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At least 19 records

UNREVIEWED COMPOSITE ANALYSIS QUESTION EVALUATION: Update of Composite Analysis Sources Potentially Interacting with the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

This unreviewed composite analysis question evaluation (UCAQE) assesses the impacts of the FFACO corrective actions on the Area 5 RWMS CA and the need to revise or update the CA Federal Facility Agreement and Consent Order (FFACO). The FFACO, a legal agreement among the NNSA/NFO, the state of Nevada, and the U.S. Department of Defense, establishes a process to identify, characterize, and implement corrective actions for historical sites on the Nevada National Security Site (NNSS) contaminated with hazardous or radioactive materials. Review of FFACO corrective actions involving sources of residual radioactive contamination potentially interacting with the Area 5 RWMS indicates that no significant changes affecting CA results and conclusions have occurred. Doses from the Area 5 RWMS, Industrial Sites, and Soils sites are a small fraction of the 0.3 mSv CA dose constraint, and significant interactions with releases from the Area 5 RWMS are unlikely. Doses from FFACO CASs, including UGTA sites, can be controlled by FFACO URs and institutional controls that have been implemented since the CA was prepared. As the interactions between the Area 5 RWMS and the FFACO CASs are negligible, the sites can be managed independently. The Area 5 RWMS CA reached the same conclusions about the interaction of the Area 5 RWMS with other sources of residual contamination. Therefore, there is no need to revise or update the Area 5 RWMS CA.

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Summary Analysis: Hanford Site Composite Analysis Update

The Hanford Site’s currently maintained Composite Analysis, originally completed in 1998, requires an update. A previous update effort was undertaken by the U.S. Department of Energy (DOE) in 2001-2005, but was ended before completion to allow the Tank Closure & Waste Management Environmental Impact Statement (TC&WM EIS) (DOE/EIS-0391) to be prepared without potential for conflicting sitewide models. This EIS was issued in 2012, and the deferral was ended with guidance in memorandum “Modeling to Support Regulatory Decision Making at Hanford” (Williams, 2012) provided with the aim of ensuring subsequent modeling is consistent with the EIS.

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Composite Analysis Vadose Zone Transport of Selected Hanford Site Composite Analysis: Vadose Zone Transport of Selected Radionuclides Released from DOE O 435.1 Waste Sites

The main objectives of the composite analysis (CA) compliance case vadose zone (VZ) facet are to simulate transport of radionuclide releases from the surface to the water table, and to provide radionuclide transfer rates to groundwater for inclusion into the Plateau-to-River (P2R) saturated zone (SZ) model (CP-57037, Model Package Report: Plateau to River Groundwater Model, Version 8.3). The parallel exascale version of the Subsurface Transport Over Multiple Phases (eSTOMP) simulator is used to simulate flow and transport for the CA VZ models. The CA compliance case approach to address the scale and distribution of contaminant sources in the VZ facet is to subdivide the Hanford Site Central Plateau into 26 models that contain contaminant sources and liquid discharges likely to commingle during migration through the VZ to the water table.

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Crystallographic and Compositional Analysis of impurity phase: U2MoSi2C in UMo Alloys

Minor impurity elements in metallic nuclear materials can critically influence the microstructural evolution and mechanical properties, making it crucial to understand the structure, composition and distribution of the impurity phases. Using Transmission Electron Microscopy, Atom Probe Tomography and ab-initio calculations we provide the atomic scale crystallographic structural and compositional analysis of a new impurity phase: U2MoSi2C in an important nuclear fuel U-10Mo alloy. We identify the new phase to have tetragonal symmetry with lattice parameters of a=6.67Å, c=4.33Å, and space group P4/mbm (No.127). Ab-initio calculations were performed to verify structural stability and to perform atom positions refinement.

Kovarik, Libor↗

Hanford Site Composite Analysis Special Analysis: Inventory and Solid Waste Release Modeling for the LLBG Sensitivity Case - UCAQ-22-01 Inventory Discrepancies for 218-E-12B, 218-W-3A, and 218-W-3AE in the Hanford Site Composite Analysis

This environmental calculation file (ECF) documents the methodologies, assumptions, and results of four sensitivity analyses that reevaluate the representativeness of solid-waste radionuclide inventory and release rate from three solid waste sites included in the recently completed Hanford Site Composite Analysis (CA) (DOE-RL-2019-52, Composite Analysis for Low-Level Waste Disposal in the Hanford Site Central Plateau (FY 2020), Rev. 1) (hereinafter called the CA Update). Specifically, this ECF reevaluates the representativeness of the base case inventory and radionuclide waste release rates from three solid waste sites (i.e., 218-E-12B, 218-W-3A, and 218-W-3AE) and two radionuclides (i.e., carbon-14 [C-14] and technetium-99 [Tc-99]). These three waste sites and two radionuclides were identified as being the most significant contributors to groundwater contamination and dose in the CA Update for the Inner Area boundary at times periods after the compliance period. This ECF first evaluates the representativeness of the C-14 and Tc-99 inventory and second, radionuclide release rates for the three waste sites1. If the inventory and release rates assumed in the CA Update are determined to be not representative, as hypothesized in the CA Update, then this ECF evaluates the impact of more representative inventories and release rates on the transfer of radionuclides to the vadose zone. The four analyses described in this ECF are as follows: 1) 218-E-12B C-14 Inventory and Release Rate Sensitivity Case – Determine the representativeness of the C-14 inventory and associated waste release rate from the 218-E-12B waste site assumed in the CA Update. If the inventory and associated waste release are more appropriately characterized as being different from the assumptions in the CA Update, then update the predicted C-14 release rate and compare the results to the results presented in the CA Update (DOE/RL-2019-52); 2) 218-W-3A C-14 Inventory and Release Rate Sensitivity Case – Determine the representativeness of the C-14 inventory and associated waste release rate from the 218-W-3A waste site assumed in the CA Update. If the inventory and associated waste release are more appropriately characterized as being different from the assumptions in the CA Update, then update the predicted C-14 release rate and compare the results to the results presented in the CA Update (DOE/RL-2019-52); 3) 218-W-3AE Tc-99 Release Rate Sensitivity Case – Determine the representativeness of the Tc-99 inventory and associated waste release rate from the 218-W-3AE waste site assumed in the CA Update. If the inventory and associated waste release are more appropriately characterized as being different from the assumptions in the CA Update, then update the predicted Tc-99 release rate and compare the results to the results presented in the CA Update (DOE/RL-2019-52); 4) 218-W-3AE Tc-99 Release Footprint Sensitivity Case – Determine the representativeness of the Tc-99 waste area footprint for the 218-W-3AE waste site assumed in the CA Update. If the footprint of the waste is more appropriately characterized as being different from the assumptions in the CA Update, then update the predicted Tc-99 release rate and compare the results to the result presented in the CA Update (DOE/RL-2019-52).

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Summary Analysis Hanford Site Composite (Analysis Update)

This Summary Analysis has three primary purposes: (1) Define the overall technical scope and approach for conducting the Hanford Site CA update; (2) Define the approach for complying with modeling requirements in the Williams (2012) memorandum; and (3) Serve as the mechanism for the Groundwater Vadose Zone Executive Council to review and approve the overall modeling approach for the Hanford Site CA.

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Finite-Element Composite-Analysis Program

Finite Element Composite Analysis Program, FECAP, special-purpose finite-element program for analyzing behavior of composite material with microcomputer. Procedure leads to set of linear simultaneous equations relating unknown nodal displacement to applied loads. Written in HP BASIC 3.0.

Bowles, David E.↗

Layered Composite Analysis Capability

Laminated composite material construction is gaining popularity within industry as an attractive alternative to metallic designs where high strength at reduced weights is of prime consideration. This has necessitated the development of an effective analysis capability for the static, dynamic and buckling analyses of structural components constructed of layered composites. Theoretical and user aspects of layered composite analysis and its incorporation into CSA/NASTRAN are discussed. The availability of stress and strain based failure criteria is described which aids the user in reviewing the voluminous output normally produced in such analyses. Simple strategies to obtain minimum weight designs of composite structures are discussed. Several example problems are presented to demonstrate the accuracy and user convenient features of the capability.

Narayanaswami, R.↗

Biomass Compositional Analysis Laboratory (Fact Sheet)

At the Biomass Compositional Analysis Laboratory, NREL scientists have more than 20 years of experience supporting the biomass conversion industry. They develop, refine, and validate analytical methods to determine the chemical composition of biomass samples before, during, and after conversion processing. These high-quality compositional analysis data are used to determine feedstock compositions as well as mass balances and product yields from conversion processes.

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Hanford Site Composite Analysis: Radionuclide Selection for Groundwater Pathway Evaluation

The updated Hanford Site Composite Analysis (CA) (DOE/RL-2019-52, Composite Analysis for Low-Level Waste Disposal in the Hanford Site Central Plateau (FY 2020)) provides an all-pathways dose projection to a hypothetical future member of the public from all planned low-level radioactive waste disposal facilities and potential contributions from all other projected end-state sources of radioactive material left at the Hanford Site following site closure. Its primary purpose is to support the decision-making process of the U.S. Department of Energy (DOE) under DOE O 435.1-1, Radioactive Waste Management, related to managing low-level waste disposal facilities at the Hanford Site. A key aspect of conducting a CA is selecting the radionuclides to be analyzed. This document describes the selection process for radionuclides to be included in the quantitative analysis.

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TEXCAD: TEXile Composite Analysis for Design

The Textile Composite Analysis for Design (TEXCAD) code provides the materials/design engineer with a user-friendly, desktop computer based tool for the analysis of a wide variety of fabric reinforced woven and braided composites. It can be used to calculate overall thermal and mechanical properties along with engineering estimates of damage progression and strength. TEXCAD also calculates laminate properties for stacked, oriented fabric constructions. It discretely models the yarn centerline paths within the textile repeating unit cell (RUC) by assuming sinusoidal undulations at yarn cross-over points and uses a year discretization scheme (which subdivides each yarn into smaller, piecewise straight yarn slices) together with a 3-D stress averaging procedure to compute overall stiffness properties. In the calculations for strength, it uses a curved beam-on-elastic foundation model for yarn undulating regions together with incremental approach in which stiffness properties for the failed yarn slices are reduced based on the predicted yarn slice failure mode. Nonlinear shear effects and nonlinear geometric effects can be stimulated. Input to TEXCAD consists of: (1) material parameters like impregnated yarn and resin properties such as moduli, Poisson's ratios, coefficients of thermal expansion, nonlinear shear parameters, axial failure strains, and in-plane failure stresses; and (2) fabric parameters like yarn sizes, braid angle, yarn packing density, filament diameter, and overall fiber volume fraction. Output consists of overall thermoelastic constants, yarn slice strains/stresses, yarn slice failure history, in-plane strain response, and ultimate failure strength. Strength can be computed under the combined action of thermal and mechanical loading (tension, compression, and shear). A brief overview of the analytical capabilities, program organization, and modules, input and output parameters, computer platforms, distribution, and modifications/extensions of the TEXCAD code are presented here.

Naik, Rajiv A.↗

Method Development and Implementation for Characterizing Uncertainties in Tank Leak Volumes for Composite Analysis.

The purpose of this environmental calculation file (ECF) is to provide a summary of methodology, inputs, assumptions, and results of a Special Analysis (SA) titled “Method Development and Implementation for Characterizing Uncertainties in Tank Leak Volumes for the Updated Composite Analysis.” This SA is one of the three SAs conducted in Fiscal Year (FY) 2024 for the Composite Analysis (CA) for the Hanford Site (DOE/RL-2019-52, Composite Analysis for Low-Level Waste Disposal in the Hanford Site Central Plateau (FY 2020)), and it is performed following the Unreviewed Composite Analysis Question Evaluation procedure, UCAQ-24-01-E (UCAQ-24-01-E, Rev. 0).

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Model Package Report: Composite Analysis Solid Waste Release Model (CASWR Model)

This document describes the implementation of a solid waste form release model in GoldSim for the Hanford Site Composite Analysis (CA) Update. This Composite Analysis Solid Waste Release model (CASWR model) was designed to generate deterministic radionuclide release rates for Hanford’s Central Plateau solid waste disposal sites using single realizations of release model coefficients. Five generalized waste form types are used for the conceptual model of waste release: surplus reactor block, cement, soil-debris, grouted residual waste, and ancillary equipment. The surplus reactor block waste form consists of radionuclide leaching from surplus production graphite reactor core blocks via unspecified processes (White et al., 1984 as cited in PNNL-15965). The cement waste form represents solidified wastes whose permeability is much lower than that of the surrounding soil. The soil-debris waste form type is defined as unconsolidated waste mixed with soil material. Tanks and canyon complexes comprise the grouted residual waste form such that their solid waste will be grouted and capped with a surface barrier at the completion of their cleanup. Finally, the ancillary equipment waste form constitutes contaminant releases from ancillary and auxiliary waste form residues associated with tank farms at closure. Individual sub-models are implemented to numerically represent a respective waste form within the CASWR Model: Surplus Reactor Block Sub-model, Cement Sub-model, SoilDebris Sub-model, Grouted Residual Waste Sub-model, and Ancillary Equipment Submodel. Advection is assumed to be the primary transport process governing the release of radionuclides in the Ancillary Equipment and Soil-Debris Sub-models. Diffusion is assumed to be the primary release process in the Grouted Residual Waste and Cement Sub-models. An unspecified zero-order release process is considered in the Surplus Reactor Block Sub-model due to the lack of information regarding actual processes involved in irradiated graphite leaching. The Surplus Reactor Block, Cement, and SoilDebris Sub-models were compared against analytical solutions (PNNL-11800, Composite Analysis for Low-Level Waste Disposal in the 200 Area Plateau of the Hanford Site). The agreement between results of these analytical solutions and the corresponding waste form models verified their correct implementation in GoldSim. A 1-D modeling abstraction approach for the Grouted Residual Waste and Ancillary Equipment Sub-models was adopted from existing Performance Assessment (PA) models. Despite the simplifications made in these sub-models, they were found to be appropriate representations of the waste forms, similar to what was used in the Waste Management Area C PA model (RPP-ENV-58782, Performance Assessment of Waste Management Area C, Hanford Site, Washington, Rev. 0). A sensitivity analysis was conducted to identify the most influential parameters in each waste form sub-model. Suggestions for considering pH-dependent and redox-dependent release mechanisms are formulated through the development of a conditional constant approach in GoldSim.

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Annual Status Report (FY 2018): Composite Analysis for Low Level Waste Disposal in the Central Plateau of the Hanford Site

In accordance with U.S. Department of Energy (DOE) requirements in DOE M 435.1-1 Chg 11, and as implemented by DOE/RL-2000-292, the DOE Richland Operations Office has prepared this annual summary of the Hanford Site Composite Analysis for fiscal year (FY) 2018. The Hanford Site Composite Analysis was originally reported in PNNL-118003 and PNNL-11800, Addendum 14 (hereinafter referred to collectively as the Hanford Site Composite Analysis). The Hanford Site Composite Analysis was approved by a 2002 memorandum. As required by DOE/RL-2000-29, an annual evaluation of new information and data developed by a number of onsite programs was completed. The reporting period for this annual evaluation is FY 2018 (October 1, 2017, through September 30, 2018).

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Issues and Recommendations Arising from the Idaho National Laboratory Remote-Handled Low-Level Waste Disposal Facility Composite Analysis - 13374

Development of the composite analysis (CA) for the Idaho National Laboratory's (INLs) proposed remote-handled (RH) low-level waste (LLW) disposal facility has underscored the importance of consistency between analyses conducted for site-specific performance assessments (PAs) for LLW disposal facilities, sites regulated by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) [1], and residual decontamination and decommissioning (D and D) inventories. Consistency is difficult to achieve because: 1) different legacy sources and compliance time-periods were deemed important for each of the sites evaluated at INL (e.g., 100 years for CERCLA regulated facilities vs. 1,000 years for LLW disposal facilities regulated under U.S. Department of Energy (DOE) Order 435.1 [2]); 2) fate and transport assumptions, parameters, and models have evolved through time at the INL including the use of screening-level parameters vs. site-specific values; and 3) evaluation objectives for the various CERCLA sites were inconsistent with those relevant to either the PA or CA including the assessment of risk rather than effective dose. The proposed single site-wide CA approach would provide needed consistency, allowing ready incorporation of new information and/or facilities in addition to being cost effective in terms of preparation of CAs and review by the DOE. A single site-wide CA would include a central database of all existing INL sources, including those from currently operating LLW facilities, D and D activities, and those from the sites evaluated under CERCLA. The framework presented for the INL RH-LLW disposal facility allows for development of a single CA encompassing air and groundwater impacts. For groundwater impacts, a site-wide MODFLOW/MT3D-MS model was used to develop unit-response functions for all potential sources providing responses for a grid of receptors. Convolution and superposition of the response functions are used to compute groundwater concentrations. A similar approach could be applied for the air pathway where air emissions are stored in a central database and air concentrations for unit releases could be scaled to actual releases. (authors)

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Composite Analysis Solid Waste Release Data Reduction of Activity Flux from Waste Sites to the Vadose Zone for Baseline Assessment

This environmental calculation file (ECF) describes the data reduction methodology for the solid waste release datasets generated by the Composite Analysis Solid Waste Release (CASWR) model (CP-62766, Model Package Report: Composite Analysis Solid Waste Release Model [CASWR Model]) and documents the resulting reduced datasets for the updated Composite Analysis (CA) baseline assessment. This ECF is in support of the updated Hanford Site CA. The purpose of the updated Hanford Site CA is to provide an estimate of the cumulative radiological impacts from active and planned low-level radioactive waste disposals and other potentially interacting radioactive waste disposal sources that will remain following Hanford Site closure. The vadose zone modeling activities associated with the CA includes solid waste forms as contaminant sources. To support the modeling of solid waste transport from the vadose zone to the groundwater at the Hanford Site, the CASWR model was designed to generate deterministic radionuclide release rates for the Hanford Site Central Plateau solid waste disposal sites. The complete CASWR model-generated dataset for the CA Baseline Assessment consists of 2,378,831 sets of time and release rates (1,073,869 sets for the 200 East Area and 1,304,962 sets for the 200 West Area), representing a course of the simulation from year 1953 to year 12,069, 16 radiological contaminants of potential concern (COPCs), and 237 solid waste sources as documented in ECFHANFORD- 19-0112, Solid Waste Release Calculations for the Composite Analysis Baseline Assessment. For several of the STOMP vadose zone models, the number of release rate data pairs required for release at all waste sites would exceed the limitations imposed by the STOMP modelling software package used to simulate contaminant transport through the vadose zone. As a result, a data reduction of the CASWR dataset is required prior to its use as a source input for the CA vadose zone modeling activities.

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