessment Phase brings together infrastructure owners and operators to identify critical assets and help the team create a structured information request. During this phase, we gain information about the critical assets from those who are most familiar with operations and interdependencies, making the time we spend on the ground conducting the assessment much more productive and enabling the team to make actionable recommendations. The Assessment Phase analyzes 10 areas: Threat environment, cyber architecture, cyber penetration, physical security, physical penetration, operations security, policies and procedures, interdependencies, consequence analysis, and risk characterization. Each of these individual tasks uses direct and indirect data collection, site inspections, and structured and facilitated workshops to gather data. Because of the importance of understanding the cyber threat, LLNL has built both fixed and mobile cyber penetration, wireless penetration and supporting tools that can be tailored to fit customer needs. The Post-Assessment Phase brings vulnerability and risk assessments to the customer in a format that facilitates implementation of mitigation options. Often the assessment findings and recommendations are briefed and discussed with several levels of management and, if appropriate, across jurisdictional boundaries. The end result is enhanced awareness and informed protective measures. Over the last 15 years, we have continued to refine our methodology and capture lessons learned and best practices. The resulting risk and decision framework thus takes into consideration real-world constraints, including regulatory, operational, and economic realities. In addition to 'on the ground' assessments focused on mitigating vulnerabilities, we have integrated our computational and atmospheric dispersion capability with easy-to-use geo-referenced visualization tools to support emergency planning and response operations. LLNL is home to the National Atmospheric Release Advisory Center (NARAC) and the Interagency Modeling and Atmospheric Assessment Center (IMAAC). NARAC/IMAAC has capabilities to respond to toxic industrial chemical spills, nuclear-power plant accidents, fires, chemical/biological agents, radiological/nuclear devices (RDDs, INDs), and other airborne hazards. Our web-based systems provide hazards assessments of critical infrastructure for defensive planning and can provide infrastructure operators and emergency responders with a baseline for planning and exercises. LLNL's infrastructure security web mapping services facilitate dissemination of technical information for all phases of disaster management. Examples of some of these products are shown in the Figure 1.

03 NATURAL GAS↗
NASA NTRS2016

Towards a New Generation of Agricultural System Data, Models and Knowledge Products: Design and Improvement

This paper presents ideas for a new generation of agricultural system models that could meet the needs of a growing community of end-users exemplified by a set of Use Cases. We envision new data, models and knowledge products that could accelerate the innovation process that is needed to achieve the goal of achieving sustainable local, regional and global food security. We identify desirable features for models, and describe some of the potential advances that we envisage for model components and their integration. We propose an implementation strategy that would link a "pre-competitive" space for model development to a "competitive space" for knowledge product development and through private-public partnerships for new data infrastructure. Specific model improvements would be based on further testing and evaluation of existing models, the development and testing of modular model components and integration, and linkages of model integration platforms to new data management and visualization tools.

Agricultural systems↗
DOE OSTI2017

Joint the Center for Applied Scientific Computing

The Center for Applied Scientific Computing serves as Livermore Lab’s window to the broader computer science, computational physics, applied mathematics, and data science research communities. In collaboration with academic, industrial, and other government laboratory partners, we conduct world-class scientific research and development on problems critical to national security. CASC applies the power of high-performance computing and the efficiency of modern computational methods to the realms of stockpile stewardship, cyber and energy security, and knowledge discovery for intelligence applications.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

Enhancing grid reliability and resilience through novel DER control, total situational awareness and integrated distribution-transmission representation

High penetration of distributed energy resources (DERs) can lead to overvoltage and thermal violations, miscoordination of protection devices and potential adverse control interactions. The challenges are exacerbated by a lack of operator situational awareness of behind-the-meter DERs, and T&D interactions. Furthermore, the large attack surface of a DER environment creates significant cyber security challenges. The motivation is to address these barriers. The main goal is to enable extreme levels of DERs in distribution systems while simultaneously enhancing their reliability and resiliency. This is achieved by a data-driven approach for operation, planning and control of distribution systems with total situational awareness and real-time DER control enabled by a network of edge intelligent devices, a cloud-based analytical platform, and secure communications.

14 SOLAR ENERGY↗
DOE OSTI2015

Analysis of Vehicle-Based Security Operations

Vehicle-to-vehicle (V2V) communications promises to increase roadway safety by providing each vehicle with 360 degree situational awareness of other vehicles in proximity, and by complementing onboard sensors such as radar or camera in detecting imminent crash scenarios. In the United States, approximately three hundred million automobiles could participate in a fully deployed V2V system if Dedicated Short-Range Communication (DSRC) device use becomes mandatory. The system s reliance on continuous communication, however, provides a potential means for unscrupulous persons to transmit false data in an attempt to cause crashes, create traffic congestion, or simply render the system useless. V2V communications must be highly scalable while retaining robust security and privacy preserving features to meet the intra-vehicle and vehicle-to-infrastructure communication requirements for a growing vehicle population. Oakridge National Research Laboratory is investigating a Vehicle-Based Security System (VBSS) to provide security and privacy for a fully deployed V2V and V2I system. In the VBSS an On-board Unit (OBU) generates short-term certificates and signs Basic Safety Messages (BSM) to preserve privacy and enhance security. This work outlines a potential VBSS structure and its operational concepts; it examines how a vehicle-based system might feasibly provide security and privacy, highlights remaining challenges, and explores potential mitigations to address those challenges. Certificate management alternatives that attempt to meet V2V security and privacy requirements have been examined previously by the research community including privacy-preserving group certificates, shared certificates, and functional encryption. Due to real-world operational constraints, adopting one of these approaches for VBSS V2V communication is difficult. Timely misbehavior detection and revocation are still open problems for any V2V system. We explore the alternative approaches that may be applicable to a VBSS, and suggest some additional research directions in order to find a practical solution that appropriately addresses security and privacy.

Connected Vehicle↗
DOE OSTI2013

Corrective Action Investigation Plan for Corrective Action Unit 571: Area 9 Yucca Flat Plutonium Dispersion Sites, Nevada National Security Site, Nevada, Revision 0

CAU 571 is a grouping of sites where there has been a suspected release of contamination associated with nuclear testing. This document describes the planned investigation of CAU 571, which comprises the following corrective action sites (CASs): • 09-23-03, Atmospheric Test Site S-9F • 09-23-04, Atmospheric Test Site T9-C • 09-23-12, Atmospheric Test Site S-9E • 09-23-13, Atmospheric Test Site T-9D • 09-45-01, Windrows Crater These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives (CAAs). Additional information will be obtained by conducting a corrective action investigation before evaluating CAAs and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable CAAs that will be presented in the investigation report. The sites will be investigated based on the data quality objectives (DQOs) developed on March 6, 2013, by representatives of the Nevada Division of Environmental Protection and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (now the Nevada Field Office). The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 571. The site investigation process will also be conducted in accordance with the Soils Activity Quality Assurance Plan, which establishes requirements, technical planning, and general quality practices to be applied to this activity. The potential contamination sources associated with CAU 571 CASs are from nuclear testing activities. The DQO process resulted in an assumption that total effective dose (TED) within a default contamination boundary exceeds the final action level (FAL) and requires corrective action. The presence and nature of contamination outside the default contamination boundaries at CAU 571 will be evaluated based on information collected from a field investigation. Radiological contamination will be evaluated based on a comparison of the TED at sample locations to the dose-based FAL. The TED will be calculated as the total of separate estimates of internal and external dose. Results from the analysis of soil samples will be used to calculate internal radiological dose. Thermoluminescent dosimeters placed at the center of each sample location will be used to measure external radiological dose. Chemical contamination will be evaluated by comparing soil sample results to the FAL. Appendix A provides a detailed discussion of the DQO methodology and the DQOs specific to each CAS.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Corrective Action Investigation Plan for Corrective Action Unit 567: Miscellaneous Soil Sites, Nevada National Security Site, Nevada, with ROTC 1 Revision 0

Corrective Action Unit (CAU) 567 is located in Areas 1, 3, 5, 20, and 25 of the Nevada National Security Site, which is approximately 65 miles northwest of Las Vegas, Nevada. CAU 567 is a grouping of sites where there has been a suspected release of contamination associated with nuclear testing. This document describes the planned investigation of CAU 567, which comprises the following corrective action sites (CASs): • 01-23-03, Atmospheric Test Site T-1 • 03-23-25, Seaweed E Contamination Area • 05-23-07, A5b RMA • 20-23-08, Colby Mud Spill • 25-23-23, J-11 Soil RMA These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives (CAAs). Additional information will be obtained by conducting a corrective action investigation before evaluating CAAs and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable CAAs that will be presented in the investigation report. The sites will be investigated based on the data quality objectives (DQOs) developed on May 6, 2013, by representatives of the Nevada Division of Environmental Protection and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Field Office. The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 567. The site investigation process will also be conducted in accordance with the Soils Activity Quality Assurance Plan, which establishes requirements, technical planning, and general quality practices to be applied to this activity. The potential contamination sources associated with CAU 567 releases are nuclear test operations and other NNSS operations. The DQO process resulted in an assumption that total effective dose (TED) within a default contamination boundary at Atmospheric Test Site T-1 exceeds the final action level (FAL) and requires corrective action. The presence and nature of contamination outside the default contamination boundary at Atmospheric Test Site T-1 and all other CAU 567 CASs will be evaluated based on information collected from a field investigation. Radiological contamination will be evaluated based on a comparison of the TED at sample locations to the dose-based FAL. The TED will be calculated as the total of separate estimates of internal and external dose. Results from the analysis of soil samples will be used to calculate internal radiological dose. Thermoluminescent dosimeters placed at the center of each sample location will be used to measure external radiological dose. Appendix A provides a detailed discussion of the DQO methodology and the DQOs specific to each CAS.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2003

Disaster Response and Preparedness Application: Emergency Environmental Response Tool (EERT)

In 2000, the National Aeronautics and Space Administration (NASA) Environmental Office at the John C. Stennis Space Center (SSC) developed an Environmental Geographic Information Systems (EGIS) database. NASA had previously developed a GIS database at SSC to assist in the NASA Environmental Office's management of the Center. This GIS became the basis for the NASA-wide EGIS project, which was proposed after the applicability of the SSC database was demonstrated. Since its completion, the SSC EGIS has aided the Environmental Office with noise pollution modeling, land cover assessment, wetlands delineation, environmental hazards mapping, and critical habitat delineation for protected species. At SSC, facility management and safety officers are responsible for ensuring the physical security of the facilities, staff, and equipment as well as for responding to environmental emergencies, such as accidental releases of hazardous materials. All phases of emergency management (planning, mitigation, preparedness, and response) depend on data reliability and system interoperability from a variety of sources to determine the size and scope of the emergency operation. Because geospatial data are now available for all NASA facilities, it was suggested that this data could be incorporated into a computerized management information program to assist facility managers. The idea was that the information system could improve both the effectiveness and the efficiency of managing and controlling actions associated with disaster, homeland security, and other activities. It was decided to use SSC as a pilot site to demonstrate the efficacy of having a baseline, computerized management information system that ultimately was referred to as the Emergency Environmental Response Tool (EERT).

Smoot, James↗
DOE OSTI2011

Corrective Action Investigation Plan for Corrective Action Unit 104: Area 7 Yucca Flat Atmospheric Test Sites, Nevada National Security Site, Nevada, Revision 0

CAU 104 comprises the 15 CASs listed below: (1) 07-23-03, Atmospheric Test Site T-7C; (2) 07-23-04, Atmospheric Test Site T7-1; (3) 07-23-05, Atmospheric Test Site; (4) 07-23-06, Atmospheric Test Site T7-5a; (5) 07-23-07, Atmospheric Test Site - Dog (T-S); (6) 07-23-08, Atmospheric Test Site - Baker (T-S); (7) 07-23-09, Atmospheric Test Site - Charlie (T-S); (8) 07-23-10, Atmospheric Test Site - Dixie; (9) 07-23-11, Atmospheric Test Site - Dixie; (10) 07-23-12, Atmospheric Test Site - Charlie (Bus); (11) 07-23-13, Atmospheric Test Site - Baker (Buster); (12) 07-23-14, Atmospheric Test Site - Ruth; (13) 07-23-15, Atmospheric Test Site T7-4; (14) 07-23-16, Atmospheric Test Site B7-b; (15) 07-23-17, Atmospheric Test Site - Climax These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives (CAAs). Additional information will be obtained by conducting a corrective action investigation before evaluating CAAs and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable CAAs that will be presented in the Corrective Action Decision Document. The sites will be investigated based on the data quality objectives (DQOs) developed on April 28, 2011, by representatives of the Nevada Division of Environmental Protection and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office. The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 104. The releases at CAU 104 consist of surface-deposited radionuclides from 30 atmospheric nuclear tests. The presence and nature of contamination at CAU 104 will be evaluated based on information collected from a field investigation. Radiological contamination will be evaluated based on a comparison of the total effective dose (TED) to the dose-based final action level (FAL). The presence of TED exceeding the FAL is considered a radiological contaminant of concern (COC). Anything identified as a COC will require corrective action. The TED will be calculated as the total of separate estimates of internal and external dose. Results from the analysis of soil samples will be used to calculate internal radiological dose. Thermoluminescent dosimeters will be used to measure external radiological dose. Based on process knowledge of the releases associated with the nuclear tests and radiological survey information about the location and shape of the resulting contamination plume, it was determined that the releases from the nuclear tests are co-located and will be investigated concurrently. A field investigation will be performed to define areas where TED exceeds the FAL and to determine whether other COCs are present at the site. The investigation will also collect information to determine the presence and nature of contamination associated with migration and excavation, as well as any potential releases discovered during the investigation. Appendix A provides a detailed discussion of the DQO methodology and the DQOs specific to each CAS.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

The surprisingly large neutron capture cross-section of 88 Zr

The probability that a nucleus will absorb a neutron, described in units of area as the neutron-capture cross section, is important to many areas of nuclear science including stellar nucleosynthesis, reactor performance, nuclear medicine, and defense applications. Although neutron-capture cross-sections have been directly measured for most stable nuclei, fewer results exist for radioactive isotopes and predictions typically have large uncertainties. There are almost no nuclear data for neutron-induced reactions on the radioactive nucleus 88 Zr, despite its significance for nuclear-security missions. By exposing 88 Zr to the intense neutron flux of a nuclear reactor, it was determined that 88 Zr has a thermal neutron capture cross section of (861,000 ± 69,000) b, which is the second-largest ever measured, despite being predicted to be only 10 b. The only other nuclei known to have thermal neutron capture cross sections greater than 1x10 5 b are 135 Xe and 157 Gd (2.6x10 6 b and 2.5x10 5 b, respectively) and no other cross section of comparable size has been discovered in the past 70 years (Fig. 1). The measurement of the 135 Xe cross section followed the determination that a fission product was poisoning the early reactors.7 The applications for 157 Gd were not immediately appreciated, but now the isotope has been developed into a detector material, burnable reactor poison, and potential medical neutron capture therapy (NCT) agent. In the case of 88 Zr, a unique aspect of the neutron-capture reaction is that both the target and the product 89 Zr nuclei are radioactive and give intense γ-ray emissions upon decay. This result suggests that as additional measurements with radioactive isotopes become feasible in the near future via access to new facilities for sample production and measurement, other cross-section surprises may be uncovered.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗