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Site assessment and permanent closure of the Idaho National Laboratory (INL) Central Facilities Area (CFA) diesel underground storage tank 98CFA00260 (DEQ Facility ID# 6-120608), in accordance with the regulatory requirements established in 40 CFR 280.71, “Permanent Closure and Changes-In-Service.”
Eight High Level Waste (HLW) tanks used to store radioactive waste slurries have been emptied and closed at the Savannah River Site (SRS). Performance Analyses (PA) modeling of the release of radionuclides from residual waste solids in these tanks into the environment over extended time periods indicated the most likely risk drivers for environmental contamination. Radionuclide leaching studies were desired to provide additional information regarding the residual waste solubility assumptions used in the models. This report serves to provide equilibrium solubility data for several radionuclides identified as risk drivers and adds to the database of solubility values reported in the previous analogous study with Tank 18F solids. Pore water leaching studies were conducted on actual SRS Tank 12H residual waste solids to support Liquid Waste tank closure efforts and closed tank Performance Analyses. Tank 12H was exposed to extensive mechanical cleaning, caustic aluminum dissolution, and oxalic acid chemical cleaning prior to closure. The methodology utilized for leach testing was developed during previous testing. Slurries of tank residual solids and grout-representative solids in simulated grout pore water solutions (based on SRS groundwater compositions) with pH and E h values expected during the aging of the closed waste tank were produced. The soluble concentrations of selected radionuclides were analyzed versus time to confirm equilibrium conditions were achieved. These are the first leach studies conducted on waste tank residuals exposed to these cleaning conditions.
Corrective Action Unit (CAU) 98: Frenchman Flat on the Nevada National Security Site was the location of 10 underground nuclear tests. CAU 98 underwent a series of investigations and actions in accordance with the Federal Facility Agreement and Consent Order to assess contamination of groundwater by radionuclides from the tests. A Closure Report completed that process in 2016 and called for long-term monitoring, use restrictions (URs), and institutional controls to protect the public and environment from potential exposure to contaminated groundwater. Three types of monitoring are performed for CAU 98: water quality, water level, and institutional control. These are monitored to determine whether the URs remain protective of human health and the environment, and to ensure that the regulatory boundary objectives are being met. Monitoring data will be used in the future, once multiple years of data are available, to evaluate consistency with the groundwater flow and contaminant transport models because the contaminant boundaries calculated with the models are the primary basis of the UR boundaries. Six wells were sampled for water-quality monitoring in 2018. Contaminants of concern were detected only in the two source/plume wells already known to contain contamination as a result of a radionuclide migration experiment. Tritium concentrations in both of these wells, RNM-2S and UE-5n, remain above the Safe Drinking Water Act maximum contaminant level of 20,000 picocuries per liter but declined in 2018 as compared to measurements in 2017. All other contaminants of concern are below the minimum detection level plus analytical error. The water-level monitoring network includes 16 wells. Depth to water measured in 2018 is generally consistent with recent measurements for all wells. Many wells continue to exhibit a long-term downward trend in water level, despite small increases in measured water levels in 2018. The sharp 2016 decline in water level in Well ER-5-3-2 remains unexplained, with the lower level persisting through 2018. Rising water-level trends continue to be observed in two relatively deep wells (ER-5-3 deep piezometer and ER-5-4-2), and also in former supply Well WW-5A. The current supply wells exhibit relatively erratic water levels associated with pumping activities. Institutional control monitoring confirmed the URs are recorded in U.S. Department of Energy and U.S. Air Force land management systems, and that no activities within Frenchman Flat basin are occurring that could potentially affect the contaminant boundaries. Survey of groundwater resources in basins surrounding Frenchman Flat similarly identify no current or pending development that would indicate the need to increase monitoring activities or would otherwise cause concern for the closure decision. The URs continue to prevent exposure of the public, workers, and the environment to contaminants of concern by preventing use of potentially contaminated groundwater.
This letter serves as the annual post-closure letter for Corrective Action Unit 98, Frenchman Flat; CAU 97, Yucca Flat/Climax Mine; and CAU 99, Rainier Mesa/Shoshone Mountain for calendar year 2022. This letter will discuss the post-closure monitoring activities that occurred during CY 2022, identify any triggers reached, and summarize water usage on the Nevada National Security Site (NNSS) and surrounding hydrographic basins at the three CAUs.
This letter serves as the annual post-closure letter for Corrective Action Unit (CAU) 98, Frenchman Flat (FF); CAU 97, Yucca Flat/Climax Mine (YF/CM); and CAU 99, Rainier Mesa/Shoshone Mountain (RM/SM) for calendar year (CY) 2024. This letter will discuss the post-closure monitoring activities that occurred during CY 2024, identify any triggers reached, and summarize water usage on the Nevada National Security Site (NNSS) and surrounding hydrographic basins at the three CAUs.
This letter serves as the annual post-closure letter for CAU 98, Frenchman Flat; CAU 97, Yucca Flat/Climax Mine; and CAU 99, Rainier Mesa/Shoshone Mountain for calendar year 2025. This letter will discuss the post-closure monitoring activities that occurred during CY 2025, identify any triggers reached, and summarize water usage on the Nevada National Security Site and surrounding hydrographic basins at the three CAUs.
This report includes visual inspection results, descriptions of maintenance and repair activities, and recommendations for CY 2025 for use restrictions (URs) at corrective action sites (CASs) located on the Nevada National Security Site and on the Nevada Test and Training Range (NTTR) that are accessed through the NNSS Main Gate. This document is arranged by project activity (i.e., Industrial Sites, Soils, and Defense Threat Reduction Agency [DTRA]); then by corrective action unit (CAU); and then by CAS. Post-closure UR inspections are performed on an annual basis, unless as noted in text. Post-closure UR inspections verify the condition of physical controls required by each UR, which may include the following activities: • Visual verification of the legibility of signs • Visual inspection of fencing, signs, monuments, and/or markers for indications of wear • Visual inspection of soil covers for indications of subsidence, erosion, or unauthorized use Deficiencies in UR requirements that were identified during CY 2024 inspections and not addressed in the CY 2024 report are addressed in this CY 2025 report.
This report provides the results of the annual post-closure use restriction (UR) inspections at the closed corrective action sites (CASs) located on the Tonopah Test Range (TTR) and Nevada Test and Training Range (NTTR) that are accessed through the TTR/NTTR main gate. This report covers post-closure UR inspections for calendar year 2019, and includes visual inspections and repair activities completed at the following corrective action units (CAUs): • CAU 400, Bomblet Pit and Five Points Landfill (TTR) • CAU 407, Roller Coaster RadSafe Area (TTR) • CAU 424, Area 3 Landfill Complexes (TTR) • CAU 453, Area 9 UXO Landfill (TTR) • CAU 487, Thunderwell Site (TTR)
We formulate a new second-order closure turbulence model by employing a recent closure for the pressure-temperature correlation at the equation level. As a result, we obtain new heat flux equations that avoid the long-standing issue of a finite critical Richardson number. The new, structurally simpler model improves on the Mellor-Yamada 1982 and Galperin et al. 1988 models; key feature includes enhanced mixing under stable conditions facilitating agreement with observational, experimental and high-resolution numerical data sets. The model predicts a planetary boundary layer height deeper than predicted by models with low critical Richardson numbers, as demonstrated in single column model runs of the GISS ModelE general circulation model.
A numerical simulation framework is presented in this paper for estimating evolution of pH and release of major species from grout within high-level waste tanks after closure. This model was developed as part of the Cementitious Barriers Partnership. The reactive transport model consists of two parts - (1) transport of species, and (2) chemical reactions. The closure grout can be assumed to have varying extents of cracking and composition for performance assessment purposes. The partially or completely degraded grouted tank is idealized as a dual regime system comprising of a mobile region having solid materials with cracks and macro-pores, and an immobile/stagnant region having solid matrix with micropores. The transport profiles of the species are calculated by incorporating advection of species through the mobile region, diffusion of species through the immobile/stagnant region, and exchange of species between the mobile and immobile regions. A geochemical speciation code in conjunction with the pH dependent test data for a grout material is used to obtain a mineral set that best describes the trends in the test data of the major species. The dual regime reactive transport model predictions are compared with the release data from an up-flow column percolation test. The coupled model is then used to assess effects of crack state of the structure, rate and composition of the infiltrating water on the pH evolution at the grout-waste interface. The coupled reactive transport model developed in this work can be used as part of the performance assessment process for evaluating potential risks from leaching of a cracked tank containing elements of human health and environmental concern. (authors)
The road-map to obtaining closure of the Middlesex Sampling Plant FUSRAP site in Middlesex, New Jersey (NJ) has required a multi-faceted approach, following the CERCLA Process. Since 1998, the US ACE, ECC, and other contractors have completed much of the work required for regulatory acceptance of site closure with unrestricted use. To date, three buildings have been decontaminated, demolished, and disposed of. Two interim storage piles have been removed and disposed of, followed by the additional removal and disposal of over 87,000 tons of radiologically and chemically-impacted subsurface soils by the summer of 2008. The US ACE received a determination from the EPA for the soils Operable Unit, (OU)-1, in September 2010 that the remedial excavations were acceptable, and meet the criteria for unrestricted use as required by the 2004 Record of Decision (ROD) for OU-1. Following the completion of OU-1, the project delivery team performed additional field investigation of the final Operable Unit for Middlesex, OU-2, Groundwater. As of December 2012, the project delivery team has completed a Supplemental Remedial Investigation, which will be followed with a streamlined Feasibility Study, Proposed Plan, and ROD. Several years of historical groundwater data was available from previous investigations and the FUSRAP Environmental Surveillance Program. Historical data indicated sporadic detections of Volatile Organic Compounds (VOCs), primarily trichloroethylene (TCE), carbon tetrachloride (CT), and methyl tert-butyl ether (MTBE), with no apparent trend or pattern indicating extent or source of the VOC impact. In 2008, the project delivery team initiated efforts to re-assess the Conceptual Site Model (CSM) for groundwater. The bedrock was re-evaluated as a leaky multi-unit aquifer, and a plan was developed for additional investigations for adequate bedrock characterization and delineation of groundwater contaminated primarily by CT, TCE, and tetrachloroethene (PCE). The investigation was designed to accumulate multiple lines of evidence to determine the source and to delineate the extent of contamination, as required to complete the CERCLA Process and gain regulatory acceptance. Investigative techniques included in-well vertical flow tracing, borehole geophysics and packer testing of temporary test holes to characterize contamination in the bedrock fractures beneath the site, and to delineate likely source areas. (authors)
The end of the Cold War has left a legacy of approximately 37 million gallons of radioactive waste in the aging waste tanks at the Department of Energy's Savannah River Site (SRS). A robust program is in place to remove waste from these tanks, treat the waste to separate into a relatively small volume of high-level waste and a large volume of low-level waste, and to actively dispose of the low-level waste on-site and close the waste tanks and associated ancillary structures. To support performance-based, risk-informed decision making and to ensure compliance with all regulatory requirements, the U.S. Department of Energy (DOE) and its current and past contractors have worked closely with the South Carolina Department of Health and Environmental Control (SCDHEC), the U.S. Environmental Protection Agency (EPA) and the Nuclear Regulatory Commission (NRC) to develop and implement a framework for on-site low-level waste disposal and closure of the SRS waste tanks. The Atomic Energy Act of 1954, as amended, provides DOE the authority to manage defense-related radioactive waste. DOE Order 435.1 and its associated manual and guidance documents detail this radioactive waste management process. The DOE also has a requirement to consult with the NRC in determining that waste that formerly was classified as high-level waste can be safely managed as either low-level waste or transuranic waste. Once DOE makes a determination, NRC then has a responsibility to monitor DOE's actions in coordination with SCDHEC to ensure compliance with the Title 10 Code of Federal Regulations Part 61 (10CFR61), Subpart C performance objectives. The management of hazardous waste substances or components at SRS is regulated by SCDHEC and the EPA. The foundation for the interactions between DOE, SCDHEC and EPA is the SRS Federal Facility Agreement (FFA). Managing this array of requirements and successfully interacting with regulators, consultants and stakeholders is a challenging task but ensures thorough and thoughtful processes for disposing of the SRS low-level waste and the closure of the tank farm facilities. (authors)
The United States (U.S.) Department of Energy (DOE) manages the largest groundwater and soil cleanup effort in the world. DOE's Office of Environmental Management (EM) has made significant progress in its restoration efforts at sites such as Fernald and Rocky Flats. However, remaining sites, such as Savannah River Site, Oak Ridge Site, Hanford Site, Los Alamos, Paducah Gaseous Diffusion Plant, Portsmouth Gaseous Diffusion Plant, and West Valley Demonstration Project possess the most complex challenges ever encountered by the technical community and represent a challenge that will face DOE for the next decade. Closure of the remaining 18 sites in the DOE EM Program requires remediation of 75 million cubic yards of contaminated soil and 1.7 trillion gallons of contaminated groundwater, deactivation and decommissioning (D and D) of over 3000 contaminated facilities and thousands of miles of contaminated piping, removal and disposition of millions of cubic yards of legacy materials, treatment of millions of gallons of high level tank waste and disposition of hundreds of contaminated tanks. The financial obligation required to remediate this volume of contaminated environment is estimated to cost more than 7% of the to-go life-cycle cost. Critical in meeting this goal within the current life-cycle cost projections is defining technically achievable end states that formally acknowledge that remedial goals will not be achieved for a long time and that residual contamination will be managed in the interim in ways that are protective of human health and environment. Formally acknowledging the long timeframe needed for remediation can be a basis for establishing common expectations for remedy performance, thereby minimizing the risk of re-evaluating the selected remedy at a later time. Once the expectations for long-term management are in place, remedial efforts can be directed towards near-term objectives (e.g., reducing the risk of exposure to residual contamination) instead of focusing on long-term cleanup requirements. An acknowledgement of the long timeframe for complete restoration and the need for long-term management can also help a site transition from the process of pilot testing different remedial strategies to selecting a final remedy and establishing a long-term management and monitoring approach. This approach has led to cost savings and the more efficient use of resources across the Department of Defense complex and at numerous industrial sites across the U.S. Defensible end states provide numerous benefits for the DOE environmental remediation programs including cost-effective, sustainable long-term monitoring strategies, remediation and site transition decision support, and long-term management of closure sites. (authors)
We report in regimes of high strain rate, the strength of materials often cannot be measured directly in experiments. Instead, the strength is inferred based on an experimental observable, such as a change in shape, that is matched by simulations supported by a known strength model. In hole closure experiments, the rate and degree to which a central hole in a plate of material closes during a dynamic loading event are used to infer material strength parameters. Due to the complexity of the experiment, many computationally expensive, three-dimensional simulations are necessary to train an emulator for calibration or other analyses. These simulations can be run at multiple grid resolutions, where dense grids are slower but more accurate. In an effort to reduce the computational cost, a combination of simulations with different resolutions can be combined to develop an accurate emulator within a limited training time. We explore the novel design and construction of an appropriate functional recursive multi-fidelity emulator of a strength model for tantalum in hole closure experiments that can be applied to arbitrarily large training data. Hence, by formulating a multi-fidelity model to employ low-fidelity simulations, we were able to reduce the error of our emulator by approximately 81% with only an approximately 1.6% increase in computing resource utilization.
A complication of the StarClose Vascular Closure System (Abbott, Des Plaines, IL) after a transarterial hepatic chemoembolization is described. After attempted clip deployment, the entire device became lodged in the tissues overlying the common femoral artery and could not be removed percutaneously. Successful removal of the device required surgical cutdown for removal and arterial repair. Entrapment of the StarClose vascular closure deployment system is a potentially serious complication that has been reported in the Manufacturer and User Facility Device Experience database, but has not been recognized in the literature.
A 46-year-old man presenting with massive hemoptysis was found to have a large pulmonary arteriovenous malformation (PAVM) in the right lung. Closure of the PAVM with an Amplatzer-type duct occluder was hampered by inability to advance the device delivery sheath into the PAVM due to vessel tortuosity and inadequate guidewire support. Atrial septal puncture was performed and a femorofemoral arteriovenous guidewire loop through the right pulmonary artery, PAVM, and left atrium was created. Traction on both ends of the guidewire loop allowed advancement of the device delivery sheath into the PAVM and successful completion of the procedure. Transseptal guidewire stabilization can be a valuable option during device closure of large PAVMs when advancement, stability, or kinking of the device delivery sheath is an issue.
Manual compression (MC) is a well-established technique for haemostasis following percutaneous arterial intervention. However, MC is labour and time intensive with potential limitations, particularly for patients who are coagulopathic, unable to comply with bed rest or obese and when large sheaths or anti-coagulants are used. There are a variety of vascular closure devices (VCDs) available to overcome these limitations. This review gives an overview of current VCDs, their mechanism of action, individual strengths and weaknesses, evidence base and utility in interventional radiology (IR) practice. The majority of the published evidence on VCDs is derived from patients undergoing cardiac interventions, which should be borne in mind when considering the applicability and transfer of this data for general IR practice. Overall, the evidence suggests that most VCDs are effective in achieving haemostasis with a similar rate of complications to MC although the complication profile associated with VCDs is distinct to that of MC. There is insufficient evidence to comparatively analyse the different types of VCDs currently available or reliably judge their cost-effectiveness. The interventional radiologist should have a thorough understanding of the available techniques for haemostasis and be able to identify and utilise the most appropriate strategy and closure technique for the individual patient.
Abstract This paper presents a sensible-enthalpy-based conditional moment closure (CMC) model for homogeneous charge compression ignition (HCCI) with temperature inhomogeneity. The focus of study is placed on the effects of a conditioning variable on the prediction of heat release rates and developing the mixing models for sensible enthalpy, a reacting scalar. The sensible-enthalpy-based CMC model is validated a priori with 2-D direct numerical simulation (DNS) data for HCCI, and compared with the total-enthalpy-based formulation. Sensible enthalpy is shown to be strongly correlated with temperature, which makes sensible enthalpy well suited for a conditioning variable in CMC for HCCI. Results show that sensible-enthalpy-based CMC performs well for the prediction of heat release rates for all temperature stratification levels investigated in this study, while total-enthalpy-based CMC leads to the overprediction of heat release rates when the temperature stratification level is high. While conditional fluctuations of species mass fractions are substantial, sensible-enthalpy-based CMC is found to accurately estimate heat release rates during ignition, as well as reaction rates of key species, due to substantially suppressed conditional temperature fluctuations. The mapping closure models for the probability density function (PDF) and conditional dissipation rates of sensible enthalpy are proposed. The proposed models are found to capture the characteristics of reactive scalar mixing.