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At least 955 records · Page 53

2011 Annual Ecological Survey: Pacific Northwest National Laboratory Site

The U.S. Department of Energy (DOE) Pacific Northwest Site Office (PNSO) oversees and manages the DOE contract for the Pacific Northwest National Laboratory (PNNL), a DOE Office of Science multi-program laboratory located in Richland, Washington. PNSO is responsible for ensuring that all activities conducted on the PNNL site comply with applicable laws, policies, and DOE Orders. The DOE Pacific Northwest Site Office Cultural and Biological Resources Management Plan (DOE/PNSO 2008) addresses the requirement for annual surveys and monitoring for species of concern and to identify and map invasive species. In addition to the requirement for an annual survey, proposed project activities must be reviewed to assess any potential environmental consequences of conducting the project. The assessment process requires a thorough understanding of the resources present, the potential impacts of a proposed action to those resources, and the ultimate consequences of those actions. The PNNL site is situated on the southeastern corner of the DOE Hanford Site, located at the north end of the city of Richland in south-central Washington. The site is bordered on the east by the Columbia River, on the west by Stevens Drive, and on the north by the Hanford Site 300 Area (Figure 1). The environmental setting of the PNNL site is described in Larson and Downs (2009). There are currently two facilities on the PNNL site: the William R. Wiley Environmental Molecular Sciences Laboratory and the Physical Sciences Facility. This report describes the annual survey of biological resources found on the undeveloped upland portions of the PNNL site. The annual survey is comprised of a series of individual field surveys conducted on various days in late May and throughout June 2011. A brief description of the methods PNNL ecologists used to conduct the baseline surveys and a summary of the results of the surveys are presented. Appendix A provides a list of plant and animal species identified in the upland areas of the PNNL site in 2011. Efforts in 2011 to control noxious weed populations (comprising plant species designated as Class B noxious weeds by the Washington State Noxious Weed Control Board) discovered in 2009 and initially treated with herbicides in 2010 are described in Appendix B.

54 ENVIRONMENTAL SCIENCES↗

Data Report: Meteorological and Evapotranspiration Data from Sagebrush and Pinyon Pine/Juniper Communities at Pahute Mesa, Nevada National Security Site, 2011-2012

Pahute Mesa is a groundwater recharge area at the Nevada National Security Site. Because underground nuclear testing was conducted at Pahute Mesa, groundwater recharge may transport radionuclides from underground test sites downward to the water table; the amount of groundwater recharge is also an important component of contaminant transport models. To estimate the amount of groundwater recharge at Pahute Mesa, an INFIL3.0 recharge-runoff model is being developed. Two eddy covariance (EC) stations were installed on Pahute Mesa to estimate evapotranspiration (ET) to support the groundwater recharge modeling project. This data report describes the methods that were used to estimate ET and collect meteorological data. Evapotranspiration was estimated for two predominant plant communities on Pahute Mesa; one site was located in a sagebrush plant community, the other site in a pinyon pine/juniper community. Annual ET was estimated to be 310±13.9 mm for the sagebrush site and 347±15.9 mm for the pinyon pine/juniper site (March 26, 2011 to March 26, 2012). Annual precipitation measured with unheated tipping bucket rain gauges was 179 mm at the sagebrush site and 159 mm at the pinyon pine/juniper site. Annual precipitation measured with bulk precipitation gauges was 222 mm at the sagebrush site and 227 mm at the pinyon pine/juniper site (March 21, 2011 to March 28, 2012). A comparison of tipping bucket versus bulk precipitation data showed that total precipitation measured by the tipping bucket rain gauges was 17 to 20 percent lower than the bulk precipitation gauges. These differences were most likely the result of the unheated tipping bucket precipitation gauges not measuring frozen precipitation as accurately as the bulk precipitation gauges. In this one-year study, ET exceeded precipitation at both study sites because estimates of ET included precipitation that fell during the winter of 2010-2011 prior to EC instrumentation and the precipitation gauges started collecting data in March 2011.

54 ENVIRONMENTAL SCIENCES↗

Corrective Action Investigation Plan for Corrective Action Unit 541: Small Boy Nevada National Security Site and Nevada Test and Training Range, Nevada with ROTC 1

Corrective Action Unit (CAU) 541 is co-located on the boundary of Area 5 of the Nevada National Security Site and Range 65C of the Nevada Test and Training Range, approximately 65 miles northwest of Las Vegas, Nevada. CAU 541 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 541, which comprises the following corrective action sites (CASs): 05-23-04, Atmospheric Tests (6) - BFa Site; 05-45-03, Atmospheric Test Site - Small Boy. 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 April 1, 2014, by representatives of the Nevada Division of Environmental Protection; U.S. Air Force; 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 541. The site investigation process also will 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 CASs 05-23-04 and 05-45-03 are from nuclear testing activities conducted at the Atmospheric Tests (6) - BFa Site and Atmospheric Test Site - Small Boy sites. The presence and nature of contamination at CAU 541 will be evaluated based on information collected from field investigations. Radiological contamination will be evaluated based on a comparison of the total effective dose at sample locations to the dose-based final action level. The total effective dose 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↗

2012 Update to the Site Discharge Pollution Prevention Plan (Rev. 1): Los Alamos/Pueblo Watershed (Vol. 1)

One historical industrial activity area is associated with R001, R-SMA-0.5: Site C-00-020. Area of Concern (AOC) C-00-020 is a suspected mortar impact area located along the north valley wall of Rendija Canyon on General Services Administration (GSA) and U.S. Forest Service (USFS) land. The 30-acre site also includes a tributary of Rendija Canyon. Most of the site lies within the Santa Fe National Forest, except for a small area on the southeastern edge that is private property. AOC C-00-020 was suspected to be a former mortar-impact area because of a “U.S. Property—No Trespassing” sign and a nearly illegible bilingual sign posted in the area. The signs no longer remain. Extensive archival searches have revealed no documentation regarding the use of this site as a munitions impact area. In addition, no field evidence of operations (e.g., munitions debris [MD], munitions and explosives of concern [MEC], unexploded ordnance [UXO], or impact scars) has ever been found at AOC C-00-020. Resource Conservation and Recovery Act (RCRA) facility investigation (RFI) activities conducted in 1993 included conducting an ordnance sweep followed by a geophysical sweep. No ordnance, MD, MEC, or UXO was located. In addition, no ordnance was found during the 2007 investigation or during the 2009 ordnance survey. The site is located within an area burned by the 2000 Cerro Grande fire. The stream channel that runs through the center of the site has been widened by flooding. Currently, there are burned and live trees on the steep slopes next to the stream. Ordnance surveys at the site resulted in no findings except for scrap metal such as bailing wire. The complete absence of ordnance and explosives waste (OEW) confirmed that the site was never used as an ordnance-impact area. In accordance with the approved investigation work plan, no further investigation was conducted at AOC C-00-020. The New Mexico Environment Department (NMED) concurred with the conclusion that no additional ordnance surveys need to be conducted at this site and issued a corrective action complete without controls for AOC C-00-020 on May 16, 2012. No industrial materials were historically managed at this Site; therefore, no potential contaminants are associated with the Site.

54 ENVIRONMENTAL SCIENCES↗

Developing Platinum-Group-Metal-Free Catalysts for Oxygen Reduction Reaction in Acid: Beyond the Single Metal Site

This project is to develop M (x) -N-C catalysts with dense multiple metal center (MMC) sites to meet the DOE 2025 activity target of 0.044 mA/cm 2 at 0.9 V IR-free ., as well as other goals such as durability. We have made important contributions to both catalyst development and fundamental understandings of the active sites in M-N-C catalysts in this project. We successfully made M (x) -N-C catalysts with some multiple metal center (MMC) sites by combining ionothermal carbonization with chemical vapor deposition (CVD). These catalysts, however, are not as active as the most active single-atom Fe-N-C catalysts made by the similar CVD process, owing likely to the low site density and the presence of inorganic Fe species such as iron carbides and nanoparticles. The most significant accomplishments we achieved in this project are: (1) we unraveled the formation pathway of Fe-N 4 sites during pyrolysis step-by-step and identified the trans-metalation mechanism, in collaboration with Deborah Myers and her colleagues at Argonne National Laboratory (ANL); (2) inspired by this finding, we pioneered the CVD synthesis of M-N-C catalysts (M = Mn, Fe, and Co), in which the Fe-N-C catalyst by CVD demonstrated an ORR activity of 33 mA/cm 2 at 0.9 V in H 2 -O 2 proton exchange membrane fuel cells (PEMFCs), very close to the ultimate goal of 35 mA/cm 2 of our project. This catalyst is the first Fe-N-C catalyst that contains only D1 sites without the D2 sites; whereas D1 and D2 sites have been always identified by Mossbauer in previous Fe-N-C catalysts. This finding helps to understand what the D1 and D2 sites are and their roles in catalyzing the ORR. (3) by improving the mass transport of the carbon matrix prior to the CVD process, the revised Fe-N-C catalyst made by CVD delivered a maximum power density of 0.53 W/cm 2 in H 2 -air PEMFCs. The improvement strategy was partly inspired by the computational modeling work by Adam Weber from LBNL, the Co-PI of this project, by developing, coding, and exercising a continuum level model of transport phenomena within a PGM-free catalyst layer. The model demonstrated that local resistances combined with limited site density of the PGM-free catalyst can result in limiting currents and poor polarization performance. The model also gave design guidance for impact of ECSA and overall catalyst-layer thickness. However, both Fe-N-C and Co-N-C catalysts developed by CVD showed poor durability in PEMFCS, in comparison with the traditional M-N-C catalysts synthesized via regular pyrolysis process. Consequently, we did not achieve the proposed durability targets. Despite so, we believe the FeNC-CVD catalysts with the poor durability and D1 sites only provides an excellent platform to understand the degradation mechanism of Fe-N-C in PEMFCs, the most important challenge in the development of M-N-C catalysts.

08 HYDROGEN↗

Hanford Site Revegetation Monitoring Report for Fiscal Year 2022

This report describes the monitoring of areas revegetated by various contractors on the Hanford Site. Revegetation sites include those revegetated by the River Corridor Closure Contractor and CH2M Hill Plateau Remediation Company that were transitioned to Mission Support Alliance (MSA) in 2017. These sites, along with sites revegetated by MSA between 2017 and 2020, were transitioned to Hanford Mission Integration Solutions (HMIS) in 2021. HMIS performs revegetation monitoring activities for these transitioned sites and for sites revegetated by HMIS and other contractors in subsequent years to determine revegetation site success. This report contains data collected in 2022 documenting the recovery of revegetation areas associated with the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 cleanup of National Priorities List waste sites and restoration of lands disturbed by ongoing mission activities at the Hanford Site in Richland, Washington. It contains vegetation monitoring data for 53 sites selected to be representative sites for areas planted between the years of fiscal year (FY) 2007 and FY 2022.

54 ENVIRONMENTAL SCIENCES↗

Corral Summit Pumped Storage Hydropower Hybrid: Site Suitability Assessment

In 2024, Idaho National Laboratory (INL) and Pacific Northwest National Laboratory (PNNL) initiated a technical-assistance project to support Cat Creek Energy, LLC, (CCE) in evaluating site suitability for the proposed Corral Summit Pumped Storage Hydropower (PSH) project in south-central Idaho near Mackay Reservoir. The Corral Summit facility incorporates battery storage and photovoltaic (PV) solar arrays in a Trybrid configuration to deliver large-volume long-duration (LVLD) storage solutions for rural electric cooperatives in eastern Idaho. The evaluation process focused on determining the most-suitable location for the upper reservoir of the PSH system, guided by a comprehensive assessment framework spanning multiple categories, including physical characteristics, environmental constraints, building infrastructure, regulatory constraints, cultural resources and sensitivity, social factors, and power market and grid integration. Each site was analyzed based on a ranking scale (0–1), which scores ranging from “severely disfavored” to “highly favored,” allowing detailed comparisons of site-specific conditions. Categories such as hydraulic head, utilities corridor, land ownership, and transmission-grid limitations emerged as key contributors to the overall assessment. Site 2 (Idaho Trust) demonstrated a slight advantage over Site 1 (Bureau of Land Management) primarily due to favorable outcomes in regulatory constraints, building infrastructure, and power-market integration. However, Site 1 outperformed Site 2 in factors related to physical characteristics and social factors. The report emphasizes the need for further evaluation of both sites before clear determination of which site is preferred, due to the limited information available on either site at the time of this report. Key areas of evaluation to clearly define the preferred site are ecological impacts, cultural-resource surveys, and economic-feasibility assessments. For successful project execution, recommended follow-up actions include seismic and geotechnical surveys, groundwater and habitat monitoring, regulatory reviews of water rights and right-of-way agreements, cultural engagement with local tribal governments, and enhanced stakeholder strategies. These efforts will ensure the Corral Summit Trybrid facility meets local energy needs while balancing environmental, social, and regulatory responsibilities.

13 - HYDRO ENERGY↗

Corral Summit Pumped Storage Hydropower Hybrid Site Suitability Assessment (Rev.1)

In 2024, Idaho National Laboratory (INL) and Pacific Northwest National Laboratory (PNNL) initiated a technical-assistance project to support Cat Creek Energy, LLC, (CCE) in evaluating site suitability for the proposed Corral Summit Pumped Storage Hydropower (PSH) project in south-central Idaho near Mackay Reservoir. The Corral Summit facility incorporates battery storage and photovoltaic (PV) solar arrays in a Trybrid configuration to deliver large-volume long-duration (LVLD) storage solutions for rural electric cooperatives in eastern Idaho. The evaluation process focused on determining the most-suitable location for the upper reservoir of the PSH system, guided by a comprehensive assessment framework spanning multiple categories, including physical characteristics, environmental constraints, building infrastructure, regulatory constraints, cultural resources and sensitivity, social factors, and power market and grid integration. Each site was analyzed based on a ranking scale (0–1), which scores ranging from “severely disfavored” to “highly favored,” allowing detailed comparisons of site-specific conditions. Categories such as hydraulic head, utilities corridor, land ownership, and transmission-grid limitations emerged as key contributors to the overall assessment. Site 2 (Idaho Trust) demonstrated a slight advantage over Site 1 (Bureau of Land Management) primarily due to favorable outcomes in regulatory constraints, building infrastructure, and power-market integration. However, Site 1 outperformed Site 2 in factors related to physical characteristics and social factors. The report emphasizes the need for further evaluation of both sites before clear determination of which site is preferred, due to the limited information available on either site at the time of this report. Key areas of evaluation to clearly define the preferred site are ecological impacts, cultural-resource surveys, and economic-feasibility assessments. For successful project execution, recommended follow-up actions include seismic and geotechnical surveys, groundwater and habitat monitoring, regulatory reviews of water rights and right-of-way agreements, cultural engagement with local tribal governments, and enhanced stakeholder strategies. These efforts will ensure the Corral Summit Trybrid facility meets local energy needs while balancing environmental, social, and regulatory responsibilities.

13 - HYDRO ENERGY↗

Representativeness assessment of the pan-Arctic eddy covariance site network and optimized future enhancements

Abstract. Large changes in the Arctic carbon balance are expected as warming linked to climate change threatens to destabilize ancient permafrost carbon stocks. The eddy covariance (EC) method is an established technique to quantify net losses and gains of carbon between the biosphere and atmosphere at high spatiotemporal resolution. Over the past decades, a growing network of terrestrial EC tower sites has been established across the Arctic, but a comprehensive assessment of the network's representativeness within the heterogeneous Arctic region is still lacking. This creates additional uncertainties when integrating flux data across sites, for example when upscaling fluxes to constrain pan-Arctic carbon budgets and changes therein. This study provides an inventory of Arctic (here > = 60∘ N) EC sites, which has also been made available online (https://cosima.nceas.ucsb.edu/carbon-flux-sites/, last access: 25 January 2022). Our database currently comprises 120 EC sites, but only 83 are listed as active, and just 25 of these active sites remain operational throughout the winter. To map the representativeness of this EC network, we evaluated the similarity between environmental conditions observed at the tower locations and those within the larger Arctic study domain based on 18 bioclimatic and edaphic variables. This allows us to assess a general level of similarity between ecosystem conditions within the domain, while not necessarily reflecting changes in greenhouse gas flux rates directly. We define two metrics based on this representativeness score: one that measures whether a location is represented by an EC tower with similar characteristics (ER1) and a second for which we assess if a minimum level of representation for statistically rigorous extrapolation is met (ER4). We find that while half of the domain is represented by at least one tower, only a third has enough towers in similar locations to allow reliable extrapolation. When we consider methane measurements or year-round (including wintertime) measurements, the values drop to about 1/5 and 1/10 of the domain, respectively. With the majority of sites located in Fennoscandia and Alaska, these regions were assigned the highest level of network representativeness, while large parts of Siberia and patches of Canada were classified as underrepresented. Across the Arctic, mountainous regions were particularly poorly represented by the current EC observation network. We tested three different strategies to identify new site locations or upgrades of existing sites that optimally enhance the representativeness of the current EC network. While 15 new sites can improve the representativeness of the pan-Arctic network by 20 %, upgrading as few as 10 existing sites to capture methane fluxes or remain active during wintertime can improve their respective ER1 network coverage by 28 % to 33 %. This targeted network improvement could be shown to be clearly superior to an unguided selection of new sites, therefore leading to substantial improvements in network coverage based on relatively small investments.

54 ENVIRONMENTAL SCIENCES↗

Salient Characteristics for Terrestrial Analog Engineering Test Sites

The use of terrestrial analog sites is an essential component of the development process for systems that are planned for lunar and planetary surfaces. These sites can also be valuable for training personnel who are expected to operate those systems. The fact that the site is an integral element, capable of influencing data and impacting test results, must not be overlooked. For tests performed in analog environments to be truly valid it is essential that the relevant characteristics of the employed sites be thoroughly understood. It is also critical that a comparative evaluation be made to assess the similarity of the analog sites to target planetary sites. Examples of relevant characteristics include terrain, soil properties, meteorology, geologic features, biological history, and remoteness. The importance of each of the characteristics varies with the type of extraterrestrial activity to be conducted. As a result, a site that is ideal for one purpose may be totally inadequate for another. It may also be appropriate to utilize multiple sites of increasing fidelity as the development process evolves. For example, early in the development process, the use of lower-fidelity sites may be elected - especially if they are available for a lower cost. Later, it may be necessary to employ higher-fidelity sites to capture greater realism, even if there is an associated increased cost. Finally, when interpreting the results of field tests, it is necessary to understand the sensitivity of the results to the relevant conditions. Knowledge of characteristics and sensitivity of results is particularly important when using field test results to validate analytical model predictions. This is especially true for activities that involve physical interaction with the site. Examples would include tests of rovers or other vehicles and associated trafficability modeling, spacesuit mobility tests, and tests associated with system deployment operations.

Watson, J.K.↗

Simulation of etch pit formation through active sites in carbon fiber micro-structures

Erosion of carbon due to oxidation does not occur uniformly but through localized etch pit formation as a result of active surface sites. In this work we demonstrate a newly developed capability to capture pitting of carbon fiber microstructures such as FiberForm, which is commonly used as the base material for NASA’s spacecraft ablative thermal protection systems (TPS). The simulations are performed at the meso-scale in order to capture the pit formation and growth using direct simulation Monte Carlo (DSMC), specifically using the Stochastic PArallel Rarefied-gas Time-accurate Analyzer (SPARTA) code. Legacy and latest models both assume uniform reactivity of carbon surface sites with oxygen even at the meso-scale level. However, in reality the carbon surface has locally different reaction rates due to the presence of defects at the atomic scale. The defective nature of these sites enhances their reactivity with atmospheric gases compared to the non-defective sites (2-3 orders of magnitude) and are termed as “active sites”. Thus, these sites tend to be the first to react and eventually get removed through the formation of gasses such as CO, CO2, and CN. Their removal results in all the neighboring atoms becoming defective, thus leading to chain reaction of localized carbon removal and formation of etch pits. Capturing the formation of pits during the ablation simulation of carbon micro-structures is critical to predicting their structural failure. 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. We have implemented the capability of a single surface having multiple site sets with different reactivities within this framework. We have used this feature to model the presence of active sites on carbon surfaces, whose reactivity is orders of magnitude higher than that of the passive sites due to the presence of defects. The active site fraction is a property of surface elements within SPARTA and 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 can capture the formation and growth of etch pits as a result of surface consumption reactions such as oxidation.

DSMC↗

Simulation of Etch Pit Formation in DSMC Through Active Sites in Carbon Fiber Micro-Structures

Erosion of carbon due to oxidation does not occur uniformly but through localized etch pit formation because of active surface sites. In this work we demonstrate a newly developed capability to capture pitting of carbon fiber microstructures such as FiberForm, which is commonly used as the base material for NASA’s spacecraft ablative thermal protection systems (TPS). The simulations are performed at the meso-scale in order to capture the pit formation and growth using direct simulation Monte Carlo (DSMC), specifically using the Stochastic PArallel Rarefied-gas Time-accurate Analyzer (SPARTA) code. Legacy and latest models both assume uniform reactivity of carbon surface sites with oxygen even at the meso-scale level. However, in reality the carbon surface has locally different reaction rates due to the presence of defects at the atomic scale. The defective nature of these sites enhances their reactivity with atmospheric gases compared to the non-defective sites (2-3 orders of magnitude) and are termed as “active sites”. Thus, these sites tend to be the first to react and eventually get removed through the formation of gases such as CO, CO2, and CN. Their removal results in all the neighboring atoms becoming defective, thus leading to chain reaction of localized carbon removal and formation of etch pits. Capturing the formation of pits during the ablation simulation of carbon micro-structures is critical to predicting their structural failure. Recently a detailed surface chemistry framework was developed in SPARTA, capable of incorporating various detailed surface reaction mechanisms. We have implemented the capability of a single surface having multiple site sets with different reactivities within this framework. We have used this feature to model the presence of active sites on carbon surfaces, whose reactivity is orders of magnitude higher than that of the passive sites due to the presence of defects. The active site fraction is a property of surface elements within SPARTA and 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 can capture the formation and growth of etch pits as a result of surface consumption reactions such as oxidation.

DSMC↗

DSMC Simulation of Etch Pit Formation Through Active Sites in Carbon Fiber Micro-Structures

Erosion of carbon due to oxidation does not occur uniformly but through localized etch pit formation because of active surface sites. In this work we demonstrate a newly developed capability to capture pitting of carbon fiber microstructures such as FiberForm, which is commonly used as the base material for NASA’s spacecraft ablative thermal protection systems (TPS). The simulations are performed at the meso-scale in order to capture the pit formation and growth using direct simulation Monte Carlo (DSMC), specifically using the Stochastic PArallel Rarefied-gas Time-accurate Analyzer (SPARTA) code. Legacy and latest models both assume uniform reactivity of carbon surface sites with oxygen even at the meso-scale level. However, in reality the carbon surface has locally different reaction rates due to the presence of defects at the atomic scale. The defective nature of these sites enhances their reactivity with atmospheric gases compared to the non-defective sites (2-3 orders of magnitude) and are termed as “active sites”. Thus, these sites tend to be the first to react and eventually get removed through the formation of gases such as CO, CO2, and CN. Their removal results in all the neighboring atoms becoming defective, thus leading to chain reaction of localized carbon removal and formation of etch pits. Capturing the formation of pits during the ablation simulation of carbon micro-structures is critical to predicting their structural failure. Recently a detailed surface chemistry framework was developed in SPARTA, capable of incorporating various detailed surface reaction mechanisms. We have implemented the capability of a single surface having multiple site sets with different reactivities within this framework. We have used this feature to model the presence of active sites on carbon surfaces, whose reactivity is orders of magnitude higher than that of the passive sites due to the presence of defects. The active site fraction is a property of surface elements within SPARTA and 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 can capture the formation and growth of etch pits as a result of surface consumption reactions such as oxidation.

DSMC↗

Collaboration in long-term stewardship at DOE Hanford Site

The U.S. Department of Energy's (DOE) Hanford Site comprises approximately 1,517 km{sup 2} (586 mi{sup 2}) of land in southeastern Washington. The site was established in 1943 as part of the Manhattan Project to produce plutonium for the nation's nuclear weapons program. As the Cold War era came to an end, the mission of the site transitioned from weapons production to environmental cleanup. As the River Corridor area of the site cleanup is completed, the mission for that portion of the site will transition from active cleanup to continued protection of environment through the Long-Term Stewardship (LTS) Program. The key to successful transition from cleanup to LTS is the unique collaboration among three (3) different DOE Programs and three (3) different prime contractors with each contractor having different contracts. The LTS Program at the site is a successful model of collaboration resulting in efficient resolution of issues and accelerated progress that supports DOE's Richland Office 2015 Vision for the Hanford Site. The 2015 Vision for the Hanford Site involves shrinking the active cleanup footprint of the surface area of the site to approximately 20 mi{sup 2} on the Central Plateau. Hanford's LTS Program is defined in DOE's planning document, Hanford Long-Term Stewardship Program Plan, DOE/RL-2010-35 Rev 1. The Plan defines the relationship and respective responsibilities between the federal cleanup projects and the LTS Program along with their respective contractors. The LTS Program involves these different parties (cleanup program and contractors) who must work together to achieve the objective for transition of land parcels. Through the collaborative efforts with the prime contractors on site over the past two years, 253.8 km{sup 2} (98 mi{sup 2}) of property has been successfully transitioned from the cleanup program to the LTS Program upon completion of active surface cleanup. Upcoming efforts in the near term will include transitioning another large parcel that includes one of the six (6) cocooned reactors on site. These accomplishments relied upon the transparency between DOE cleanup programs and their contractors working together to successfully transition the land while addressing the challenges that arise. All parties, the three different DOE Programs and their respective prime contractors are dedicated to working together and continuing the progress of transitioning land to LTS, in alignment with the Program Plan and compliant with contractual requirements. This paper highlights the accomplishments and collaborative efforts to address the challenges faced as work progresses from the cleanup to transitioning of land parcels to LTS Program.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Overview of the U.S. Department of Energy Formerly Utilized Sites Remedial Action Program - 12189

The U.S. Department of Energy (DOE) Formerly Utilized Sites Remedial Action Program (FUSRAP) was established in 1974 to address residual radiological contamination at sites where work was performed for the Manhattan Engineer District and U.S. Atomic Energy Commission. Initially, FUSRAP activities began with a records search for sites that had the potential to contain residual radiological contamination; 46 sites were identified that were eligible for and required remediation. Remedial action began in 1979. In 1997, Congress assigned responsibility for the remediation of FUSRAP sites to the U.S. Army Corps of Engineers (USACE). DOE retains responsibility for determining if sites are eligible for FUSRAP remediation and for providing long-term surveillance and maintenance (LTS&M) of remediated FUSRAP sites. DOE LTS&M activities are designed to ensure that FUSRAP sites remain protective of human health and the environment and to preserve knowledge regarding FUSRAP sites. Additional elements include eligibility determinations, transition of remediated sites from USACE to DOE, LTS&M operations such as inspections and institutional controls management, stakeholder support, preservation of records, and real property and reuse. DOE maintains close coordination with USACE and regulators to ensure there is no loss of protectiveness when sites transition to DOE for LTS&M.

Radiological contamination, Grand Junction, Colora↗

Transfer and Transition: Interagency Coordination for Managing Public Lands at UMTRCA Title II Sites in Wyoming – 16614

By the end of fiscal year 2025, the U.S. Department of Energy (DOE) Office of Legacy Management (LM) is anticipating adding 17 sites remediated under Title II of the Uranium Mill Tailings Radiation Control Act (UMTRCA) to the current inventory of 90 sites that it manages. Among the new sites are ones where federal public lands occur within the proposed long-term care boundary, the boundary determined by the Nuclear Regulatory Commission and LM as necessary to maintain site protectiveness for the entombed uranium mill tailings and residual groundwater contamination. For these sites, public land withdrawals for land and minerals will need to be established. LM’s primary mission at UMTRCA sites is to protect the public and the environment from exposure to contamination at the sites. For the sites with public lands or federally controlled minerals that will be transferring to LM, the Office will apply to the Department of the Interior (DOI) Bureau of Land Management (BLM) for new, public land and mineral withdrawals. At most current LM UMTRCA sites that involved public lands and minerals, DOI granted DOE “full administrative jurisdiction” and permanent withdrawals. Hence, these withdrawals are, permanently, no longer subject to public land, mining, and mineral-leasing laws and regulations. LM is coordinating with DOI/BLM in Wyoming to permanently withdraw full and partial jurisdiction at future UMTRCA Title II sites in that state. This approach would allow LM to fully administer surface lands and minerals, where necessary, and DOI and LM to administer surface lands and leasable minerals where it would not jeopardize sites’ radiological safety and long-term public and environmental protection. This “shared-jurisdiction approach” will meet LM’s strategic goal of protecting human health and the environment but also allow BLM to fulfill their mission to “manage and conserve the lands under the mandate of multiple-use and sustained yield.” In addition, LM could also fulfill the fourth goal of its Strategic Plan, to optimize land use and assets.

54 ENVIRONMENTAL SCIENCES↗

Collaboration in Long-Term Stewardship at DOE's Hanford Site - 13019

The U.S. Department of Energy's (DOE) Hanford Site comprises approximately 1,517 km{sup 2} (586 mi{sup 2}) of land in southeastern Washington. The site was established in 1943 as part of the Manhattan Project to produce plutonium for the nation's nuclear weapons program. As the Cold War era came to an end, the mission of the site transitioned from weapons production to environmental cleanup. As the River Corridor area of the site cleanup is completed, the mission for that portion of the site will transition from active cleanup to continued protection of environment through the Long-Term Stewardship (LTS) Program. The key to successful transition from cleanup to LTS is the unique collaboration among three (3) different DOE Programs and three (3) different prime contractors with each contractor having different contracts. The LTS Program at the site is a successful model of collaboration resulting in efficient resolution of issues and accelerated progress that supports DOE's Richland Office 2015 Vision for the Hanford Site. The 2015 Vision for the Hanford Site involves shrinking the active cleanup footprint of the surface area of the site to approximately 20 mi{sup 2} on the Central Plateau. Hanford's LTS Program is defined in DOE's planning document, Hanford Long-Term Stewardship Program Plan [1]. The Plan defines the relationship and respective responsibilities between the federal cleanup projects and the LTS Program along with their respective contractors. The LTS Program involves these different parties (cleanup program and contractors) who must work together to achieve the objective for transition of land parcels. Through the collaborative efforts with the prime contractors on site over the past two years,, 253.8 km{sup 2} (98 mi{sup 2}) of property has been successfully transitioned from the cleanup program to the LTS Program upon completion of active surface cleanup. Upcoming efforts in the near term will include transitioning another large parcel that includes one of the six (6) cocooned reactors on site. These accomplishments relied upon the transparency between DOE cleanup programs and their contractors working together to successfully transition the land while addressing the challenges that arise. All parties, the three different DOE Programs and their respective prime contractors are dedicated to working together and continuing the progress of transitioning land to LTS, in alignment with the Program Plan and compliant with contractual requirements. (authors)

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Scheduling the Remediation of Port Hope: Logistical and Regulatory Challenges of a Multiple Site Urban Remediation Project - 13119

The Port Hope Project is part of the larger CAN$1.28 billion Port Hope Area Initiative (PHAI), a community-based program for the development and implementation of a safe, local, long-term management solution for historic Low-Level Radioactive Waste (LLRW) in the Municipalities of Port Hope and Clarington, Ontario, Canada. Atomic Energy of Canada (AECL) is the Project Proponent, Public Works and Government Services (PWGSC) is managing the procurement of services and the MMM Group Limited - Conestoga Rovers and Associates Joint Venture (MMM-CRA Joint Venture) is providing detailed design and construction oversight and administration services for the Project. The Port Hope Project includes the construction of a long-term waste management facility (LTWMF) in the Municipality of Port Hope and the remediation of 18 (eighteen) large-scale LLRW, numerous small-scale sites still being identified and industrial sites within the Municipality. The total volume to be remediated is over one million cubic metres and will come from sites that include temporary storage sites, ravines, beaches, parks, private commercial and residential properties and vacant industrial sites all within the urban area of Port Hope. Challenges that will need to be overcome during this 10 year project include: - Requirements stipulated by the Environmental Assessment (EA) that affect Project logistics and schedule. - Coordination of site remediation with the construction schedule at the LTWMF. - Physical constraints on transport routes and at sites affecting production rates. - Despite being an urban undertaking, seasonal constrains for birds and fish (i.e., nesting and spawning seasons). - Municipal considerations. - Site-specific constraints. - Site interdependencies exist requiring consideration in the schedule. Several sites require the use of an adjacent site for staging. (authors)

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