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DOE OSTI2019

Analysis of Tank 23H (HTF-23-19-23, -24, -25) Samples for Support of the Enrichment Control and Corrosion Control Programs

SRNL analyzed samples from Tank 23H to support ECP and CCP. The results of the analysis indicate the concentrations of species in Tank 23H increase with depth in the tank. The sample obtained from the lowest level of 60” from the bottom of the tank shows the highest concentrations for most species analyzed. The surface sample and the 140” sub-surface sample show similar compositions with the sub-surface sample being slightly more concentrated, and both are more dilute than the lowest 60” sub-surface sample for most species analyzed. The total uranium concentration in the three Tank 23H samples show a slight increase from the surface sample to the next lower sub-surface sample, but then a slight decrease in the uranium concentration in the lowest sub-surface sample. The U-235 weight fraction ranges from 0.94-1.2% in the Tank 23H samples. The sum of the major cations versus the sum of the major anions shows a difference of ~5% or less for all three of the Tank 23H samples indicating good data quality for the non-radioactive analytes in the table. Small %RSD values for the replicate analyses with the exception of species close to the detection limit (e.g., Fe) provide another indication of good data quality for the non-radioactive species. The silicon concentrations measured in the Tank 23H samples were all below detection.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2020

Summary of Expedited Results from Samples Supporting Tank Closure Cesium Removal (TCCR) Batch 3

Savannah River Remediation (SRR) is currently operating the Tank Closure Cesium Removal (TCCR) process to remove 137 Cs from tank waste supernate using an ion exchange process. As part of that process, Savannah River National Laboratory (SRNL) receives and analyzes samples in support of the qualification of each batch to be processed. SRNL recently received supernate samples retrieved from Tank 10H as well as in-tank batch contact samples for characterization in support of qualifying Batch 3 for processing through the TCCR unit. SRNL received and characterized a set of dip samples collected from Tank 10H (one surface and one variable depth sample). No solids were observed in either sample and therefore the samples were combined, and a suite of analyses were performed on the composite sample. The density of the combined sample was 1.174 g/mL (0.18 %RSD), which was consistent with the measured sodium concentration of 3.54 M (0.08 %RSD). The 137Cs activity in the sample was 4.75E+07 dpm/mL (4.28 %RSD) and the total Cs concentration was calculated to be 1.54 mg/L (1.16E-05 M). The in-tank batch contact samples consist of 0.1 g of crystalline silicotitanate (CST) contained within a teabag device. Duplicate samples were submerged in Tank 10H supernate for a period of about 13 days, after which time they were retrieved and transferred to SRNL for analysis. At SRNL the CST was rinsed to remove excess salt solution and the CST was then air dried before being digested for analysis. Results of the analysis indicated a 137 Cs loading of 3.66E+10 ± 1.40E+09 dpm/g or 16.5 ± 0.63 Ci/kg CST . This value represents a bounding upper limit as it includes the addition of two sigma uncertainty from replicate analysis of the individual teabag samples as well as the addition of the small amount of 137 Cs activity measured in the rinse solutions. The above values are based on the air-dried mass of CST. Correcting to the true dry mass using a F-factor of 0.8191 results in a maximum loading of 20.2 ± 0.77 Ci/kg CST .

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2017

The SDSS-IV MaNGA Sample: Design, Optimization, and Usage Considerations

We describe the sample design for the SDSS-IV MaNGA survey and present the final properties of the main samples along with important considerations for using these samples for science. Our target selection criteria were developed while simultaneously optimizing the size distribution of the MaNGA integral field units (IFUs), the IFU allocation strategy, and the target density to produce a survey defined in terms of maximizing signal-to-noise ratio, spatial resolution, and sample size. Our selection strategy makes use of redshift limits that only depend on i-band absolute magnitude (M {sub i}), or, for a small subset of our sample, M {sub i} and color (NUV − i). Such a strategy ensures that all galaxies span the same range in angular size irrespective of luminosity and are therefore covered evenly by the adopted range of IFU sizes. We define three samples: the Primary and Secondary samples are selected to have a flat number density with respect to M {sub i} and are targeted to have spectroscopic coverage to 1.5 and 2.5 effective radii (R {sub e}), respectively. The Color-Enhanced supplement increases the number of galaxies in the low-density regions of color–magnitude space by extending the redshift limits of the Primary sample in the appropriate color bins. The samples cover the stellar mass range 5×10{sup 8}⩽M{sub ∗}⩽3×10{sup 11} M{sub ⊙} h{sup −2} and are sampled at median physical resolutions of 1.37 and 2.5 kpc for the Primary and Secondary samples, respectively. We provide weights that will statistically correct for our luminosity and color-dependent selection function and IFU allocation strategy, thus correcting the observed sample to a volume-limited sample.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2021

Ice-nucleating particles in precipitation samples from the Texas Panhandle

Ice-nucleating particles (INPs) influence the formation of ice crystals in clouds and many types of precipitation. This study reports unique properties of INPs collected from 42 precipitation samples in the Texas Panhandle region from June 2018 to July 2019. We used a cold stage instrument called the West Texas Cryogenic Refrigerator Applied to Freezing Test system to estimate INP concentrations per unit volume of air (nINP) through immersion freezing in our precipitation samples with our detection capability of >0.006 INP L -1 . A disdrometer was used for two purposes: (1) to characterize the ground-level precipitation type and (2) to measure the precipitation intensity as well as size of precipitating particles at the ground level during each precipitation event. While no clear seasonal variations of n INP values were apparent, the analysis of yearlong ground-level precipitation observation as well as INPs in the precipitation samples showed some INP variations, e.g., the highest and lowest n INP values at -25°C both in the summer for hail-involved severe thunderstorm samples (3.0 to 1130 INP L -1 ), followed by the second lowest at the same temperature from one of our snow samples collected during the winter (3.2 INP L -1 ). Furthermore, we conducted bacteria community analyses using a subset of our precipitation samples to examine the presence of known biological INPs. In parallel, we also performed metagenomics characterization of the bacterial microbiome in suspended ambient dust samples collected at commercial open-lot livestock facilities (cattle feedyards hereafter) in the Texas Panhandle (i.e., the northernmost counties of Texas, also known as “West Texas”) to ascertain whether local cattle feedyards can act as a source of bioaerosol particles and/or INPs found in the precipitation samples. Some key bacterial phyla present in cattle feedyard samples appeared in precipitation samples. However, no known ice nucleation active species were detected in our samples. Overall, our results showed that cumulative n INP in our precipitation samples below -20°C could be high in the samples collected while observing > 10 mm h -1 precipitation with notably large hydrometeor sizes and an implication of cattle feedyard bacteria inclusion.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2015

Ball assisted device for analytical surface sampling

A system for sampling a surface includes a sampling probe having a housing and a socket, and a rolling sampling sphere within the socket. The housing has a sampling fluid supply conduit and a sampling fluid exhaust conduit. The sampling fluid supply conduit supplies sampling fluid to the sampling sphere. The sampling fluid exhaust conduit has an inlet opening for receiving sampling fluid carried from the surface by the sampling sphere. A surface sampling probe and a method for sampling a surface are also disclosed.

33 ADVANCED PROPULSION SYSTEMS↗

DOE OSTI2014

Adsorptive Films in Support of In-field UF6 Destructive Assay Sample Collection and Analysis

International Atom Energy Agency (IAEA) safeguard verification measures in gaseous centrifuge enrichment plants (GCEPs) rely on environmental sampling, non-destructive assay (NDA), and destructive assay (DA) sampling and analysis to determine uranium enrichment. UF6 bias defect measurements are made by DA sampling and analysis to assure that enrichment is consistent with declarations. DA samples are collected from a limited number of cylinders for high precision, offsite mass spectrometer analysis. Samples are typically drawn from a sampling tap into a UF6 sample bottle, then packaged, sealed, and shipped under IAEA chain of custody to an offsite analytical laboratory. Future DA safeguard measures may require improvements in efficiency and effectiveness as GCEP capacities increase and UF6 shipping regulations become increasingly more restrictive. The Pacific Northwest National Laboratory (PNNL) DA sampler concept and Laser Ablation Absorption Ratio Spectrometry (LAARS) assay method are under development to potentially provide DA safeguard tools that increase inspection effectiveness and reduce sample shipping constraints. The PNNL DA sampler concept uses a handheld sampler to collect DA samples for either onsite LAARS assay or offsite laboratory analysis. The DA sampler design will use a small sampling planchet that is coated with an adsorptive film to collect controlled quantities of UF6 gas directly from a cylinder or process sampling tap. Development efforts are currently underway at PNNL to enhance LAARS assay performance to allow high-precision onsite bias defect measurements. In this paper, we report on the experimental investigation to develop adsorptive films for the PNNL DA sampler concept. These films are intended to efficiently capture UF6 and then stabilize the collected DA sample prior to onsite LAARS or offsite laboratory analysis. Several porous material composite films were investigated, including a film designed to maximize the chemical adsorption and binding of gaseous UF6 onto the sampling planchet.

destructive assay↗

DOE OSTI2018

Nevada National Security Site Integrated Groundwater Sampling Plan, Revision 1

The purpose is to provide a comprehensive, integrated approach for collecting and analyzing groundwater samples to meet the needs and objectives of the DOE/EM Nevada Program’s UGTA Activity. Implementation of this Plan will provide high-quality data required by the UGTA Activity for ensuring public protection in an efficient and cost-effective manner. The Plan is designed to ensure compliance with the UGTA Quality Assurance Plan (QAP) (NNSA/NFO, 2015); Federal Facility Agreement and Consent Order (FFACO) (1996, as amended); and DOE Order 458.1, Radiation Protection of the Public and the Environment (DOE, 2013). The Plan’s scope comprises sample collection and analysis requirements relevant to assessing both the extent of groundwater contamination from underground nuclear testing and impact of testing on water quality in downgradient communities. This Plan identifies locations to be sampled by CAU and location type, sampling frequencies, sample collection methodologies, and the constituents to be analyzed. In addition, the Plan defines data collection criteria such as well purging, detection levels, and accuracy requirements/recommendations; identifies reporting and data management requirements; and provides a process to ensure coordination between NNSS groundwater sampling programs for sampling analytes of interest to UGTA. Information used in the Plan development—including the rationale for selection of wells, sampling frequency, and the analytical suite—is discussed under separate cover (N-I, 2014) and is not reproduced herein. This Plan does not address compliance for those wells involved in a permitted activity. Sampling and analysis requirements associated with these wells are described in their respective permits and are discussed in NNSS environmental reports (see Section 5.2). In addition, sampling for UGTA CAUs that are in the Closure Report (CR) stage are not included in this Plan. Sampling requirements for these CAUs are described in the CR. Frenchman Flat is currently the only UGTA CAU in the CR stage. Sampling requirements for this CAU are described in Underground Test Area (UGTA) Closure Report for Corrective Action Unit 98: Frenchman Flat Nevada National Security Site, Nevada (NNSA/NFO, 2016).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2020

Estimating rates and patterns of diversification with incomplete sampling: a case study in the rosids

Premise Recent advances in generating large‐scale phylogenies enable broad‐scale estimation of species diversification. These now common approaches typically are characterized by (1) incomplete species coverage without explicit sampling methodologies and/or (2) sparse backbone representation, and usually rely on presumed phylogenetic placements to account for species without molecular data. We used empirical examples to examine the effects of incomplete sampling on diversification estimation and provide constructive suggestions to ecologists and evolutionary biologists based on those results. Methods We used a supermatrix for rosids and one well‐sampled subclade (Cucurbitaceae) as empirical case studies. We compared results using these large phylogenies with those based on a previously inferred, smaller supermatrix and on a synthetic tree resource with complete taxonomic coverage. Finally, we simulated random and representative taxon sampling and explored the impact of sampling on three commonly used methods, both parametric (RPANDA and BAMM) and semiparametric (DR). Results We found that the impact of sampling on diversification estimates was idiosyncratic and often strong. Compared to full empirical sampling, representative and random sampling schemes either depressed or inflated speciation rates, depending on methods and sampling schemes. No method was entirely robust to poor sampling, but BAMM was least sensitive to moderate levels of missing taxa. Conclusions We suggest caution against uncritical modeling of missing taxa using taxonomic data for poorly sampled trees and in the use of summary backbone trees and other data sets with high representative bias, and we stress the importance of explicit sampling methodologies in macroevolutionary studies.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2023

Multi-site evaluation of stratified and balanced sampling of soil organic carbon stocks in agricultural fields

Estimating soil organic carbon (SOC) stocks in agricultural fields is essential for environmental and agronomic research, management, and policy. Stratified sampling is a classic strategy for estimating mean soil properties, and has recently been codified in SOC monitoring protocols. However, for the specific task of estimating the SOC stock of an agricultural field, concrete guidance is needed for which covariates to stratify on and how much stratification can improve estimation efficiency. It is also unknown how stratified sampling of SOC stocks compares to modern alternatives, notably doubly balanced sampling. To address these gaps, we collected high-density (average of 7 samples ha -1 ) and deep (average of 75 cm) measurements of SOC stocks at eight commercial fields under maize-soybean production in two US Midwestern states. We combined these measurements with a Bayesian geostatistical model to evaluate stratified and balanced sampling strategies that use a set of readily-available geographic, topographic, spectroscopic, and soil survey data. We examined the number of samples needed to achieve a given level of SOC stock estimation accuracy. While stratified sampling using these variables enables an average sample size reduction of 17% (95% CI, 11% to 23%) compared to simple random sampling, doubly balanced sampling is consistently more efficient, reducing sample sizes by 32% (95% CI, 25% to 37%). The data most important to these efficiency gains are a remotely-sensed SOC index, SSURGO estimates of SOC stocks, and the topographic wetness index. We conclude that in order to meet the urgent challenge of climate change, SOC stocks in agricultural fields could be more efficiently estimated by taking advantage of this readily-available data, especially with doubly balanced sampling.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2024

Investigating the ecological fallacy through sampling distributions constructed from finite populations

Correlation coefficients and linear regression values computed from group averages can differ from correlation coefficients and linear regression values computed using individual scores. This observation known as the ecological fallacy often assumes that all the individual scores are available from a population. In many situations, one must use a sample from the larger population. In such cases, the computed correlation coefficient and linear regression values will depend on the sample that is chosen and the underlying sampling distribution. The sampling distribution of correlation coefficients and linear regression values for group averages will be identical to the sampling distribution for individuals for normally distributed variables for random samples drawn from infinitely large continuous distributions. However, data that is acquired in practice is often acquired when sampling without replacement from a finite population. Our objective is to demonstrate through Monte Carlo simulations that the sampling distributions for correlation and linear regression will also be similar for individuals and group averages when sampling without replacement from normally distributed variables. These simulations suggest that when a random sample from a population is selected, the correlation coefficients and linear regression values computed from individual scores will not be more accurate in estimating the entire population values compared to samples when group averages are used as long as the sample size is the same.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2015

Tests of a High Temperature Sample Conditioner for the Waste Treatment Plant LV-S2, LV-S3, HV-S3A and HV-S3B Exhaust Systems

Tests were performed to evaluate a sample conditioning unit for stack monitoring at Hanford Tank Waste Treatment and Immobilization Plant (WTP) exhaust stacks with elevated air temperatures. The LV-S2, LV-S3, HV-S3A and HV-S3B exhaust stacks are expected to have elevated air temperature and dew point. At these emission points, exhaust temperatures are too high to deliver the air sample directly to the required stack monitoring equipment. As a result, a sample conditioning system is considered to cool and dry the air prior to its delivery to the stack monitoring system. The method proposed for the sample conditioning is a dilution system that will introduce cooler, dry air to the air sample stream. This method of sample conditioning is meant to reduce the sample temperature while avoiding condensation of moisture in the sample stream. An additional constraint is that the ANSI/HPS N13.1-1999 standard states that at least 50% of the 10 μm aerodynamic diameter (AD) particles present in the stack free stream must be delivered to the sample collector. In other words, depositional loss of particles should be limited to 50% in the sampling, transport, and conditioning systems. Based on estimates of particle penetration through the LV-S3 sampling system, the diluter should perform with about 80% penetration or better to ensure that the total sampling system passes the 50% or greater penetration criterion.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2019

Successes and Lessons Learned in the Design, Construction and Use of a Tool for Sampling the WR-1 Reactor Core - 1900z

Whiteshell Laboratories, located in Manitoba, Canada, provided research facilities for the Canadian nuclear industry since the early 1960's. The facility was centered on an organically cooled, heavy water moderated nuclear reactor in the world, Whiteshell Reactor 1 (WR-1). WR-1 was safely shut down in 1985, de-fueled and drained, and has been in a safe Storage with Surveillance (Deferred Decommissioning) state until present day. In support of an Environmental Assessment for proposed In Situ Decommissioning of WR-1, detailed characterization information regarding the reactor core components (calandria, calandria tubes, pressure tubes) was necessary to verify inventory estimates and neutron activation models produced circa 1992. The Fuel Channels of WR-1 (pressure tubes) were expected to be the most activated components of the reactor core, and to account for about 60% of the reactor core inventory. The interior surface of the fuel channel is also the most readily accessible surface within the reactor core. As such the decision was made to collect a sample of one of each of 3 Fuel Channel material types (Stainless Steel, Zr-2.5Nb, Ozhenite) for comparison to modelled estimates of neutron activation of various core materials. The expected dose rates from the samples were between 5 and 100 mSv (500-10,000 mrem) on contact based on a 200 mg sample. Sampling the Fuel Channels required verification the Fuel Channel was drained of organic coolant, removal of residual organic coolant from the Fuel Channel wall, removal of material from the interior surface of the Fuel Channel at the centerline of flux (∼25' below the operator position), and extraction of that material from the core. Several options for existing tooling and technologies, including hydraulic scrapers, and horizontal drill technologies, were looked at for their applicability to WR-1. While suitable approaches to higher radiation field sample collection, they were overly complex, costly and time consuming for the configuration at WR-1. In an effort to reduce costs, and to simplify the sampling process, a specialized and simple tool was developed to mechanically scrape a small sample of the interior wall of the Fuel Channels, collect the sample into a vial, and remove the sample from the core for analysis. The tool was designed, constructed, tested and implemented in the field entirely by Canadian Nuclear Laboratories Staff. The tool required no powered components, or electronic guidance or measurements; and was designed and constructed for a fraction of the cost of other commercially available technologies for sample collection within reactor cores. The samples were successfully collected without any injuries, contamination events or equipment failures. The tool remains operational in the event additional sampling is required. This paper provides additional details of the design, construction, testing and use of the tool and the successes and lessons learned during the various stages of design and implementation. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2017

K‐band luminosity–environment relation in three different galaxy samples of the Sloan Digital Sky Survey III

The aim of this work is to examine the environmental dependence of K‐band luminosity in the Main, Low Redshift (LOWZ), and Constant Mass (CMASS) galaxy samples of the Sloan Digital Sky Survey Data Release 10 (SDSS DR10). Overall, the environmental dependence of K‐band luminosity is very mild. In two volume‐limited Main samples with the luminosity −20.5 ≤ M r ≤ −18.5 and −22.5 ≤ M r ≤ −20.5, respectively, we find that the environmental dependence of K‐band luminosity in the luminous volume‐limited Main galaxy sample still can be observed, but this dependence in the faint volume‐limited Main galaxy sample is very weak. Considering the disadvantages of the use of volume‐limited samples, we apply the apparent magnitude‐limited Main galaxy sample, divide the Main galaxy sample of the SDSS DR10 into subsamples with a redshift binning size of Δ z =0.01, and then analyze the environmental dependence of K‐band luminosity of subsamples in each redshift bin. Such a method also is used in the LOWZ and CMASS galaxy samples. K‐band luminosity of the Main galaxies shows substantial correlation with the local environment in many redshift bins. In the LOWZ galaxy sample, K‐band luminosity of galaxies shows substantial correlation with the local environment only in the redshift region 0.16 ≤ z ≤ 0.21, while K‐band luminosity of CMASS galaxy sample is only weakly correlated with the local environment. Statistical results also show that in the apparent magnitude‐limited main galaxy sample and the LOWZ galaxy sample, environmental dependence of K‐band luminosity becomes weak with increasing redshift.

Deng, X. ‐F.↗

DOE OSTI2015

Low surface brightness galaxies selected from the 40% sky area of the ALFALFA H i Survey. I. Sample and statistical properties

The population of low surface brightness (LSB) galaxies, which are objects with central surface brightnesses at least one magnitude fainter than the night sky, is crucial for understanding the extremes of galactic formation and evolution of the universe. As LSB galaxies are mostly rich in gas (H i), the α.40 Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) sample is one of the best survey combinations to select a sample of them in the local universe. Since the sky backgrounds are systematically overestimated for galactic images by the SDSS photometric pipeline, particularly for luminous galaxies or galaxies with extended LSB outskirts, in this paper, we above all estimated the sky backgrounds of SDSS images accurately in both the g and r bands for each galaxy in the α.40 SDSS DR7 sample, using a precise method of sky subtraction. Once subtracting the sky background, we did surface photometry with the Kron elliptical aperture using the SExtractor software and fitted geometric parameters with an exponential profile model using the Galfit software for each galactic image in the α.40 SDSS DR7 sample. Based on the photometric and geometric results, we further calculated the B-band central surface brightness, μ{sub 0}(B), for each galaxy and ultimately defined a sample of LSB galaxies consisting of 1129 galaxies with μ{sub 0}(B) > 22.5 mag arcsec{sup −2} and the axis ratio b/a > 0.3 from the 12,423 α.40 SDSS DR7 galaxies. This H i-selected sample of LSB galaxies is a relatively unbiased sample of gas-rich and disk-dominated LSB galaxies, which is complete both in H i observation and the optical magnitude within the limit of the SDSS DR7 photometric survey. This LSB galactic sample spans from 22.5 to 28.3 in μ{sub 0}(B) with a fraction of 4% fainter than 25.0 mag arcsec{sup −2} in B-band central surface brightness and distributes from −27.0 to −12.3 mag in absolute magnitude in the B band (M(B)), including the 43 faintest galaxies (M(B) > −17.3 mag). This sample is a blue LSB galactic sample, of which 98% are bluer than 0.75 mag in B–V color. As for 21 cm H i properties, our LSB galactic sample has a median M{sub H i}/L{sub B} = 0.87, and a large portion (95%) has high mass of H i (M(H i) > 10{sup 7.7}M⊙), which supports galaxies in this LSB galactic sample being mostly gas-rich. Additionally, we statistically investigated the environment of our LSB galaxies and found that up to 92% of the total LSB galaxies have less than eight neighboring galaxies, which provides strong evidence that LSB galaxies prefer to reside in the low-density environment.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2016

Sample Preparation Techniques for Grain Boundary Characterization of Annealed TRISO-Coated Particles

Crystallographic information about chemical vapor deposition layers of silicon carbide (SiC) is essential to understanding layer performance, especially when the layers are in non planar geometries, such as spherical. We performed electron Back Scatter Diffraction (EBSD) analysis of spherical SiC layers using a different approach to sample focus ion beam milling technique to avoid the negative impacts of traditional sample polishing and to address the need of very small samples of irradiated materials for analysis. Mechanical and chemical grinding and polishing of sample surfaces can introduce lattice strains and result in unequal removal of SiC and surrounding layers of different material due to the hardness differences of these materials. The nature of layer interfaces is thought to play a key role in performance of the SiC; therefore, analysis of representative samples at these interfacial areas is crucial. In work reported here, a focused ion beam (FIB) was employed in a novel manner to prepare a more representative sample for EBSD analysis from TRISO layers free of effects introduced by mechanical and chemical preparation methods. In addition, the difficulty of handling neutron irradiated microscopic samples such as those analyzed in this work has been simplified with pre tilted mounting stages. Our study showed that although the average grain size of samples may be similar, the grain boundary characteristics may differ significantly. It was also found that low angle grain boundaries, comprises 25% in the FIB-prepared sample vs only 1-2% in the polished sample measured in the same particle. From this study it was determined that results of FIB prepared sample will provide more repeatable results, as the role of sample preparation is eliminated.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2016

Results of Hg speciation testing on DWPF SMECT-4, SMECT-6, and RCT-2 samples

The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team.i,ii The fifteenth shipment of samples was designated to include Defense Waste Processing Facility (DWPF) Slurry Mix Evaporator Condensate Tank (SMECT) samples from Sludge Receipt and Adjustment Tank (SRAT) Batch 738 and a Recycle Condensate Tank (RCT) sample from SRAT Batch 736. The DWPF sample designations for the three samples analyzed are provided in Table 1. The Batch 738 ‘Baseline’ SMECT sample was taken prior to Precipitate Reactor Feed Tank (PRFT) addition and concentration and therefore, precedes the SMECT-5 sample reported previously. iii The Batch 738 ‘End of SRAT Cycle’ SMECT sample was taken at the conclusion of SRAT operations for this batch (PRFT addition/concentration, acid additions, initial concentration, MCU addition, and steam stripping). Batch 738 experienced a sludge slurry carryover event, which introduced sludge solids to the SMECT that were particularly evident in the SMECT-5 sample, but less evident in the ‘End of SRAT Cycle’ SMECT-6 sample. The Batch 736 ‘After SME’ RCT sample was taken after completion of SMECT transfers at the end of the SME cycle.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2016

The Effect of Rolling As-Cast and Homogenized U-10Mo Samples on the Microstructure Development and Recovery Curves

Over the past several years Pacific Northwest National Laboratory (PNNL) has been actively involved in supporting the U.S. Department of Energy National Nuclear Security Administration Office of Material Management and Minimization (formerly Global Threat Reduction Initiative). The U.S. High- Power Research Reactor (USHPRR) project is developing alternatives to existing highly enriched uranium alloy fuel to reduce the proliferation threat. One option for a high-density metal fuel is uranium alloyed with 10 wt% molybdenum (U-10Mo). Forming the U-10Mo fuel plates/foils via rolling is an effective technique and is actively being pursued as part of the baseline manufacturing process. The processing of these fuel plates requires systematic investigation/understanding of the pre- and post-rolling microstructure, end-state mechanical properties, residual stresses, and defects, their effect on the mill during processing, and eventually, their in-reactor performance. In the work documented herein, studies were conducted to determine the effect of cold and hot rolling the as-cast and homogenized U-10Mo on its microstructure and hardness. The samples were homogenized at 900°C for 48 h, then later annealed for several durations and temperatures to investigate the effect on the material’s microstructure and hardness. The rolling of the as-cast plate, both hot and cold, was observed to form a molybdenum-rich and -lean banded structure. The cold rolling was ineffective, and in some cases exacerbated the as-cast defects. The grains elongated along the rolling direction and formed a pancake shape, while the carbides fractured perpendicularly to the rolling direction and left porosity between fractured particles of UC. The subsequent annealing of these samples at sub-eutectoid temperatures led to rapid precipitation of the ' lamellar phase, mainly in the molybdenum-lean regions. Annealing the samples above the eutectoid temperature did not refine the grain size or the banded microstructure. However, annealing the samples led to quick recovery in hardness as evidenced by a drop in Vickers hardness of 20%. Hot rolling was performed at 650 and 800°C. The hot-rolling mill loads (load separation force) were approximately 40 to 50% less than the cold-rolling for the same reduction and thickness. It was observed that hot rolling the samples with 50% or more reduction in thickness were responsible for dynamic recrystallization in the hot-rolled samples and led to grain refinement. Unlike the cold-rolled samples, the hot-rolled samples did not fracture the carbides and appeared to heal the casting defects. The recovery phenomenon was similar to the cold-rolled samples above the eutectoid temperatures, but owing to the refined grain size, the precipitation of the lamellar phase was far more rapid in these samples and the hardness increased more rapidly than in the cold rolled sample when heated below the eutectoid temperature. The data generated from these rolling efforts has been used to make the process modeling efforts more robust and applicable to all USHPRR partner rolling mills. The flow stress for cold rolling the samples was determined to be between 170-190 ksi, with frictional forces between 0.2 and 0.4 for the PNNL mill. The measured roll separation forces and those simulated using finite element methods for hot and cold rolling for the PNNL rolling mill were in good agreement.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2016

Data Validation Package June 2016 Groundwater and Surface Water Sampling at the Old and New Rifle, Colorado, Processing Sites September 2016

Sampling Period: June 14–17 and July 7, 2016. Water samples were collected from 36 locations at New Rifle and Old Rifle, Colorado, Disposal/Processing Sites. Planned monitoring locations are shown in Attachment 1, Sampling and Analysis Work Order. Duplicate samples were collected from New Rifle locations 0216 and 0855, and Old Rifle location 0655. One equipment blank was collected after decontamination of non-dedicated equipment used to collect one surface water sample. See Attachment 2, Trip Report for additional details. Sampling and analyses were conducted as specified in the Sampling and Analysis Plan for U.S. Department of Energy Office of Legacy Management Sites (LMS/PRO/S04351, continually updated, http://energy.gov/lm/downloads/sampling-and- analysis-plan-us-department-energy-office-legacy-management-sites). New Rifle Site Samples were collected at the New Rifle site from 16 monitoring wells and 7 surface locations in compliance with the December 2008 Groundwater Compliance Action Plan [GCAP] for the New Rifle, Colorado, Processing Site (LMS/RFN/S01920). Monitoring well 0216 could not be sampled in June because it was surrounded by standing water due to the high river stage from spring runoff, it was later sampled in July. Monitoring well 0635 and surface location 0322 could not be sampled because access through the elk fence along Interstate 70 has not been completed at this time. Old Rifle Site Samples were collected at the Old Rifle site from eight monitoring wells and five surface locations in compliance with the December 2001 Ground Water Compliance Action Plan for the Old Rifle, Colorado, UMTRA Project Site (GJ0-2000-177-TAR).

54 ENVIRONMENTAL SCIENCES↗