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DOE OSTI2017

COBRA-SFS thermal-hydraulic analysis code for spent fuel storage and transportation casks: Models and methods

COBRA-SFS, a thermal-hydraulics code developed for steady-state and transient analysis of multi-assembly spent-fuel storage and transportation systems, has been incorporated into the Used Nuclear Fuel-Storage, Transportation and Disposal Analysis Resource and Data System tool as a module devoted to spent fuel package thermal analysis. This paper summarizes the basic formulation of the equations and models used in the COBRA-SFS code, showing that COBRA-SFS fully captures the important physical behavior governing the thermal performance of spent fuel storage systems, with internal and external natural convection flow patterns, and heat transfer by convection, conduction, and thermal radiation. Of particular significance is the capability for detailed thermal radiation modeling within the fuel rod array.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2015

Methods for Quantifying the Uncertainties of LSIT Test Parameters, Test Results, and Full-Scale Mixing Performance Using Models Developed from Scaled Test Data

This report discusses the statistical methods for quantifying uncertainties in 1) test responses and other parameters in the Large Scale Integrated Testing (LSIT), and 2) estimates of coefficients and predictions of mixing performance from models that relate test responses to test parameters. Testing at a larger scale has been committed to by Bechtel National, Inc. and the U.S. Department of Energy (DOE) to “address uncertainties and increase confidence in the projected, full-scale mixing performance and operations” in the Waste Treatment and Immobilization Plant (WTP).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2013

Preliminary Scaling Estimate for Select Small Scale Mixing Demonstration Tests

The Hanford Site double-shell tank (DST) system provides the staging location for waste that will be transferred to the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Specific WTP acceptance criteria for waste feed delivery describe the physical and chemical characteristics of the waste that must be met before the waste is transferred from the DSTs to the WTP. One of the more challenging requirements relates to the sampling and characterization of the undissolved solids (UDS) in a waste feed DST because the waste contains solid particles that settle and their concentration and relative proportion can change during the transfer of the waste in individual batches. A key uncertainty in the waste feed delivery system is the potential variation in UDS transferred in individual batches in comparison to an initial sample used for evaluating the acceptance criteria. To address this uncertainty, a number of small-scale mixing tests have been conducted as part of Washington River Protection Solutions’ Small Scale Mixing Demonstration (SSMD) project to determine the performance of the DST mixing and sampling systems.

Double-shell Tank↗

DOE OSTI2013

Scaling Theory for Pulsed Jet Mixed Vessels, Sparging, and Cyclic Feed Transport Systems for Slurries

This document is a previously unpublished work based on a draft report prepared by Pacific Northwest National Laboratory (PNNL) for the Hanford Waste Treatment and Immobilization Plant (WTP) in 2012. Work on the report stopped when WTP’s approach to testing changed. PNNL is issuing a modified version of the document a year later to preserve and disseminate the valuable technical work that was completed. This document establishes technical bases for evaluating the mixing performance of Waste Treatment Plant (WTP) pretreatment process tanks based on data from less-than-full-scale testing, relative to specified mixing requirements. The technical bases include the fluid mechanics affecting mixing for specified vessel configurations, operating parameters, and simulant properties. They address scaling vessel physical performance, simulant physical performance, and “scaling down” the operating conditions at full scale to define test conditions at reduced scale and “scaling up” the test results at reduced scale to predict the performance at full scale. Essentially, this document addresses the following questions: • Why and how can the mixing behaviors in a smaller vessel represent those in a larger vessel? • What information is needed to address the first question? • How should the information be used to predict mixing performance in WTP? The design of Large Scale Integrated Testing (LSIT) is being addressed in other, complementary documents.

non-Newtonian↗

DOE OSTI2013

The Continued Need for Modeling and Scaled Testing to Advance the Hanford Tank Waste Mission

Hanford tank wastes are chemically complex slurries of liquids and solids that can exhibit changes in rheological behavior during retrieval and processing. The Hanford Waste Treatment and Immobilization Plant (WTP) recently abandoned its planned approach to use computational fluid dynamics (CFD) supported by testing at less than full scale to verify the design of vessels that process these wastes within the plant. The commercial CFD tool selected was deemed too difficult to validate to the degree necessary for use in the design of a nuclear facility. Alternative, but somewhat immature, CFD tools are available that can simulate multiphase flow of non-Newtonian fluids. Yet both CFD and scaled testing can play an important role in advancing the Hanford tank waste mission—in supporting the new verification approach, which is to conduct testing in actual plant vessels; in supporting waste feed delivery, where scaled testing is ongoing; as a fallback approach to design verification if the Full Scale Vessel Testing Program is deemed too costly and time-consuming; to troubleshoot problems during commissioning and operation of the plant; and to evaluate the effects of any proposed changes in operating conditions in the future to optimize plant performance.

Fluid Dynamics↗

DOE OSTI2013

Physical Attributes of Pulse Jet Mixer Operation

Vessels mixed using pulse jet mixers that produce a periodic, rather than steady, flow present challenges with respect to modeling slurry mixing. A PJM is a cylindrical tank within the mixed tank that has a conical bottom with an orifice through which process fluid cyclically enters and is expelled forcefully by pressurizing the air space above the liquid in the PJM. Between pulses, some of the solids settle from the slurry, which nominally is a failure in mixing, but during the pulses (if operated to attain bottom clearing conditions), all of the solids are resuspended and made available for processing or transfer. Overall, mixing is successful if the solids are processed and removed from the vessel as needed when averaged over repeated PJM cycles. This paper describes the physics of pulse jet mixing process based on physical observation during experiments and analysis of experimental concentration profile data obtained during the mixing cycle.

Newtonian↗

DOE OSTI2012

Comparison of Waste Feed Delivery Small Scale Mixing Demonstration Simulant to Hanford Waste

The Hanford double-shell tank (DST) system provides the staging location for waste that will be transferred to the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Specific WTP acceptance criteria for waste feed delivery describe the physical and chemical characteristics of the waste that must be met before the waste is transferred from the DSTs to the WTP. One of the more challenging requirements relates to the sampling and characterization of the undissolved solids (UDS) in a waste feed DST because the waste contains solid particles that settle and their concentration and relative proportion can change during the transfer of the waste in individual batches. A key uncertainty in the waste feed delivery system is the potential variation in UDS transferred in individual batches in comparison to an initial sample used for evaluating the acceptance criteria. To address this uncertainty, a number of small-scale mixing tests have been conducted as part of Washington River Protection Solutions' Small Scale Mixing Demonstration (SSMD) project to determine the performance of the DST mixing and sampling systems. A series of these tests have used a five-part simulant composed of particles of different size and density and designed to be equal or more challenging than AY-102 waste. This five-part simulant, however, has not been compared with the broad range of Hanford waste, and thus there is an additional uncertainty that this simulant may not be as challenging as the most difficult Hanford waste. The purpose of this study is to quantify how the current five-part simulant compares to all of the Hanford sludge waste, and to suggest alternate simulants that could be tested to reduce the uncertainty in applying the current testing results to potentially more challenging wastes.

Hanford Waste↗

DOE OSTI2011

Comparison of Waste Feed Delivery Small Scale Mixing Demonstration Simulant to Hanford Waste

The Hanford double-shell tank (DST) system provides the staging location for waste feed delivery to the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Hall (2008) includes WTP acceptance criteria that describe physical and chemical characteristics of the waste that must be certified as acceptable before the waste is transferred from the DSTs to the WTP. One of the more challenging requirements relates to the sampling and characterization of the undissolved solids (UDS) in a waste feed DST. The objectives of Washington River Protection Solutions' (WRPS) Small Scale Mixing Demonstration (SSMD) project are to understand and demonstrate the DST sampling and batch transfer performance at multiple scales using slurry simulants comprised of UDS particles and liquid (Townson 2009). The SSMD project utilizes geometrically scaled DST feed tanks to generate mixing, sampling, and transfer test data. In Phase 2 of the testing, RPP-49740, the 5-part simulant defined in RPP-48358 was used as the waste slurry simulant. The Phase 2 test data are being used to estimate the expected performance of the prototypic systems in the full-scale DSTs. As such, understanding of the how the small-scale systems as well as the simulant relate to the full-scale DSTs and actual waste is required. The focus of this report is comparison of the size and density of the 5-part SSMD simulant to that of the Hanford waste. This is accomplished by computing metrics for particle mobilization, suspension, settling, transfer line intake, and pipeline transfer from the characterization of the 5-part SSMD simulant and characterizations of the Hanford waste. In addition, the effects of the suspending fluid characteristics on the test results are considered, and a computational fluid dynamics tool useful to quantify uncertainties from simulant selections is discussed.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2011

Comparison of Waste Feed Delivery Small Scale Mixing Demonstration Simulant to Hanford Waste (Rev.1)

The Hanford double-shell tank (DST) system provides the staging location for waste that will be transferred to the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Specific WTP acceptance criteria for waste feed delivery describe the physical and chemical characteristics of the waste that must be met before the waste is transferred from the DSTs to the WTP. One of the more challenging requirements relates to the sampling and characterization of the undissolved solids (UDS) in a waste feed DST because the waste contains solid particles that settle and their concentration and relative proportion can change during the transfer of the waste in individual batches. A key uncertainty in the waste feed delivery system is the potential variation in UDS transferred in individual batches in comparison to an initial sample used for evaluating the acceptance criteria. To address this uncertainty, a number of small-scale mixing tests have been conducted as part of Washington River Protection Solutions' Small Scale Mixing Demonstration (SSMD) project to determine the performance of the DST mixing and sampling systems. A series of these tests have used a five-part simulant composed of particles of different size and density and designed to be equal or more challenging than AY-102 waste. This five-part simulant, however, has not been compared with the broad range of Hanford waste, and thus there is an additional uncertainty that this simulant may not be as challenging as the most difficult Hanford waste. The purpose of this study is to quantify how the current five-part simulant compares to all of the Hanford sludge waste, and to suggest alternate simulants that could be tested to reduce the uncertainty in applying the current testing results to potentially more challenging wastes.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2011

EMSL Pore Scale Modeling Challenge/Workshop

The design and implementation of cost-effective remediation strategies for subsurface contamination not only relies on descriptive models of contaminant distribution but predictive models of contaminant fate and transport. The development of such predictive models is of great importance to many government agencies including the Department of Energy (DOE), Department of Defense, and the Environmental Protection Agency. Accurate prediction of the fate and transport of environmental contaminants in the subsurface has driven development of increasingly sophisticated subsurface flow and transport models. Even without considering spatial and temporal scalability, contaminant transport at the field scale is complex, and this almost inevitably results in an especially sophisticated model being developed for a specific field site. Unfortunately, these models are not easily generalizable to other field sites or and can only be used by the model authors to generate meaningful results. Over time, this results in the existence of numerous specialized models that are not readily comparable to each other and difficult to cross-validate. There is a lack of fundamental experimental observations at the pore scale that can be used to support model development and validation at the field scale.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗