Organic scintillator-based alpha/beta detector for radiological decontamination
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Multimodal Characterization of Materials and Decontamination Processes for Chemical Warfare Protection
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99 GENERAL AND MISCELLANEOUS↗
Nuclear Decontamination Evolution and Revolution - 20349
Decontamination, one of the oldest practices in the nuclear industry, is about to change. While no single approach to decontamination is appropriate in all situations, decontamination of highly contaminated surfaces is historically viewed as difficult and/or marginally effective and fixatives and strippable coatings are often called on to manage time sensitive contamination control issues. The deferral of proper decontamination can lead to accumulated concentrations of radioactive material increasing the risk of cross-contamination of workers and equipment while also increasing radiation levels, which further discourages decontamination. The results of the subject testing demonstrate that superior decontamination factors are readily achievable and the ALARA benefit of decontamination is viable through advanced decontamination technologies in conjunction with innovative application techniques. The collateral benefits will save countless radiological man-hours and personnel radiological exposure. The appropriate use of radiological decontamination techniques can prevent or limit the adverse effects of highly radioactive contamination in the work area. High levels of radiological contamination are typically associated with some of the most physically demanding work in the nuclear industry. Additionally, working in highly contaminated environments increases the risk of exposure to elevated levels of airborne radioactivity and radiation from the source term of the contamination, particularly in hard to reach areas or complex equipment. Veolia's Alaron Nuclear Services (Alaron), a fully integrated nuclear facility, has provided the nuclear industry waste treatment, consolidation, repackaging, and broad decontamination services for almost 35 years. In looking at solutions for its customers, as well as for their own facility, Alaron has recently collaborated with Environmental Alternatives, Inc. (EAI), which has provided innovative solutions addressing difficult nuclear decontamination and industrial cleaning challenges since 1989. This broad range of experience along with the products to support the work created an ideal partner for Alaron's needs at their facility. The benefits of collaboration were immediately recognizable to the management of both companies although the decontamination challenge was significant. Due to the nature of the services offered, contamination at the Alaron facility is routine. The recent decontamination experience at Alaron utilized an innovative surfactant process that quickly produces remarkably higher decontamination factors for both removable surface contamination and fixed contamination. Considering the time to decontaminate areas historically designated for high radiological hazard work, the results from this decontamination effort not only reduced contamination levels but also significantly lowered exposure rates in the working environment. The relative ease with which the surfactant is applied, combined with extraordinary decontamination test results, indicates the potential to alter current radiological work processes in a way that improves worker comfort, and removes radiological engineering barriers, allowing Alaron to complete complex radiological tasks more efficiently and effectively. In a series of two simple applications of the decontamination agent to contaminated high bay vertical surfaces, as well as a variety of horizontal and vertical surfaces with variable porousness and surface sealants, there was an overall reduction in removable contamination of approximately 73% with a reduction in area dose of approximately 93%. The results indicate additional reduction in fixed contamination with application of the surfactant. These values are much higher than experienced with more traditional decontamination agents. In conjunction with demonstrating EAI's surfactant on room surfaces, additional studies were conducted on complex geometry equipment including waste processing equipment, tools, and heavily contaminated parts normally handled from Alaron's customers. Evaluations were made with straight application of EAI's surfactant as well as adding additional techniques to the treatment which afforded revolutionary improvements in the levels of contamination removed. Successful decontamination with up to 95% reduction in removable contamination with just one application were demonstrated in several of the trials. This paper outlines the planned approach to use this technology, the variety of surfaces and equipment treated, and the results of the decontamination efforts. Furthermore, this paper discusses options for pretreatment of certain heavily contaminated equipment prior to employees handling and/or working with the equipment. The potential for dose saving and the reduced risk of cross-contamination with the added benefit of lower PPE requirements, produces an enormous potential for cost and time savings. Attendees will benefit from Alaron's experiences and more fully understand the capabilities of EAI's decontamination process. With the variety of contamination agents, forms and surfaces on which the technology was demonstrated, the information will be valuable to a broad cross-section of industry users. The significance of this report demonstrates superior decontamination factors are achievable utilizing the next evolution of decontamination technology and that the ALARA benefits of decontamination are available through advanced and modern decontamination efforts. The collateral benefits will save countless radiological man-hours and valuable personnel radiological exposure. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Current Status of Decommissioning Plans and Chemical Decontamination of Metal Scraps in Chinshan NPP - 19304
The decommissioning of nuclear facilities has become a significantly attractive and worldwide topic due to the end of lifetime of many nuclear power plants within next coming years. In Taiwan, Chinshan nuclear power plant owned by the Taiwan Power Company will be the first candidate to be decommissioned according to the Nuclear Reactor Facilities Regulation Act. The Chinshan nuclear power plant located in New Taipei City has two units of 636 MWe boiling water reactors (BWRs) for the generation of 9 billion kWh of electricity per year. The date of cessation of operation of Unit No. 1 and Unit No. 2 will be December in 2018 and July in 2019, respectively. Based on the Regulations for the Review and Approval of Applications for a Decommissioning Permit of Nuclear Reactor Facilities, Taiwan Power Company have submitted a decommissioning plan of Chinshan nuclear power plant to the authority, Atomic Energy Council (AEC). After the review process, the decommissioning plan of Chinshan nuclear power plant has been permitted by AEC in 2017. Decontamination is generally utilized during the period of decommissioning of nuclear facility in order to minimize the radiation exposure of personnel and the cost of management of radioactive wastes. The successful decontamination also probably provides the benefits of lowering the level of radioactive wastes, facilitating potential releases, permitting the reuse of metals and facilitating the radiation principle of As Low As Reasonably Achievable (ALARA) management. Decontamination aims at the removal of radioactive materials from the contaminated surfaces by several technologies such as washing, heating, chemical reaction and mechanical process. The selection of proper decontamination technologies are depended on the requirement of the target materials and the purpose of the decontamination. Chemical decontamination has been proven to be an effective in reducing the radioactivity for metallic materials by using chemical reagents in contact with the contaminated surfaces. During the operation of Chinshan nuclear power plant, chemical decontamination was performed for Unit No.1 and No.2 in 2000 to decontaminate the Reactor Recirculation System (RRS) and Reactor Water Clean-up Systems (RWCU) by using LOMI-NP-LOMI process. Based on the previous experience of chemical decontamination, the dismantled metallic piping is provided as sample by Chinshan nuclear power plant for the evaluation of the feasibility of chemical decontamination. The provided metallic sample is composed of carbon steel with dose rate around 0.2 mSv/hr. In this report, a multistep decontamination process using strongly oxidizing solution and organic acid solution is performed to remove the contaminated oxide layer from the metal surface, and the resulting contact dose rate and decontamination factor (DF) are also shown to discuss the performance in relation to the process control factors. In this paper, the recent progress in decommissioning programs and preliminary results of the decontamination experiment are described to provide usable information regarding the future decommissioning for Chinshan nuclear power plant. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Electrolytically Assisted Surface Decontamination (EASD{sup TM}) for POCO Operations - 20282
NNL in collaboration with C-Tech Innovation Ltd and Sellafield Ltd has been exploring innovative technologies to enable a significant reduction of radiological hazards within facilities during the Post Operational Clean Out (POCO) phase of a nuclear plant's life cycle. Reducing the hazard by effectively decontaminating plants in-situ during POCO delivers huge cost reductions for future decommissioning operations. These cost reduction benefits are realized by reducing the number and complexity of remote operations as well as lowering the long-term waste disposal costs. Whilst chemical decontamination can achieve the desired level of decontamination, applying aggressive chemical reagents is hazardous, potentially difficult to control and requires there to be complimentary effluent treatment and waste routes. This work has aimed to develop flexible and controllable decontamination processes which could be operated without the additional complexity and issues associated with chemical decontamination. The processes needed to be relatively fast and effective to minimize the time operators would spend in an active area. In addition, there was a driver to produce decontamination methodologies which generated a secondary waste compatible with current routes and which takes advantage of current waste capacity. The strategy therefore was to come up with a solution that works with, rather than against, the science and engineering behind process plants at Sellafield. Electrolytically Assisted Surface Decontamination (EASD{sup TM}) is an innovative electrochemical decontamination process (developed by NNL and C-Tech Innovation Ltd) that can remove activity from contaminated metal in very short time periods. Application of the patented electric waveform to the surface when treating contaminated metal with nitric acid has been shown to significantly enhance the decontamination performance. When compared to proposed baseline washout procedures at Sellafield, the only change to the process is the applied electrical waveform which is temporary and controllable. The current causes dissolution of the metal surface being decontaminated which leads to activity transferring from the plant item into the nitric acid effluent stream. This innovation has the potential to transform the POCO process and allow a nitric acid based washout approach to deliver POCO quickly and cost effectively within the existing infrastructure. Several devices have now been designed that incorporate this EASD{sup TM} technology and enable the decontamination process to be applied to a range items commonly identified as being contaminated during nuclear decommissioning programmes such as pipework, tanks and hotspots of walls/floors. Inactive and active laboratory-scale testing has been completed using both simulated and 'real-life' contaminated (low level waste) metallic items retrieved from different nuclear sites. Active trials demonstrated that contaminated items could be treated to free release levels within minutes. Engineering scale tests are currently being performed, with guidance from Sellafield's system engineers and plant managers, to provide the necessary re-assurance the designed devices could be successfully deployed in an on-plant scenario. The final stage of this development work is to carry out an active demonstration of the decontamination technology on Thorp at Sellafield. This paper aims to highlight progress made to date with the EASD{sup TM} technology and, more specifically, the development of an in-situ decontamination device for deployment within radioactive pipework. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Lessons Learned from Most Recent Chemical Decontamination for Decommissioning Projects - 19280
In 2017, Westinghouse performed a full system chemical decontamination of Units 1 and 2 of the Bohunice V1 Nuclear Power Plant. Bohunice V1 is a VVER 440 design with six loops. The application was performed two loops at a time, with the reactor core bypassed. The Pressurizer and Pressurizer Relief Tank (Bubble Tank) were decontaminated as well, in a separate application. This was a recovery decontamination that had been attempted by another company prior to Westinghouse. Several modifications to equipment and design of process were required to make the decontamination successful. The project was initiated to perform pre-dismantling chemical decontamination of primary circuits of both V1 units using Decontamination for Decommissioning (DfD) to meet the following objectives (see References 1 and 2 for process descriptions of DfD): - Remove activity from the primary circuit components; - Reduce dose rates around piping and components; - Simplify access to the installations, making it possible to use hands-on techniques for dismantling, rather than the more expensive use of robotics or manipulators; - Minimize the potential for spreading contamination during decommissioning activities - Reduce the activity of components that they may be disposed of at a lower classification, therefore more economical, waste disposal category. Several techniques were employed that were unique, or first of a kind, to aid in the decontamination, including resin regeneration and bypass of the reactor core, while still providing enough flow to to allow sufficient dispersal through all the steam generator tubes. Equipment that was already available on site was evaluated and, when possible, combined with Westinghouse equipment to minimize application cost and schedule. The lessons learned from the first unit (Unit 2) were applied to the second unit (Unit 1) application. The partial relocation of equipment allowed for the most efficient schedule to complete the second decontamination. The paper will describe in more detail the results and lessons learned from the full system chemical decontaminations performed, as well as updates on another recent decontamination project. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
The Evaluation of Chemical Decontamination for Contaminated Carbon Steel Scrap by Multiphase Treatment Process - 20249
There is a significant growth in the field of decommissioning of nuclear facilities due the fact that for a lot of them their end of life is nearing. In Taiwan, the government plans to steadily reduce the dependence on nuclear power and moves gradually towards a nuclear-free homeland. Therefore, the development of decommissioning technology becomes the significant issue for the next coming years. The decommissioning of a nuclear power plant is a long process and practical work including radiological surveys, decontamination, dismantling, and the subsequent waste management. Chemical decontamination is an important task in the decommissioning of nuclear power plants and is usually performed by circulating the chemical solution in selected systems or full systems in order to reduce dose levels. However, the decontamination of segmented metal parts is also considered to reduce the contamination to such levels that they may be disposed of at a lower classification or be unconditionally released, and it helps to achieve the goal of waste minimization and provide a more economical cost for disposal management. Chemical decontamination technology is used to remove the contaminated oxides deposited on the surface of metals by dissolving them with chemical mechanisms, such as chelation, acidic or alkaline dissolution, redox reaction and so on. Carbon steel is the major material used in systems and pipelines in the nuclear power plant, thus it is also commonly selected as the target to be decontaminated in the decommissioning process. In this study, the effectiveness of chemical decontamination is evaluated by using multiphase treatment process including the reduction and the oxidation steps. In the step of redox reaction, the oxidation state of the substance is very important. Especially metals of some oxidation states show solubility in water, which has a decisive influence on the chemical decontamination. The experiment of decontamination of metal scraps is carried out by the immersion method within a chemical solution. The relative operation parameters such as temperature, pH, and concentration of the chemical solution are recorded to demonstrate the effect of the decontamination process. (authors)
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The Effects of Contaminant-Aging on Decontamination Efficacy for Rapid Remediation of Concrete Surfaces - 20412
Understanding the relationship between decontamination efficacy and contaminant aging is imperative for developing effective remediation strategies following a large-scale contamination event. Non-destructive decontamination of concrete following a contamination incident becomes more difficult with increased time between contamination and decontamination because contaminants may chemically bind to concrete and/or penetrate into the concrete subsurface. In this work, we evaluated the decontamination efficacy of two decontamination methods on concrete samples contaminated with soluble Cesium-137 (Cs-137) and silica particles with 0.5 μm and 2 μm diameters. Concrete samples were aged between 1 and 59 days, with half of the coupons receiving 1 mL of artificial rainwater about once every three days. After aging, coupons were either decontaminated or analyzed to determine contaminant penetration depths. Coupons were decontaminated with 0.1 M Potassium Chloride (KCI) solution applied either by flowing solution across the contaminated coupon face or non-destructive power washing. Contaminant depth profiles were created by removing the top surface of the coupon at least 15 times, measuring the activity in each removed layer, normalizing the total activity removed to the measured decontamination efficacy following the last layer removal, and determining the penetration thickness using the coupon dimensions, bulk density, and mass of material removed for each layer. Pressurized washing effectively removed particles, but not soluble cesium, despite the majority of Cs-137 being located within the first millimeter of the subsurface. Soluble cesium removal by flowing 0.1 M KCI solution across the contaminated surface dropped to less than 12% within the first ten days. This drop in Cs-137 removal efficacy occurred within the first five days for coupons experiencing artificial rainfall events. Flowing 0.1 M KCI solution across the contaminated face was ineffective at removing particles, likely because particles had localized in surface depressions. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
COVID-19 global pandemic planning: Performance and electret charge of N95 respirators after recommended decontamination methods
Shortages of N95 respirators for use by medical personnel have driven consideration of novel conservation strategies, including decontamination for reuse and extended use. Decontamination methods listed as promising by the Centers for Disease Control and Prevention (CDC) (vaporous hydrogen peroxide (VHP), wet heat, ultraviolet irradiation (UVI)) and several methods considered for low resource environments (bleach, isopropyl alcohol and detergent/soap) were studied for two commonly used surgical N95 respirators (3M™ 1860 and 1870+ Aura™). Although N95 filtration performance depends on the electrostatically charged electret filtration layer, the impact of decontamination on this layer is largely unexplored. As such, respirator performance following decontamination was assessed based on the fit, filtration efficiency, and pressure drop, along with the relationship between (1) surface charge of the electret layer, and (2) elastic properties of the straps. Decontamination with VHP, wet heat, UVI, and bleach did not degrade fit and filtration performance or electret charge. Isopropyl alcohol and soap significantly degraded fit, filtration performance, and electret charge. Pressure drop across the respirators was unchanged. Modest degradation of N95 strap elasticity was observed in mechanical fatigue testing, a model for repeated donnings and doffings. CDC recommended decontamination methods including VHP, wet heat, and UV light did not degrade N95 respirator fit or filtration performance in these tests. Extended use of N95 respirators may degrade strap elasticity, but a loss of face seal integrity should be apparent during user seal checks. NIOSH recommends performing user seal checks after every donning to detect loss of appropriate fit. Decontamination methods which degrade electret charge such as alcohols or detergents should not be used on N95 respirators. The loss of N95 performance due to electret degradation would not be apparent to a respirator user or evident during a negative pressure user seal check.
60 APPLIED LIFE SCIENCES↗
Enhanced Techniques for Concrete Decontamination During Decommissioning - 19005
As the primary material of construction for nuclear power plant structures, concrete naturally represents the largest fraction of contaminated material by surface area. As such, decontamination of concrete is a major activity during decommissioning projects. As reported in EPRI 3002005412, Characterization and Remediation of Contaminated Concrete, currently used techniques for decontamination of contaminated concrete are generally slow and labor-intensive to apply. This report notes that little change to the techniques used for concrete decontamination have been made during the past 20 years. There is a clear need for improvement to the techniques available for decontamination of concrete. Needed enhancements include substantial improvements in efficiency, waste management, industrial safety, and worker radiation exposure. Potential areas for development include increased automation of existing techniques, improvement in delivery systems for decontamination equipment, and further development of alternative techniques such as microwave and laser scabbling, and nitrogen blasting. To address this need, EPRI is conducting a project to develop enhanced techniques for concrete decontamination. The project focuses on two primary areas: 1. Adaption of existing techniques to improve efficiency through automation and/or altering the delivery systems for the decontamination equipment (for example, through use of exiting robotic systems); and 2. Field demonstration of technologies currently in the engineering development stage, such as nitrogen blasting and laser scabbling. This paper will report the initial results of this EPRI project, which includes identification of promising candidate technologies that will be demonstrated during the next project phase. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Developing Surrogate Far-Field Nuclear Fallout and its Rapid Decontamination from Aircraft Surfaces
Naval aircraft and vehicles deployed in response to the tsunami of 2011 and subsequent nuclear meltdown at the Fukushima Daiichi nuclear power station were exposed to and contaminated with radioactive materials released to the atmosphere. In response, the Navy and Argonne National Laboratory are testing various decontamination methods to clean aircraft surfaces exposed to far-field nuclear fallout. Far-field fallout, which can travel hundreds of miles, includes dissolved radionuclides and fine particulate matter. To simulate contamination with such materials, dissolved cesium-137 ( 137 Cs) and radiolabeled particles were deposited on coupons (1 x 1 in. sections) of tire, acrylic, and painted metal surfaces. These coupons were subjected to six different decontamination methods, including ones involving four strippable products, a soap solution, and tap water. Removals of dissolved 137 Cs were generally high: over 90% of the deposited radionuclide was removed after three decontaminations. To simulate exposure to inert, radioactive fallout or other inert, airborne particulate, silica (SiO 2 ) particles were used as surrogate fine particulate matter. The silica particles were radio-labeled by first depositing europium-152 ( 152 Eu) or americium-241 ( 241 Am) on the particle surface as sesquioxides (Eu 2 O 3 or Am 2 O 3 ), then coating it with sodium silicate. Scanning electron microscopy confirmed that particle size was not altered by the treatment, while leaching studies into numerous solutions and decontamination agents confirmed that minimal amounts of the radiolabel dissolved into solution. Three different methods to apply the radioactive particles to the silica were evaluated. Pressing the coupons into a dish containing the particles resulted in particle clumping on the surface, while applying the particles within water also resulted in heterogeneous surface coverage. Suspending the particles in ethanol and then applying them to the surface supplied homogeneous surface coverage that provided acute and precise removal percentages. Finally, particle-surface interactions seemingly play an important role in radiological decontamination as the removal percentages were lower than those of soluble 137 Cs for aqueous decontamination methods. These decreased removal percentages indicate that more complex methods such as strippable decontamination agents are required to remove particulate far-field fallout from aircraft and similar vehicle surfaces.
36 MATERIALS SCIENCE↗
Trimming and Decontamination of Metagenomic Data can Significantly Impact Assembly and Binning Metrics, Phylogenomic and Functional Analysis
Background: Investigators using metagenomic sequencing to study microbiomes often trim and decontaminate reads without knowing their effect on downstream analyses. Objective: This study was designed to evaluate the impacts JGI trimming and decontamination procedures have on assembly and binning metrics, placement of MAGs into species trees, and functional profiles of MAGs extracted from complex rhizosphere metagenomes, as well as how more aggressive trimming impacts these binning metrics. Methods: Twenty-three Miscanthus x giganteus rhizosphere metagenomes were subjected to different combinations and thresholds of force, kmer, and quality trimming and decontamination using BBDuk. Reads were assembled and binned in KBase. Phylogenomic and statistical analyses were applied to evaluate the effects of trimming and decontamination on downstream analyses. Results: We found that JGI trimmed and decontaminated reads had significant impacts on assembly and binning metrics compared to raw reads, including significantly higher total contig counts, more contigs greater than 10k bp in length, and larger total lengths of raw assemblies compared to QC assemblies, and 2.0% lower average contamination of QC MAGs compared to raw MAGs. We also found that differences in the placement of MAGs in species trees increased with decreasing completeness and contamination thresholds. Furthermore, aggressive trimming (Q20) was found to significantly reduce MAG counts. Conclusion: Trimming and decontamination of metagenomics reads prior to assembly can change an investigator’s answer to the questions, “Who is there and what are they doing?” However, mild trimming and decontamination of metagenomic reads with high-quality scores are recommended for removing sample processing and sequencing artifacts.
Whitham, Jason M.↗
Overview of Novel Canadian Approaches for Decontamination of Solid Radioactive and Mixed Waste - 19476
The availability of decontamination-for-release technology options provide a path forward to economically decontaminate radioactive metallic waste and enable its disposal as clean scrap metal, to decontaminate tools/equipment for unrestricted refurbishment or reuse, and to carry out inspection of in-service components. Projects involving management of solid mixed waste pose complex technical challenges that require the development and application of novel decontamination processes. The objective of this paper is to present project case studies that provide an overview of Kinectrics' experience with the decontamination of solid radioactive and mixed waste. Novel approaches to decontamination, recent developments, key results and lessons learned will also be discussed. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
The Argonne SuperGel for CBRN Decontamination - 20160
The Argonne SuperGel was developed between 2003 and 2015 to fill a gap in our nation's capability to quickly decontaminate important structures following a radiological or nuclear release event. Specifically, the decontamination technology was developed to minimize damage to monuments, high valued structures, and critical infrastructure while reducing environmental and health impacts. An important criterion during its development, common reagents were employed that could be easily acquired in order to minimize the timeline for its deployment. Its current formulation uses off-the-shelf super-absorbing hydrogels common to the food and agricultural industry and common salts. Over the years, two formulations of the Argonne SuperGel have been developed to specifically target radioactive cesium contaminations and then, more generically, actinide and fission product contaminations. A biodegradable derivative of phosphoric acid is used in small amounts to promote the removal of insoluble actinide species. The original order of unit operations for the SuperGel technology was 1) applying the wash solution to promote mobility of the contaminants on the surface, 2) applying the hydrogel to absorb the wash solution and contaminants, and 3) removing the hydrogel for disposal. During the course of our studies, we tested a new formulation of the gel technology that eliminated the need for a separate step to apply the wash solution without a compromise in decontamination factors. Greater than 70% and >95% of Cs-137 were removed from concrete and tile coupons, respectively, after two decontaminations, with the best results using wash solutions of 1.0 M KCl and 1.0 M NH{sub 4}Cl formulations. We found no statistical difference between results at 30 deg. C and 40 deg. C or at 70% and 90% relative humidity. We tested the gel under strong UV irradiation to simulate extreme environments. While a tropical noontime UV flux did not adversely affect the gel system decontamination of Cs-137 from concrete or tile coupons, the noontime flux resulted in significant dehydration of the gel after two hours of constant exposure. The rehydration of the gel by the humid air (at 90% humidity and 40 deg. C) was slow and may not be sufficient to offset dehydration by the sun. Americium decontamination from concrete was 70% after optimizing the phosphoric acid derivative and carbonate salt concentration in the wash solution. Since its development, we have had the opportunity to test the SuperGel in the removal of legacy contaminations in hot cell facilities and former glovebox facilities at Argonne. This has provided a unique opportunity to evaluate the SuperGel on a range of contaminants outside the original specifications for its use. We will report on the origin of the gel formulation, some highlighted experimental data including independent testing by the US EPA which has never been reported, and its efficacy for removing legacy alpha contaminations and its potential use for removal of chemical and biological hazardous agents. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Tool for Developing Integrated Strategies for Decontamination and Waste Management - 20291
Management of waste from chemical, biological, and radiological incidents is complicated by the fact that decontamination decisions have a profound impact on the characteristics of resulting waste streams. Wide-area biological and radiological incidents could produce massive quantities of waste that may need to be treated on-site and sent for subsequent disposal as non-contaminated materials, or else be directly disposed of as contaminated materials. The EPA has developed the Waste Estimation Support Tool (WEST) for characterizing and quantifying biological and radiological waste that may be generated from decontamination efforts. This paper focuses on the WEST's uses for radiological incidents. WEST combines Geographic Information System (GIS)-based analysis of externally-supplied plume data, infrastructure databases derived from the Federal Emergency Management Agency's (FEMA's) Hazus tool [1], and satellite imagery surface recognition algorithms to combine the composition and square footage of the buildings in the plume with estimates of the materials between the buildings in the plume. The resulting GIS data files are then imported into a Microsoft Access database application, where they are combined with information about the nature and concentration of contaminants, and then subjected to decontamination strategies for different contaminated surfaces. The tool provides estimates of the type and quantities of potential wastes resulting from simulated decontamination and/or demolition activities and includes estimates of the remaining contamination levels including residual contamination contained within each waste stream. Estimates are presented at several levels of detail, allowing users to obtain needed data at the desired resolution. These include estimates for the total affected area, estimates by contamination zone, estimates by decontamination method(s), and estimates by building type (occupancy classification). EPA is currently developing the next version of WEST which will include several substantial enhancements. The most significant improvement for the next version of WEST will include the ability for users to develop contamination scenarios and waste estimates based on previously developed, readily available, and geographically specific infrastructure data. Instead of using WEST's default infrastructure data based on FEMA's Hazus tool, users will be able to import their own building data specific to the geographically affected area. This capability may substantially decrease uncertainties in the resulting waste estimates because the results will be based on actual building data (numbers of each type, square footage, building height, etc.). Two other significant enhancements will be the ability to generate waste estimates for vehicles and biomass. In addition to building debris and building decontamination waste, vehicles and biomass will likely constitute a significant percentage of the total waste which may result from wide area contamination events. This presentation will present the most recent version of WEST, which includes such considerations as affected biomass (e.g., trees), vehicles, and the ability to replace the default Hazus infrastructure databases with custom infrastructure databases. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Designing a Decontamination Solution for the Low-Earth-Orbit, Cryogenic SPHEREx Mission
To address the scientific goals of NASA’s astrophysics division, the JPL and Caltech’s SPHEREx mission conducts the first near-infrared all-sky spectral survey in low-earth-orbit using a passively-cooled, cryogenic telescope. Several unique water contamination issues arise due to the combination of cryogenic operation temperatures and the limited temperature control authority of passive cooling. Because water molecules have adsorption bands within the wavelengths of interest for SPHEREx’s survey, it is imperative that water contamination be controlled and minimized. In this work, a model is developed for the SPHEREx mission to predict the transport and accumulation of outgassed water onto sensitive payload components. The model utilizes the time dependent thermal profiles of the individual payload components, initial water content, and spacecraft geometry to calculate the time dependent water diffusion, transport, and adsorption. This model is subsequently used to predict water contamination risks and design decontamination solutions for each risk. Two major water contamination risks were predicted, water accumulation during cooldown and on cryogenic surfaces during the mission. The first risk occurs during the cooldown of the payload to cryogenic temperatures, predicting water accumulation on optical surfaces in excess of the allowable levels. To mitigate this accumulation, the temperature of the optical surfaces is controlled during cooldown through a combination of heaters and spacecraft pointing. The second risk is that over the course of the mission, is unavoidable water accumulation onto the payload thermal system’s cryogenic surfaces, possibly jeopardizing thermal performance and temperature stability, both of which are required for science success. To decontaminate any water that had collected onto cryogenic thermal system surfaces, a decontamination maneuver was designed. In this decontamination maneuver, cryogenic surfaces of the thermal system are warmed to a temperature where water will desorb by spacecraft pointing while still meeting all avoidance constraints, and thereby avoiding undue risk to the observatory hardware. Through application of the developed analytical model and inclusion of the decontamination maneuver in the mission design, SPHEREx can confidently demonstrate that it is able to decontaminate, at the start of and during the mission as needed to meet its end of life science performance requirements.
Soares, Carolos E.↗
Impact of BBDuk metagenomic read trimming and decontamination
Background Investigators using metagenomic sequencing to study their microbiomes are often provided data that has been trimmed and decontaminated or do it themselves without knowing the effect these procedures can have on their downstream analyses. Here we evaluated the impact that JGI trimming and decontamination procedures had on assembly and binning metrics, placement of metagenome assembled genomes into species trees, and functional profiles of metagenome-assembled genomes (MAGs) extracted from twenty three complex rhizosphere metagenomes. We also investigated how more aggressive trimming impacts these binning metrics. Results We found that JGI trimmed and decontamination of input reads had some significant impacts in assembly and binning metrics compared to raw reads, and that differences in placement of MAGs in species trees increased with decreasing completeness and contamination thresholds. More aggressive trimming beyond those used by JGI were found to reduce MAG counts. Conclusions Mild trimming and decontamination of metagenomics reads prior to assembly can change an investigator’s answer to the questions, “Who is there and what are they doing? However, mild trimming and decontamination of metagenomic reads with high quality scores is recommended for those who elect to do so.
59 BASIC BIOLOGICAL SCIENCES↗
Integrated Waste Treatment Unit Plan for Vessel and Canister Decontamination - 19283
The Integrated Waste Treatment Unit (IWTU) was designed to use a proprietary fluidized-bed steam reforming process to treat 3,400,000 L (898,184 gal) of radioactive sodium bearing waste (SBW). IWTU is currently in commissioning and startup phase prior to future processing of SBW. The current simulant SBW is introduced into the denitration mineralization reformer and transformed into a dry, granular product that is filtered and eventually transferred into a product canister. The intention of the facility is to process the SBW and store the product canisters in vaults to await shipping to a depository at a later date. The IWTU is a part of the Idaho Cleanup Project Core, located at the INL Site and operated by Fluor Idaho, LLC. During early operation and testing of the facility, it was observed that the original process equipment decontamination system did not possess the capability to recover from plant shutdowns that result from upset conditions or maintenance outages; thus, a need for a redesigned decontamination system was identified. This paper discusses current decontamination methods and their capabilities and areas where these methods fall short of decontaminating process equipment and product canisters. This paper discusses the design and purpose of the decontamination methods being tested and developed for implementation into the IWTU. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗