Results for “Contamination Control Engineering” — Page 10

NASA NTRSDate not supplied

Plume Impingement Studies in Space Environments for NASA Deep Space Logistics

NASA’s Artemis program is preparing to return Americans to the moon, in preparation for future deep space missions to Mars and beyond. The Lunar Gateway – a space station to be placed in orbit around the moon – serves as a critical component of the Artemis program, and will be the launchpad for future astronauts to visit the lunar surface and for humanity to learn how to live in a deep space environment. Much like the ISS, during operations and visiting vehicles approaches, the Lunar Gateway structures will be impinged upon from various plume sources: reaction control system rocket engine plumes, wastewater venting plumes, and plasma plumes from electric thrusters for station keeping. This presentation will describe the engineering challenges associated with each of these plume impingement scenarios and will detail the physical models and simulation approaches to predict the thermomechanical loading, contamination accretion, and erosion of station components due to plume impingement in space environments.

computational fluid dynamics↗

NASA NTRSDate not supplied

Plume Impingement Studies in Space Environments for NASA Deep Space Logistics

NASA’s Artemis program is preparing to return Americans to the moon, in preparation for future deep space missions to Mars and beyond. The Lunar Gateway – a space station to be placed in orbit around the moon – serves as a critical component of the Artemis program, and will be the launchpad for future astronauts to visit the lunar surface and for humanity to learn how to live in a deep space environment. Much like the ISS, during operations and visiting vehicles approaches, the Lunar Gateway structures will be impinged upon from various plume sources: reaction control system rocket engine plumes, wastewater venting plumes, and plasma plumes from electric thrusters for station keeping. This presentation will describe the engineering challenges associated with each of these plume impingement scenarios and will detail the physical models and simulation approaches to predict the thermomechanical loading, contamination accretion, and erosion of station components due to plume impingement in space environments.

Plume Impingement↗

NASA NTRSDate not supplied

Genesis Solar Wind Sample Curation Documentation

Introduction: A scientist with experience as a sample science analyst, provider of flight hardware for multiple missions, and senior engineer in an ISO 2000-rated manufacturing plant has described the timeline of key participants in any PI-led sample return mission, the breadth of the organizations involved [1,2], and, of interest to this meeting, choosing the types of data to preserve and issues of future data accessibility. This work broadens that perspective by giving similar lessons from Genesis sample curation point-of-view. Curation participation regarding data gathering was part of the mission review process from the beginning. Genesis’ story illustrates outcome of several choices about types of data to record and preserve. Precision analysis of solar wind atoms captured in pure, ultraclean substrates is the driving science goal; therefore, detailed documentation was captured from all mission and curation phases and from investigator laboratories because these processes affect the final analytical results [3]. Pre-flight: Design and fabrication of the spacecraft. Like many modern small sample return missions, Genesis was a tightly managed team integrated across science, engineering and curation. Communication across the team was excellent, and, for the most part, the hands-on engineering technicians understood the impacts of “small choices” they routinely make, and the eyes-on oversight of manufacturing processes by scientists was mindful of details. The payload was designed by the Jet Propulsion Laboratory and the spacecraft by Lockheed Martin. Solar wind collectors and instruments were fabricated by multiple vendors and laboratories. The main portion of the payload was assembled at JSC. Fabrication procedures and contamination-control data (with witness coupons) were stored primarily at JSC. The original composition, dimensions and configuration of components, results of thermal testing, etc. are still needed for interpretation of analytical data. At times, these must be estimated from secondary information acquired pre-flight. Moreover, some files (e.g., original 3-D models and early Powerpoint) cannot be opened using software. Archived curation data includes 2-D drawings, material usage lists, QA documentation and analyses of consumables used during fabrication. Important chemical information still resides in archived hardware, paints and lubricants, material coupons, cleaning coupons, environmental witness plates and reference materials from manufacturing facilities. Purity and cleanliness of collector substrates. Semi-conductor vendors provided surface cleanliness data and some purity data. Purity for specific elements of interest was verified by science team members in their laboratories [4]. Curation archived procurement and shipping records, analysis reports, and non-proprietary fabrication data. A physical archive of flight collector reference materials is maintained for future use so additional data can be collected as analytical techniques improve. These are of increased value due to the hard landing upon re-entry. Cleaning and cleanliness assessments of flight hardware. Cleaning of the science canister payload was performed at JSC in a dedicated ISO 4 cleanroom using ultrapure water (UPW). The cleanliness of this UPW was monitored throughout processing. The archive for the clean lab also includes airborne particle counts, airborne molecular and inorganic contamination measurements as well as cleanroom construction material coupons and witness coupons. Hardware cleanliness was assessed by particle counts in rinse water batches. This information is recorded in batch cleaning forms and logbooks, and are, perhaps, of decreased value due to the hard landing. Post-flight: Curation-generated data. The curation handling history of each Genesis sample is documented in a typical astromaterials sample database which captures sample location, physical description and characterization data. Samples have a “shelf life”. Crucial to the preservation of samples is ongoing documentation of the sample environment, initially under curatorial control but is now a separate facility function with requires coordination. PI-generated data. Data on sample characterization and cleaning techniques continues to be generated by sample users [5]. These are often captured in LPSC abstracts, but these “engineering” results often are not publishable as stand-alone papers. We are actively looking for ways to make this information more accessible to users. Ion implants into samples have aided science return and can be shared among investigators. These (and similar) materials should be added to the curatorial collection with appropriate process and characterization data generated externally. Summary: Complete data archives for returned astromaterial samples must be broad in types and formats, and inclusive of environmental monitoring.

Genesis↗

DOE OSTI2019

Environmental Systems Biology Approach to Bioremediation

Pollution is everywhere. Microbes are also everywhere, and many have the ability to degrade environmental contaminants. Understanding how these microbial communities work to degrade environmental contaminants will enable us to use these microbes to clean up the pollution. Understanding, monitoring, and controlling the environment with biological processes, i.e., an environmental systems biology approach to bioremediation, answer the need which is everywhere. By using an environmental systems approach to bioremediation, we make sure we know of any “fatal flaws” in the approach, get a much better handle on life-cycle cost analysis, and can grade an engineered solution into a natural attenuation solution. The whole is greater than the sum of its parts. By using an environmental systems biology approach to bioremediation and cross-linkage of systems at all levels providing multiple lines of evidence involving environmental observations, laboratory testing, microcosm simulations, hypothesis refinement, field testing and validation, and multiple iterations of this circle, we will be able to make new theories and paradigms for bioremediation of contaminated environments.

Hazen, Terry C.↗

DOE OSTI2019

Dust Control Planning

At the Hanford Site, dust control is required during many activities for health and safety purposes and to prevent contaminant dispersal via atmospheric transport. Water is commonly used to reduce dust dispersal, but can mobilize contaminants and facilitate transport through the vadose zone to groundwater as observed with past activities within the River Corridor. To prevent contaminant mobilization associated with remediation activities in the Central Plateau, alternative approaches for dust suppression are presented considering site-specific requirements at Hanford. There are two high-level categories of approaches to dust control: proactive work strategies to minimize fugitive dust generation and reactive engineered controls to mitigate dust generation and/or capture fugitive dust. Because a variety of activities have the potential to generate fugitive dust at a given site, there is no unique response to dust prevention and control. In fiscal year 2018, an evaluation was completed to identify alternatives, determine limits on surface water additions, and develop information suitable for consideration in feasibility studies. The technical basis detailed in the 2018 evaluation has been condensed into this document that provides a practical Dust Control Plan template and site-specific guidance in the appendices. This Dust Control Plan template specifically provides a workflow to 1) identify key project information, 2) identify fugitive dust sources, 3) assign dust control methods, and 4) determine appropriate monitoring practices to mitigate impacts to groundwater.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

NASA NTRS1991

Fourth Annual Workshop on Space Operations Applications and Research (SOAR 90)

The papers from the symposium are presented. Emphasis is placed on human factors engineering and space environment interactions. The technical areas covered in the human factors section include: satellite monitoring and control, man-computer interfaces, expert systems, AI/robotics interfaces, crew system dynamics, and display devices. The space environment interactions section presents the following topics: space plasma interaction, spacecraft contamination, space debris, and atomic oxygen interaction with materials. Some of the above topics are discussed in relation to the space station and space shuttle.

Savely, Robert T.↗

NASA NTRS2016

Cleaning Genesis Sample Return Canister for Flight: Lessons for Planetary Sample Return

Sample return missions require chemical contamination to be minimized and potential sources of contamination to be documented and preserved for future use. Genesis focused on and successfully accomplished the following: - Early involvement provided input to mission design: a) cleanable materials and cleanable design; b) mission operation parameters to minimize contamination during flight. - Established contamination control authority at a high level and developed knowledge and respect for contamination control across all institutions at the working level. - Provided state-of-the-art spacecraft assembly cleanroom facilities for science canister assembly and function testing. Both particulate and airborne molecular contamination was minimized. - Using ultrapure water, cleaned spacecraft components to a very high level. Stainless steel components were cleaned to carbon monolayer levels (10 (sup 15) carbon atoms per square centimeter). - Established long-term curation facility Lessons learned and areas for improvement, include: - Bare aluminum is not a cleanable surface and should not be used for components requiring extreme levels of cleanliness. The problem is formation of oxides during rigorous cleaning. - Representative coupons of relevant spacecraft components (cut from the same block at the same time with identical surface finish and cleaning history) should be acquired, documented and preserved. Genesis experience suggests that creation of these coupons would be facilitated by specification on the engineering component drawings. - Component handling history is critical for interpretation of analytical results on returned samples. This set of relevant documents is not the same as typical documentation for one-way missions and does include data from several institutions, which need to be unified. Dedicated resources need to be provided for acquiring and archiving appropriate documents in one location with easy access for decades. - Dedicated, knowledgeable contamination control oversight should be provided at sites of fabrication and integration. Numerous excellent Genesis chemists and analytical facilities participated in the contamination oversight; however, additional oversight at fabrication sites would have been helpful.

Allton, J. H.↗

DOE OSTI2019

Dry Cask Shipments of ATR Spent Nuclear Fuel at INL - 19600

The High Load Charger (HLC) cask will be replacing the Advanced Test Reactor (ATR) spent fuel transfer cask that has been used at Idaho National Laboratory (INL) to wet-transfer spent ATR fuel elements from ATR to Idaho Nuclear Technology and Engineering Center (INTEC) in order to support future plans at both facilities. INTEC intends to discontinue use of the CPP-666 storage pools in compliance with the Idaho Settlement Agreement and the basins will no longer be available to store spent ATR fuel elements. In order to support the core-internals change out in 2021 for ATR, spent ATR fuel elements must be removed from the canal and shipped to INTEC. INL contractors will use the HLC cask for safe, dry transfer of spent Advanced Test Reactor (ATR) fuel elements between the ATR Complex managed by Battelle Energy Alliance, LLC and the Idaho Nuclear Technology and Engineering Center (INTEC) managed by Fluor Idaho, LLC. The HLC cask (also known as the High Load Charging Cask or High Load Charger) is a lead-shielded, stainless steel transfer container originally designed in 1954 by the Idaho Nuclear Corporation to meet the radiation and contamination controls requirements of the time for shipment of spent nuclear fuel. The cask has been modified over the years and is currently used for wet-to-dry transfers at INTEC. It is approved only for out-of-commerce transfers. The cask will arrive at the ATR where eight spent ATR fuel elements will be loaded into two, newly-designed buckets. Each bucket is a quarter section, right-cylinder shape that has four compartments. The cask will be lifted out of the ATR canal allowing most of the water to drain from the cask. Processing the 12,500 kg cask will be completed in ATR and then transported on a tractor trailer to INTEC where the loaded buckets will be removed from the cask. The loaded buckets will undergo a drying process before placing the four buckets into a canister for long-term storage in the Irradiated Fuel Storage Facility (IFSF) at INTEC. A new transportation plan that was submitted to, and approved by, the U.S. Department of Energy to provide the cask safety basis, which describes the hazard analysis and accident analysis for the cask during transport. Supporting accident analysis include criticality, thermal, dose, and drop analyses. Of particular interest for this cask was the drop analysis from which was derived the speed limit for the transport. The drop analysis addressed drops in air onto an unyielding surface and in water onto an energy-absorbing pad for the cask in the ATR facility. These analyses are typically applied as the bounding drop scenarios during transport; however, this resulted in a safety basis speed limit of 12.9 kph. In order to more accurately represent the in-transit accident scenario, LS-DYNA software was procured and the model was updated to more closely represent the potential drop heights and impact surfaces of asphalt and soil for the cask while in transit. This analysis resulted in a safety basis speed limit of 48 kph. This safety basis speed limit is more practical to implement and control. (authors)

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NASA NTRSDate not supplied

CONTAMINATION CONTROL FOR ULTRA-SENSITIVE LIFE DETECTION SCIENCE MISSIONS

"This study report summarizes technological developments in science-required contamination control for cost-capped, life-detection missions in the Solar System. Technology advances focus on developing implementable strategies to restrict contamination of the spacecraft and instruments by the launch vehicle hardware. Secondary bake out operations during cruise further reduce molecular contaminants down to femtomolar levels in the sample path. The study validated a full-spacecraft, deployable barrier design as an effective strategy to isolate the spacecraft from the pre-launch processing and launch environment (e.g., fairing acoustic materials). It accommodates late mounting of RTGs and other required prelaunch activities. A new, high-fidelity physics, contamination-transport model for particles (including cells and their parts) and science-relevant molecules (e.g., possible biomolecules) was developed to validate the barrier concept. Importantly, this model takes into account the physics of extremely clean surfaces achieved by the best traditional contamination engineering. The ability to deal with very low levels of particulate and molecular contamination makes this model unique among standard contamination modeling approaches. Modeling also demonstrated that a high-temperature bake out during interplanetary cruise of the sample collector that comprises the largest surface area in the sample path for an Enceladus orbiter reference mission, was extremely effective. This study included the evaluation of other details necessary for an effective contamination control strategy for life detection missions including feasibility of achieving parts per trillion level cleanliness for semi-volatile hydrocarbons in nitrogen purge gas, identification of launch vehicle services required for the baseline contamination control, and defining additional contamination control measures to be taken during launch operations. Key results of the study are: • New spacecraft barrier design that accommodates RTGs is readily cleanable and repairable. Deployment of a 1/3 scale model was successfully demonstrated. • The barrier reduces particle contamination (likely biological) from fairing to spacecraft by 1e-2 to 1e-3. • On-cruise bake-out of critical surfaces significantly reduced molecular contamination (by as much as 1e-12). Subsequently, the probability of a surface contamination particle being transported to an instrument by an ice particle is less than 5.1e-5 (for microbes specifically, 4.39e-10). The report concludes that a full-spacecraft barrier designed specifically for life-detection missions that require stringent control of particulate and molecular contaminates is an effective means of mitigating risks of false positive and negative results for life signature investigations. Further, secondary cleaning steps for critical sections of the sample path can be highly effective at reducing molecular contaminants to low femtomolar levels."

Contamination↗

NASA NTRSDate not supplied

Contamination Control for Ultra-Sensitive Life-Detection Missions

"This study report summarizes technological developments in science-required contamination control for cost-capped, life-detection missions in the Solar System. Technology advances focus on developing implementable strategies to restrict contamination of the spacecraft and instruments by the launch vehicle hardware. Secondary bake out operations during cruise further reduce molecular contaminants down to femtomolar levels in the sample path. The study validated a full-spacecraft, deployable barrier design as an effective strategy to isolate the spacecraft from the pre-launch processing and launch environment (e.g., fairing acoustic materials). It accommodates late mounting of RTGs and other required prelaunch activities. A new, high-fidelity physics, contamination-transport model for particles (including cells and their parts) and science-relevant molecules (e.g., possible biomolecules) was developed to validate the barrier concept. Importantly, this model takes into account the physics of extremely clean surfaces achieved by the best traditional contamination engineering. The ability to deal with very low levels of particulate and molecular contamination makes this model unique among standard contamination modeling approaches. Modeling also demonstrated that a high-temperature bake out during interplanetary cruise of the sample collector that comprises the largest surface area in the sample path for an Enceladus orbiter reference mission, was extremely effective. This study included the evaluation of other details necessary for an effective contamination control strategy for life detection missions including feasibility of achieving parts per trillion level cleanliness for semi-volatile hydrocarbons in nitrogen purge gas, identification of launch vehicle services required for the baseline contamination control, and defining additional contamination control measures to be taken during launch operations. Key results of the study are: • New spacecraft barrier design that accommodates RTGs is readily cleanable and repairable. Deployment of a 1/3 scale model was successfully demonstrated. • The barrier reduces particle contamination (likely biological) from fairing to spacecraft by 1e-2 to 1e-3. • On-cruise bake-out of critical surfaces significantly reduced molecular contamination (by as much as 1e-12). Subsequently, the probability of a surface contamination particle being transported to an instrument by an ice particle is less than 5.1e-5 (for microbes specifically, 4.39e-10). The report concludes that a full-spacecraft barrier designed specifically for life-detection missions that require stringent control of particulate and molecular contaminates is an effective means of mitigating risks of false positive and negative results for life signature investigations. Further, secondary cleaning steps for critical sections of the sample path can be highly effective at reducing molecular contaminants to low femtomolar levels."

contamination, life detection, barrier, modeling↗

DOE OSTI2023

Influence of oxygen on performance of multi-principal element alloy as braze filler for Ni-base alloys

In manufacturing of multi-principal element alloys (MPEAs), the casting process is often a primary point of oxygen introduction to the material system, which was demonstrated by the laboratory scale button arc-melting process. Oxygen introduction raises concerns for the mechanical performance of these alloys if employed as structural materials alone or in engineering applications, such as serving as filler materials to enable joining of similar or dissimilar alloy pairs that are conventionally considered difficult to join. In this work, oxide inclusions in an as-cast off-equiatomic MnFeCoNiCu MPEA and Ni-base alloy braze joints made with this MPEA were evaluated by synchrotron x-ray diffraction mapping and electron microscopy. MnO was found to be prevalent throughout the cast MPEA and was chemically reduced during brazing by trace Al from the base material, Ni-base Alloy 600. Incomplete reaction of the MnO with Al, and some alternative reaction with Cr, left a mixture of MnO, Al 2 O 3 , and Cr 2 O 3 in the as-brazed joint, with the oxides concentrated near the braze centerline due to directional solidification. Further, in the braze joints, the non-oxide constituent phases detected were an FCC matrix and particles of Cr 23 C 6 , Cr 7 C 3 , and TiN which are all native to Alloy 600. The evolution of oxides within the brazed joints at elevated service temperatures of 600-800°C was also evaluated. While MnO and Al 2 O 3 were stable during high-temperature service, Cr 2 O 3 particles grew to several hundred microns, with dissolved oxygen in the MPEA providing a significant source for oxide growth. Comparing tensile performance of the as-brazed condition with post-service conditions showed that the evolution of oxide particles contributed to an increase in strength and decrease in ductility of the brazed joints. Evaluating particle morphologies among fracture surfaces of individual specimens demonstrated that large Cr 2 O 3 particles and continuous cluster networks of Al 2 O 3 were the features most detrimental to total elongation. Hence, unmitigated evolution of oxygen-containing species during brazing and service conditions is detrimental to the ductility of the brazed joints, which highlights the importance of oxygen control in initial manufacturing of MPEAs for engineering applications.

36 MATERIALS SCIENCE↗

NASA NTRS2017

The James Webb Space Telescope: Contamination Control and Materials

The James Webb Space Telescope (JWST), expected to launch in 2018 or early 2019, will be the premier observatory for astronomers worldwide. It is optimized for infrared wavelengths and observation from up to 1 million miles from Earth. JWST includes an Integrated Science Instrument Module (ISIM) containing the four main instruments used to observe deep space: Near-Infrared Camera (NIRCam), Near-Infrared Spectrograph (NIRSpec), Mid-Infrared Instrument (MIRI), and Fine Guidance Sensor/Near InfraRed Imager and Slitless Spectrograph (FGS/NIRISS). JWST is extremely sensitive to contamination directly resulting in degradation in performance of the telescope. Contamination control has been an essential focus of this mission since the beginning of this observatory. A particular challenge has been contamination challenges in vacuum chamber operations.

James Webb Space Telescop↗

DOE OSTI2014

Post-Remediation Radiological Dose Assessment, Linde Site, Tonawanda, New York

A post-remediation radiological dose assessment was conducted for the Formerly Utilized Sites Remedial Action Program (FUSRAP) Linde Site by using the measured residual concentrations of the radionuclides of concern following the completion of the soils remedial action. The site’s FUSRAP-related contaminants of concern (COCs) are radionuclides associated with uranium processing activities conducted by the Manhattan Engineer District (MED) in support of the Nation’s early atomic energy and weapons program and include radium-226 (Ra-226), thorium-230 (Th-230), and total uranium (Utotal). Remedial actions to address Linde Site soils and structures were conducted in accordance with the Record of Decision for the Linde Site, Tonawanda, New York (ROD) (USACE 2000a). In the ROD, the U.S. Army Corps of Engineers (USACE) determined that the cleanup standards found in Title 40, Part 192 of the Code of Federal Regulations (40 CFR Part 192), the standards for cleanup of uranium mill sites designated under the Uranium Mill Tailings Radiation Control Act (UMTRCA), and the Nuclear Regulatory Commission (NRC) standards for decommissioning of licensed uranium and thorium mills, found in 10 CFR Part 40, Appendix A, Criterion 6(6), are Applicable or Relevant and Appropriate Requirements (ARARs) for cleanup of MED-related contamination at the Linde Site. The major elements of this remedy will involve excavation of the soils with COCs above soil cleanup levels and placement of clean materials to meet the other criteria of 40 CFR Part 192.

61 RADIATION PROTECTION AND DOSIMETRY↗

NASA NTRS2013

Shear Stress Sensing using Elastomer Micropillar Arrays

The measurement of shear stress developed as a fluid moves around a solid body is difficult to measure. Stresses at the fluid-solid interface are very small and the nature of the fluid flow is easily disturbed by introducing sensor components to the interface. To address these challenges, an array of direct and indirect techniques have been investigated with various advantages and challenges. Hot wire sensors and other indirect sensors all protrude significantly into the fluid flow. Microelectromechanical systems (MEMS) devices, although facilitating very accurate measurements, are not durable, are prone to contamination, and are difficult to implement into existing model geometries. One promising approach is the use of engineered surfaces that interact with fluid flow in a detectable manner. To this end, standard lithographic techniques have been utilized to generate elastomeric micropillar arrays of various lengths and diameters. Micropillars of controlled length and width were generated in polydimethylsiloxane (PDMS) elastomer using a soft-lithography technique. The 3D mold for micropillar replication was fabricated using laser ablative micromachining and contact lithography. Micropillar dimensions and mechanical properties were characterized and compared to shear sensing requirements. The results of this characterization as well as shear stress detection techniques will be discussed.

Wohl, Christopher J.↗

DOE OSTI2012

Controls on Fe(II)-Activated Trace Element Release from Goethite and Hematite

Electron transfer and atom exchange (ETAE) between aqueous Fe(II) and Fe(III) oxides induces surface growth and dissolution that affects trace element fate and transport. We have recently demonstrated Ni(II) cycling through goethite and hematite (adsorbed Ni incorporates into the mineral structure and preincorporated Ni releases to solution) during Fe(II)-Fe(III) ETAE. However, the chemical parameters affecting net trace element release remain unknown. Here, we examine the chemical controls on Ni(II) and Zn(II) release from Ni- and Zn-substituted goethite and hematite during reaction with Fe(II). Release follows a rate law consistent with surface reaction limited mineral dissolution and suggests that release occurs near sites of Fe(III) reductive dissolution during Fe(II)-Fe(III) ETAE. Metal substituent type affects reactivity; Zn release is more pronounced from hematite than goethite, whereas the opposite trend occurs for Ni. Buildup of Ni or Zn in solution inhibits further release but this resumes upon fluid exchange, suggesting that sustained release is possible under flow conditions. Mineral and aqueous Fe(II) concentrations as well as pH strongly affect sorbed Fe(II) concentrations, which directly control the reaction rates and final metal concentrations. Our results demonstrate that structurally incorporated trace elements are mobilized from iron oxides into fluids without abiotic or microbial net iron reduction. Such release may affect micronutrient availability, contaminant transport, and the distribution of redox-inactive trace elements in natural and engineered systems.

54 ENVIRONMENTAL SCIENCES↗

NASA NTRS1979

Initial comparison of single cylinder Stirling engine computer model predictions with test results

A NASA developed digital computer code for a Stirling engine, modelling the performance of a single cylinder rhombic drive ground performance unit (GPU), is presented and its predictions are compared to test results. The GPU engine incorporates eight regenerator/cooler units and the engine working space is modelled by thirteen control volumes. The model calculates indicated power and efficiency for a given engine speed, mean pressure, heater and expansion space metal temperatures and cooler water inlet temperature and flow rate. Comparison of predicted and observed powers implies that the reference pressure drop calculations underestimate actual pressure drop, possibly due to oil contamination in the regenerator/cooler units, methane contamination in the working gas or the underestimation of mechanical loss. For a working gas of hydrogen, the predicted values of brake power are from 0 to 6% higher than experimental values, and brake efficiency is 6 to 16% higher, while for helium the predicted brake power and efficiency are 2 to 15% higher than the experimental.

Tew, R. C., Jr.↗

NASA NTRS1992

On-orbit characterization of electric propulsion on LEO satellites

Utilizing commercial or military satellites as testbeds for subsystems is a potential platform for small devices. Electric propulsion is a viable and upcoming subsystem that is of high interest to planetary mission engineers as well as commercial satellite developers. It is proposed that by incorporating small lightweight electric propulsion devices onto small satellites as external or 'bolt-on' experiments, an increase in the number of flight opportunities can occur. Specific problems are spacecraft body interaction, contamination effects, thermal interface problems, power conditioning control electronics, and propulsion feed system interfaces.

Barnhart, D.↗

DOE OSTI2015

Environmental cleanup of the East Tennessee Technology Park - Year three - A status report - 15522

On August 1, 2011, URS - CH2M Oak Ridge LLC (UCOR) began its five-year, $1.4 billion cleanup of the East Tennessee Technology Park (ETTP), the former Oak Ridge Gaseous Diffusion Plant, located on the U.S. Department of Energy's (DOE) Oak Ridge Reservation (Reservation) in Tennessee. Under the contract, the base period scope of work to be completed by 2016 includes demolition of both the K-25 and K-31 gaseous diffusion buildings and all demolition waste dispositioned, initiation of demolition on the remaining K-27 gaseous diffusion building, safe storage of transuranic (TRU) waste for eventual transfer to the Transuranic Waste Processing Center, previously designated -No-Path-To-Disposition Waste- dispositioned to the extent possible, and completion of design and engineering of a mercury treatment system to be installed at the Y-12 National Security Complex (Y-12). UCOR will have also managed DOE Oak Ridge Office of Environmental Management (OREM)-owned facilities at ETTP, Oak Ridge National Laboratory (ORNL), and Y-12 in a safe and cost-effective manner. Since assuming responsibilities as the ETTP and Oak Ridge Reservation cleanup contractor, UCOR has completed its life-cycle Performance Measurement Baseline; received its Earned Value Management System (EVMS) certification; completed the deactivation and demolition (D and D) of the 44-acre K-25 gaseous diffusion building; removed and disposed of a contaminated underground storage tank (Tank W-1A) at ORNL; dispositioned mercury-contaminated storage tanks at Y-12; completed closure of the Toxic Substances Control Act Incinerator; disposed of more than 158,000 cubic yards of cleanup waste while managing the on-site Environmental Management Waste Management Facility (EMWMF); and conducted operations, surveillance, and maintenance activities at 180 DOE EM facilities at ETTP, ORNL, and Y-12 in a safe and cost-effective manner. In 2014, UCOR completed the removal and disposal of all of the K-25 demolition debris; completed the removal of asbestos-laden transite siding on the K-31 gaseous diffusion building and began demolition of that 17-acre building; advanced the characterization and deactivation of the K-27 gaseous diffusion building, readying the building for the start of demolition in 2015; advanced the design and engineering of a Mercury Treatment Facility to be located at Y-12; continued the cost-effective and safe disposition of all cleanup wastes; and readied ETTP for Voluntary Protection Program Star Status Assessment in 2015. Project performance as of December 31, 2014, continued to be excellent: - Cost Performance Index - 1.12 - Schedule Performance Index - 1.02 At the same time, since safety is the foundation of all cleanup work, UCOR's safety record goes hand-in-hand with its excellent project performance. Through calendar year 2014, UCOR's recordable injury rate was 1.04 occurrences per 200,000 work hours, and the lost workday case rate was 0.52. This performance continues to be due, in large part, to the people and processes URS and CH2M HILL, the parent companies of UCOR, brought to the project. Key enablers included: - Selected and deployed experienced staff in key leadership positions throughout the organization, continually re-energizing the organization with new leaders - Implemented previously successful safety programs and initiatives from other DOE sites, such as DOE's Voluntary Protection Program - Brought fresh thinking and innovation to tackling tough project issues, such as the deactivation of the Technetium-99-contaminated areas of K-27, applying lessons learned from the D and D of K-25; and implementing a -waste factory- approach to cleanup - Maintained continuing alignment between UCOR's contract with DOE and its Performance Measurement Baseline - rapidly addressing contract changes when they arose - Maintained a readiness both from a process as well as experienced personnel perspective to support DOE OREM in performing other significant Oak Ridge Reservation cleanup activities. (authors)

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