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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

25 Years of Contamination Control on the James Webb Space Telescope

The James Webb Space Telescope (JWST) has actively been in process since 1996, and at last, on Christmas Day 2021, it launched. This launch was the fulfillment of an astounding level of work performed by thousands of people across the globe in dozens of disciplines. From the start, effective contamination control was considered essential for the JWST mission due to the large, exposed optics and tight sensitivity required to measure first light and faint signals at the dawn of the universe. This paper will present the JWST mission and requirements overview, including mission requirements that led to optimizing performance for collecting light in the Near Infrared (NIR, 0.6μm) – Mid Infrared (MIR, 29μm) range. Molecular films absorb in the IR bands and can alter thermal emissivity, resulting in increased noise at the longer wavelengths (MIRI). Particles increase light scatter and background noise levels at the shorter wavelengths (NIRSpec, NIRCam and FGS). The passively cooled design of JWST led to an open architecture for the optical telescope element (OTE), presenting the challenge of maintaining cleanliness throughout assembly, integration, and test in a multitude of environments. The paper will describe the mission and will introduce the specific areas of contamination control developed and advanced to keep JWST clean at an unsurpassed level of cleanliness.

Contamination Control↗
NASA NTRSDate not supplied

Contamination monitoring of the OSIRIS-REx ISO5 asteroid sample cleanroom

The OSIRIS-REx mission to asteroid Bennu successfully collected hundreds of grams of asteroid regolith in October 2020 [1]. The spacecraft departed Bennu in May 2021 for Earth return and will release the sample canister to be recovered in Utah in September 2023 [2]. Samples will be transported to the curation facility at NASA Johnson Space Center, where an ISO5 equivalent cleanroom has been designed in 2017 and completed in 2021. Aspects of the design and material selection for the cleanroom and its supporting facilities (air handling system, cleanroom floors and walls, filters, paints, etc.) were optimized to minimize effects of organic and inorganic contaminants and offgassing [3]. Since its completion, the lab has been carefully monitored to understand and establish a baseline with respect to multiple environmental aspects – measurement of particle counts, deploying Si wafer witness plates for organic and inorganic contaminants, deploying aluminum foils for a focus on organics with JSC in-house expertise, gas samples, and regular microbial and fungal measurements on selected surfaces and air samples in the cleanroom. This contribution will report on nearly one year of monitoring and highlight several specific aspects that have led to a better understanding of the new cleanroom environment.

carbonaceous asteroid↗
NASA NTRSDate not supplied

25 Years of Contamination Control on the James Webb Space Telescope

The James Webb Space Telescope (JWST) has actively been in process since 1996, and at last, on Christmas Day 2021, it launched. This launch was the fulfillment of an astounding level of work performed by thousands of people across the globe in dozens of disciplines. From the start, effective contamination control (CC) was considered essential for the JWST mission due to the large, exposed optics and tight sensitivity required to measure first light and faint signals at the dawn of the universe. This presentation will present the JWST mission and requirements overview, including mission requirements that led to optimizing performance for collecting light in the Near Infrared (NIR, 0.6μm) – Mid Infrared (MIR, 29μm) range. Molecular films absorb in the IR bands and can alter thermal emissivity, resulting in increased noise at the longer wavelengths (MIRI). Particles increase light scatter and background noise levels at the shorter wavelengths (NIRSpec, NIRCam and FGS). The passively cooled design of JWST led to an open architecture for the optical telescope element (OTE), presenting the challenge of maintaining cleanliness throughout assembly, integration, and test in a multitude of environments for over 2 decades. The presentation will describe CC for the mission starting with the first architecture in 1996, then introducing the specific areas of contamination control developed and advanced to keep JWST clean at an unsurpassed level of cleanliness.

Contamination Control↗
NASA NTRS2024

Removing Contamination From Genesis Sapphire Collectors By Polishing

The Array Collectors of the Genesis spacecraft collected bulk solar wind (SW), as well as three subsets of SW (fast, slow, and coronal mass ejection) in a variety of materials. In all cases the SW implant peaked within < 0.2 microns of the surface. So, when the sample return capsule crashed on landing, cleaning the surfaces for analysis became an extremely difficult, but imperative, task. One collector material was “sapphire”, commercial single crystal corundum. Only ~7.7% of the Genesis Array collectors were sapphire (SAP) but a much higher percentage survived the crash. In fact, surviving bulk SW sapphire collectors have an average area ~10x that of their silicon counterparts since SAP is physically tough, and hard (MOHS 9, by definition) as well as is chemically inert. So, SAP is a good candidate for analytical techniques for measuring SW that require clean areas larger than a millimeter; e.g., synchrotron TXRF and INAA. It is also possible to measure SW in SAP using laser ablation and secondary ion mass spectrometry (SIMS) and, recently, more researchers are choosing to analyze sapphire. Thus, removing surface contamination from SAP could enable many research projects. This report extends the task presented in Schmeling et al. ([4]) that used polishing compounds to remove contamination from Genesis sapphire. It focuses on how polishing with their two top candidates (colloidal silica and cerium oxide) affects the SW layer in SAP.

Genesis solar wind↗
DOE OSTI2019

FX2 Fogging Fixative Deployment for Radioactive Contamination Control

Idaho National Laboratory’s FX2 fixative solution was deployed as part of the decontamination and decommissioning (D&D) of an alpha-contaminated glovebox. The fixative was dispensed via fogging. The goal of the deployment was to reduce friable alpha radioactive contamination prior to removal of the glovebox. Information about the deployment and the efficacy of the treatment is presented.

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DOE OSTI2021

The Impact of Anomalous Resistivity in Vacuum Contaminant Plasmas on the Electrothermal Instability

This manuscript presents an assessment of the electrothermal instability (ETI) in the presence of anomalous resistivity (AR) in vacuum contaminant plasmas (VCP) when applied to a magnetized liner inertial fusion (MagLIF)-like load.Pulsed-power driven dielectrically coated metallic liners, like in MagLIF, experience the current-driven electrothermal instability which occurs when a material’s resistivity changes with temperature and is subject to ohmic heating. Large scale pulsed-power facilities that use magnetically insulated transmission lines (MITL) have been shown to generate low-density plasma which enters the target chamber and coalesces around the load. The low-density high-temperature vacuum contaminant plasmas (VCP) can parasitically divert current from the load through causing a short in the anode-cathode gap inside the target chamber. Resistive magnetohydrodynamic (MHD) simulations of these VCP experience unphysical runaway ohmic heating due to under predicting the resistivity by using a purely collisional resistivity model.AR provides a physics-based way to address this runaway heating through increasing the resistivity in a proportional way with the drift speed. In this work, 1D simulations probe the effect that AR in VCP has on the magnetic diffusion rate, and 2D simulations show how this effect manifests in the nonlinear striation form of the ETI for a MagLIF-like load. Beryllium and aluminum dielectrically coated liners are used for the 1D and 2D simulations in this work. The1D simulations show that a VCP causes a delay in the current delivery to the load by upwards of 8 ns at 60 ns into atypical current pulse for an 1 × 10 7 A scale pulsed-power accelerator. The 2D simulations show the delay observed in the 1D simulations is reduced substantially (4 ns) by 2D turbulence that disrupts the VCP layer early in time. Here, the 2Dsimulated ETI growth varies across AR models, more so for the beryllium liner than the aluminum liner because the beryllium liner shows an enhanced rate of penetration for the magnetic diffusion wave in comparison to the aluminum liner. The 2D simulations show the bulk dielectric thickness varies across AR models with the Davidson AR model beingthe largest and the Buneman AR model being the smallest, and in connection with the thickness the Rayleigh-Taylor bubble-spike distances varies correspondingly.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2017

Autonomous Unmanned Aerial Vehicles for Examining Current and Evolving Distribution of Contamination from the FDNPP Accident - 17020

Estimates as well as subsequent measurements of the radiation released following the events at the Fukushima Daiichi Nuclear Power Plant in March 2011 place the incident as the second greatest nuclear event to have ever occurred - duly rated at the maximum of Level 7 on the INES Event Scale. The releases of radioactivity from the plant were detected worldwide, however the multi-reactor nature of the events at the FDNPP has complicated the understanding of the radionuclide release inventory and the subsequent distribution of the material. As a result of this highly-complex release scenario, it is important to understand the current and evolving state of contamination within the rapidly evolving, topographically extreme and frequently typhoon impacted environment on Japan's eastern coast. Existing systems rely either on high-altitude manned aircraft to perform such contamination surveys, correcting results to ground-level, or, on humans manually measuring the dose-rate on foot. In order to overcome the shortcomings of both methods, a low-altitude unmanned aerial vehicle (UAV) has been developed at the University of Bristol and successfully deployed to the affected areas surrounding the FDNPP. In contrast to these other methods; the use of low-altitude UAVs provides a spatial resolution previously achievable only through the deployment of humans on the ground, with the potential for significant radiation exposure. This high-resolution monitoring allows for subsequent modelling to inform our understanding of the behaviour and long-term stability of the fallout material. (authors)

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DOE OSTI2017

Operator Evaluation of Mobile Robotic Systems for Inventory, Inspection, and Contamination Survey Tasks in D and D Environments - 17314

The Nuclear and Applied Robotics Group (NRG) has developed two mobile systems with simple, intuitive Human-Machine Interfaces (HMIs). Thus, the systems can be operated by operators who are not robotics experts to perform inventory, inspection and routine contamination surveys in areas where Special Nuclear Material (SNM) is stored and handled. This effort presents feedback collected from EM operators using the two systems at the Portsmouth Gaseous Diffusion Plant in Piketon, OH who used the robotic solutions to perform tasks on site and with minimal training. This approach has the potential to address issues related to ALARA, ergonomics, and reliably completing dull, repetitive tasks while maintaining domain-specific experts in the control loop. The two systems were shipped to - and demonstrated in - a DOE designated area and demonstrated completing contamination testing using a combination of real and surrogate sensors. This paper reviews the initial hardware development, demonstration requirements, and the modifications/improvements made to deploy the systems for this effort. It then summarizes the feedback garnered from EM operators who used the systems at the DOE facility. (authors)

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DOE OSTI2017

Purpose-Built UAVs for Physical Sampling of Trace Contamination at the Portsmouth Gaseous Diffusion Plant - 17331

The sampling of trace amounts of contamination, particularly of low-energy byproducts such as americium, presents a challenge for non-contact sensing. In many cases, such as determining the need for cleaning inside the exhaust shaft of the Waste Isolation Pilot Plant or sampling the walls of the enormous Gaseous Diffusion Plant at Portsmouth, it may be desirable to take physical swab samples at carefully distributed sample locations for analysis by mass spectrometry. Because of the danger posed to human workers in such scenarios, including risk of falls from lethal heights and exposure to low levels of radiation and the hassle of donning and doffing PPE, a low-cost robotic solution is desired. The inaccessibility of the heights involved suggest Unmanned Aerial Vehicle (UAV) solutions, rather than Unmanned Ground Vehicle (UGV) solutions, but conventional quadrotor UAVs are ill-suited to precise physical interaction with their surroundings. Quadrotors are under-actuated, rendering them non-holonomic and preventing the dexterous application of arbitrary generalized force/torques in interaction with the environment. At Purdue University, the authors have developed a number of novel UAV platforms suitable for dexterous interaction with the environment, making them ideal for such applications. These platforms can independently control forces in all directions, allowing for controlled application of the swab to the surface. Because of the scale of these structures (over 2 km in the case of the Gaseous Diffusion Plant), flight efficiency is of supreme importance. The Purdue team is took a variety of vehicles to the Gaseous Diffusion Plant for field trials on site in August, 2016. (With results available prior to the meeting.) The Purdue Dexterous Hexrotor is a fully-actuated Hexrotor capable of exerting forces in all six directions of force and torque. Operating alone or in swarms, the Dexterous Hexrotor can fly in free space, transition to contact through impact control, and sample the surface through force control. The Purdue I-BoomCopter is a tri-copter with an extra horizontal propeller that enables long-distance flight without pitching and the ability to apply closed-loop forces horizontally. Finally, the Purdue Tiltrotor VTOL is an under-actuated hybrid UAV that combines tilting rotors for vertical takeoff and landing, with a fixed-wing, flying-body design that is ultra-efficient for long-distance flight. The Dexterous Hexrotor provided two demonstrations of physical sampling of walls and crane rails. In sampling the large open sections of the inside of the plant, a small swarm of three UAVs is commanded to sample three distinct points on an internal map of the building. Human-supervised autonomy permits the UAVs to take off by themselves, find a clear elevation at which to fly through uncluttered space, navigate to their designated sampling points, and pause for confirmation by the human supervisor. The supervisor is presented with a video image of the intended sampling spot, which, if confirmed, the UAV will automatically approach and sample. The UAVs then autonomously return to the take-off spot. The second demo involved a single UAV searching upwards, then transitioning into 3-D SLAM mode to wait for a safe sampling spot on the 3-D scan to acquire the sample from the crane rail. The human supervisor, in this case, is responsible for ensuring the absence of cables and other obstacles. I-BoomCopter demonstrated its high-speed, long-distance coverage ability by making a few fast passes before homing in on a mock-up electrical panel with door, which it opened and closed. The dexterity of the I-BoomCopter results from its large propellers, which allow for controlled hovering and the horizontal thruster for applying forces of significant magnitude. Finally, the Tiltrotor VTOL is highly efficient in fixed-wing mode, but the tilt-rotor is under-actuated in hover. The tilt-rotor will take off vertically, then transition to high-speed, long-distance flight to make a number of passes inside the facility. The significance of these demos is the low-cost implementation of physical sampling over prescribable locations in difficult-to-reach areas of potentially contaminate facilities. To make this tractable over very large facilities, the demonstration of combinations of dexterous hovering ability and long-distance/high-speed flight is also in evidence. (authors)

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DOE OSTI2017

Emerging Contaminants: Investigation and Remediation of Poly- and Perfluoroalkyl Substances in the Environment - 17339

The group of chemicals known as PFAS (poly- and perfluoroalkyl substances) has come under increasing scientific and regulatory scrutiny in recent years as more is understood about their toxicity, their environmental persistence and their potential to bio-accumulate. PFAS are used in a wide range of industrial applications and commercial products due to their unique surface tension and levelling properties. They include stain repellents for textiles and carpeting, grease-proof paper, water- and oil-resistant coatings, and mist suppressants. PFAS are also major components of the class B fire fighting foams known as aqueous film forming foam (AFFF), Fluoro-protein Foams (FP) and Film Forming Fluoro-protein Foams (FFFP) commonly used at Federal and Commercial facilities throughout the world. Long chain PFASs (>5 or 6perfluroalkyl-carbons) such perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), bio-accumulate. Currently, PFOS, PFOA, and a few other PFASs are increasingly regulated outside of the U.S., and at varying levels in drinking water or groundwater in select U.S. states. The U.S. EPA recently established a long-term exposure criteria of 70 ng/L for combined PFOS and PFOA in drinking water. While PFOS and PFOA have the most regulatory attention, there are thousands of chemicals in the PFAS class; some PFASs are precursor compounds capable of transforming to PFOS and PFOA or analogs. The remedial options available to address PFAS contamination are limited by the unique physico-chemical properties of these compounds. Technologies currently used for the remediation of PFAS contaminated sites include soil incineration or excavation to landfill, and groundwater extraction with PFAS adsorption onto activated carbon or resins. Emerging technologies for PFAS, include stabilization in soil, photolysis/ photo-catalysis, reductive decomposition, advanced oxidation, reduction and sonolysis for groundwater. However, the evidence that these technologies effectively break the fully fluorinated backbone of PFAS, or can treat or sequester all carbon chain lengths is limited. To date these technologies are unproven or considered infeasible for high flowrate, low concentration applications. New in-situ techniques, including an oxidation / reduction method known as ScisoR{sup R} (Smart combined in situ oxidation and Reduction), are currently being tested in the lab and some are being applied in field demonstrations. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Conservation and Recycling for Radiological-Contaminated Laundry Applications - 16044

Recovery and reuse of materials exposed to radioactive environments is a critical element for those whom are involved with processing such materials. In order to minimize the disposal of radiological-contaminated Personal Protective Equipment (PPE, laundry, respirators, etc.) the need for environmentally-friendly and cost-effective technologies to provide laundering services is needed for current and future processes. A by-product of the laundry process is contaminated water. In order to reduce waste generation, we developed a radiological water filtration system custom-designed for laundry applications, which is used as both a filtration device as well as a water recycling system. The filtration process utilizes membrane filtration, suspended solids and organic filtration, ion-exchange capture, and ozonization/UV as germicidal reducers. In addition, ultrafiltration is used as a final step in order to return clean water back to the washing process system. The system was originally designed for non-radiological industrial laundry applications (hospitality, health care, correctional and governmental settings, etc). This process reduces the water consumption and discharge by up to 75% while retaining heat to minimize energy input costs. Principle components of the system include lint shakers and collection tanks with ozone injection, suspended solids filter, activated charcoal, ultraviolet lamp treatment cell, ion exchange columns, ultrafiltration filters, and final holding tank with ozone injection. Although up-front equipment costs are required, we believe that the reduction in waste generated through recycle and reuse of the water, along with avoiding premature disposal of PPE as radioactive waste, greatly outweighs up-front effort. (authors)

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DOE OSTI2016

Change vs. Transformation, Hard Edges to Soft - The Role of Integrated Land Use Planning in the Adaptive Reuse of Contaminated Sites - 16431

Between the bookends of World War II and the Cold War, numerous cycles of up-sizing, down-sizing, and right sizing resulted in changing needs for federal real property to support government missions. The end of the Cold War has yielded many opportunities for reuse of federal facilities as defense-related property needs have been lessened. These federal facilities have both a historic and an environmental legacy, from radionuclides to unexploded ordnance to landfills and everything in between. Private-sector manufacturing sites have been especially affected by changing market demands. Obsolescence and advancing technologies have made the 'have to have it' product into the 'what was that for?' The result has been thousands of hectares (acres) of contaminated land throughout the country. While site histories go back in time, it is the environmental cleanup contaminants that have the ability to go forward in time and influence the future use of a site. Demonstrating that property conditions are protective of human health and the environment facilitates reuse options for these properties. Site reuse creates land for communities to attract businesses, grow their tax bases, add open space, and implement sustainability efforts, such as renewables, or set the property aside for future possibilities. A broad range of sites have been made available across the country as a result of federal mission changes and changed economic market conditions affecting private industry. This broad range of properties should have similarly broad recipes for reuse. Even with the constraints of zoning, topographic/natural conditions and use restrictions necessitated by past operations, the pathways to creative, adaptive, and sustainable reuse can be taken by integrating the planning with the remediation or, in a more community-sensitive approach, by integrating the remediation with the planning. Situations do exist where a like-kind use is an ideal reuse option, but a redevelopment of sameness need not be a foregone conclusion. Unlike the operational and imposed environments from which these sites came, with their engineered features often developed in a systematic manner with straight lines and hard edges, they can indeed be transformed into functional, relaxed, and engaging places and be productive again. A site's transformation can begin with how the remediation incorporates sustainable techniques that consider the future use of a site, and how the sustainable remediation can dovetail with the community's reuse plans. Rather than building on Greenfields and extending infrastructure and services to more distant locations, many communities are looking within their already developed footprints for growth possibilities. For some communities this is their only source of growth. Stigmatized and challenged as they may be to reuse, the nation's excess, under-utilized, surplus, and abandoned industrial past presents opportunities well worth considering for improvement to local and regional economies. Communities that are engaged in remediation and reuse planning efforts at these sites have the opportunity to shape their futures, transform their identities and incorporate sustainable practices throughout the process. Unlike the simple name change of a facility, transformative change takes time. Transformative change relies on working partnerships, dedication to achieving something better, open communication, and cooperative planning. It is this type of change that tends to be lasting and tailored to a place. (authors)

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DOE OSTI2018

Climatic Controls on Residual Contaminants Under Sustainable Remediation - 18699

We investigate the impact of climate change on residual contaminants in soil and groundwater under sustainable remediation. We illustrate seven climate change scenarios which mimic shifts in the precipitation regime as well as the failure of the source-zone cap. We evaluate different performance metrics including contaminant concentrations at multiple wells and export to a creek. The approach is demonstrated by simulating the tritium plume migration at the Savannah River Site F-Area, USA. The cap integrity is critical not only to reduce the well concentrations and export but also to reduce the uncertainty associated with the climatic variability. Sampling or in situ monitoring near the source zone is important for the early detection of plume mobility changes. Realistic hydrological models are necessary to evaluate the trade-offs (mobility vs dilution)

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DOE OSTI2019

Depth of the Biologically Active Zone in Terrestrial Habitats at the Chalk River Laboratories Site: Implications for Contaminated Site Assessment and Ecological Risk Assessment - 19272

Plants, soil invertebrates and burrowing mammals penetrate the soil layer to varying depths. As Canadian Nuclear Laboratories (CNL) assesses risks and remediates soils contaminated with radioactive and other hazardous wastes at the Chalk River Laboratories (CRL) site, a site-specific characterization of the biologically active zone is required to help to identify the relevant depth in soil for exposure assessment of ecological receptors. A defined biologically active zone is also required to determine the depth to which remedial actions should be taken to protect the environment, help prioritize locations for remediation efforts based on ecological risk and avoid unnecessary cleanup efforts. By taking advantage of the abundance of information on contaminant locations and depths, biodiversity, and hydrogeology available for the well-studied CRL site, it is possible to produce a site-specific estimation of the biologically active zone in CRL upland soils. A literature review was conducted to determine rooting and burrowing depths for vascular plants, soil invertebrates and burrowing mammals documented to be present (or potentially present) on the CRL site. This literature review was supplemented with field surveys to fill data gaps in our understanding of species composition (e.g., soil invertebrates and plant understory). Overall, we found that there was significant variability in maximum rooting/burrowing depths among plant, mammal and invertebrate species present on the CRL site. The majority of biological activity occurs in the top 0.5 m of soil. However, about 19% of burrowing or rooting receptors present at CRL may be in contact with soils up to 1 m depth, 9% of receptors present may be in contact with soils up to 2 m depth, and only about 2% of receptors may be in contact with soils up to 3 m depth. It is highly unlikely that any ecological receptor present at CRL is in direct contact with soils deeper than about 3.6 m. Further site-specific results pertaining to burrowing and rooting depths estimated for the CRL site will be presented, and these results will be compared to generic/default 'depth of biologically-active layer' guidelines recommended by various agencies. (authors)

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

A Gamma Assay System for Characterizing Excavated Soil with High {sup 137}Cs and {sup 90}Sr Contamination - 19460

We report on the recent development of a remote gamma-assay system for the measurement and characterization of high-activity soil excavated as part of an ongoing remediation project. The soil below a hot cell in our customer's facility has been contaminated with high concentrations of radionuclides {sup 137}Cs and {sup 90}Sr over the past several decades. The contaminated soil is to be remotely excavated from beneath the hot cell floor, to a depth of several feet, and placed in steel-walled waste bins for assay and disposition. The project requires measuring the {sup 137}Cs activity to a minimum detectable concentration (MDC) of 1 micro curie per gram. The high dose-rate of the material and the expectation of high Bremsstrahlung background, due to an unknown ratio of {sup 90}Sr admixture with the {sup 137}Cs, present unique measurement challenges. A novel assay system was designed to make measurements through a small access port in a 4-foot thick concrete wall isolating operators from the high-dose excavation area. Waste bins filled with soil are placed by a remotely operated crane onto an automated turntable, and initial dose measurements are taken for all bins. When excavation has proceeded to the point that dose rates below 20 Rad/hr on contact are reached, gamma spectroscopy will be used to characterize the {sup 137}Cs content. Gamma assay is performed with a 1 cm{sup 3} CZT detector in a collimated tungsten shield, which is extended through the access port toward the side of the bin by means of a seven foot long aluminum pipe. Each of the four sides of the bin is assayed in a discrete measurement, and the individual segments and summed result are reported. Canberra's NDA2000 software is used to collect and analyze the spectroscopic data and to control the turntable movement during the assay. The system is expected to meet the required MDC limits within a forty minute assay time under the most adverse conditions anticipated, with total measurement uncertainty of less than 25%. We describe in this paper the design and construction of the assay system, its calibration using the ISOCS software, and the evaluation of performance estimates. (authors)

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DOE OSTI2019

New Project on the Analysis of Contamination Mechanisms of Concrete at the Fukushima Daiichi Nuclear Power Station - 19511

For the decommissioning of a nuclear power station (NPS) after a severe accident, estimation of contamination depth and radioactivity level in concrete is essential. This paper outlines a recently begun project on the analysis of the contamination mechanisms of concrete in the Fukushima Daiichi NPS. For this analysis, data on various parameters are required, such as the materials used in the NPS, the environmental conditions of the exposed concrete, the conditions of exposure during the accident and until decommissioning, and the fundamental transport characteristics of nuclides in concrete. These aspects of this project are illustrated with some examples. (authors)

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DOE OSTI2019

Compressing the Recovery Timeline for an Urban Contamination Event - 19539

This study identified equipment that has the potential to support mitigation activities associated with a radiological or nuclear release in the urban environment. Equipment capabilities, availability, and usefulness was assessed for potential deployment following the initial emergency phase of a response. The study was devised to connect emergency management and homeland security offices at the city, state, and federal agencies and discuss the availability and potential response capabilities of equipment reserves. This project focused on connecting with relevant emergency management and homeland security offices at the city, state, and regional level, including major cities across the United States, and with federal agencies. Within these offices, we consulted with subject matter experts (SMEs) in discussions via workshops, phone conversations, and small meetings. The result was a compilation and assessment of approaches to address realistic contamination scenarios and the types of equipment assets that would or could assist in the response and recovery activities. Recommendations on how current equipment reserves can be best used or modified to improve the resilience of a community during a radiological or nuclear contamination event were documented. (authors)

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DOE OSTI2019

Advanced Modeling of Contaminant Fate and Transport in Soil and Groundwater from F-Canyon and the Central Laboratory Facility

F-Canyon (221-F) was constructed in the early 1950's and, together with FB Line, began operations in 1954 as the main processing facilities in FArea of SRS. The primary operations conducted in F-Canyon and FB Line included the separation and recovery of Pu-239 and U-238 from irradiated materials and the stabilization of plutonium residues. The F/H Laboratory Complex consists of buildings 772-F, 772-1F, and 772-4F which began operations in 1954, 1987, and 1993, respectively. The primary mission of the F/H Laboratory Complex for the last 45 years has been to support the chemical separations processing activities at Building 221-F and H-Canyon. The objective of this study is to determine the radionuclide and hazardous material holdup in F-Canyon and its support facilities, and to evaluate In-Situ Disposal (ISD) alternatives for deactivation and decommissioning (D and D) of these facilities to ensure groundwater protection and environmental compliance with the South Carolina Department of Health and Environmental Services (SCDHES) and the United States Environmental Protection Agency (USEPA). GoldSim is a dynamic probabilistic simulation software that allows modeling of chemical mass transport through engineered and environmental systems For this study, it will model the potential future release of radiological contamination through the vadose zone, Upper Three Runs (UTR) Aquifer and the Upper Three Runs Creek. Using a GoldSim model developed for building 235-F D and D, contaminant inventories as well as building geometry were updated to create the basis of the new F-Canyon model. The inventories from F-Canyon, FB Line, and the 800 Series Tanks (Tanks 804, 808, and 809) as well as F/H labs (including buildings 772-F, 772-1F, and 772- 4F) were used to make a total of four sources. The concentrations of total uranium and beta-gamma are within compliance for the study, while radium and alpha concentrations exceed their MCL's around 30,000 years and total effective water dose exceeds its MCL around 1,200 years. This suggests that some level of action will be needed to meet SCDHES and USEPA requirements. This evaluation was conducted only for the no-action alternative. Consideration and modeling of other alternatives will be required in the future to determine the best ISD alternative for D and D of F-Canyon and F/H labs with regard to groundwater protection, worker safety, and financial cost.

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