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At least 739 records · Page 41
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Record of Technical Change (ROTC) for the CADD/CR for CAU 550: Smoky Contamination Area, Revision 0

This ROTC replaces the Use Restriction (UR) forms listed in the CAU 550 CADD/CR (DOE/NV--1532). These UR forms have been updated to list all UR requirements, including but not limited to: post-closure site controls, inspection and maintenance requirements, Geographic Information Systems (GIS) coordinate information. The UR Forms attached to this ROTC are the current UR requirements for each UR in this CAU and supersede any existing UR documentation.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Transport of Organic Contaminants Mobilized from Coal through Sandstone Overlying a Geological Carbon Sequestration Reservoir

Column experiments were conducted using a wetted sandstone rock installed in a tri-axial core holder to study the flow and transport of organic compounds mobilized by scCO2 under simulated geologic carbon storage (GCS) conditions. The sandstone rock was collected from a formation overlying a deep saline reservoir at a GCS demonstration site. Rock core effluent pressures were set at 0, 500, or 1000 psig and the core temperature was set at 20 or 50°C to simulate the transport to different subsurface depths. The concentrations of the organic compounds in the column effluent and their distribution within the sandstone core were monitored. Results indicate that the mobility though the core sample was much higher for BTEX compounds than for naphthalene. Retention of organic compounds from the vapor phase to the core appeared to be primarily controlled by partitioning from the vapor phase to the aqueous phase. Adsorption to the surfaces of the wetted sandstone was also significant for naphthalene. Reduced temperature and elevated pressure resulted in greater partitioning of the mobilized organic contaminants into the water phase.

Zhong, Lirong↗
DOE OSTI2012

In-Situ Radiological Surveys to Address Nuclear Criticality Safety Requirements During Remediation Activities at the Shallow Land Disposal Area, Armstrong County, Pennsylvania - 12268

Cabrera Services Inc. (CABRERA) is the remedial contractor for the Shallow Land Disposal Area (SLDA) Site in Armstrong County Pennsylvania, a United States (US) Army Corps of Engineers - Buffalo District (USACE) contract. The remediation is being completed under the USACE's Formerly Utilized Sites Remedial Action Program (FUSRAP) which was established to identify, investigate, and clean up or control sites previously used by the Atomic Energy Commission (AEC) and its predecessor, the Manhattan Engineer District (MED). As part of the management of the FUSRAP, the USACE is overseeing investigation and remediation of radiological contamination at the SLDA Site in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), 42 US Code (USC), Section 9601 et. seq, as amended and, the National Oil and Hazardous Substance Pollution Contingency Plan (NCP), Title 40 of the Code of Federal Regulations (CFR) Section 300.430(f) (2). The objective of this project is to clean up radioactive waste at SLDA. The radioactive waste contains special nuclear material (SNM), primarily U-235, in 10 burial trenches, Cabrera duties include processing, packaging and transporting the waste to an offsite disposal facility in accordance with the selected remedial alternative as defined in the Final Record of Decision (USACE, 2007). Of particular importance during the remediation is the need to address nuclear criticality safety (NCS) controls for the safe exhumation and management of waste containing fissile materials. The partnership between Cabrera Services, Inc. and Measutronics Corporation led to the development of a valuable survey tool and operating procedure that are essential components of the SLDA Criticality Safety and Material Control and Accountability programs. Using proven existing technologies in the design and manufacture of the Mobile Survey Cart, the continued deployment of the Cart will allow for an efficient and reliable methodology to allow for the safe exhumation of the Special Nuclear Material in existing SLDA trenches. (authors)

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

Fully Robotic Hot Cell Crane for Target Hall Operations at Isotope Research Facility - 18329

There are many types of equipment used in high radiation environments, but the super-sized and high precision lifting requirements for an isotope research facility in the USA called for one of the largest fully robotic cranes in the US. The 20 Ton Remote Handling Bridge Crane provided by PaR Systems met many challenging requirements for accuracy, repeatability and unique lifting motions in the radiation-shielded target hall of this facility. This robotic system was designed to address four main issues. The first is that the crane needed to be operated remotely due to high radioactivity during the time when it is needed most. Second is that high precision is needed due to the complex fit of multiple heavy shielding blocks. Third problem is that automated routines and exclusion areas were needed due to the remote operation of the system around high capital cost equipment. Lastly is the survivability of the equipment due to the high radiation environment. The facility robotic crane is an overhead top running multiple girder hot cell bridge crane (hereafter referred to as the system). The system is intended to be used in either manually operated or automated operation under computer control. Under automated control, the system provides highly accurate motion control in three linear axes as well as hook rotation. Using motion control programming, this highly accurate system ensures safe, remote movement of in-cell components. The system was designed to be remotely operated by a technician from the remote handling control room in the facility. This is facilitated by computer control using the System Graphical User Interface with feedback from a facility supplied video system. It can also be operated using a wireless hand held controller. The system will be used to place sensitive components with high precision in locations that will be difficult to observe directly. In order to accomplish this, it is critical that the system be capable of moving its payload with minimal swing, and with high accuracy, repeatability and reliability. The system will be operating in an environment where it will be exposed to both high energy neutrons and gamma radiation. Under beam-off conditions, the target hall will be hands-on accessible to accommodate crane maintenance. The system was installed and tested in early 2017 in advance of the live operations of the facility. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2014

Influence of impurities on the transition from minority to mode conversion heating in ({sup 3}He)-H)- plasmas

Ion cyclotron resonance heating (ICRH) is one of the main auxiliary heating systems used in present-day tokamaks and is planned to be installed in ITER. In the initial full-field phase of ITER operating with hydrogen majority plasmas, fundamental resonance heating of helium-3 ions is one of a few ICRH schemes available. Past JET experiments with the carbon wall revealed a significant impact of impurities on the ICRH performance in ({sup 3}He)-H plasmas. A significant reduction of the helium-3 concentration, at which the transition from minority ion to mode conversion heating occurs, was found to be due to a high plasma contamination with carbon ions. In this paper we discuss the effect of Be and another impurity species present at JET after the installation of a new ITER-like wall on the transition helium-3 concentration in ({sup 3}He)-H plasmas. We suggest a potential method for controlling helium-3 level needed for a specific ICRH regime by puffing an extra helium-4 gas to the plasma.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Erosion Control Measures at Oak Ridge Reservation Landfills Oak Ridge, Tennessee - 19190

URS-CH2M Oak Ridge LLC (UCOR) manages the cleanup of the 2,200-acre East Tennessee Technology Park (ETTP) for its client, the U.S. Department of Energy (DOE), in Oak Ridge, Tennessee. The ETTP was contaminated with radioactive, hazardous and industrial wastes generated by more than 40 years of national defense and energy missions. In disposing of low-level radioactive and other wastes from demolition activities, the UCOR approach relies on the availability of onsite facilities to streamline disposal, reduce costs and enhance cleanup schedules while confining shipments and related hazards onsite. The sanitary/industrial waste facility, known as the Oak Ridge Reservation Landfill Facility (ORRLF) is a solid waste operation that receives and disposes of sanitary/industrial, construction/demolition and classified, special waste; and spoil materials types of waste generated at the U.S. Department of Energy (DOE) Oak Ridge facilities. ETTP is the primary generator; however, the landfill accepts waste from Y-12 National Security Complex (Y-12), Oak Ridge National Laboratory and other DOE prime contractors in the Oak Ridge area. ORRLF's mission is to receive nonhazardous, non-radioactive, and non-Resource Conservation and Recovery Act of 1976 (RCRA)-regulated solid wastes. Approved operations include receiving, compacting, and covering wastes; leachate management, site drainage; erosion control and prevention, inspections, maintenance and recording keeping. The Oak Ridge Reservation has three separate State of Tennessee-permitted active landfills (Landfill IV, Landfill V, and Landfill VII) that meet different disposal needs -- classified industrial waste, industrial waste that includes office trash and cafeteria waste, and construction and demolition debris,. As with a typical landfill, strategic waste placement and covering involves moving a lot of soil, usually resulting in large areas of exposed land. After increased sediment was noted in streams following heavy rains, a concerted erosion prevention and sediment control effort began in 2017. While not uncommon for landfills, the ORRLF staff knew they could do better in controlling sediment. In response, the ORRLF staff developed an approach of aggressive revegetation, ditch improvements and other erosion controls. Staff developed a list of all the areas that needed the most attention and requested resources. UCOR management arranged funding for needed improvements. The oldest of the three landfills is Industrial Landfill IV, which opened in 1989 and has an expected remaining 60 years of life. Therefore, how the landfills are maintained/managed today directly affects the compliance posture, the capacity, and the infrastructure in the future. A systematic, aggressive and multi-pronged approach was taken to address the major concerns first, then continue with longer-term, and/or lower priority projects. Buy-in was obtained from both craft and supervision, resulting in approaches like 'Ditch of the Month'. In addition, management support at the highest levels has provided resources and recognition that further fuels progress. After working on the site for the past year, what used to be exposed brown hills looks more like a golf course now. Now that the grass is established and other erosion controls are in place, the amount of sediment leaving the site has been reduced, and the appearance of the landfills is improved. Vegetation dissipates the kinetic energy from rain droplets while the root system helps hold the soil in place, and wire-reinforced silt fences and straw wattles have greatly improved erosion control. Improved ditches reduce the runoff velocities allowing sediments to fall out of suspension in the stormwater before they reach the receiving waters, and structures are in place to let finer sediment settle in ponds rather than going downstream. In addition, the project has added more stone to roadways to minimize tracking dirt down the road as an average of 20 to 40 trucks per day enter and leave the site. Ongoing landfill erosion and sediment control must be funded and maintained continually. The lack of attention to either resource will negatively affect the condition of the landfill fairly quickly. Constant compliance commitment is necessary to ensure protection to the environment, the operator/workers and the public. Operations must include sediment control, pond maintenance and clean out, road maintenance and construction, erosion prevention, seeps repair, leachate management, landfill expansion, mowing and grounds upkeep and much more. Knowledgeable/experience staff is also crucial. Knowing how to build lifts, create leachate drainage windows, respond to high rains events, compact waste will impact operations today and future operations into the closure / post closure periods. (author)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Axenisation of oleaginous microalgal cultures via anoxic photosensitisation

Growing interest in sustainable food and biofuel research has necessitated high quality axenic oleaginous microalgal strains. Unfortunately, most strains available in culture banks contain commensal microbes such as bacteria and the default decontamination method involves antibiotic treatment which has begun to exacerbate the emergence of antibiotic resistance. To overcome this problem, anoxic photosensitisation was investigated as an alternate approach. Four oleaginous microalgal species (Tetradesmus obliquus, Desmodesmus armatus, Chlorella vulgaris and Nannochloropsis limnetica) were incubated in varying concentrations of Rose Bengal (0 μM, 1 μM, 3 μM or 9 μM) either in normal (oxic) or anoxic conditions, for 72 h under light (8.85 ± 0.4 W/m 2 ) in a specially designed heterotrophic growth complex (HGC) medium, followed by 72 h in standard Bold's Basal Medium (BBM). Commonly used antibiotics-based protocol was used as the control method. Post treatment, cell numbers and percentage populations were counted with Flow Cytometry, and viability was tested using standard plating methods using BBM and LB. Additionally, the contaminating microbes in the cultures were profiled using 16Ss rRNA sequencing. Anoxic conditions were able to significantly decrease bacterial content, albeit with an equally detrimental effect on the microalgal population. Although the responses differed between the microalgae, anoxic incubation along with Rose Bengal at 3 μM was able to completely decontaminate N. limnetica and C. vulgaris, while D. armatus and T. obliquus could be decontaminated with an additional streak-plating step. None of the cultures could be decontaminated using antibiotics treatment. These results suggest that axenisation of microalgal cultures was largely due to anoxy, that was synergistically enhanced by Rose Bengal at a concentration of ≥3 μM.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Green hydrogen from microalgal liquefaction byproducts with ammonia recovery and effluent recycle for developing circular processes

Hydrothermal liquefaction is a promising technology for microalgae-based biofuel production. However, hydrothermal liquefaction’s aqueous wastes have little established reuse, and contain significant fractions of toxic ammoniacal nitrogen. Careful reuse of this waste can assure microalgae-based biofuels are produced with less environmental impact and larger energy efficiency. Microbial electrolysis cells were investigated to valorize this waste product by converting the leftover organics into hydrogen and remove ammonia. Waste hydrothermal liquefaction aqueous phase from two microalgal strains, Tetraselmis sp. and Chlorella sp. were used as feedstocks for hydrogen production in microbial electrolysis cells. Chlorella and Tetraselmis aqueous phase-fed microbial electrolysis cells reach an average current density of 5.1 ± 0.19 A/m 2 and 3.8 ± 0.08 A/m 2 . Compound removal rates and mass removal percentages were also investigated for each feedstock. Additionally, acetic acid, propionic acid, ethanol, and glycerol were effectively removed from the aqueous byproduct. Further, microbial electrolysis cells separated up to 34.3% of ammoniacal nitrogen present in the aqueous phase. Charge transfer analysis indicated that proton transfer, not ammonium transfer, contributed to the majority of the hydrogen production in the cathode. Finally, the microbial electrolysis cell effluent was reused to grow the same microalgal strains, leading to the development of a circular biofuel production system. Microalgae regrowth studies using microbial electrolysis cell effluent showed nearly complete removal of total organic carbon, but significantly less removal of total nitrogen. Tetraselmis sp. growth occurred with the Tetraselmis-derived MEC effluent, however, the control medium without effluent produced the most growth. These findings support the possibility of a circular biofuel framework using MECs, but additional constraints, including the removal of inorganic contaminants, are necessary to realize the circular processes.

09 BIOMASS FUELS↗
DOE OSTI2021

A comparative study of machine learning models for predicting the state of reactive mixing

Mixing phenomena are important mechanisms controlling flow, species transport, and reaction processes in fluids and porous media. Accurate predictions of reactive mixing are critical for many Earth and environmental science problems such as contaminant fate and remediation, macroalgae growth, and plankton biomass evolution. Here, to investigate the evolution of mixing dynamics under different scenarios (e.g., anisotropy, fluctuating velocity fields), a finite-element-based numerical model was built to solve the fast, irreversible bimolecular reaction-diffusion equations to simulate a range of reactive-mixing scenarios. A total of 2,315 simulations were performed using different sets of model input parameters comprising various spatial scales of vortex structures in the velocity field, time-scales associated with velocity oscillations, the perturbation parameter for the vortex-based velocity, anisotropic dispersion contrast (i.e., ratio of longitudinal-to-transverse dispersion), and molecular diffusion. The outputs comprised concentration profiles of reactants and products. The inputs to and outputs from these simulations were concatenated into feature and label matrices, respectively, to train 20 different machine learning (ML) models intended to emulate system behavior. These 20 ML emulators, based on linear methods, Bayesian methods, ensemble learning methods, and multilayer perceptrons (MLPs), were trained to classify the state of mixing and predict three quantities of interest (QoIs) characterizing species production, decay (i.e., average concentration, square of average concentration), and degree of mixing (i.e., variances of species concentration). Unsurprisingly, linear classifiers and regressors failed to reproduce the QoIs; however, ensemble methods (classifiers and regressors) and the MLP model accurately classified the state of reactive mixing and the QoIs. Among ensemble methods, random forest and decision-tree-based AdaBoost faithfully predicted the QoIs. At run time, trained ML emulators produced results times faster than the finite-element simulations. Due to their low computational expense and high accuracy, ensemble and MLP models are excellent emulators for these numerical simulations and great utilities in uncertainty quantification exercises, which can require 1,000s of forward model runs.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

Towards maintaining canine training aid integrity: Effects of environmental factors and operational use on the triacetone triperoxide polymer odor capture‐and‐release system

Abstract There are many factors that may affect the longevity of or guide the use of canine training aids. Literature to date has mainly focused on identifying the headspace volatiles associated with training aids or odors and only minimal research exists into how different variables may alter those volatiles. The current study examines several factors affecting canine training aids: humidity, air flow, transportation, and operational deployment, using the triacetone triperoxide polymer odor capture‐and‐release canine training aid (TATP POCR) as the target. The TATP POCR is an absorption‐based canine training aid developed to be used to safely train canines to detect the odor of the explosive TATP in operational settings. Comparisons of the TATP POCR to neat TATP are made throughout the manuscript. First, humidity increased the background components of the POCR matrix, as well as the amount of TATP recovered was above the POCR. Humidity thus affected the amount of TATP detected but did not prevent detection. Second, air flow lessened the lifetime of the TATP POCR. Third, the practice of using primary and secondary containment successfully prevented contamination, cross‐contamination, and significant target loss, thereby maintaining kit integrity. Finally, the absorption of background odors from training environments was not observed. TATP headspace concentrations between a Deployed and Control POCR kit were not significantly different at time 0 (i.e., upon opening), which suggests that the operational use does not affect the function of the TATP POCR system. This information provides pivotal evidence for explosives detection canine handlers or trainers who utilize the TATP POCR.

Legal Medicine↗
DOE OSTI2013

Lower Three Runs Remediation Safety Preparation Strategy - 13318

The Savannah River Site (SRS) is a 310-square-mile United States Department of Energy (US DOE) nuclear facility located along the Savannah River near Aiken, South Carolina that contains six primary stream/river systems. The Lower Three Runs Stream (LTR) is one of the primary streams within the site that is located in the southeast portion of the Savannah River Site. It is a large blackwater stream system that originates in the northeast portion of SRS and follows a southerly direction before it enters the Savannah River. During reactor operations, secondary reactor cooling water, storm sewer discharges, and miscellaneous wastewater was discharged and contaminated a 20 mile stretch of Lower Three Runs Stream that narrows and provides a limited buffer of US DOE property along the stream and flood-plain. Based on data collected during the years 2009 and 2010 under American Recovery and Re-investment Act funding, the stream was determined to be contaminated with cesium-137 at levels that exceeded acceptable risk based limits. In agreement with the Environmental Protection Agency and the South Carolina Department of Health and Environmental Control, three areas were identified for remediation [1] (SRNS April 2012). A comprehensive safety preparation strategy was developed for safe execution of the LTR remediation project. Contract incentives for safety encouraged the contractor to perform a complete evaluation of the work and develop an implementation plan to perform the work. The safety coverage was controlled to ensure all work was observed and assessed by one person per work area within the project. This was necessary due to the distances between the fence work and three transects being worked, approximately 20 miles. Contractor Management field observations were performed along with DOE assessments to ensure contractor focus on safe performance of the work. Dedicated ambulance coverage for remote worker work activities was provided. This effort was augmented with access to medical evacuation services. The areas where the work was performed were remote and difficult to get emergency vehicles to in a timely manner in case of an accident. Satellite phones were utilized due to intermittent phone coverage. High visibility vests were utilized to enable any hunters in the area to see the workers; due to the limited buffer areas along the stream route. An innovative approach to providing the necessary protection for workers during periods of extreme heat and humidity was also employed, which included the use of 'heat islands' with fans and crew trailers and ice vests for workers. (authors)

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

Robotic Measurement of Holdup Deposit Volume in Gaseous Diffusion Piping to Quantify U-235 Content - 18375

During D and D of old gaseous diffusion uranium enrichment facilities, radiometric assay of U-235 holdup in pipes is a costly, time consuming, and labor-intensive process. Subject to human interpretation using approximate modeling, radiometric assay introduces significant challenges. Taking advantage of routine demolition activities in which D and D cuts pipes open, robotic in-pipe assay is explored. The novel method introduced here generates models of the internal pipe and deposit surface geometries that are used to derive volumetric quantities. The pipe surface is sensed using a non-contact inductive proximity sensor and the deposit surface is sensed using an optical laser triangulation sensor. These sensors are mounted on a spinning disk and driven down the pipe to construct a helical point cloud of discrete measurements. Surfaces are fit to each of the two point clouds to create a watertight volume that represents the holdup. This provides the location and volume per foot of pipe that is used to compare against criticality incredible (CI) thresholds during evaluation. The robotic system collects data autonomously, deploying and returning to the same pipe opening from which it is launched. This provides redundant measurements of the pipe and deposit surfaces as well as odometry used in localization. (authors)

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

Model Study and Site Experience of Radiation Physics Analysis for Research Reactor Decommissioning - 18586

The University of Alberta Safe Low Power Kritical Experiment (SLOWPOKE II) nuclear reactor facility (UASF) was commissioned on April 22, 1977. It was designed, built and installed by Atomic Energy of Canada Limited (AECL) and was the fourth SLOWPOKE II research reactor installed at a Canadian university at that time. The reactor was used as a source of neutrons for radionuclide production and elemental analysis via neutron activation analysis, to provide a service to industry, government and to support research and teaching at the University of Alberta. It was licensed to operate at 20 kW, less than the heat produced by a small residential furnace, and work with the reactor was typically performed at one-tenth full power. After nearly four decades of service, the reactor reached the end of its useful life in August 2017 when defueling and the project to decommission the reactor began. Decommissioning of the UASF is a process to dismantle the facility by progressively removing the reactor core and other radioactive components as well as managing the balance of contaminated materials around the reactor in a safe manner. The objective of the project is to release the site from the Canadian Nuclear Safety Commission's (CNSC) regulatory control and return the site to a 'greenfield' status. This paper will discuss the radiation physics analysis that was undertaken to support the decommissioning of the University of Alberta SLOWPOKE II Facility Reactor which took place from July - October 2017. It will address the radiation physics model study, development of the radiation protection (RP) plan, site experience and how the lessons learned from this project can be utilized for best practice on other similar projects. (authors)

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

UNREVIEWED COMPOSITE ANALYSIS QUESTION EVALUATION: Update of Composite Analysis Sources Potentially Interacting with the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

This unreviewed composite analysis question evaluation (UCAQE) assesses the impacts of the FFACO corrective actions on the Area 5 RWMS CA and the need to revise or update the CA Federal Facility Agreement and Consent Order (FFACO). The FFACO, a legal agreement among the NNSA/NFO, the state of Nevada, and the U.S. Department of Defense, establishes a process to identify, characterize, and implement corrective actions for historical sites on the Nevada National Security Site (NNSS) contaminated with hazardous or radioactive materials. Review of FFACO corrective actions involving sources of residual radioactive contamination potentially interacting with the Area 5 RWMS indicates that no significant changes affecting CA results and conclusions have occurred. Doses from the Area 5 RWMS, Industrial Sites, and Soils sites are a small fraction of the 0.3 mSv CA dose constraint, and significant interactions with releases from the Area 5 RWMS are unlikely. Doses from FFACO CASs, including UGTA sites, can be controlled by FFACO URs and institutional controls that have been implemented since the CA was prepared. As the interactions between the Area 5 RWMS and the FFACO CASs are negligible, the sites can be managed independently. The Area 5 RWMS CA reached the same conclusions about the interaction of the Area 5 RWMS with other sources of residual contamination. Therefore, there is no need to revise or update the Area 5 RWMS CA.

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

Performance and Emissions Control of Commercial-Scale Biochar Production Unit

Abstract. Two commercial biochar production machines – a single-auger unit and a larger dual-auger version – were operated to evaluate feedstock specifications, biochar quality, throughput rates, and emissions profiles. Biochar was produced from woody biomass feedstocks of various species, contamination levels, comminution methods, and moisture contents. Feedstocks with ash content exceeding 15% dry basis or moisture content exceeding 25% wet basis were observed to decrease fixed carbon content of biochar and to increase the labor effort required to operate the machine. The dual-auger version of the machine was able to process 380 kg h -1 of biomass feedstock (dry basis) to produce 63 kg h -1 of biochar with a mean electricity demand of 4.5 kW. Average CO, propane, NO x , and SO 2 emission rates from the flare of this machine were measured to be 160, 120, 51, and 43 g h -1 , respectively, with total particulate matter (PM), PM 10 , and PM 2.5 emission rates of 380, 40, and 4.5 g h -1 , respectively. Results from these experiments indicate that high-quality biochar can be produced from a variety of feedstocks, including forest residuals, as long as the ash and moisture content are within the specifications. Future research and development should focus on increasing the throughput of the machine, implementing an automated control system to reduce the operational effort, and improving safety and product consistency. Keywords: Biochar, Biomass, Biomass conversion technology, Carbon sequestration, Forest residuals, Gasification, Pyrolysis.

Agriculture↗
DOE OSTI2026

Beam-water Interaction System for PFAS Treatment

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that resist conventional water treatment due to the strength of their carbon fluorine bonds. Electron-beam irradiation has shown potential for PFAS degradation; however, its effectiveness is limited by shallow energy penetration, restricting treatment to the upper region of the water surface. This project addresses this limitation through the design of a compact mixing chamber and recirculation system to enhance surface renewal and improve treatment efficiency. The system, constrained to approximately 10 cm 20 cm 20 cm, was developed using computer-aided design, computational fluid dynamics (CFD), and MATLAB-based hydraulic analysis to evaluate flow behavior, head loss, and pump compatibility. A perforated-baffle geometry and controlled flow range of 1 3 GPM were implemented to promote uniform mixing while maintaining a stable free surface for electron-beam exposure. Modeling results indicate improved flow distribution and reduced dead zones, supporting more consistent interaction between contaminated water and the beam. The final design enhances hydrodynamic performance within system constraints, contributing to scalable electron-beam water treatment technologies for improved PFAS degradation.

Ramos, Gerardo [Northern Illinois U.]↗
DOE OSTI2020

Atomically Dispersed Single Ni Site Catalysts for Nitrogen Reduction toward Electrochemical Ammonia Synthesis Using N 2 and H 2 O

Ammonia (NH 3 ) electrosynthesis gains significant attention as NH 3 is essentially important for fertilizer production and fuel utilization. However, electrochemical nitrogen reduction reaction (NRR) remains a great challenge because of low activity and poor selectivity. Herein, a new class of atomically dispersed Ni site electrocatalyst is reported, which exhibits the optimal NH 3 yield of 115 µg cm -2 h -1 at –0.8 V versus reversible hydrogen electrode (RHE) under neutral conditions. High faradic efficiency of 21 ± 1.9% is achieved at -0.2 V versus RHE under alkaline conditions, although the ammonia yield is lower. The Ni sites are stabilized with nitrogen, which is verified by advanced X-ray absorption spectroscopy and electron microscopy. Density functional theory calculations provide insightful understanding on the possible structure of active sites, relevant reaction pathways, and confirm that the Ni-N 3 sites are responsible for the experimentally observed activity and selectivity. Extensive controls strongly suggest that the atomically dispersed NiN 3 site-rich catalyst provides more intrinsically active sites than those in N-doped carbon, instead of possible environmental contamination. Overall, this work further indicates that single-metal site catalysts with optimal nitrogen coordination is very promising for NRR and indeed improves the scaling relationship of transition metals.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Removal Action Design Plan (RADP) with Effectiveness Monitoring Plan (EMP) for the C-Area Groundwater (CAGW) Operable Unit (OU) (U)

The purpose of this Removal Action Design Plan (RADP) with Environmental Monitoring Plan (EMP) is to provide the final design information for the implementation of the non-time critical (NTC) removal action at the C-Area Groundwater (CAGW) Operable Unit (OU) and the post-construction plan for monitoring. Groundwater associated with the CAGW OU is contaminated with tritium and volatile organic compounds (VOCs), primarily trichloroethylene (TCE), due to releases associated with reactor operations. This removal action focusses on the TCE contamination in the distal portion of the groundwater plume. The United States Department of Energy (USDOE), US Environmental Protection Agency (USEPA), and South Carolina Department of Health and Environmental Control (SCDHEC), and USDOE agreed to conduct a NTC removal action at the CAGW OU to reduce potential risk to human health and the environment. This RADP presents the design details for the removal action including a description of the removal action construction strategy, removal action activities, and effectiveness monitoring plan. The removal action along with the Applicable or Relevant and Appropriate Requirements are presented in the Action Memorandum (AM), Revision 0 (USDOE 2018) for the CAGW OU and the Removal Site Evaluation Report/Engineering Evaluation/Cost Analysis (RSER/EE/CA) for C-Area Groundwater Operable Unit (SRNS 2018).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗