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Analytical Modeling of Planetary Excavation for in Situ Resource Utilization

The space-faring capabilities of humans are dependent on the ability to interact with plan-etary surfaces safely and efficiently and utilize local re-sources. Since planetary regolith will be the primary feedstock for in situ resource utilization (ISRU) and infrastructure development activities [1,2], the site-specific geomechanical properties must be understood to optimize excavation operations [3]. Excavating planetary regolith is challenging due to its unique geomechanical properties, 1/6th G reduced gravity extreme conditions, and limited energy resources. Therefore, it is critical to develop technologies that reduce excavation force requirements and minimize tool path inefficiencies to save time and energy during planetary re-source acquisition and infrastructure development [3]. There have been several experimental investigations of methods to optimize planetary excavations [4,5], but none developed predictive capabilities. This abstract presents a simple analytical method that will be used to model laboratory and mission excavation data. Future work will build on the simple analytical method here to include high-fidelity numerical simulations of planetary excavation mechanics.

Regolith↗

Understanding and Utilizing PBL Height Data from Multiple Observing Systems in the GEOS System

The accuracy of PBL height simulation is a key issue in many applications including forecasting near surface meteorology and air quality, however, it is a very challenging problem due to the lack of not only comprehensive, global Planetary Boundary Layer (PBL) observations but also a strategy and infrastructure to utilize PBL height data from a variety of sensors. Following the designation of PBL as an incubation class observable in the 2017 Decadal Survey, the PBL Incubation Study Team Report [14] made clear that “a future global PBL observing system requires modeling and data assimilation as essential components.” There is an urgent need for global modeling development in order to utilize Program of Record (POR) observations, assess their impacts, and identify gaps to be filled by future PBL missions. Our overall objective is to develop PBL data assimilation capabilities in the NASA Global Earth Observing System (GEOS), focusing on PBL height from multiple observing systems, to support the assessment and use of future PBL observations. The NASA GEOS system is composed of the GEOS global atmospheric general circulation model (AGCM) and the atmospheric data assimilation system (ADAS). The PBL parameterizations include the “Lock” K-profile scheme driven by surface and cloud-top buoyancy fluxes ([4]), and the “Louis” local scheme for stable conditions based on the Richardson number ([5]). Above the mixed layer defined by the Lock surface plume, shallow cumulus convection is represented by the mass flux scheme of [9]. Additional parameterizations are summarized in [1]. The ADAS employs the hybrid 4D Ensemble- Variational (EnVar) configuration ([15]), with the ensemble providing flow-dependent background error covariance information. The resultant analysis increments are fed back to the forecast model through the 4D incremental analysis update (IAU) approach ([11]). In this study, PBL height data are being or have been generated from radiosondes, GNSS RO, satellite (CATS, CALIPSO and ICESat-2) and ground-based (MPLNET) lidars, and wind profiler. Investigations have been conducted to specify quality marks for PBL height retrievals for the data assimilation purpose. These PBL height data have different strengths and weaknesses ([2], [3], [6], [7], [8], [10]), and the satellite PBL height data provide better global coverage and complement in-situ PBL height data. Radiosondes offer high accuracy and in situ measurement of temperature and humidity profiles, but with poor spatio-temporal sampling. The in-situ observing systems like MPLNET and wind profiler provide long history of PBL height records at each station. The GNSS RO based PBL height is retrieved based on the sharp gradients in refractivity profile that represent the fine vertical structure of temperature and moisture changes above the PBL. However, not all RO refractivity profiles reach the surface depending on location and regime, and RO refractivity retrievals can be negatively biased below 2km. The PBL height data from satellite lidars provide high resolution along track PBL height retrievals, but over land they are affected by previous day convective PBL aerosol and strongly associated with mixing layer and retrievals cannot be made below thick, attenuating clouds. A successful assimilation of PBL height data requires a thorough understanding of the observing method and the retrieval algorithm for each observing system in order to use the PBL height data from multiple observing systems properly. Due to the sensitivity of PBL height data to the observing method and choice of algorithm, it is important to use a model definition appropriate for each observation type to compute differences between PBL height data and model PBL height (OmFs). The GEOS model currently includes two PBL height definitions suitable for direct comparison with observed PBL height, and additional definitions are being added in this study. Evaluation of different model PBL height definitions is underway. Meanwhile, efforts have been made in the GEOS data assimilation system to develop PBL height data assimilation capability. PBL height data can be assimilated using two different approaches. The traditional approach is to construct an observation operator and its tangent linear and adjoint, which link control variables to PBL height data from each observing system. This observation operator can be very complicated, e.g., the lidar-based PBL height observation operator includes the backscatter lidar forward observation operator, the algorithm to derive PBL height from attenuated total backscatter, interpolation, and calculations handling the mismatch between observed and model scales. The other approach is to augment PBL height to the control variable vector, and it is adopted in this study. The latter approach was also used in previous studies, e.g., the assimilation of PBL height data from radiosonde and aircraft in the Real Time Mesoscale Analysis (RTMA) system for a dispersion modelling study ([13]); the PBL height assimilation study using lidar PBL height data at Greensburg, Kansas for a field campaign ([12]). The PBL height assimilation from multiple observing systems in this study allows us to take advantage of the diverse PBL height data that provide much better global coverage collectively under different meteorological conditions and with different temporal and spatial scales. As all the PBL heights are tightly coupled with the PBL thermodynamic variables, the strong correlations, which are provided by the 4D ensemble forecast, enable PBL height data from various sources to interact and combine coherently and provide additional information for PBL temperature and moisture fields. The results of comparisons among PBL height data from different sources and the evaluation of the model PBL height definitions with the PBL height data will be presented, and the PBL height data synergy strategies and preliminary results will also be discussed at the conference.

Y. Zhu↗

Advancements to Wind Tunnel Testing at the Marshall Space Flight Center Aerodynamic Research Facility by the Utilization of Additively Manufactured Models

In recent years, the Aerodynamic Research Facility (ARF) at NASA’s Marshall Space Flight Center (MSFC) has heavily utilized additive manufacturing (AM) technology for the manufacturing of models for aerodynamic testing in the 14 x 14-inch Trisonic Wind Tunnel (TWT). This process change resulted in speed and cost improvements to the design and manufacture of model parts, which has provided the capability to perform parametric tests at a rapid pace with high fidelity models that are more finely detailed than previously tested. This paper outlines the model design and fabrication workflow of the ARF and the improvements made, focusing specifically on two vehicles tested. First, identical traditionally machined and AM models of a test missile configuration were tested to isolate effects of differences in manufacturing. Second, a high-fidelity model of NASA’s Space Launch System (SLS) was tested to investigate improvements in data quality possible by utilizing AM on small-scale wind tunnel tests. This paper also discusses detailed model inspections and data comparisons that were performed to prove the reliability of data across the TWT’s entire Mach range.

Ryan C Connelly↗

Analysis of a Landing System for Planetary Payloads Utilizing Passive Energy Absorbing Composite Structure

Delivery of a payload from space to a planetary surface currently requires the development of an application specific landing system to protect the payload from forces imparted during impact with the planet surface. Often, active energy attenuating systems such as retro-rockets, deployable parachutes, and airbags are utilized within these landing systems to reduce landing impact energy. Unfortunately, these active systems come at a cost; active energy attenuating systems are susceptible to system faults which may limit or completely negate their energy attenuating capability. Additionally, components needing to be stowed such as fuel, parachutes, and airbags increase design complexity, cost, and weight. To overcome these limitations, this study examines the potential of passive energy attenuation through energy absorbing structural design and composite materials to mitigate landing loads for small payload planetary delivery. Researchers at the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) have conducted extensive research into developing energy absorbing structures and components for the attenuation of impact energy under various loading conditions including aircraft crash and spacecraft impact. The current study leverages this research to design a lightweight planetary delivery system which utilizes unique outer mold line (OML) geometry and passive energy absorbing structural design to limit landing loads across potential planetary surface environments. The OML geometry is designed to control impact orientation and provide self-righting capabilities for slopped impact surfaces. The internal structure is composed of composite material structures arranged to provide energy absorption which is robust to impact angle and impact velocity. The developed planetary delivery design concept will be evaluated using finite element (FE) model analysis. Simulations of landing impacts with representative soil surface environments will be used to characterize the energy absorbing capabilities of the landing system. Sensitivity of predicted impact force to landing environment, impact angle, and impact velocity will be assessed to identify capabilities and limitations of the initial structural design. Results will be used to determine the feasibility of a lightweight composite structure to passively absorb landing energy for robust planetary payload delivery.

Crashworthiness↗

Hawai’i Climate: Utilizing NASA Earth Observations to Assess Thermal Stress Impacts on Coastal Hawaiian Fishponds

Hawaiian fishponds (loko i’a), ancient aquaculture systems created over 1500 years ago, historically served to harvest prized native fish species. Colonization-induced changes in land management have reduced active loko i’a from over 500 to ~20, destabilizing nearshore ecosystems and diminishing native Hawaiian cultural traditions. In recent decades, efforts to restore loko i’a have intensified as part of a broader emphasis on preserving Hawaiian cultural identity. Anthropogenic-induced climate change threatens these systems, particularly through the increase in frequency and magnitude of marine heatwaves. Though largely unexplored, these events are effectively studied utilizing remote sensing via Earth observations. Leveraging this technique enables autonomous extraction of water quality parameters to inform fishpond management. This study examined seven loko i’a across the main Hawaiian Islands (Hawai’i Island, Moloka’i, Maui, O’ahu, Kaua’i). Sea surface temperature and normalized difference chlorophyll index measurements were derived in fishponds utilizing Landsat 8 Thermal Infrared Sensor Thermal Infrared Sensor and Sentinel-2 MultiSpectral Instrument between 2013 to 2023, while regional patterns in temperature and chlorophyll-a were observed via Aqua’s Moderate Resolution Imaging Spectroradiometer (2002-2021). Employing these sensors, we focused analysis around the 2015 and 2019 marine heatwaves in the Pacific. We observed a heat stress gradient across the archipelago, creating thermally sheltered and unsheltered fishponds, yet identified no notable localized relationships between temperature and chlorophyll-a. Additionally, we applied pre-determined thermal maxima for culturally significant fish species (Striped Mullet: Mugil cephalus; Milkfish: Chanos Chanos) to assess historical habitat suitability within fishponds. While the direct impacts of marine heatwaves on loko i’a ecology are unknown, temperature patterns observed in this study are cause for concern.

Raz Wachtel↗

Northern Colorado Water Resources: Using Earth Observations to Assess Relationships between Snowpack and Wildfires for Water Utility Management

In recent years, wildfires in the western U.S. have increased in size, frequency, and severity. Colorado is no exception to this trend, with many recent wildfires raising concerns. The Cameron Peak and East Troublesome Fires, the two largest recorded wildfires in Colorado history, burned over 400,000 acres in 2020. Wildfires pose a significant threat to high-elevation ecosystems, especially in terms of disturbances to watershed resources. Colorado’s annual water supply is dependent upon the melt and runoff of high-elevation snowpack, thus understanding wildfire effects is crucial. This project partnered with Northern Water, a water management company in Colorado, to explore fire impacts on Colorado Front Range watersheds and water supply forecasts. We investigated the use of remote sensing to study the influences of wildfire on snow depth, as Northern Water had previously relied on field-based observations of snowpack for their water supply forecasts. This project utilized airborne LiDAR data from Airborne Snow Observatories, Inc., Landsat 8 OLI derived products, as well as in situ snow survey data from Colorado State University to assess and model changes in snowpack over time. We uncovered key drivers of change in snowpack such as burn severity and snow zone and created a random forest model to determine and investigate their relationships. Despite temporal data availability limitations, analysis also showed that remotely-sensed snow depth measurements were strongly correlated with in situ snow depth measurements, revealing the accuracy and feasibility of using remote sensing technologies to study landscape-scale snowpack characteristics for water utility management purposes.

airborne LiDAR↗

Demonstration of in-Situ Resource Utilization of Lunar Regolith for Plant Growing Systems Through Scaled Capillary Models

The development of reliable and bioregenerative crop growth production systems is vital for human exploration into deep space. As the National Aeronautics and Space Administration (NASA) prepares for the Artemis missions, scientists need to find a way to provide consistent and sufficient water delivery for all stages of a plant’s life cycle. NASA has been able to successfully model passive flow through felt material, to mimic the water uptake and transport through a plant, in microgravity. However, more studies need to be conducted to adapt the model for a substrate-based system and incorporate how flow will change during each stage of plant growth. For future missions, payload requirements to support crop production systems will need to be limited, leading to the use of available resources, such as lunar regolith. Although numerous lunar regolith simulants are commercially available, few have been evaluated for their suitability in agricultural applications. First, a base regolith simulant will need to be identified based on its physical and chemical properties. Then, additional amendments to improve the properties of the simulants to support plant growth will be identified. The design and composition of the substrate will be based on water transport requirements for different stages of plant growth. Scaled capillary models can be utilized to study surface-tension driven flows through various designer substrates to modify the physical properties of the selected regolith simulant. These models can accurately represent how flow will act in a reduced gravity environment, which can be used to design a full-scale facility for surface missions. This project will aid space researchers in the design of future crop production systems for surface missions by creating a refined model that can be used at all stages of plant growth and utilize in situ resources.

Fluids↗

Fundamental Research to Enable In-Situ Resource Utilization for NASA’s Artemis Program and Beyond Taking Place at The Glenn Research Center

In Situ Resource Utilization (ISRU) is regarded by many to be the key to future sustainability in space. The National Aeronautics & Space Administration’s (NASA) Space Technology Mission Directorate (STMD) recently published a list of ranked technology shortfalls. ISRU specific capabilities of ‘Extraction and separation of water from extraterrestrial surface material’, ‘Extraction and separation of oxygen from extraterrestrial surface material’, and ‘Produce propellants and mission consumables from extracted in-situ resources’ are within the top 80 shortfalls identified. A team of researchers and engineers at NASA’s Glenn Research Center (GRC) in Cleveland, Ohio, are performing fundamental research and technology maturation to ensure concepts and technologies are ready to support when the mission architecture is primed for ISRU to activate. Through analytical modeling and initial lab-scale testing, researchers are establishing concepts that mature to more sophisticated tests in relevant environments. Numerous studies are underway assessing fundamental behaviors of regolith during various steps of a conceptual ISRU production plant. This paper shares some of GRC’s recent advancements in ISRU research and technology development, in the hopes of providing valuable information to the ISRU community at large, spark ideas for future collaborative endeavors, as well as spur interest in utilizing some of the world-class expertise and facilities GRC has to offer.

ISRU↗

Terrestrial Proving Ground Capabilities Needed for Lunar In Situ Resource Utilization (ISRU) & Construction Concepts of Operation

Incorporating any new technology or system into a human exploration mission or architecture requires development well in advance of the mission to eliminate technology, cost, and schedule risk concerns. It is often stated that technologies need to be at a Technology Readiness Level (TRL) of 6, i.e. ‘system/subsystem model or prototype demonstration in a relevant environment (ground or space)’, by Authority To Proceed (ATP) or by the Preliminary Design Review (PDR) for the mission at the latest. There are two game changing capabilities for sustained human exploration of space that can have a significant effect on the overall exploration architecture and the technologies and systems included in the architecture. The first game changing capability, known as In Situ Resource Utilization (ISRU), involves the search for, acquisition, and processing of resources on the Moon and Mars into mission consumables and usable products, and the second is the ability to utilize space resources in the construction of roads, structures, and surface infrastructure. ISRU and surface construction capabilities have the potential to greatly reduce the cost and risk of human exploration while enabling sustained lunar surface and commercial operations. However, ISRU and surface construction systems are complex and must operate in extremely harsh environments, with abrasive regolith and pervasive dust, for long-periods of time, with potentially limited opportunities for maintenance and repair by humans. The complexity of these capabilities and operations also means that there are a limited number of companies that can design, build, and operate end-to-end systems on their own. The majority of the technologies being developed for these systems are by small companies and at the component or subsystem level. With the overarching strategy of the United States National Aeronautics and Space Administration (NASA) Space Technology Mission Directorate (STMD) to enable industry to implement ISRU and surface infrastructure for Artemis and space commercialization, it is therefore important to establish processes and capabilities to promote and foster collaborations among large and small companies involved in ISRU and surface infrastructure development. For ISRU and infrastructure systems and capabilities to be used in Artemis missions and future commercial lunar surface operations, a coordinated framework with virtual/physical integration and testing locations, or ‘Proving Grounds’, needs to be established and operated on a regular basis and open to all. This paper will discuss the ISRU and surface construction near and long-term concepts of operations, and review operations and lessons-learned from the previous ISRU analog field tests. From this information, requirements and capabilities will be proposed to support and enable the integration and testing of ISRU and construction systems with industry, academia, and international agencies, as well as what facilities and organizations could help establish these Proving Grounds.

ISRU↗

A Non-Nuclear, Solar Powered Mission to Uranus Utilizing the PowerSail - a Large Solar Sail with Embedded Solar Cells

Powering missions to the outer solar system is a significant challenge. These missions are typically powered by a Radioisotope Thermoelectric Generator (RTG). Though these sources provide stable power regardless of location in space, they are expensive to produce, difficult to integrate, and have both safety concerns as well as negative sociopolitical connotations. Perhaps most importantly, the availability of their fuel, plutonium-238, is scarce. Solar power is often considered a more attractive option. However, photovoltaic generation falls off at the distance from the sun squared. This drives the size of traditional solar generators to infeasible levels for deep space and their utilization at locations deeper the Jupiter is currently non-existent. Herein, a hypothetical solution, the PowerSail, and its application to a non-nuclear Uranus mission is presented. The PowerSail is a marriage of solar sails and thin-film solar cell assemblies. Herein the application of PowerSail spacecraft to a high priority science mission, the Applied Physics Laboratory’s Uranus Probe and Explorer, is studied. The overall mission design along with key subsystems design changes are discussed, ultimately showing that a PowerSail could be utilized as a non-nuclear option to reach destinations very deep in our solar system. Key needed technology developments to make the PowerSail and such a mission a reality are given.

John A. Carr↗

Airfoil Table Generation Comparison Utilizing XFOIL and UNS2D Flow Solvers

The flow solvers XFOIL and UNS2D were utilized within the airfoil table generator AFTGen to generate airfoil performance tables, and these results were compared to determine accuracy at low Mach numbers that may be relevant to Urban Air Mobiltiy (UAM) applications. Airfoil tables were generated for the NACA 0012 airfoil as well as a set of three asymmetrical airfoils developed in this study from which the rotor blade CSUS 001 was comprised. To determine which solver more accurately represented real-world aerodynamics, the airfoils were experimentally tested in the CSU 2-foot by 2-foot wind tunnel. The results of XFOIL and UNS2D were compared to the experimental results. It is important to note that due to differences in the Reynolds numbers between simulations and experimental testing, the magnitude of the section lift and drag coefficient varies between the two methods. However, observations on the accuracy of XFOIL and UNS2D could still be made based on the trends of the data. For the symmetrical NACA 0012 airfoil, it was found that XFOIL and UNS2D accurately predicted the trends of the section lift and drag coefficients. However, XFOIL predicted slightly lower section drag coefficients than UNS2D for the tested angles of attack. For the asymmetrical CSUS 001 airfoils, XFOIL could not predict a steady to decreasing section lift coefficient phenomenon at negative angles of attack observed in both the UNS2D and experimental results. Similarly, XFOIL was unable to predict an increased section drag coefficient at negative angles of attack for the CSUS 001 airfoils as observed in the UNS2D and experimental results. Additionally, 3D computational fluid dynamics was utilized through RotCFD to compare the performance of a rotor blade using the CSUS 001 airfoils versus a rotor blade using the NACA 0012 airfoil.

UAM↗

Xylose utilization in recombinant zymomonas

Xylose-utilizing Zymomonas strains studied were found to accumulate ribulose when grown in xylose-containing media. Engineering these strains to increase ribose-5-phosphate isomerase activity led to reduced ribulose accumulation, improved growth, improved xylose utilization, and increased ethanol production.

59 BASIC BIOLOGICAL SCIENCES↗

Overview of reductants utilized in nuclear fuel reprocessing/recycling

Most of the aqueous processes developed, or under consideration worldwide for the recycling of used nuclear fuel (UNF) utilize the oxido-reduction properties of actinides to separate them from other radionuclides. Generally, after acid dissolution of the UNF, (essentially in nitric acid solution), actinides are separated from the raffinate by liquid-liquid extraction using specific solvents, associated along the process, with a particular reductant that will allow the separation to occur. For example, the industrial PUREX process utilizes hydroxylamine as a plutonium reductant. Hydroxylamine has numerous advantages: not only does it have the proper attributes to reduce Pu(IV) to Pu(III), but it is also a non-metallic chemical that is readily decomposed to innocuous products by heating. However, it has been observed that the presence of high nitric acid concentrations or impurities (such as metal ions) in hydroxylamine solutions increase the likelihood of the initiation of an autocatalytic reaction. Recently there has been some interest in the application of simple hydrophilic hydroxamic ligands such as acetohydroxamic acid (AHA) for the stripping of tetravalent actinides in the UREX process flowsheet. This approach is based on the high coordinating ability of hydroxamic acids with tetravalent actinides (Np and Pu) compared with hexavalent uranium. Thus, the use of AHA offers a route for controlling neptunium and plutonium in the UREX process by complexant based stripping of Np(IV) and Pu(IV) from the TBP solvent phase, while U(VI) ions are not affected by AHA and remain solvated in the TBP phase. In the European GANEX process, AHA is also used to form hydrophilic complexes with actinides and strip them from the organic phase into nitric acid. However, AHA does not decompose completely when treated with nitric acid and hampers nitric acid recycling. In lieu of using AHA in the UREX + process, formohydroxamic acid (FHA), although not commercially available, hold promises as a replacement for AHA. FHA undergoes hydrolysis to formic acid which is volatile, thus allowing the recycling of nitric acid. Unfortunately, FHA powder was not stable in the experiments we ran in our laboratory. In addition, AHA and FHA also decompose to hydroxylamine which may undergo an autocatalytic reaction. Other reductants are available and could be extremely useful for actinides separation. The review presents the current plutonium reductants used in used nuclear fuel reprocessing and will introduce innovative and novel reductants that could become reducers for future research on UNF separation.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Utilization of Local Law Enforcement Aerial Resources in Consequence Management (CM) Response

During the past decade the U.S. Department of Homeland Security (DHS) was instrumental in enhancing the nation’s ability to detect and prevent a radiological or nuclear attack in the highest risk cities. Under the DHS Securing the Cities initiative, nearly 13,000 personnel in the New York City region have been trained in preventive radiological and nuclear detection operations, and nearly 8,500 pieces of radiological detection equipment have been funded. As part of the preventive radiological/nuclear detection (PRND) mission, several cities have received funding to purchase commercial aerial radiation detection systems. In 2008, the U.S. Department of Energy, National Nuclear Security Administration Aerial Measuring System (AMS) program started providing Mobile Aerial Radiological Surveillance (MARS) training to such assets, resulting in over 150 HAZMAT teams’ officers and pilots from 10 law enforcement organizations and fire departments being trained in the aerial radiation detection. From the beginning, the MARS training course covered both the PRND and consequence management (CM) missions. Even if the law enforcement main focus is PRND, their aerial assets can be utilized in the collection of initial radiation data for post-event radiological CM response. Based on over 50 years of AMS operational experience and information collected during MARS training, this presentation will focus on the concepts of CM response using aerial assets as well as utilizing law enforcement/fire department aerial assets in CM. Also discussed will be the need for establishing closer relationships between local jurisdictions’ aerial radiation detection capabilities and state and local radiation control program directors, radiological health department managers, etc. During radiological events these individuals may become primary experts/advisers to Incident Commanders for radiological emergency response, especially in the early stages of a response. The knowledge of the existence, specific capabilities, and use of local aerial radiation detection systems would be critical in planning the response, even before federal assets arrive on the scene. The relationship between local and federal aerial assets and the potential role for the further use of the MARS training and expanded AMS Reachback capabilities in facilitating such interactions will be discussed.

consequence management, CM, local law enforcement,↗

Utilization of Heat Pump Water Heaters for Load Management

The Energy Conservation Standards for Residential Water Heaters require residential electric storage water heaters with volumes larger than 55 gallons to have an energy factor greater than 2.0 after April 2015. While this standard will significantly increase the energy efficiency of water heaters, large electric storage water heaters that do not use heat pump technologies may no longer be available. Since utilities utilize conventional large-volume electric storage water heaters for thermal storage in demand response programs, there is a concern that the amended standard will significantly limit demand response capacity. To this end, Oak Ridge National Laboratory partnered with the Tennessee Valley Authority to investigate the load management capability of heat pump water heaters that meet or exceed the forthcoming water heater standard. Energy consumption reduction during peak periods was successfully demonstrated, while still meeting other performance criteria. However, to minimize energy consumption, it is important to design load management strategies that consider the home s hourly hot water demand so that the homeowner has sufficient hot water.

Boudreaux, Philip R↗

Extending the utility of a radioactive material package

Once a package has been certified for the transportation of DOT Hazard Class 7 – Radioactive Material in compliance with the requirements of 10 CFR 71, it is often most economical to extend its utility through the addition of content-specific configuration control features or the addition of shielding materials. The SRNL Model 9977 Package’s authorization was expanded from its original single to twenty contents in this manner; and most recently, the 9977 was evaluated for a high-gamma source content. This paper discusses the need for and the proposed shielding modifications to the package for extending the utility of the package for this purpose.

42 ENGINEERING↗

PRELIMINARY ENVIRONMENTAL, HEALTH AND SAFETY RISK ASSESSMENT ON THE INTEGRATION OF A PROCESS UTILIZING LOW-ENERGY SOLVENTS FOR CARBON DIOXIDE CAPTURE ENABLED BY A COMBINATION OF ENZYMES AND VACUUM REGENERATION WITH A SUBCRITICAL PC POWER PLANT

The results of the preliminary environmental, health and safety (EH&S) risk assessment for an enzyme-activated potassium carbonate (K2CO3) solution post-combustion CO2 capture (PCC) plant, integrated with a subcritical pulverized coal (PC) power plant, are presented. The expected emissions during normal steady-state operation have been estimated utilizing models of the PCC plant developed in AspenTech’s AspenPlus® software, bench scale test results from the University of Kentucky, and industrial experience of emission results from a slipstream PCC plant utilizing amine based solvents. A review of all potential emission species and their sources was undertaken that identified two credible emission sources, the absorber off-gas that is vented to atmosphere via a stack and the waste removed from the PCC plant in the centrifuge used to reclaim enzyme and solvent. The conditions and compositions of the emissions were calculated and the potential EH&S effects were considered as well as legislative compliance requirements. Potential mitigation methods for emissions during normal operation have been proposed and solutions to mitigate uncontrolled releases of species have been considered. The potential emissions were found to pose no significant EH&S concerns and were compliant with the Federal legislation reviewed. The limitations in predicting full scale plant performance from bench scale tests have been noted and further work on a larger scale test unit is recommended to reduce the level of uncertainty.

Fitzgerald, David↗

Opportunities to more fully utilize safeguards information reported to the IAEA at Gas Centrifuge Enrichment Plants

In an effort to increase transparency and to strengthen IAEA safeguards, more countries are adopting practices that provide the IAEA with more timely, safeguards-relevant information to confirm nuclear operations are as declared. At Gas Centrifuge Enrichment Plants (GCEPs) potential examples include installing unattended IAEA instruments that transmit selected information back to Vienna, instruments that collect and store measurement information on-site, and daily facility operator submissions of material receipts, shipments, or utilization of key operational systems (e.g., UF6 feed stations) to on-site mail boxes. Recently the IAEA has implemented the use of on-site mailbox systems supplemented with short notice or unannounced inspections to maintain effectiveness without significantly increasing the number of inspection days. While these measures significantly improves the IAEA’s effectiveness, we have identified several opportunities for how the use of this information could be improved and how some additional information would further improve safeguards. This paper presents concepts for how the safeguards information currently collected at GCEPs could be more effectively utilized through enhancing the way that raw data is displayed visually so that it is more intuitive to the inspector and provides for more effective inspection planning and execution, comparing information with previous IAEA inspection activities (lists of previous verified inventory), through comparing data with operator supplied data when inspectors arrive (notional inventory change reports), and through evaluating the data over time to provide even greater confidence in the data and operations as declared in between inspections. This paper will also discuss several potential improvements to the submissions themselves, such as including occupancy information about product and tails stations and including weight information for each station.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗