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All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Radionuclide Risk Coefficient Uncertainty Distributions for Use in Performance Assessments - 19156

Traditionally, radiation dose has been used as the regulatory criterion for decision making in performance assessments (PAs), despite the concept of cancer risk arguably being a more easily understood endpoint than dose for the public, and a preferable metric for decision analysis. However, the United States Environmental Protection Agency (EPA) has developed risk parameters for use in risk assessments and PAs in the form of radionuclide-specific risk coefficients, or RCs, which are published in various Federal Guidance Reports (FGRs). RCs are employed as scalars to convert environmental radionuclide exposure (via ingestion, inhalation, and external exposure) estimates to incremental lifetime cancer risk (ILCR). ILCR is the additional cancer risk averaged over a lifetime, over-and-above all-cause cancer risk, associated with carcinogen exposure. Uncertainties associated with RCs are discussed in FGR 13 and in a joint report published by EPA and Oak Ridge National Laboratory, but statistical distributions for the RCs were not directly developed. The uncertainty assessments in the EPA/ONRL report were based on dosimetric modeling and elicitation of nine experts. From these sources, five uncertainty categories were defined based on ratios of the 5. and 95. quantiles of uncertainty. Thus, the representations of uncertainty defined by EPA/ORNL are not distributions in a traditional sense. Furthermore, the authors only addressed uncertainty in RCs for inhalation and ingestion pathways. We develop a methodology for assigning statistical distributions to EPA's published mortality RC values (i.e. to estimate the probability of dying from radiation-induced cancers) for the inhalation (slow, medium, and fast absorption types), ingestion (water, food, and soil), and external exposure pathways associated with all cancer types. We employed the same dosimetric concepts and assumptions as EPA/ORNL, including cancer risk (dose-response) distributional information from a previous expert elicitation, which was also employed by EPA/ORNL in their work. We assumed that uncertainty in RCs can be described by lognormal distributions based on the modeling conducted previously by EPA/ORNL, and that point estimates tabulated in FGR 13 represent median values of the distributions. We also extended EPA/ORNL's uncertainty ratios to statistical distributions for external exposure RCs. The results are a set of radionuclide-specific distributions that are applicable in PAs that focus on cancer mortality. These distributions are currently and will subsequently be employed in PAs at various sites, in addition to the required regulatory dose limits. Quantification of ILCRs and associated uncertainty in PAs will provide regulators and the public with additional information for good decision making. Future directions include further refinement of the distributions and development of statistical distributions for morbidity RCs, which are used to estimate the probability of developing, but not necessarily dying as a result of, radiation-induced cancer. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Effective dose and persistence of Rhodamine-B in wild pig Vibrissae

Due to substantial ecological and economic damage attributed to wild pigs (Sus scrofa), there is international interest in using pharmaceutical baits to control populations. To assess the efficacy and specificity of baiting programs, one may use chemical biomarkers to evaluate uptake of pharmaceutical baits. In particular, Rhodamine B (RB) is known to be an effective biomarker in wild pigs. However, significant data gaps exist regarding the minimum effective dosage and the persistence of RB in wild pigs. To investigate this we used a controlled double-blind study, administering a one-time dose of RB at three treatment levels (5, 15, or 30 mg/kg) to 15 pigs, with five pigs per treatment group. Facial vibrissae were collected pre-RB ingestion as a control and every 2 weeks post-RB ingestion for 12 weeks. We examined samples for RB presence and used a generalized linear mixed model (GLMM) to determine the influence of treatment dose on persistence of RB. Additionally, we measured distance moved by the RB mark away from the vibrissae root and used a GLMM to assess movement rates of RB bands along growing vibrissae. Here, we found consistently greater persistence of RB in the 15 and 30 mg/kg treatments across the sampling period (p = 0.005 and p = <0.0001, respectively). A significant, positive movement trend in RB bands was observed within the 15 and 30mg/kg groups. Based on our results, a 15 mg/kg dosage can be considered a minimum effective dose for wild pigs and will reliably produce a detectable RB mark up to and likely beyond 12 weeks post-ingestion.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Comparison of two small bowel distending agents for enterography in pediatric small bowel imaging

Objective: To evaluate the ability of pediatric patients with known or suspected inflammatory bowel disease to ingest a new oral distending agent at CT or MR enterography (CTE/MRE), and to determine the impact on small bowel (SB) distension and diagnostic confidence. Materials and methods: The study design is that of retrospective review of pediatric patients who underwent CTE or MRE from January 2014 to June 2016. Patients ingested low-concentration barium suspension or flavored beverage containing sorbitol and mannitol. The need for nasogastric tube (NGT) administration, amount ingested, emesis, distal extent of contrast, SB distension, terminal ileum (TI) transverse dimension, and diagnostic confidence in TI disease were assessed. Three radiologists each blindly reviewed a subset of the studies. Results: Of the total 591 scans in 504 patients, 316 scans used low-concentration barium suspension and 275 scans flavored beverage. Nearly all consumed the entire amount (97% vs. 96%). Low-concentration barium suspension exams required NGT more often (7% [23/316] vs. 1% [3/275]; p < 0.0003), and tended to have more emesis (3% [9/316] vs. 1% [3/275]; p = 0.13). Diagnostic confidence score was nearly identical (p = 0.94). Qualitative and quantitative analyses showed no difference in SB distension, except for distension of mid-ileum (flavored beverage > low-concentration barium suspension; p = 0.02). Flavored beverage exams demonstrated a slight increase in distal extent of luminal distension (p = 0.02). Conclusions: A new flavored beverage distends small bowel as well as low-concentration barium suspension, with decreased requirement for NGT insertion and improved distal extent of luminal distension, and without any decrease in diagnostic confidence in the presence or the absence of TI disease.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

End-of-injection fuel dribble of multi-hole diesel injector: Comprehensive investigation of phenomenon and discussion on control strategy

The needle shutdown of fuel injectors leads to an undesired fuel dribble that forms unburned hydrocarbons and decreases the engine thermal efficiency in modern engines. Understanding of the fuel dribbling process is of great importance to establish its minimization strategy for optimal use of conventional fuels. However, the detailed needle dynamics and in- and near-nozzle flow characteristics governing the fuel dribble process have not been thoroughly understood. In this study, the needle dynamics, in- and near-nozzle flow characteristics and fuel dribble of a mini-sac type three-hole diesel injector were investigated using a highspeed X-ray phase-contrast imaging technique at different injection pressures. The results showed that an increase in injection pressure increased the flow evacuation velocity at the needle close that induced a more intense fuel cavitation and air ingestion inside the nozzle. The fuel dribbling process showed a high shot-toshot deviation. A statistical analysis of 50-shot results exhibited two breakup modes of fuel dribble determined by the flow evacuation velocity at the needle close and presence of air ingestion. In the first mode, the fast breakup with a short residence time of fuel dribble occurred. Meanwhile, the dripping of undisturbed liquid column with a long residence time of fuel dribble occurred in the second mode. An increase in injection pressure increased the population of the first mode due to more intense air ingestion that primarily caused by an increase in needle closing speed other than an increase in peak injection velocity. Based on the results, the formation mechanism and control strategies of the fuel dribble from modern diesel injectors were discussed.

Moon, Seoksu↗
DOE OSTI2018

Sterilized bifidobacteria suppressed fat accumulation and blood glucose level

Highlights: • Determined the effects of oral killed probiotics on lipid- and glucose metabolism. • Administered oral sterilized Bifidobacteria to mice on high-fat diet for four weeks. • Probiotics significantly lowered serum glucose, cholesterol, and triglycerides. • Probiotics significantly reduced lipopolysaccharides and hepatic triglycerides. • Probiotics improved glucose tolerance, insulin resistance, and gut microflora. Probiotics such as Lactobacillus and Bifidobacterium improve the balance of intestinal microflora and have various physiological functions beneficial to human health. It is not always known whether the ingested microbial cells are viable- or killed. However, even sterilized bacterial cells are functional. Bacterial cell functions are strain-specific and their modes of action are still poorly understood. The aim of this study was to elucidate the roles of sterilized bifidobacteria in obesity and lipid metabolism. To this end, mice were orally ingested sterilized bacteria. Male C57BL/6J mice aged 7 wks were raised on a high-fat diet and received oral sterilized bifidobacteria for 4 wks. Although the amount of food they ingested did not change in response to bifidobacteria administration, both weight gain and epididymal body fat mass were significantly reduced. In addition, the elevated blood glucose, triglyceride, and total cholesterol levels observed in the mice on the high-fat diet all decreased in response to bifidobacteria treatment. Hepatic triglyceride levels also decreased. Furthermore, oral glucose tolerance and insulin resistance tests indicated that sterilized bifidobacteria improved glucose tolerance and diminished insulin resistance. Sterilized bifidobacteria also decreased blood lipopolysaccharides and altered intestinal flora. The present study indicates that in mice on a high-fat diet, sterilized bifidobacteria suppressed fat accumulation, improved insulin resistance, and lowered blood glucose levels.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Soil quality in the Lomellina area using in vitro models and ecotoxicological assays

Soil quality is traditionally evaluated by chemical characterization to determine levels of pollutants. Biological tools are now employed for soil monitoring since they can take account of the global biological effects induced by all xenobiotics. A combined monitoring of soils based on chemical analyses, human-related in vitro models and ecotoxicological assay was applied in the Lomellina, a semirural area of northern Italy. Chemical characterization indicated overall good quality of the soils, with low levels of toxic and carcinogenic pollutants such as heavy metals, PAHs, PCDD/Fs and PCBs. HepG2 cells were used as a model for the human liver and BALB/c 3T3 cells to evaluate carcinogenic potential. Cells were treated with soil extractable organic matter (EOM) and the MTS assay, DNA release and morphological transformation were selected as endpoints for toxicity and carcinogenicity. Soil EOMs induced dose-dependent inhibition of cell growth at low doses and cytotoxicity only at doses of 500 and 1000 mg soil equivalents/ml. Potential issues for human health can be hypothesized after ingestion of soil samples from some sites. No statistically significant inductions of foci were recorded after exposure to EOMs, indicating that the levels of the soil-extracted organic pollutants were too low to induce carcinogenesis in our experimental conditions. An acute phytotoxicity test and studies on Caenorhabditis elegans were used as ecotoxicological assays for plants and small invertebrates. No significant alerts for ecotoxicity were found. In this proposed case study, HepG2 cells detected differences in the toxicity of soil EOMs, indicating that this cell line could be appropriate to assess the potential harm caused by the ingestion of contaminated soil. Additional information on the carcinogenic potential of mixtures was provided by the cell transformation assay, strengthening the combined approach. - Highlights: • A combined approach for evaluation of soil quality is proposed. • Organic extracts from investigated soils inhibited HepG2 cell proliferation. • The carcinogenic potential of extracts was evaluated by cell transformation assay. • Potential alerts were estimated after ingestion of soils. • Caenorhabditis elegans and phytotest were used to evaluate ecological effects.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

The pumice raft-forming 2012 Havre submarine eruption was effusive

A long-standing conceptual model for deep submarine eruptions is that high hydrostatic pressure hinders degassing and acceleration, and suppresses magma fragmentation. The 2012 submarine rhyolite eruption of Havre volcano in the Kermadec arc provided constraints on critical parameters to quantitatively test these concepts. This eruption produced a >1 km 3 raft of floating pumice and a 0.1 km 3 field of giant (>1 m) pumice clasts distributed down-current from the vent. We address the mechanism of creating these clasts using a model for magma ascent in a conduit. We use water ingestion experiments to address why some clasts float and others sink. We show that at the eruption depth of 900 m, the melt retained enough dissolved water, and hence had a low enough viscosity, that strain-rates were too low to cause brittle fragmentation in the conduit, despite mass discharge rates similar to Plinian eruptions on land. There was still, however, enough exsolved vapor at the vent depth to make the magma buoyant relative to seawater. Buoyant magma was thus extruded into the ocean where it rose, quenched, and fragmented to produce clasts up to several meters in diameter. We show that these large clasts would have floated to the sea surface within minutes, where air could enter pore space, and the fate of clasts is then controlled by the ability to trap gas within their pore space. We show that clasts from the raft retain enough gas to remain afloat whereas fragments from giant pumice collected from the seafloor ingest more water and sink. The pumice raft and the giant pumice seafloor deposit were thus produced during a clast-generating effusive submarine eruption, where fragmentation occurred above the vent, and the subsequent fate of clasts was controlled by their ability to ingest water.

58 GEOSCIENCES↗
DOE OSTI2021

Plumbojarosite Remediation of Soil Affects Lead Speciation and Elemental Interactions in Soil and in Mice Tissues

Lead (Pb) contamination of soils is of global concern due to the devastating impacts of Pb exposure in children. Because early-life exposure to Pb has long-lasting health effects, reducing exposure in children is a critical public health goal that has intensified research on the conversion of soil Pb to low bioavailability phases. Recently, plumbojarosite (PLJ) conversion of highly available soil Pb was found to decrease Pb relative bioavailability (RBA <10%). However, there is sparse information concerning interactions between Pb and other elements when contaminated soil, pre- and post-remediation, is ingested and moves through the gastrointestinal tract (GIT). Addressing this may inform drivers of effective chemical remediation strategies. In this study, we utilize bulk and micro-focused Pb X-ray absorption spectroscopy to probe elemental interactions and Pb speciation in mouse diet, cecum, and feces samples following ingestion of contaminated soils pre- and post-PLJ treatment. RBA of treated soils was less than 1% with PLJ phases transiting the GIT with little absorption. In contrast, Pb associated with organics was predominantly found in the cecum. These results are consistent with transit of insoluble PLJ to feces following ingestion. The expanded understanding of Pb interactions during GIT transit complements our knowledge of elemental interactions with Pb that occur at higher levels of biological organization.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

Basis for the ICRP’s updated biokinetic model for carbon inhaled as CO 2

Here, the International Commission on Radiological Protection (ICRP) is updating its biokinetic and dosimetric models for occupational intake of radionuclides (OIR) in a series of reports called the OIR series. This paper describes the basis for the ICRP's updated biokinetic model for inhalation of radiocarbon as carbon dioxide (CO 2 ) gas. The updated model is based on biokinetic data for carbon isotopes inhaled as carbon dioxide or injected or ingested as bicarbonate $({{{\rm{HCO}}}_{3}}^{-}).$ The data from these studies are expected to apply equally to internally deposited (or internally produced) carbon dioxide and bicarbonate based on comparison of excretion rates for the two administered forms and the fact that carbon dioxide and bicarbonate are largely carried in a common form (CO 2 –H${{{\rm{CO}}}_{3}}^{-})$ in blood. Compared with dose estimates based on current ICRP biokinetic models for inhaled carbon dioxide or ingested carbon, the updated model will result in a somewhat higher dose estimate for 14 C inhaled as CO 2 and a much lower dose estimate for 14 C ingested as bicarbonate.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2022

Dose Coefficients for Internal Dose Assessments for Exposure to Radioactive Fallout

This paper presents values as well as the bases for calculating internal dose coefficients suitable for estimating organ doses from the exposure to radioactive fallout that could result from the detonation of a nuclear fission device. The 34 radionuclides discussed are the same as those given in a priority list of radionuclides for fallout dose assessments presented in a companion overview paper. The radionuclides discussed are those that are believed to account for a preponderance of the organ doses that might be received by intake by persons of all ages (including in utero and via breast feeding for infants) following exposure to radioactive fallout. The presented dose coefficients for ingestion account for age and include modifications for variations in solubility with distance as discussed previously in the literature, and those for inhalation similarly account for age, solubility, and particle sizes that would be relevant at various distances of exposure as discussed in a companion paper on ingestion dose methods. The proposed modifications peculiar to radioactive fallout account for systematic changes in solubility and particle sizes with distance from the site of detonation, termed here as the region of “local fallout” and the region “beyond local fallout.” Brief definitions of these regions are provided here with more detailed discussion in a companion paper on estimating deposition of fallout radionuclides. This paper provides the dose coefficients for ingestion and inhalation (for particle sizes of 1 μm, 5 μm, 10 μm, and 20 μm) for the region “local fallout.” These dose coefficients for “local fallout” are specific for particles formed in a nuclear explosion that can be large and have radionuclides, particularly the more refractory ones, distributed throughout the volume where the radionuclide has reduced solubility. The dose coefficients for the region “beyond local fallout” are assumed to be the ones published by the International Commission on Radiological Protection (ICRP) in 1995. Comparisons of the presented dose coefficients are made with values published by the ICRP.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2025

Optimizing Management of Persistent Data Structures in High-Performance Analytics

Large-scale data analytics workflows ingest massive input data into various data structures, including graphs and key-value datastores. These data structures undergo multiple transformations and computations and are typically reused in incremental and iterative analytics workflows. Persisting in-memory views of these data structures enables reusing them beyond the scope of a single program run while avoiding repetitive raw data ingestion overheads. Memory-mapped I/O enables persisting in-memory data structures without data serialization and deserialization overheads. However, memory-mapped I/O lacks the key feature of persisting consistent snapshots of these data structures for incremental ingestion and processing. The obstacles to efficient virtual memory snapshots using memory-mapped I/O include background writebacks outside the application’s control, and the significantly high storage footprint of such snapshots. To address these limitations, we present Privateer, a memory and storage management tool that enables storage-efficient virtual memory snapshotting while also optimizing snapshot I/O performance. Here, we integrated Privateer into Metall, a state-of-the-art persistent memory allocator for C++, and the Lightning Memory-Mapped Database (LMDB), a widely-used key-value datastore in data analytics and machine learning. Privateer optimized application performance by 1.22× when storing data structure snapshots to node-local storage, and up to 16.7× when storing snapshots to a parallel file system. Privateer also optimizes storage efficiency of incremental data structure snapshots by up to 11× using data deduplication and compression.

Computer science↗
DOE OSTI2024

RAIS Slope Factors for Radionuclides

For a given radionuclide, Slope Factors (SFs) represent the ELCR equivalent per unit intake (i.e., ingestion or inhalation) or external exposure of that radionuclide. These SFs are used to convert a radionuclide concentration in soil, air, water, or foodstuffs to a radiation ELCR. The primary use of SFs, also called risk coefficients, is to compute the ELCR resulting from site-related exposures. This is accomplished by multiplying the route-specific SF by the CDI of each radionuclide of potential concern for each route of exposure. Ingestion and inhalation slope factors are central estimates in a linear model of the age-averaged, lifetime attributable radiation cancer incidence (fatal and nonfatal cancer) risk per unit of activity inhaled or ingested, expressed as risk/picocurie (pCi). External exposure SFs are central estimates of lifetime attributable radiation cancer incidence risk for each year of exposure to external radiation from photon-emitting radionuclides distributed uniformly in a thick layer of soil, expressed as risk/year per pCi/gram soil. External exposure SF units can also be risk/year per pCi/square centimeters (cm2) of soil. When combined with site-specific media concentration data and appropriate exposure assumptions, SFs can be used to estimate lifetime cancer risks to members of the general population due to radionuclide exposures. The SFs presented on are updated values from Federal Guidance Report (FGR) 13 supplement using the International Commission on Radiological Protection (ICRP) 107 decay data. The derivation and values are found in “Calculations of Slope Factors and Dose Coefficients” (ORNL, 2014).

Noto, Katie [Oak Ridge National Laboratory (ORNL),↗
DOE OSTI2012

Peak Dose Assessment for Proposed DOE-PPPO Authorized Limits

The Oak Ridge Institute for Science and Education (ORISE), a U.S. Department of Energy (DOE) prime contractor, was contracted by the DOE Portsmouth/Paducah Project Office (DOE-PPPO) to conduct a peak dose assessment in support of the Authorized Limits Request for Solid Waste Disposal at Landfill C-746-U at the Paducah Gaseous Diffusion Plant (DOE-PPPO 2011a). The peak doses were calculated based on the DOE-PPPO Proposed Single Radionuclides Soil Guidelines and the DOE-PPPO Proposed Authorized Limits (AL) Volumetric Concentrations available in DOE-PPPO 2011a. This work is provided as an appendix to the Dose Modeling Evaluations and Technical Support Document for the Authorized Limits Request for the C-746-U Landfill at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky (ORISE 2012). The receptors evaluated in ORISE 2012 were selected by the DOE-PPPO for the additional peak dose evaluations. These receptors included a Landfill Worker, Trespasser, Resident Farmer (onsite), Resident Gardener, Recreational User, Outdoor Worker and an Offsite Resident Farmer. The RESRAD (Version 6.5) and RESRAD-OFFSITE (Version 2.5) computer codes were used for the peak dose assessments. Deterministic peak dose assessments were performed for all the receptors and a probabilistic dose assessment was performed only for the Offsite Resident Farmer at the request of the DOE-PPPO. In a deterministic analysis, a single input value results in a single output value. In other words, a deterministic analysis uses single parameter values for every variable in the code. By contrast, a probabilistic approach assigns parameter ranges to certain variables, and the code randomly selects the values for each variable from the parameter range each time it calculates the dose (NRC 2006). The receptor scenarios, computer codes and parameter input files were previously used in ORISE 2012. A few modifications were made to the parameter input files as appropriate for this effort. Some of these changes included increasing the time horizon beyond 1,050 years (yr), and using the radionuclide concentrations provided by the DOE-PPPO as inputs into the codes. The deterministic peak doses were evaluated within time horizons of 70 yr (for the Landfill Worker and Trespasser), 1,050 yr, 10,000 yr and 100,000 yr (for the Resident Farmer [onsite], Resident Gardener, Recreational User, Outdoor Worker and Offsite Resident Farmer) at the request of the DOE-PPPO. The time horizons of 10,000 yr and 100,000 yr were used at the request of the DOE-PPPO for informational purposes only. The probabilistic peak of the mean dose assessment was performed for the Offsite Resident Farmer using Technetium-99 (Tc-99) and a time horizon of 1,050 yr. The results of the deterministic analyses indicate that among all receptors and time horizons evaluated, the highest projected dose, 2,700 mrem/yr, occurred for the Resident Farmer (onsite) at 12,773 yr. The exposure pathways contributing to the peak dose are ingestion of plants, external gamma, and ingestion of milk, meat and soil. However, this receptor is considered an implausible receptor. The only receptors considered plausible are the Landfill Worker, Recreational User, Outdoor Worker and the Offsite Resident Farmer. The maximum projected dose among the plausible receptors is 220 mrem/yr for the Outdoor Worker and it occurs at 19,045 yr. The exposure pathways contributing to the dose for this receptor are external gamma and soil ingestion. The results of the probabilistic peak of the mean dose analysis for the Offsite Resident Farmer indicate that the average (arithmetic mean) of the peak of the mean doses for this receptor is 0.98 mrem/yr and it occurs at 1,050 yr. This dose corresponds to Tc-99 within the time horizon of 1,050 yr.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Approximating Dose and Risk for Contaminants in Groundwater from the Underground Nuclear Test Areas of the Nevada National Security Site (NNSS)

As part of the Environmental Management Program at the Nevada National Security Site (NNSS), the Underground Test Area (UGTA) Activity investigates the potential impacts of radionuclides that were introduced into groundwater from the underground nuclear tests conducted near or below the NNSS water table between 1951 and 1992. Groundwater models are being used to simulate contaminant transport and forecast contaminant boundaries that encompass areas where the groundwater has a five percent or greater probability of containing contaminants above the Safe Drinking Water Act Maximum Contaminant Levels (SDWA MCLs) at any time during the next 1,000 years. Transport modeling conducted for the Frenchman Flat Corrective Action Unit (CAU) at the NNSS identified the beta/photon-emitting radionuclides tritium (3H), carbon-14 ( 14 C), chlorine-36 ( 36 Cl), technetium-99 ( 99 Tc), and iodine-129 ( 129 I) as having the greatest influence in defining the farthest extent of the modeled CAU contaminant boundary. These same radionuclides are assumed here as the contaminants of concern (COCs) for all underground nuclear tests at the NNSS because models are not yet complete for the other CAUs. Potential public exposure to the COCs will only occur and be of concern if the COCs migrate into the groundwater beneath public or private lands at levels that exceed either individual SDWA MCLs or dose and risk limits. Groundwater flow directions strongly suggest that any contaminant boundary predicted by contaminant fate and transport modeling to overlap public or private lands is more likely to occur to the west and/or southwest of the NNSS and the adjacent Nevada Test and Training Range (NTTR). Well-established, rural communities exist in these directions. Estimates of representative activity concentrations at the applicable SDWA MCL were developed for the five COCs. It is assumed that these COC concentrations may collectively occur at some public or private location in the future, but that situation does not exist today. These representative activity concentrations are evaluated with respect to conforming collectively to a modern annual committed effective dose (CED) and lifetime excess cancer morbidity risk for a hypothetical reasonably maximally exposed individual (RMEI). This approach goes beyond the SDWA MCL focus of the contaminant boundary because individual COC concentrations may comply with the SDWA MCL but not collectively meet the modern health-protection metrics and the SDWA language, especially if future modeling studies or monitoring activities show multiple radionuclides from different SDWA MCL categories to be COCs. For the drinking water exposure pathway alone, the annual committed effective dose (CED) for the RMEI from all five COCs that are collectively at estimated activity concentrations equal to their SDWA MCL is well below the U.S. Department of Energy health-protective CED limit of 100 millirem (mrem)/yr. This is consistent using both the NNSS unclassified, 1992 decay-corrected radionuclide atom inventory and the atom inventory based on radionuclides measured in groundwater obtained from the ALMENDRO cavity in 2009 to calculate the SDWA MCL activity concentrations in groundwater. The RMEI’s total lifetime excess cancer risk from the drinking water exposure pathway for both atom inventories is within the range of 1 × 10 -4 to ≤ 1 × 10 -6 , which is considered health protective according to modern SDWA MCL regulatory language. The biosphere exposure pathways are drinking water, garden produce, animal products, inadvertent soil ingestion, and indoor and outdoor air inhalation. The exposure parameters for communities west and southwest of the NNSS were developed when the Yucca Mountain high-level, nuclear-waste disposal facility was under consideration. For all biosphere exposure pathways, calculations of the annual CED and lifetime excess cancer morbidity risk for the RMEI revealed that: 1) The annual CED is well within health-protective guidance (<< 100 mrem CED /yr) for the COC activity concentrations at the SDWA MCL, regardless of the atom inventory used. 2) The calculated 70-year lifetime excess cancer morbidity risk (6 x 10 -5 ) is within the health-protective range when the five COC activity concentrations are derived using the NNSS 1992 atom inventory, but it is at the upper limit of the acceptable range (1 x 10 -4 ) using the ALMENDRO 2009 atom inventory. 3) Tritium (3H) is the principal COC for producing annual dose and lifetime excess cancer risk, regardless of the atom inventory used. 4) Overall, the drinking water ingestion pathway is the dominant exposure pathway contributing to the total annual CED and lifetime excess cancer risk, followed by eating locally grown produce and animal products. 5) When tritium completely decays (after about 100 years), the RMEI’s lifetime risk will fall well within the health-protective range (i.e., 1 × 10-4 to ≤ 1 × 10 -6 ) and 36Cl will then become the most important contributor to the RMEI’s total annual CED and lifetime excess cancer morbidity risk from eating local produce and animal products. In the event that radionuclide concentrations begin to approach SDWA MCLs, a reasonable risk-management strategy for keeping lifetime risk more in compliance with regulatory guidance would be to use local sources of groundwater that are below SDWA MCLs or to limit the consumption of local produce and animal products that have ingested COC-contaminated groundwater. The viability of the latter strategy increases where the annual CED due to 36Cl approaches that of 3H.The dose and risk values calculated here for an RMEI are specific to the assumption that the five COCs occur in groundwater beneath public or private lands at concentrations that are collectively at the SDWA MCL. Currently, these COCs are essentially absent from groundwater beneath public or private lands beyond the boundaries of the NNSS and NTTR other than at very low, naturally occurring concentrations. The analyses presented here can be readily applied to determine dose and risk for COC concentrations actually measured in future monitoring samples.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

Risks to Ecological Receptors Posed by Contaminants of Potential Concern in the Lower Three Runs Cooling Ponds and Canals

The upper portion of Lower Three Runs includes several ponds, reservoirs, and canals that were formerly used as a cooling system for nuclear production reactors. This area was divided into nine exposure areas (EAs) for the assessment of environmental contamination resulting from past reactor operations and other industrial processes. A tiered screening process identified several contaminants of potential concern including aluminum, cyanide, lead, manganese, mercury, DDD, DDE, and DDT. Risks posed by these contaminants to ecological receptors (river otter, belted kingfisher, raccoon, and blue heron) were assessed using contaminant exposure models that estimated contaminant intake resulting from ingestion of food, water, and sediment/ soil and compared these intakes with toxicity reference values (TRVs). The contaminant exposure models showed that the TRVs were not exceeded in the otter model, exceeded by aluminum in EA 7 (Pond 2 and associated canals) in the raccoon model, and exceeded by mercury in EAs 2, 3 (Pond B), 6 (Par Pond), and 8 (Ponds 4 and 5 and Canal to Pond C) in both the kingfisher and blue heron models. Hazard quotients (total exposure dose divided by the TRV) were 2.8 for aluminum and 1.7- 3.6 for mercury. The primary route of exposure for aluminum was the ingestion of soil, and the primary route of exposure for mercury was the ingestion of mercury contaminated fish. Elevated levels of mercury in fish were at least partly the result of the aerial deposition of mercury onto Lower Three Runs and its watershed. The atmospheric deposition of mercury creates pervasive contamination in fish throughout the Savannah River basin. Another possible source of mercury was the discharge of mercury contaminated Savannah River water into the Lower Three Runs cooling ponds and canals during previous years of reactor operation. This contamination originated from industries located upstream of the SRS. The aluminum exceedance for the raccoon was likely the result of naturally high aluminum levels in SRS soils rather than SRS operations. Aluminum exceedances have previously been observed in relatively undisturbed background locations as well as areas affected by SRS operations. Aluminum exceedances are more likely with the raccoon than the other receptors because it consumes more soil as a result of its feeding habits. Sensitivity analysis showed that model uncertainty can be reduced by adequate sampling of key variables (e.g., fish and sediments). Although sediment samples were collected from all EAs, fish samples were not collected from three EAs and some analytes (pesticides and cyanide) were not measured in fish. Water-to-fish concentration ratios were used to estimate contaminant levels in fish when direct measurements from fish were unavailable; however, such estimates are potentially less accurate than direct measurements.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

FY19Q3 LL17-GEOVIS-PD3SS

NFIX has been licensed to ORNL, LANL, SNL and LBNL for use on the MINOS venture. We continue to meet with the MINOS data team to receive feedback and suggestions for additional features. We are accommodating feature requests within our resources. • A new feature was added to NFIX that lists out sensor metadata files (json files) that NFIX is not able to ingest due to formatting errors. This feature has greatly eased the effort required by the MINOS team to identify errant json files. Our summer student used this new feature to determine the number of sensor data metafiles that NFIX was not ingesting (a small number) and found the root cause to be a particular set of formatting problems. The MINOS team is using this information to correct the mis-formatted files. Our summer student also developed a tutorial for the NFIX users. She was in a unique position to develop a tutorial as she had to come up to speed on the tool in order to use it for our data ingest study. The tutorial is planned to appear as an appendix in the project final report. A white paper on using GeoVisipedia technology for detecting changes at portals using satellite imagery was submitted to NA21. The technique uses GeoVisipedia’s model projection technology as a view-invariant segment technique thereby greatly enhancing the robustness of detecting changes. We demonstrated NFIX to our program manager and his technical advisor in April. Per headquarters direction we were not required to present at a DNN R&D Joint Program Review this year.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2026

Grid Operator Analytics and Assessment Tools for Inverter- Based Resources Dominated Grid (GOAAT-IBR) Project Update

This presentation provides an update on the OPTIMA GOAAT project, with emphasis on the cloud-native data platform developed in-house to ingest, manage, and operationalize high-resolution power system data. Since our last NASPI presentation, accessible via OSTI ID #2671437, the project team advanced the design and deployment of a scalable architecture capable of handling both synchronized and non-synchronized streams, including PMU, point-on-wave (POW), COMTRADE, and SCADA data. These materials review the project status, recent progress, and key lessons learned. The core of the presentation examines the architecture and engineering of our cloud-native ingestion and data management platform. We then explain how pipelines were designed to collect, normalize, time-align, store, and serve heterogeneous data at scale. We will discuss design choices such as data models, streaming versus batch ingestion, storage tiers, and interoperability with analytics applications. Practical experiences with cloud-native technologies were shared during the event, including benefits, limitations, and integration challenges in a utility environment, along with methods used to improve performance, reduce latency, and optimize resource usage. The presentation also showcases user interface designs and visualization tools that convert raw measurements and analytics results into intuitive, actionable insights for operators and engineers. During the presentation examples were provided demonstrating how visualization, event views, and summarized analytics enhance situational awareness and support operational decision-making. These use cases illustrate how a well-designed data infrastructure can bridge the gap between high-volume measurements and practical grid operations.

Aminifar, Farrokh↗
DOE OSTI2018

New Neutron-capture Site in Massive Pop III and Pop II Stars as a Source for Heavy Elements in the Early Galaxy

We propose a new neutron-capture site in early metal-poor and metal-free stars of ~20–30 M ⊙ that results from proton ingestion in the He shell during late stages of the stars' lives. Most of the neutron capture occurs in the first lesssim106 s following proton ingestion when 13 C(α, n) 16 O produces neutron densities typical of the intermediate neutron-capture process. This phase may be followed by another lasting gsim10 7 s with 17 O(α, n) 20 Ne producing much lower neutron densities typical of the slow neutron-capture process. We explore the dependence of the proposed neutron-capture nucleosynthesis on the amount and time of proton ingestion, the initial metallicity, and the ensuing supernova shock. We obtain a range of heavy-element abundance patterns, including those attributed to the slow neutron-capture process or a combination of the slow and rapid neutron-capture processes. Our results can account for the observed ubiquity of heavy elements such as Sr and Ba in the early Galaxy and explain puzzling abundance patterns of these elements in at least some very metal-poor (VMP) stars, including those of the carbon-enhanced varieties. In the latter case, the explanation by the single site proposed here differs from the existing paradigm that attributes various classes of VMP stars to enrichment by multiple different sites.

79 ASTRONOMY AND ASTROPHYSICS↗