Renee L. Russell

Development and Demonstration of Ultrafiltration Simulants

According to Bechtel National, Inc. (BNI) Test Specification 24590-PTF-TSP-RT-06-006, Rev 0, Simulant Development to Support the Development and Demonstration of Leaching and Ultrafiltration Pretreatment Processes,” simulants for boehmite, gibbsite, and filtration are to be developed that can be used in subsequent bench and integrated testing of the leaching/filtration processes for the waste treatment plant (WTP). These simulants will then be used to demonstrate the leaching process and to help refine processing conditions which may impact safety basis considerations (Smith 2006). This report documents the results of the filtration simulant development.

Database and Interim Glass Property Models for Hanford HLW Glasses

The purpose of this report is to provide a methodology for an increase in the efficiency and a decrease in the cost of vitrifying high-level waste (HLW) by optimizing HLW glass formulation. This methodology consists in collecting and generating a database of glass properties that determine HLW glass processability and acceptability and relating these properties to glass composition. The report explains how the property-composition models are developed, fitted to data, used for glass formulation optimization, and continuously updated in response to changes in HLW composition estimates and changes in glass processing technology. Further, the report reviews the glass property-composition literature data and presents their preliminary critical evaluation and screening. Finally the report provides interim property-composition models for melt viscosity, for liquidus temperature (with spinel and zircon primary crystalline phases), and for the product consistency test normalized releases of B, Na, and Li. Models were fitted to a subset of the screened database deemed most relevant for the current HLW composition region.

Development and Characterization of Boehmite Component Simulant

According to Bechtel National Inc.’s (BNI’s) Test Specification 24590-PTF-TSP-RT-06-006, Rev 0, “Simulant Development to Support the Development and Demonstration of Leaching and Ultrafiltration Pretreatment Processes,” simulants for boehmite, gibbsite, and filtration are to be developed that can be used in subsequent bench and integrated testing of the leaching/filtration processes. These simulants will then be used to demonstrate the leaching process and to help refine processing conditions that may impact safety basis considerations (Smith 2006). This report documents the results of the boehmite simulant development.

Sulfur Partitioning During Vitrification of INEEL Sodium Bearing Waste: Status Report

The sodium bearing tank waste (SBW) at Idaho National Engineering and Environmental Laboratory (INEEL) contains high concentrations of sulfur (roughly 5 mass% of SO3 on a nonvolatile oxide basis). The amount of sulfur that can be feed to the melter will ultimately determine the loading of SBW in glass produced by the baseline (low-temperature, joule-heated, liquid-fed, ceramic-lined) melter. The amount of sulfur which can be fed to the melter is determined by several major factors including: the tolerance of the melter for an immiscible salt layer accumulation, the solubility of sulfur in the glass melt, the fraction of sulfur removed to the off-gas, and the incorporation of sulfur into the glass up to it?s solubility limit. This report summarizes the current status of testing aimed at determining the impacts of key chemical and physical parameters on the partitioning of sulfur between the glass, a molten salt, and the off-gas.

Shear Strength Correlations for Kaolin/Water Slurries: A Comparison of Recent Measurements with Historical Data

This report documents testing funded by CH2M Hill Plateau Remediation and performed by Pacific Northwest National Laboratory (PNNL) in collaboration with Fauske and Associates, LLC (FAI) to determine the behavior of vessel spanning bubbles. The shear strengths of four samples of kaolin/water mixtures obtained by PNNL from FAI were measured and are reported here. The measured shear strengths of these samples were then used to determine how the Rassat correlation fit these new measurements or if a new correlation was needed. These results were then compared with previously reported data.

The Disruption of Vessel-Spanning Bubbles with Sloped Fins in Flat-Bottom and 2:1 Elliptical-Bottom Vessels

Radioactive sludge was generated in the K-East Basin and K-West Basin fuel storage pools at the Hanford Site while irradiated uranium metal fuel elements from the N Reactor were being stored and packaged. The fuel has been removed from the K Basins, and currently, the sludge resides in the KW Basin in large underwater Engineered Containers. The first phase to the Sludge Treatment Project being led by CH2MHILL Plateau Remediation Company (CHPRC) is to retrieve and load the sludge into sludge transport and storage containers (STSCs) and transport the sludge to T Plant for interim storage. The STSCs will be stored inside T Plant cells that are equipped with secondary containment and leak-detection systems. The sludge is composed of a variety of particulate materials and water, including a fraction of reactive uranium metal particles that are a source of hydrogen gas. If a situation occurs where the reactive uranium metal particles settle out at the bottom of a container, previous studies have shown that a vessel-spanning gas layer above the uranium metal particles can develop and can push the overlying layer of sludge upward. The major concern, in addition to the general concern associated with the retention and release of a flammable gas such as hydrogen, is that if a vessel-spanning bubble (VSB) forms in an STSC, it may drive the overlying sludge material to the vents at the top of the container. Then it may be released from the container into the cell’s secondary containment system at T Plant. A previous study demonstrated that sloped walls on vessels, both cylindrical coned-shaped vessels and rectangular vessels with rounded ends, provided an effective approach for disrupting a VSB by creating a release path for gas as a VSB began to rise. Based on the success of sloped-wall vessels, a similar concept is investigated here where a sloped fin is placed inside the vessel to create a release path for gas. A key potential advantage of using a sloped fin compared to a vessel with a sloped wall is that a small fin decreases the volume of a vessel available for sludge storage by a very small fraction compared to a cone-shaped vessel. The purpose of this study is to quantify the capability of sloped fins to disrupt VSBs and to conduct sufficient tests to estimate the performance of fins in full-scale STSCs. Experiments were conducted with a range of fin shapes to determine what slope and width were sufficient to disrupt VSBs. Additional tests were conducted to demonstrate how the fin performance scales with the sludge layer thickness and the sludge strength, density, and vessel diameter based on the gravity yield parameter, which is a dimensionless ratio of the force necessary to yield the sludge to its weight.( ) Further experiments evaluated the difference between vessels with flat and 2:1 elliptical bottoms and a number of different simulants, including the KW container sludge simulant (complete), which was developed to match actual K-Basin sludge. Testing was conducted in 5-in., 10-in., and 23-in.-diameter vessels to quantify how fin performance is impacted by the size of the test vessel. The most significant results for these scale-up tests are the trend in how behavior changes with vessel size and the results from the 23-in. vessel. The key objective in evaluating fin performance is to determine the conditions that minimize the volume of a VSB when disruption occurs because this reduces the potential for material inside the STSC from being released through vents.

Methods to avoid post-filtration precipitation in treatment of high-level waste

The Hanford Tank Waste Treatment and Immobilization Plant, currently under construction for treating high level waste at the Hanford Site, will rely on ultrafiltration to provide solids/liquid separation as a core part of the treatment process. A series of bench-scale simulant tests have been performed to evaluate the potential for post-filtration precipitation. These tests focused on identifying precipitation from a range of potential feed compositions and providing the data required to evaluate mitigation options. This data is also important to the Savannah River Site as they are also attempting to dissolve saltcake from their tanks. Inadvertent solids formation after saltcake dissolution, either within a staging tank or in transfer piping can have serious repercussions on the eventual retrieval and transfer of the waste. A series of tests were performed using a variety of simulant samples. These tests identified the expected extent of supersaturation that develops under normal operations and identified and characterized the solids phases that are expected to form when the filtrate solutions are stored. In addition, tests identified the potential to mitigate the formation of these solids through both dilution and the application of increased temperature.

Hanford Sludge Simulant Selection for Soil Mechanics Property Measurement

The current System Plan for the Hanford Tank Farms uses relaxed buoyant displacement gas release event (BDGRE) controls for deep sludge (i.e., high level waste [HLW]) tanks, which allows the tank farms to use more storage space, i.e., increase the sediment depth, in some of the double-shell tanks (DSTs). The relaxed BDGRE controls are based on preliminary analysis of a gas release model from van Kessel and van Kesteren. Application of the van Kessel and van Kesteren model requires parametric information for the sediment, including the lateral earth pressure at rest and shear modulus. No lateral earth pressure at rest and shear modulus in situ measurements for Hanford sludge are currently available. The two chemical sludge simulants will be used in follow-on work to experimentally measure the van Kessel and van Kesteren model parameters, lateral earth pressure at rest, and shear modulus.

Filtration Understanding: FY10 Testing Results and Filtration Model Update

This document completes the requirements of Milestone 2-4, Final Report of FY10 Testing, discussed in the scope of work outlined in the EM31 task plan WP-2.3.6-2010-1. The focus of task WP 2.3.6 is to improve the U.S. Department of Energy’s (DOE’s) understanding of filtration operations for high-level waste (HLW) to improve filtration and cleaning efficiencies, thereby increasing process throughput and reducing the Na demand (through acid neutralization). Developing the cleaning/backpulsing requirements will produce much more efficient operations for both the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and the Savannah River Site (SRS), thereby significantly increasing throughput by limiting cleaning cycles. The scope of this work is to develop the understanding of filter fouling to allow developing this cleaning/backpulsing strategy.

Ion Exchange Kinetics Testing with SRF Resin

The U.S. Department of Energy (DOE) Hanford Site contains more than 53 million gallons of legacy waste generated as a byproduct of plutonium production and reprocessing operations. The wastes are a complex mixture composed mostly of NaNO3, NaNO2, NaOH, NaAlO2, Na3PO4, and Na2SO4, with a number of minor and trace metals, organics, and radionuclides stored in underground waste tanks. The DOE Office of River Protection (ORP) has contracted Bechtel National Incorporated (BNI) to build a pretreatment facility, the River Protection Project-Waste Treatment Plant (RPP-WTP), that will separate long-lived transuranics (TRU) and highly radioactive components (specifically 137Cs and, in selected cases, 90Sr) from the bulk (non-radioactive) constituents and immobilize the wastes by vitrification. The plant is designed to produce two waste streams: a high-volume low-activity waste (LAW) and a low-volume high-activity waste (HLW).