Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “siting”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Visible, Durable, Enforceable Institutional Controls: Weldon Spring Site - A 10-Year Journey - 13190

The DOE Office of Legacy Management's (LM's) mission is to manage the DOE's post-closure responsibilities and ensure the future protection of human health and the environment. LM has control and custody of legacy land, structures, and facilities and is responsible for maintaining them at levels suitable for their long-term use. This includes all engineered and institutional controls (ICs) designed as another level of assurance to prevent exposure to residual contamination and waste. The development and management of ICs has been, and continues to be, a critical component to the success of LM surveillance and maintenance activities. Many major federal laws, Executive Orders, regulations, and various other drivers influence the establishment and use of ICs at LM sites. LM uses a wide range of ICs to appropriately limit access to, or uses of, land, facilities, and other real and personal properties; protect the environment; maintain the physical safety and security of DOE facilities; and prevent or limit inadvertent human and environmental exposure to residual contaminants and other hazards. The ICs at the Weldon Spring, Missouri, Site were developed in close coordination with federal and state regulators. An Explanation of Significant Differences (ESD) was issued in February 2005, which clarified the use restrictions necessary for the remedial actions specified in the Records of Decision for the separate operable units to remain protective over the long-term. The operable units included the Chemical Plant Operable Unit, the Chemical Plant Groundwater Operable Unit, and the Quarry Residuals Operable Unit. The ESD clarified specific requirements for each site area that needed use restrictions and established how DOE would implement, maintain, and monitor the specific requirements. DOE developed the Long-Term Surveillance and Maintenance Plan for the U.S. Department of Energy Weldon Spring, Missouri, Site (LTS and M Plan) that addressed the full scope of the site management activities necessary to ensure that the Weldon Spring Site remains protective over the long-term. The LTS and M Plan is revised periodically to ensure its applicability to changing site, regulatory, or procedural conditions. In addition to addressing such activities as long-term groundwater monitoring and disposal cell maintenance, the LTS and M Plan was developed and issued to ensure that the use restrictions identified in the ESD were properly imposed and maintained. The LTS and M Plan included a detailed IC Implementation Plan, which includes a process for evaluating and identifying specific IC mechanisms that best accomplish the objectives set out in the ESD. Consistent with EPA guidance on selecting ICs, various IC mechanisms were evaluated, including government controls, proprietary controls, enforcement tools, and informational devices. Where appropriate, redundant mechanisms were employed to increase the effectiveness of the ICs. Information in the IC Implementation Plan includes: (1) a discussion of current site conditions (reflecting post-remedial action conditions for the Chemical Plant and Quarry Areas and the risk-basis for why use restrictions are needed); (2) the objectives of, or performance expectations for, the use restrictions; (3) specific ICs already in place and additional mechanisms identified for implementation; (4) a schedule for implementing additional ICs; (5) procedures for maintaining the ICs and for conducting periodic inspections; and (6) general provisions for the implementing ICs for the site. The actual agreements and documentation of the various ICs are included in an appendix of the LTS and M Plan. These documents are also available via the internet from the authorizing agencies (County, Missouri Department of Natural Resources, EPA, etc.) The Weldon Spring Site personnel have been successful in finalizing each of the ICs that were established for the site. The planning, establishment, and implementation of the ICs was a long and detailed process with several lessons-learned that were identified along the way. (authors)

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

Using Prescribed Fire to Manage the Fernald On-Site Disposal Facility Vegetated Cap - 17401

The Fernald Preserve is a former uranium processing plant that underwent extensive remediation pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). It is situated on a 425 ha (1,050 acre) tract of land, approximately 29 km (18 miles) northwest of Cincinnati, Ohio. Remedial activities and subsequent ecological restoration have converted the site from an industrial production facility to an undeveloped park, encompassing a series of wetlands, prairies, and forested communities. The remediation of buildings and soil contamination was completed in 2006, but aquifer remediation is ongoing. Since 2007, the site has been managed by the US Department of Energy (DOE) Office of Legacy Management. Portions of the site are open to the public, with approximately 11 km (7 miles) of walking trails that are open year-round and a visitors center. Site remediation included the construction of an On-Site Disposal Facility (OSDF) for the long-term disposal of contaminated soil and building materials. The OSDF consists of eight disposal cells that encompass approximately 30 hectares (75 acres) on the eastern portion of the Fernald site. Cells are lined and capped, and each has a separate leak detection and leachate collection system. The integrated cap is vegetated with native grasses and forbs. Management of the Fernald Preserve includes the monitoring and maintenance of ecologically restored communities and the vegetated OSDF cap, as required by the site's institutional controls plan. Prescribed burning is recognized as the preferred method for prairie management. Prescribed fire has been used at the Fernald site since 2009 for established prairies in restored areas, but not on the OSDF cap. Stakeholders had reservations regarding the safety of using prescribed fire on the OSDF cap. Because of that, vegetation on the cap was managed as a grassland community. It was mowed, raked, and baled to remove thatch, and promote the continued establishment of native grasses and forbs. Since agricultural use is restricted at the site, the resulting hay bales were kept on property and reused as organic matter and mulch. Over time, more hay bales were being generated in a season than were reused. Therefore in 2015, DOE decided to revisit stakeholder acceptance of prescribed fire on the OSDF cap. Ongoing relationships with local stakeholders allowed for extensive discussions regarding the current management and proposed use of prescribed fire on the OSDF cap. The public was provided information about the planning and implementation of prescribed burns at the site and invited to observe the execution of a successful site burn. This approach led to stakeholder acceptance of DOE's proposal, and vegetation on the caps of cells 4, 5, and 6 was burned in late March 2016. The burn was successful and resulted in several benefits from a land stewardship and cost perspective. This paper details the stakeholder engagement approach and the resulting benefits from the use of prescribed fire on the OSDF cap. (authors)

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

Execution Strategy Analysis (ESA) Origin Sites Readiness Model - 19073

This is a technical paper that does not take into account the contractual limitations under the Standard Contract for Disposal of Spent Nuclear Fuel and/or High-Level Radioactive Waste (Standard Contract) (10 CFR Part 961). Under the provisions of the Standard Contract, DOE does not consider spent nuclear fuel in multi-assembly canisters to be an acceptable waste form, absent a mutually agreed to contract amendment. To the extent discussions or recommendations in this paper conflict with the provisions of the Standard Contract, the Standard Contract provisions prevail. The DOE Office of Nuclear Energy (DOE-NE) Office of Spent Fuel and Waste Disposition (SFWD) Integrated Waste Management System (IWMS) program is developing an Execution Strategy Analysis (ESA) Origin Sites Readiness Model using the Goldsim{sup TM} software application to provide information on potential future approaches for removing SNF and HLW from origin sites such as commercial nuclear power plant sites. The purpose of this ESA model is to apply integrated waste management system analysis, system engineering, and decision analysis principles to inform future decisions regarding potential future nuclear waste management system architectures. The ESA Origin Sites Readiness Model is a dynamic simulation modeling capability. It is developed for use in the analysis and comparison of potential future implementation strategies associated with an integrated nuclear waste management program. The model is designed to be independent of the destination of the SNF or HLW so the results from the Origin Sites Readiness Model are equally applicable to a wide range of scenarios involving shipments to generic destinations in an integrated waste management system. The model explicitly takes significant assumptions, uncertainties, and risks into account. Currently, the ESA Origin Sites Readiness Model includes 14 shutdown sites (Maine Yankee, Yankee Rowe, Connecticut Yankee, Vermont Yankee, La Crosse, Big Rock Point, Zion, Kewaunee, Fort Calhoun, Trojan, Rancho Seco, Humboldt Bay, San Onofre, and Crystal River) and is designed to be modular so that other sites can be added in the future. The model also includes multiple transportation modes (heavy haul truck, rail, and barge), activities related to the acquisition of transportation assets such as railcars and transportation casks, and site-specific considerations of on-site and near-site transportation infrastructure. The model was developed using the ESA process with Subject Matter Experts (SME); it incorporates uncertainty and risks and provides a structured, systematic methodology for evaluating potential SNF campaign scenarios. The model also complements other system-level logistics tools being developed by SFWD. (authors)

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

Status Update on TRAC: A DOE-EM Tool for Tracking Groundwater Cleanup and Progress Toward Site Closure - 20245

The U.S. Department of Energy (DOE) Office of Environmental Management (EM) uses a customized, web-based mapping tool called TRAC (Tracking Restoration and Closure) to communicate information on plume sizes, remedial approaches, regulatory drivers, exit strategies, and long-term stewardship requirements at all sites within the DOE-EM complex. The web-based GIS story maps provide robust geospatial visualization of plumes at DOE sites using an intuitive interface that allows users to explore the plume maps, explanatory text, photographs, and video. This collection of story maps not only communicates information for each individual site, but also summarizes pertinent metrics on cleanup and remaining contaminants across all EM sites. This paper describes a new design within TRAC for communicating metrics on plume status, regulatory cleanup progress, and technology implementation. A principal benefit of TRAC is the ability to view individual pieces of data at a time, permitting targeted questions to be addressed, such as the status of regulatory decisions, site cleanup priorities, and site closure needs for each site within the DOE-EM complex. TRAC manages communication and supports decision-making through knowledge access, data and information transparency and traceability, and inclusive participation. It serves as a common resource that provides consistent information for DOE managers, site personnel, regulators and stakeholders. Because long-term stewardship of legacy waste sites requires ongoing coordination and communication among DOE, regulators, and stakeholders, TRAC can also be used to help transition EM sites to the Office of Legacy Management at site closure. (authors)

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

The application of ALARP to legacy residues recovery processes on the Springfields site in the United Kingdom - 14333

In the United Kingdom, the legal framework for nuclear safety is established principally through the Health and Safety at Work Act 1974 (HSAW74) and the Nuclear Installations Act 1965 (NIA 65). Under HSAW74, employers are responsible for reducing risks, so far as is reasonably practicable, to their workers and others (including the public). This responsibility is elaborated further in relation to nuclear sites by NIA65, which establishes a nuclear site licensing regime whereby Nuclear Site Licenses are granted and subsequently regulated by the Office for Nuclear Regulation (ONR) within the Health and Safety Executive (HSE). In essence, ensuring that a risk has been reduced to 'As Low As Reasonably Practicable' (ALARP) is about weighing-up the risk against the sacrifice needed to reduce it. To avoid having to make this sacrifice, the Nuclear Site License holder (the Site Licensee) must be able to show that it would be grossly disproportionate to the benefits of risk reduction that would be achieved. Using 'reasonably practicable' allows the ONR to set goals for the Site Licensee, rather than being prescriptive. This flexibility can be a great advantage in that it allows the Site Licensee to consider a variety of options, and hence supports innovative approaches. However, it has drawbacks in that it requires both the Site Licensee and the regulators to exercise judgement; in reality, many decisions about risks and the measures that achieve ALARP are not straight-forward. Fortunately, various resources are available to the Site Licensee to aid these decisions. Three key facilities on the Westinghouse, Springfields Fuels Limited site at Preston in the UK (including the National Nuclear Laboratory's Preston Laboratory) undertake the clean-up of legacy residues from both fuel manufacturing operations on the site itself (dating back well over fifty years) and the wider nuclear industry. This paper discusses the key features of these three facilities to illustrate how ALARP considerations have shaped the operating regimes and associated criticality controls in those areas. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

High-fidelity pool boiling simulations on multiple nucleation sites using interface capturing method

Boiling has proved to be one of the most efficient means for heat transfer and is a very important phenomenon during severe accident scenarios in light water reactors. High-fidelity pool boiling simulations can provide a numerical database for improving mechanistic boiling models by allowing for specific evaluation of interactions among bubbles. Previously published pool boiling simulations investigated two nucleation sites in which bubble growth at one site suppressed nucleation at the other site. Based on previous study results, more complicated interface-capturing simulations on pool boiling were conducted using PHASTA code with locally refined unstructured mesh. First, different boundary conditions (BCs) were assessed to support robustness and reproducibility of the boiling model. Then, a scale study was conducted at a larger domain with nine nucleation sites where either nine or four nucleation sites are activated. Involving more nucleation sites increased the complexity of bubble interactions from surrounding sites. Finally, bubble departure behavior influenced by wall heat flux was investigated. In this work, when heat flux was increased, the order of bubble departure changed, but diagonal bubbles always departed after one another. The departure time interval between the first and second bubble reduced as heat flux increased. The corresponding frequency was almost linearly proportional to the heat flux. In addition, bubble departure behavior was found to be greatly influenced by the nucleation site pattern. Multiple nucleation sites resulted in superimposed inhibitive effects from surrounding sites to each bubble, which extensively delayed the departure. This new observation was not discussed in previously published works. The work presented here provides new insight on the fundamental understanding of boiling phenomena, contributes to the development of a 3D multiphase computational fluid dynamics (M-CFD) model, and provides a more comprehensive database for data-driven pool boiling studies.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

Active Sites in the Dealuminated Beta Zeolite-Supported Cobalt Catalyst for Non-Oxidative Ethane Dehydrogenation

Dispersed metal species in siliceous zeolites have been actively studied for non-oxidative dehydrogenation of ethane (NDE). Fundamental insights into the dynamics of metal species in zeolites under reaction conditions have rarely been explored. Herein, we report an atomic level understanding of the dynamics and activity of cobalt (Co) sites in dealuminated Beta zeolite (DeAl-BEA) for NDE during induction and reaction conditions with extensive characterization techniques such as diffuse reflectance UV–vis, solid state nuclear magnetic resonance and X-ray photoelectron, X-ray diffraction along with in situ Fourier transform infrared and X-ray absorption spectroscopy. For a catalyst with 0.5 mass % Co loading, tetrahedral Co 2+ mononuclear sites, di-coordinated to the zeolite framework and with two silanol groups in vicinity (i.e., (≡SiO) 2 Co(HO–Si≡) 2 ), form upon exposure to hydrogen during induction and persist through the NDE reaction. Increasing the Co loading to 3.0 mass % yielded Co sites with similar electronic and coordination structures but slightly elongated Co–O bonds. Upon cooling to room temperature, the Co sites persisted in the same coordination environment, though the disappearance of a feature in the Co K-edge near-edge region revealed changes in the active site’s electronic structure coinciding with modest shifts in bond lengths. The electronic structure and activity of (≡SiO) 2 Co(HO–Si≡) 2 sites were studied comparatively to a few other hypothetical Co 2+ coordination structures, using electronic structure calculations and microkinetic simulations. The simulations showed that NDE is controlled by β-hydride elimination following C–H bond activation and that Co-sites possessing flexibility because of neighboring silanol defects are more active. Interestingly, dinuclear Co–O–Co sites (i.e., (≡SiO)Co(HO–Si≡) 2 –O–(HO–Si≡) 2 Co(≡SiO)) were more active than the mononuclear (≡SiO) 2 Co(HO–Si≡) 2 sites because of favorable hydrogen bonding with the vicinal silanol groups. In conclusion, the present study bridges the gap between the knowledge acquired by ex-situ characterizations and the active sites under the reaction conditions in alkane dehydrogenation chemistry.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Impact of microkinetic modeling assumptions on predicted kinetics and mechanisms over undercoordinated sites

Accurate modeling of catalytic reactions on undercoordinated sites requires accounting for the structural and ensemble-specific nature of the active sites. This study examines how common microkinetic modeling (MKM) assumptions affect predicted kinetics and mechanisms on the stepped Pt(211) facet for the ethane dehydrogenation (EDH) and the ethane hydrogenolysis (EH). Six (211) MKMs were developed, differing in (i) the number of active sites represented, (ii) adsorbate site occupancy treatment, and (iii) inclusion of cross-facet interactions. These models are benchmarked against a particle-based microkinetic model (PB-MKM), which best represents step-edge behavior. MKM assumptions caused deviations in turnover frequencies exceeding ten orders of magnitude and led to contrasting mechanistic and selectivity predictions. Multi-site MKMs overestimate activity by inflating free site availability, single-site models underestimate activity, and uniform occupancy models overpredict coverage of multi-dentate intermediates, leading to reaction-specific artifacts. Overall, the Combined Site Edge Model (CSEM), a single-site MKM accounting for site occupancy and cross-facet interactions, most closely approximates PB-MKM predictions. All models predict similar kinetics when surfaces are clean or primarily occupied by monodentate species. This work provides practical guidance for selecting MKM frameworks for undercoordinated catalytic surfaces and highlights the critical role of modeling assumptions in catalytic predictions.

(211) facet↗
DOE OSTI2024

IEA Wind Task 49: Reference Site Conditions for Floating Wind Arrays

The commercial-scale deployment of floating offshore wind (FOW) projects is expected to take place in a diverse range of sites that may differ significantly from existing fixed-bottom projects. FOW farms are particularly sensitive to the water depth and the meteorological and oceanographic (metocean) and geotechnical conditions at the project site due to the wave-induced system motions and loads as well as the anchoring system constraints imposed by the seafloor conditions. Uncertainty around the site conditions will permeate through all aspects of project design, leading to suboptimal and overly conservative designs, increased costs, and adversely affected performance. As FOW expands into a global industry, metocean and geotechnical conditions will increasingly vary for projects located in different geographic regions or in far-from-shore, deep-water sites. This study represents the outputs of work package 1 of International Energy Agency Wind Task 49, which focuses on the integrated design of floating wind arrays. The primary goal of this study is to establish the type of parameters and constraints required to characterize FOW array reference sites; provide a realistic and publicly available set of reference site conditions to the FOW community as a baseline set of data for individual research projects; identify and categorize any critical gaps in the existing data or methodologies required to define reference site characteristics; and inform and support the design of reference FOW arrays. A building block concept was developed for synthesizing reference sites for the design of FOW arrays. The building blocks include three classes of site conditions focusing on the techno-economic design of FOW projects: metocean conditions, seabed conditions, and coastal infrastructure. All reference site data produced and collected in this study are publicly available.

17 WIND ENERGY↗
DOE OSTI2023

Geospatial Information, Metadata, and Maps for Global River Corridor Science Focus Area Sites (v5)

This dataset provides geospatial information, metadata, and maps for the Pacific Northwest National Laboratory (PNNL) River Corridor Science Focus Area (RC-SFA; https://www.pnnl.gov/projects/river-corridor) sites. The RC-SFA works to transform understanding of spatial and temporal dynamics in river corridor hydrobiogeochemical functions from molecular reaction to watershed and basin scales. The knowledge we gain is used to formulate and test hypotheses and to improve mechanistic representation of river corridor processes and their response to disturbances in multiscale models of integrated hydrobiogeochemical function. The data provided includes Site ID, latitude, longitude, stream name, and common ID (COMID) for sites used across the RC-SFA. The COMID can be used to find and download data from NHDPlus (https://www.epa.gov/waterdata/nhdplus-national-hydrography-dataset-plus) and other platforms. The sites included are non-exhaustive. Sites (including past sites) will be added to this data package in the future. Data generated from the RC SFA can be accessed at https://data.ess-dive.lbl.gov/portals/PNNLRiverCorridorSFA. This data package was originally published in April 2023. It was updated in June 2023 (v2; modified files), December 2023 (v3; modified files), January 2025 (v4; modified files), and December 2025 (v5; modified files). See the change history section in the readme for more details. This dataset is comprised of one main data folder. The data folder consists of (1) file-level metadata; (2) data dictionary; (3) readme; (4) methods codes; (5) geospatial information for all RC SFA sites including International Generic Sample Number (IGSN); (6) maps of all sites and sites in Washington State, USA; and (7) a subfolder with the shapefile of all sites. All files are .csv, .pdf, .shp, .cpg, .dbf, .prj, .qmd, or .shx. We thank the Confederated Tribes and Bands of the Yakama Nation for access to field locations where some data were collected in Washington state. We also thank the Yakama Nation Tribal Council and Yakama Nation Fisheries for working with us to facilitate sample collection and optimization of data usage according to their values and worldview.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Nevada National Security Site Environmental Report 2014

This Nevada Nuclear Security Site Environmental Report (NNSSER) was prepared to satisfy DOE Order DOE O 231.1B, “Environment, Safety and Health Reporting.” Its purpose is to (1) report compliance status with environmental standards and requirements, (2) present results of environmental monitoring of radiological and nonradiological effluents, (3) report estimated radiological doses to the public from releases of radioactive material, (4) summarize environmental incidents of noncompliance and actions taken in response to them, (5) describe the NNSA/NFO Environmental Management System and characterize its performance, and (6) highlight significant environmental programs and efforts.This NNSSER summarizes data and compliance status for calendar year 2014 at the Nevada National Security Site (NNSS) (formerly the Nevada Test Site) and its two support facilities, the North Las Vegas Facility (NLVF) and the Remote Sensing Laboratory–Nellis (RSL-Nellis). It also addresses environmental restoration (ER) projects conducted at the Tonopah Test Range (TTR) and the Nevada Test and Training Range (NTTR). Through a Memorandum of Agreement, NNSA/NFO is responsible for the oversight of these ER projects, and the Sandia Field Office of NNSA (NNSA/SFO) has oversight of all other TTR and NTTR activities. NNSA/SFO produces the TTR annual environmental report, which is available at http://www.sandia.gov/news/publications/environmental/index.html.Major Site Programs and Facilities NNSA/NFO directs the management and operation of the NNSS and six sites across the nation. The six sites include two in Nevada (NLVF and RSL-Nellis) and four in other states (RSL-Andrews in Maryland, Livermore Operations in California, Los Alamos Operations in New Mexico, and Special Technologies Laboratory in California). Los Alamos, Lawrence Livermore, and Sandia National Laboratories are the principal organizations that sponsor and implement the nuclear weapons programs at the NNSS. National Security Technologies, LLC (NSTec), is the current Management and Operating contractor accountable for the successful execution of work and ensuring that work is performed in compliance with environmental regulations. The six sites all provide support to enhance the NNSS as a location for weapons experimentation and nuclear test readiness. The three major NNSS missions include National Security/Defense, Environmental Management, and Nondefense. The major programs that support these missions are Stockpile Stewardship and Management, Nonproliferation and Counterterrorism, Nuclear Emergency Response, Strategic Partnership Projects, Environmental Restoration, Waste Management, Conservation and Renewable Energy, Other Research and Development, and Infrastructure. The major facilities that support the programs include the U1a Facility, Big Explosives Experimental Facility (BEEF), Device Assembly Facility, Dense Plasma Focus Facility, Joint Actinide Shock Physics Experimental Research Facility, Radiological/Nuclear Countermeasures Test and Evaluation Complex, Nonproliferation Test and Evaluation Complex (NPTEC), Radiological/Nuclear Weapons of Mass Destruction Incident Exercise Site (known as the T-1 Site), Area 5 Radioactive Waste Management Complex (RWMC), and the Area 3 Radioactive Waste Management Site (RWMS).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

Development of a site analysis tool for distributed wind projects

The Cadmus Group, Inc., in collaboration with the National Renewable Energy Laboratory (NREL) and Encraft, was awarded a grant from the Department of Energy (DOE) to develop a site analysis tool for distributed wind technologies. As the principal investigator for this project, Mr. Shawn Shaw was responsible for overall project management, direction, and technical approach. The product resulting from this project is the Distributed Wind Site Analysis Tool (DSAT), a software tool for analyzing proposed sites for distributed wind technology (DWT) systems. This user-friendly tool supports the long-term growth and stability of the DWT market by providing reliable, realistic estimates of site and system energy output and feasibility. DSAT-which is accessible online and requires no purchase or download of software-is available in two account types; Standard: This free account allows the user to analyze a limited number of sites and to produce a system performance report for each; and Professional: For a small annual fee users can analyze an unlimited number of sites, produce system performance reports, and generate other customizable reports containing key information such as visual influence and wind resources. The tool’s interactive maps allow users to create site models that incorporate the obstructions and terrain types present. Users can generate site reports immediately after entering the requisite site information. Ideally, this tool also educates users regarding good site selection and effective evaluation practices.

17 WIND ENERGY↗
NASA NTRSDate not supplied

Implementation of active sites to capture pitting of oxidizing carbon materials in DSMC.

In this work we demonstrate a newly developed capability to capture pitting of carbon fibers in DSMC simulations, specifically using the Stochastic PArallel Rarefied-gas Time-accurate Analyzer (SPARTA) code [1]. State-of-the-art reactive surface models in DSMC compute collision dependent carbon consumption rates (usually through desorption of CO) based on a set of surface reactions that has been derived from molecular beam experiments [2]. The reactivity on each carbon surface element is constant in those models, such that the carbon surface recedes uniformly as a result of ablation. However, it is well known that in reality the carbon surface has locally different reaction rates due to the presence of defects at the atomic scale [3]. These defective sites have a much higher reactivity than the average sites (2-3 orders of magnitude) and are first to react during ablation leading to its removal. This causes all the neighboring atoms to be defective and increase their reactivity, thus leading to the localized carbon removal around these ”active” sites (as shown in Fig. 1). In this manner, these highly reactive defective sites serve as nucleation sites for the formation and growth of etch pits with potentially detrimental effects on the structural integrity. Recently a detailed surface chemistry framework was developed in SPARTA, capable of incorporating various reaction mechanisms such as adsorption, desorption, Eley-Rideal (ER) and Langmuir-Hinshelwood (LH) mechanisms [4]. Within this framework, we have implemented the capability of a single surface having multiple site sets with different reactivities. Using this feature, we can simulate the presence of active sites on carbon surfaces, whose reactivity is much greater than an average site as a result of defects. We have implemented the active site fraction as a property of surface elements within SPARTA, which is directly proportional to the local reactivity of each surface element. By introducing an initial distribution of the active site fraction across the carbon surface, and propagating it in a manner that mimics the evolution of real reacting carbon surfaces, we are able to capture the formation and growth of etch pits as a result of surface consumption reactions such as oxidation.

DSMC↗
NASA NTRSDate not supplied

Implementation of Active Sites in DSMC to Capture Pitting of Oxidizing Carbon Materials

In this work we demonstrate a newly developed capability to capture pitting of carbon fibers in DSMC simulations, specifically using the Stochastic PArallel Rarefied-gas Time-accurate Analyzer (SPARTA) code. State-of-the-art reactive surface models in DSMC compute collision dependent carbon consumption rates (usually through desorption of CO) based on a set of surface reactions that has been derived from molecular beam experiments. The reactivity on each carbon surface element is constant in those models, such that the carbon surface recedes uniformly as a result of ablation. However, it is well known that in reality the carbon surface has locally different reaction rates due to the presence of defects at the atomic scale. These defective sites have a much higher reactivity than the average sites (2-3 orders of magnitude) and are first to react during ablation leading to its removal. This causes all the neighboring atoms to be defective and increase their reactivity, thus leading to the localized carbon removal around these ”active” sites. In this manner, these highly reactive defective sites serve as nucleation sites for the formation and growth of etch pits with potentially detrimental effects on the structural integrity. Recently a detailed surface chemistry framework was developed in SPARTA, capable of incorporating various reaction mechanisms such as adsorption, desorption, Eley-Rideal (ER) and Langmuir-Hinshelwood (LH) mechanisms. Within this framework, we have implemented the capability of a single surface having multiple site sets with different reactivities. Using this feature, we can simulate the presence of active sites on carbon surfaces, whose reactivity is much greater than an average site as a result of defects. We have implemented the active site fraction as a property of surface elements within SPARTA, which is directly proportional to the local reactivity of each surface element. By introducing an initial distribution of the active site fraction across the carbon surface, and propagating it in a manner that mimics the evolution of real reacting carbon surfaces, we are able to capture the formation and growth of etch pits as a result of surface consumption reactions such as oxidation.

DSMC↗
DOE OSTI2014

Site transition framework for long-term surveillance and maintenance

This document provides a framework for all U.S. Department of Energy (DOE) facilities and sites where DOE may have anticipated long-term surveillance and maintenance (LTSM) responsibilities. It is a tool to help facilitate a smooth transition from remediation to LTSM, providing a systematic process for affected parties to utilize in analyzing the baseline to understand and manage the actions from EM mission completion through a site’s transition into LTSM. The framework is not meant to provide an exhaustive list of the specific requirement and information that are needed. Sites will have unique considerations that may not be adequately addressed by this tool, and it is anticipated that a team comprised of the transferring and receiving organization will use judgment in utilizing this augmenting with other DOE guidance. However the framework should be followed to the extent possible at each site; and adapted to accommodate unique site-specific requirements, needs, and documents. Since the objective of the tool is facilitate better understanding of the conditions of the site and the actions required for transfer, the transition team utilizing the checklist is expected to consult with management of both the receiving and transferring organization to verify that major concerns are addressed. Ideally, this framework should be used as early in the remediation process as possible. Subsequent applications of the Site Transition Framework (STF) to the site should be conducted periodically and used to verify that all appropriate steps have been or will be taken to close-out the site and that actions by both organization are identified to transfer the site to LTSM. The requirements are provided herein.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Giving Back: Collaborations with Others in Ecological Studies on the Nevada National Security Site - 13058

Formerly named the Nevada Test Site, the Nevada National Security Site (NNSS) was the historical site for nuclear weapons testing from the 1950's to the early 1990's. The site was renamed in 2010 to reflect the diversity of nuclear, energy, and homeland security activities now conducted at the site. Biological and ecological programs and research have been conducted on the site for decades to address the impacts of radiation and to take advantage of the relatively undisturbed and isolated lands for gathering basic information on the occurrence and distribution of native plants and animals. Currently, the Office of the Assistant Manager for Environmental Management of the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (NNSA/NSO) oversees the radiological biota monitoring and ecological compliance programs on the NNSS. The top priority of these programs are compliance with federal and state regulations. They focus on performing radiological dose assessments for the public who reside near the NNSS and for populations of plants and animals on the NNSS and in protecting important species and habitat from direct impacts of mission activities. The NNSS serves as an invaluable outdoor laboratory. The geographic and ecological diversity of the site offers researchers many opportunities to study human influences on ecosystems. NNSA/NSO has pursued collaborations with outside agencies and organizations to be able to conduct programs and studies that enhance radiological biota monitoring and ecosystem preservation when budgets are restrictive, as well as to provide valuable scientific information to the human health and natural resource communities at large. NNSA/NSO is using one current collaborative study to better assess the potential dose to the off-site public from the ingestion of game animals, the most realistic pathway for off-site public exposure at this time from radionuclide contamination on the NNSS. A second collaborative study is furthering desert tortoise conservation measures onsite. It is the goal of NNSA/NSO to continue to develop such collaborations in the sharing of resources, such as personnel, equipment, expertise, and NNSS land access, with outside entities to meet mutually beneficial goals cost effectively. (authors)

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

Launching a Research Archive for FUSRAP Site Records - 17057

The US Department of Energy Office of Legacy Management (LM) maintains a broad set of Formerly Utilized Sites Remedial Action Program (FUSRAP) document collections. The LM FUSRAP technical staff regularly needs access to documents contained in these record collections. The majority of the FUSRAP records are maintained in a large paper-based collection in the LM records storage facility. These records cover the period prior to 1997 in which DOE was responsible for the remediation efforts of FUSRAP sites. Other FUSRAP records are maintained as PDF files in LM's record keeping system. LM also maintains FUSRAP information in reference repositories in SharePoint directories and on network drives. The reference collection allows LM to keep abreast of active site remediation by the U.S. Army Corps of Engineers (USACE) since 1997. Searching these FUSRAP collections in its current arrangement can be time-consuming and can result in incomplete searches. In response, LM proactively developed the FUSRAP Document Information System (FDIS) to provide a rapid, single-point search and retrieval system to provide real-time access to reference copies of FUSRAP documents. Each entry in FDIS includes metadata listing the FUSRAP site, document title, date, source collection, and pertinent keywords. More significant entries (e.g., certification documents, site characterization reports, waste manifests) include a PDF scan of the entire document. Each PDF file is processed using an advanced optical character recognition (OCR) tool. The first significant content added to FDIS is 45,000 entries documenting remediation work performed primarily in the early 1990's by Bechtel National, Inc. With the entries in FDIS, technical staff will be able to search the collection by site, category and keyword to quickly locate precise required content. LM records staff are also adding records that document remediation and monitoring work at FUSRAP sites where cleanup activities are considered complete. Documents for completed FUSRAP sites will be processed before documents for sites currently being remediated. In the future, FDIS will be populated with information about FUSRAP sites with ongoing remediation work as they are released to LM stewardship. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

System Analysis Support of Consent-Based Siting Efforts - 23400

To better enable informed decision-making regarding the back end of the nuclear fuel cycle, the Integrated Waste Management (IWM) program within the U.S. Department of Energy, Office of Nuclear Energy (DOE-NE) has been sponsoring the development and application of system analysis tools capable of analyzing various system options for the management of spent nuclear fuel (SNF) and high-level radioactive waste. With these tools, integrated waste management system (IWMS) architecture analyses are being conducted to support the future deployment of a comprehensive nuclear waste management system that considers all major back-end aspects of the nuclear fuel cycle (i.e., transportation, storage, and disposal). System analyses and assessments typically use these modeling and simulation tools to investigate things like the implications of changes in various assumptions and parameters such as acceptance rates, receipt logic, facility capacities and capabilities, use of standardized canisters, and different assumed system operation start dates. Some example system analysis results have been published previously. With the passage of the consolidated appropriations acts for fiscal years 2021 and 2022, Congress provided funding and direction for the DOE to move forward with interim storage to support near-term action in managing the nation’s SNF as an important component of an IWMS. Consent-based siting is a phased, adaptive, and collaborative approach to siting facilities that focuses on the needs and concerns of people and communities. Communities participate in the siting process by working carefully through a series of phases and steps with the DOE (as the implementing organization). Each step and phase helps a community determine whether and how hosting a facility to manage SNF is aligned to the community’s goals. By its nature, a consent-based siting process must be transparent, flexible, adaptive, and responsive to community concerns. Thus, the phases and steps are intended to serve as a guide, not a prescriptive set of instructions. System analysis research analysts interface with DOE’s consent-based siting for a federal interim storage program and can perform preliminary system analyses as requested to support various aspects of the consent-based siting team’s work. This paper provides an overview of IWM program’s system analysis activities that support the ongoing consent-based siting process. The questions that decision-makers, planners, communities, and stakeholders might have during the consent-based siting process are similar to questions that have been explored by system analysts previously. Specifically, this paper discusses work that will inform consent-based siting efforts in the areas of community impacts, cost estimates, various SNF acceptance rates by potential facilities, potential consolidated interim storage facility (CISF) capacities and configurations, and the implications of a CISF on the overall waste management system. It is expected that system analysis will continue to be performed to support the consent-based siting process in the future.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗