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At least 1,279 records · Page 71
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Update to the Phase II Corrective Action Investigation Plan for Corrective Action Units 101 and 102, Central and Western Pahute Mesa, Nevada National Security Site, Nye County, Nevada

This report is an update to the Phase II Corrective Action Investigation Plan for Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nevada Test Site, Nye County, Nevada (NNSA/NSO, 2009) activities resulting from data collection and analysis conducted between 2009 and 2019. This report contains two sections: (1) a summary of how the new data have informed the updated approach to complete the characterization activities under the corrective action investigation (CAI), and (2) a table documenting the specific activities identified in the CAIP with a status and expected outcome of each activity (see Table A-1 in Appendix A). As stated in Sections 1.5 and 1.5.1 of the CAIP, the CAIP was conceptualized to be iterative, with continuous review and assessment of the data, data analysis, and modeling to provide a guide for decisions regarding additional work. This report provides the revised plan, based on an assessment of the data, to complete the characterization activities identified in the CAIP.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Event Screening Methods for the Eastern Interconnection Situational Awareness and Monitoring System (ESAMS)

The Eastern Interconnection Situational Awareness and Monitoring System (ESAMS) is a tool developed to explore the applications and advantages of sharing phasor measurement unit (PMU) data among operating entities. An initial conclusion from testing was that detected events required further screening before being reported to ensure that events would be of interest to system operators. The methods described in this report were integrated into ESAMS to meet this need. First, an event is screened for whether the change in voltage angle measurements indicates that the detected disturbance is sufficiently large. Next, an event is classified to determine if it was related to a loss of generation. Finally, a neural network is used to determine if the system’s response to the disturbance is normal or abnormal. These methods were tested with one month of field-measured PMU data. Results indicate that the additional information provided by these additional screening tools will improve selection of events for inclusion in the daily event reports automatically generated by ESAMS.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2022

Liquefaction of pelleted corn cobs

Liquid slurries at high loadings (pumpable slurries) are critical to handle the streams between the unit operations in a biorefinery. Their liquefaction potential was initially tested with a small-scale method using 3FPU Ctec-2 /g dry biomass, and results were confirmed in 1L bioreactors experiments. Liquid slurries of cobs were observed in small scale tests (based on visual appearance, and reducing sugars released). Results were confirmed in 1L bioreactors under similar experimental conditions. Yield stress value in bioreactor was 34 ± 6Pa at 96 h, and glucan and xylan conversion to glucose and xylose, respectively, were 41 and 21%. In addition, work has been initiated with liquefaction of other pelleted corn stover fractions: Husk/Leaf (A),Husk (B), Stems (D) and controls (whole corn stover; F and G). Compositional analysis of the pellets showed glucan content (%) in the samples ranged from 31.9 to 36.1, xylan from 19.1 to 20.9, total lignin 13.1 to 18.8,and total ash 1.73 to 10.19. The moisture content ranged from 6.21 to 11.66%. Given these similar characteristics, we also examined liquefaction of these other samples, and they also showed that liquid slurries are possible. Work is continuing to define favourable conditions for liquid slurries formation.

Cruz, Antonio↗
DOE OSTI2024

Design and Manufacturing of High Performance, Reduced Charge Heat Exchangers

Air-to-fluid heat exchangers (HXs) play a critical role as the main heat transfer component in Heating, Ventilation, Air-Conditioning, and Refrigeration (HVAC&R) systems. However, their airside thermal resistance significantly inhibits their overall performance. Furthermore, these HXs must be continually more compact to meet the latest refrigerant charge limits to reduce emissions. Recent literature suggests that traditional HX geometries (e.g., round or flat tubes with fins), have reached their limits, and more sophisticated shape- and topology-optimized designs are required to achieve the next jump in performance. This research sheds light on the next generation of air-to-refrigerant HXs and aims to address several practical issues to commercialization such as novelty challenges (improved performance for significant charge reduction; modeling expertise & time investment), manufacturing challenges (non-round tube manufacturing; tube-header integration; product qualification, e.g., burst pressure testing, extreme operational environment, etc.), and operational challenges (flow maldistribution, fouling & wetting, noise & vibration). For example, a >20% improvement on one (or more) HX-level performance metrics (e.g., envelope volume, airside pressure drop, face area, capacity, refrigerant charge, weight, cost, etc.) must be achieved before a HX design is considered for commercialization. We present a new, comprehensive and experimentally validated air-to-refrigerant HX optimization framework with simultaneous thermal-hydraulic performance and mechanical strength considerations for novel, non-round, shape- and topology-optimized tubes capable of optimizing single and two-phase HX designs for any refrigerant choice and performance requirement with significant engineering time savings compared to conventional design practices. The framework was exercised for a wide range of applications and refrigerants, resulting in HXs which achieved greater than 20% improved performance, 20% reductions in size, and 25% reductions in refrigerant charge. To enable non-round tube bundle use in next generation HVAC&R equipment, novel manufacturing techniques were investigated, including the development of conventional manufacturing methods for small diameter, non-round tubes and novel tube-header integration strategies. In total, ten HX prototypes were manufactured, nine using conventional methods directly attributed to this project and one using advanced additive manufacturing methods. The five-year manufacturing feasibility of the proposed HXs was found to have a good outlook. The non-round tube HX simulated performance was validated through comprehensive experimental testing, including nine in-house component-level tests, one independent component-level test at an industry partner laboratory, and in-house system-level tests of using a commercially-available, residential packaged A/C unit which was retrofitted with a non-round tube prototype HX. It was found that HX designs proposed by the new framework can successfully predict experimental thermal-hydraulic performance within ±10-20% the first time with no manual design changes, eliminating the need for time-consuming and expensive prototyping efforts. This work will accelerate design and time to market for next generation HXs while simultaneously facilitating industry transition to new refrigerants at lower charge.

42 ENGINEERING↗
DOE OSTI2026

Development of a High-Efficiency Hybrid Dry Cooler System for sCO 2 Power Cycles in CSP Applications

This project addressed a major gap in supercritical CO 2 (sCO 2 ) power cycle research by focusing on the pre-cooler, a component that had received little attention despite its significant impact on cycle efficiency and plant economics. The team developed a compact dry cooler using brazed/diffusion-bonded microchannel passages paired with formed air-side fins, advancing the technology from TRL-2 toward commercial readiness. Compared to conventional fin-tube coolers, the design cuts installation footprint by roughly half for 10+ MWth systems while achieving better heat transfer and lower approach temperatures, translating into a projected LCOE reduction from 6.04 ¢/kWh to between 5.85 and 5.94 ¢/kWh. While fabrication of an aluminum MW-scale prototype revealed brazing and sealing challenges at larger scales, lessons learned informed a subsequent 1 MWth unit that was successfully built and delivered for integration into Sandia's Gen3 Particle Pilot Plant, advancing the technology to TRL-7 with a path toward TRL-8 pending successful testing.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2016

DOE Challenge Home Multifamily Development - Mixed Climate

The U.S. Department of Energys Zero Energy Ready Home (ZERH) recognition program builds upon the building science requirements of ENERGY STAR Certified Homes, Version 3 and best practices tested by the Building America research and demonstration program. Multifamily units (units in buildings with five or more apartments) comprise an increasingly important segment in the U.S. new housing market. Over the past 30 years, this segment has averaged 24% of residential building permits and since the recession in 2008 averages 34% of new residential building permits. This study analyses two multifamily homes, one townhouse and one apartment. The study looks to improve the efficiency of these homes to meet ENERGY STAR standards. Apartment - 2 bedroom apartment unit Townhome - 3 bedroom townhome unit

Array↗
DOE OSTI2020

Active Experiments in Space: Past, Present, and Future

Between 1958 and 1962 the United States and the Soviet Union performed several nuclear detonation tests in the atmosphere, including the Starfish Prime event which involved a 1.4 Mt explosion at 400 km altitude over Johnston island on July 9, 1962 (Gombosi et al., 2017). These tests can be considered as the beginning of active experiments in space (i.e., experiments that deliberately perturb the local environment). They demonstrated the potential destructive power of high-altitude nuclear explosions, both in terms of the resulting electromagnetic pulse as well as for the creation of a potentially long-lasting artificial radiation belt from the radioactive fission debris. For instance,one of the unintended consequences of Starfish Prime was to cripple at least seven spacecraft in low-Earth orbit (LEO), about a third of the LEO spacecraft of the time (Gombosi et al., 2017).

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

Radiation Embrittlement Archive Project

The Radiation Embrittlement Archive Project (REAP), which is being conducted by the Probabilistic Integrity Safety Assessment (PISA) Program at Oak Ridge National Laboratory under funding from the U.S. Nuclear Regulatory Commission s (NRC) Office of Nuclear Regulatory Research, aims to provide an archival source of information about the effect of neutron radiation on the properties of reactor pressure vessel (RPV) steels. Specifically, this project is an effort to create an Internet-accessible RPV steel embrittlement database. The project s website, https://reap.ornl.gov, provides information in two forms: (1) a document archive with surveillance capsule(s) reports and related technical reports, in PDF format, for the 104 commercial nuclear power plants (NPPs) in the United States, with similar reports from other countries; and (2) a relational database archive with detailed information extracted from the reports. The REAP project focuses on data collected from surveillance capsule programs for light-water moderated, nuclear power reactor vessels operated in the United States, including data on Charpy V-notch energy testing results, tensile properties, composition, exposure temperatures, neutron flux (rate of irradiation damage), and fluence, (Fast Neutron Fluence a cumulative measure of irradiation for E>1 MeV). Additionally, REAP contains data from surveillance programs conducted in other countries. REAP is presently being extended to focus on embrittlement data analysis, as well. This paper summarizes the current status of the REAP database and highlights opportunities to access the data and to participate in the project.

Klasky, Hilda B↗
DOE OSTI2014

Colorimetric chemical analysis sampler for the presence of explosives

A tester for testing for explosives comprising a body, a lateral flow swab unit operably connected to the body, a explosives detecting reagent contained in the body, and a dispenser operatively connected to the body and the lateral flow swab unit. The dispenser selectively allows the explosives detecting reagent to be delivered to the lateral flow swab unit.

47 OTHER INSTRUMENTATION↗
DOE OSTI2012

National Geothermal Data System: A Geothermal Data System for Exploration and Development

Geothermal-relevant geosciences data from all 50 states (www.stategeothermaldata.org), federal agencies, national labs, and academic centers are being digitized and linked in a distributed online network funded by the U.S. Department of Energy Geothermal Data System (GDS) to foster geothermal energy exploration and development through use of interactive online ‘mashups,’data integration, and applications. Emphasis is first to make as much information as possible accessible online, with a long range goal to make data interoperable through standardized services and interchange formats. A growing set of more than thirty geoscience data content models is in use or under development to define standardized interchange formats for: aqueous chemistry, borehole temperature data, direct use feature, drill stem test, seismic event hypocenter, fault feature, geologic contact feature, geologic unit feature, thermal/hot spring description, metadata, quaternary fault, volcanic vent description, well header feature, borehole lithology log, crustal stress, gravity, heat flow/temperature gradient, permeability, and feature description data like developed geothermal systems, geologic unit geothermal characterization, permeability, production data, rock alteration description, rock chemistry, and thermal conductivity. Map services are also being developed for isopach maps, aquifer temperature maps, and several states are working on geothermal resource overview maps. Content models are developed based on existing community datasets to encourage widespread adoption and promulgate content quality standards. Geoscience data and maps from other GDS participating institutions, or “nodes” (e.g., U.S. Geological Survey, Southern Methodist University, Oregon Institute of Technology, Stanford University, the University of Utah) are being supplemented with extensive land management and land use resources from the Western Regional Partnership (15 federal agencies and 5 Western states) to provide access to a comprehensive, holistic set of data critical to geothermal energy development. As of May 2012 , we have nearly 37,000 records registered in the system catalog, and 550,075 data resources online, along with hundreds of Web services to deliver integrated data to the desktop for free downloading or online use. The data exchange mechanism is built on the U.S. Geoscience Information Network (USGIN, http://usgin.org and http://lab.usgin.org) protocols and standards developed as a partnership of the Association of American State Geologists (AASG) and U.S. Geological Survey (USGS). Keywords Data

15 GEOTHERMAL ENERGY↗
DOE OSTI2014

SUBTASK 3.12 – GASIFICATION, WARM-GAS CLEANUP, AND LIQUID FUELS PRODUCTION WITH ILLINOIS COAL

The goal of this project was to evaluate the performance of Illinois No. 6 coal blended with biomass in a small-scale entrained-flow gasifier and demonstrate the production of liquid fuels under three scenarios. The first scenario used traditional techniques for cleaning the syngas prior to Fischer–Tropsch (FT) synthesis, including gas sweetening with a physical solvent. In the second scenario, the CO2 was not removed from the gas stream prior to FT synthesis. In the third scenario, only warm-gas cleanup techniques were used, such that the feed gas to the FT unit contained both moisture and CO2. The results of the testing showed that the liquid fuels production from the FT catalyst was significantly hindered by the presence of moisture and CO2 in the syngas. Further testing would be needed to determine if this thermally efficient process is feasible with other FT catalysts. This subtask was funded through the EERC–U.S. Department of Energy (DOE) Joint Program on Research and Development for Fossil Energy-Related Resources Cooperative Agreement No. DE-FC26-08NT43291. Nonfederal funding was provided by the Illinois Clean Coal Institute.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2018

Update on the use of Neutron Absorbers for Storage Applications at Y-12

The Y-12 National Security Complex has a high density enriched uranium storage system at the Highly Enriched Uranium Materials Facility (HEUMF) that has been deployed for nearly 10 years. A robust neutron absorber system is provided through the design of Rackable Can Storage Boxes (RCSBs) and their configuration into storage racks. The requirements from ANSI/ANS-8.21, Use of Fixed Neutron Absorbers in Nuclear Facilities outside Reactors, are met with the RCSB and rack system at HEUMF through various design aspects, verification criteria, functional testing, and simulation modeling. Previous publications on a neutron absorber storage system at Y-12 were present at ANS in 2001 and 2002, when the RCSBs were still in a conceptual phase. The publications focused on ongoing studies at the time of what materials worked best for storage applications and how to test those materials, as well the practical design of the unit. The RCSBs have proven to provide a safe, static, and low maintenance storage system, with some minor design issues and several opportunities for future improvement.

42 ENGINEERING↗
DOE OSTI2017

Performance of a Dual Fluidized Bed Reactor for Chemical Looping Combustion with Oxygen Uncoupling

Chemical looping with oxygen uncoupling (CLOU) is a variant of chemical looping combustion which uses as fluidized bed particles specific solid oxygen carriers which readily liberate gaseous oxygen (O2) in the fuel reactor. This enables much more efficient combustion of solid fuels such as coal than conventional chemical looping combustion, which relies on in situ gasification of char in to produce syngas that can react heterogeneously with the solid oxygen carrier. The CLOU process for coal is an especially interesting application of fluidized bed technology since several types of reactions take place within the reactors. For copper-based oxygen carrier particles, the copper cycles between cuprous and cupric oxide (Cu2O + ½ O2 ↔ 2 CuO). Volatiles released from coal during pyrolysis may react with oxidized copper or with released oxygen gas. Char reacts primarily with released oxygen. Balancing oxygen supply to the fuel reactor, heat generation and temperatures and global and internal circulation rates is a challenge. The University of Utah has been researching CLOU technology for 10 years, studying fundamental reaction kinetics for copper-based CLOU oxygen carriers, performing lab- and bench-scale experiments in single and dual fluidized beds, and developing reactor models through computational fluid dynamic modeling using Barracuda VR™. Recently the university began testing a 200 kWth dual circulating fluidized bed process development unit (PDU) for processing coal. The design process for that reactor, reactor simulations, operational experience and practical challenges of the PDU system are presented.

Whitty, Kevin J.↗
DOE OSTI2020

A Comparison of Groundwater Sampling Technologies, Including Passive Diffusion Sampling, for Radionuclide Contamination - 20205

Using traditional high-flow purge methods for long-term water quality monitoring of deep groundwater wells can be expensive, affect contaminant migration, and produce excessive volumes of discharge water that can be difficult to manage. The use of low-flow pumping methods and depth discrete bailers (DDBs) can reduce the cost of sampling deep groundwater wells. In general, using different pumping methods to obtain reproducible and representative groundwater can be challenging. Passive diffusion samplers (PDSs) have successfully been used in long-term monitoring for volatile organic compounds, major ions, and trace-elements, but application has been limited for stable and radioactive isotopes. Beginning in 2018, the United States Geological Survey (USGS) conducted three sampling events to test the ability of PDSs and DDBs to obtain reproducible and representative groundwater samples. The sampled well is completed in a regional, permeable carbonate aquifer and is one in a set of wells that have historically been used for tritium tracer testing. All samples were obtained at 180 m (590 ft) below land surface (bls) in a 13.97 cm (5.5 inch) uncased well that has a total depth of 202 m (662 ft) bls. The first sampling event deployed a regenerated cellulose dialysis membrane (RCDM) PDS for 14 days with deionized water as the blank. The second sampling event deployed a RCDM for 27 days also with deionized water as the blank. The third sampling event deployed a Dual Membrane (DM) PDS for 65 days using a blank of tritium-dead carbonate water. The DM PDS was used to assess the effect of longer term deployment on tritium concentrations and address whether or not the PDSs reached equilibrium with ambient groundwater. The day after each of the three passive samplers were retrieved a DDB was used to obtain discrete non-integrated groundwater samples. For each DDB sampling day, the bailer was lowered into the well 10 consecutive times to determine if the water chemistry changed from the first to the last bailed sample. Quality assurance samples including blanks and duplicates were obtained during all three sampling events. All blank waters had tritium concentrations less than 21±33 pCi/L. Major ion (e.g. calcium, chloride, sodium, and sulfate) results were compared between all samples obtained with RCDM and DDB. Major ion concentrations showed a coefficient of variation of less than 6% between all RCDM and DDB samples; however, the coefficient of variation between the different deployment times and the two different methods for trace-element concentrations was much larger, particularly for manganese (82%), lead (41%), and zinc (33%). Stable isotope values were compared between the RCDM and DDB samples. The DDB sample results all fell within analytical uncertainty and were considered representative of the formation groundwater. The stable isotope values from the RCDM samples indicated that a longer deployment time was necessary to gain equilibrium and to obtain representative groundwater samples. Tritium results from groundwater samples obtained from the RCDM, DM, and DDB indicate that groundwaters obtained with PDSs produced tritium concentrations 2 to 3 times higher (between 1,426 and 3,060±87 pCi/L) than groundwaters obtained with a DDB (479 to 1,219±51 pCi/L). The longer the passive diffusion samplers were deployed, the higher the tritium concentration, suggesting that equilibrium with tritium was not reached within a 27-day deployment. DDB samples showed tritium results declining from the first to the last bailed sample for all three sampling events. This research suggests that tritium results from groundwater samples obtained from PDSs are more reproducible than samples obtained from DDBs. Also, PDSs likely do not accumulate isotopes of water but rather equilibrate with the ambient groundwater. On the other hand, both PDSs and DDBs were able to provide representative groundwater samples for major ions and have the potential to produce representative groundwater samples for stable isotopes of water (δD and δ{sup 18}O). Utilizing the most effective method for sampling groundwater is important for long-term groundwater monitoring. Quantifying the ability of passive diffusion groundwater samplers to obtain representative radioactive chemistry samples will help determine if these methods can be a useful alternative to pumping and purging wells for long-term monitoring. (authors)

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

Cesium Removal from Tank Waste Simulants Using Crystalline Silicotitanate at 12% and 100% TSCR Bed Heights

The Direct Feed Low-Activity Waste flowsheet provides for the early production of immobilized low-activity waste (LAW) by feeding waste directly from Hanford tank farms to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) for vitrification. Prior to the transfer of feed to the WTP LAW Vitrification Facility, tank waste supernatant will be pretreated by the Tank Side Cesium Removal (TSCR) system to meet the WTP LAW waste acceptance criteria (<3.18E-5 Ci 137 Cs/mole of Na). This pretreatment will remove cesium from the waste stream using ion exchange (IX). The selected media for IX is crystalline silicotitanate (CST), product number UOP-IONSIV-R9140-B, manufactured by Honeywell UOP LLC (Des Plaines, IL). Testing was requested by Washington River Protection Solutions to better define IX processing using Low-Activity Waste Pretreatment System (LAWPS) prototypic IX unit operation process steps at full height and medium height. The information is intended to significantly contribute towards establishing accurate process flowsheets for the individual feed campaigns planned for the LAWPS. Column testing at both the medium (12% of the full bed height) and full height scales was conducted to evaluate process variables and scale up performance of Cs exchange onto the CST, Lot 8056202-999. Nominal process conditions used 5.6 M Na simulant processed at 1.8 bed volumes per hour (BV/h) at 20 °C. Process variables included 1) increased process temperature to 35 °C, 2) increased Na concentration to 6.0 M, 3) added organics to the 5.6 M Na simulant, and 4) flowrate changes. The medium scale tests used single columns containing 44 mL of <25 mesh CST in a 1.44 cm diameter column, 27 cm tall CST bed. The full height columns used lead/lag columns containing 1.15 L unsieved (as-received) CST in 2.54-cm-diameter columns, 226 cm tall CST beds. Two process flowrates were tested at the full height: 1.30 and 1.82 BV/h. IX testing with simulant solutions was conducted using TSCR prototypic IX unit operations: feed processing, feed displacement with 0.1 M NaOH, water rinse, and solution expulsion with compressed air.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Structure and optical properties of a noncentrosymmetric borate RbSr{sub 4}(BO{sub 3}){sub 3}

A new noncentrosymmetric borate, RbSr{sub 4}(BO{sub 3}){sub 3} (abbreviated as RSBO), has been grown from Rb{sub 2}O--B{sub 2}O{sub 3}--RbF flux and its crystal structure was determined by single crystal x-ray diffraction. It crystallizes in space group Ama2 with cell parameters of a=11.128(10) A, b=12.155(15) A, c=6.952(7) A, Z=4. The basic structural units are isolated planar BO{sub 3} groups. Second harmonic generation (SHG) test of the title compound by the Kurtz-Perry method shows that RSBO can be phase matchable with an effective SHG coefficient about two-thirds as large as that of KH{sub 2}PO{sub 4} (KDP). Finally, based on the anionic group approximation, the optical properties of the title compound are compared with those of the structure-related apatite-like compounds with the formula 'A{sub 5}(TO{sub n}){sub 3}X'. - Graphical abstract: RbSr{sub 4}(BO{sub 3}){sub 3} and some other borate NLO compounds, namely Ca{sub 5}(BO{sub 3}){sub 3}F RCa{sub 4}(BO{sub 3}){sub 3}O (R=Y or Gd) and Na{sub 3}La{sub 2}(BO{sub 3}){sub 3} can be viewed as the derivatives of apatite. They have similar formula composed of five cations and three anion groups (we call them 5/3 structures). The detailed SHG coefficients and optical properties of the apatite-like NLO crystals were compared and summarized. Highlights: Black-Right-Pointing-Pointer A new noncentrosymmetric borate RbSr{sub 4}(BO{sub 3}){sub 3} was grown from flux. Black-Right-Pointing-Pointer The RbSr{sub 4}(BO{sub 3}){sub 3} can be viewed as a derivative of the apatite-like structure. Black-Right-Pointing-Pointer The structure and its relationship to the optical properties of RbSr{sub 4}(BO{sub 3}){sub 3} are compared with other NLO crystals with apatite-like structures. Black-Right-Pointing-Pointer The basic structural units are the planar BO{sub 3} groups in the structure. Black-Right-Pointing-Pointer Second harmonic generation (SHG) test shows that RbSr{sub 4}(BO{sub 3}){sub 3} can be phase matchable with an effective SHG coefficient about two-thirds as large as that of KH{sub 2}PO{sub 4}.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Deep Vadose Zone Treatability Test for the Hanford Central Plateau: Soil Desiccation Pilot Test Results

Over decades of operation, the U.S. Department of Energy (DOE) and its predecessors have released nearly 2 trillion L (450 billion gal) of liquid into the vadose zone at the Hanford Site. Much of this liquid waste discharge into the vadose zone occurred in the Central Plateau, a 200 km2 (75 mi2 ) area that includes approximately 800 waste sites. Some of the inorganic and radionuclide contaminants in the deep vadose zone at the Hanford Site are at depths below the limit of direct exposure pathways, but may need to be remediated to protect groundwater (DOE 2008a; Dresel et al. 2011). The Tri-Party Agencies (DOE, U.S. Environmental Protection Agency, and Washington State Department of Ecology) established Milestone M-015-50, which directed DOE to submit a treatability test plan for remediation of Tc-99 and uranium in the deep vadose zone. These contaminants are mobile in the subsurface environment and have been detected at high concentrations deep in the vadose zone, and at some locations have reached groundwater. Testing technologies for remediating Tc-99 and uranium will also provide information relevant for remediating other contaminants in the vadose zone. The desiccation test described herein was conducted as an element of the test plan published in March 2008 to meet Milestone M-015-50 (DOE 2008a). This field test report was prepared and submitted in response to Milestone M-015-110D, which set a date for desiccation field test activities to be reported to the Tri-Party Agencies. The desiccation field test was conducted at the Hanford Site 200-BC-1 Operable Unit. This waste site contains 26 cribs and trenches that received about 110 million L (29 million gal) of liquid waste primarily in the mid-1950s. The waste contained about 410 curies of Tc-99 (Corbin et al. 2005). There is no evidence the contamination has reached groundwater, located about 100 m (330 ft) below ground surface (bgs) in this area. Initial characterization efforts indicated the Tc-99 inventory is located mostly at a depth in the vadose zone of between about 30 and 70 m (98 and 230 ft) bgs. However, transport model predictions have indicated the potential for this contamination to adversely impact groundwater in the future (Ward et al. 2004). The test was conducted in two steps to provide information about desiccation that is intended for use in subsequent feasibility studies for waste sites with inorganic and radionuclide contaminants in the deep vadose zone. The first step was field-scale test site characterization conducted as described in a characterization work plan (DOE 2008b). Results of the characterization effort have been previously reported in DOE (2010a) and Um et al. (2009). A field test plan (DOE 2010b) was prepared and used to guide the desiccation field testing effort. Laboratory and numerical modeling efforts (Truex et al. 2011; Ward et al. 2008; Oostrom et al. 2009, 2011, 2012, In Press) preceded and accompanied the field test and are incorporated herein as their results pertain to assessment of desiccation for future feasibility studies.

desiccation↗