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Title: Estimation of Physical Properties of AN-107 Cesium and Technetium Eluate Blend

Abstract

The objective of this study, as defined in the associated test specifications and task technical and quality assurance plan, was to estimate all the physical properties that are required to design the storage and transport facilities for the concentrated cesium and technetium eluates. Specifically, the scope of this study included: (1) modeling of the aqueous electrolyte chemistry of Tank 241-AN-107 Cs and Tc eluate evaporators, (2) process modeling of semi-batch and continuous evaporation operations, (3) determination of the operating vacuum and target endpoint of each evaporator, (4) calculation of the physical properties of the concentrated Cs and Tc eluate blend, and (5) development of the empirical correlations for the physical properties thus estimated.

Authors:
Publication Date:
Research Org.:
Savannah River Site (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
782040
Report Number(s):
WSRC-TR-2000-00527
TRN: US0103085
DOE Contract Number:
AC09-96SR18500
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 12 Jun 2001
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; RADIOACTIVE WASTE FACILITIES; CESIUM; ELECTROLYTES; EVAPORATORS; PHYSICAL PROPERTIES; QUALITY ASSURANCE; SPECIFICATIONS; STORAGE FACILITIES; TECHNETIUM; PIPELINES; MATHEMATICAL MODELS; LIQUID WASTES

Citation Formats

Choi, A.S. Estimation of Physical Properties of AN-107 Cesium and Technetium Eluate Blend. United States: N. p., 2001. Web. doi:10.2172/782040.
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Choi, A.S. Estimation of Physical Properties of AN-107 Cesium and Technetium Eluate Blend. United States. doi:10.2172/782040.
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Choi, A.S. Tue . "Estimation of Physical Properties of AN-107 Cesium and Technetium Eluate Blend". United States. doi:10.2172/782040. https://www.osti.gov/servlets/purl/782040.
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@article{osti_782040,
title = {Estimation of Physical Properties of AN-107 Cesium and Technetium Eluate Blend},
author = {Choi, A.S.},
abstractNote = {The objective of this study, as defined in the associated test specifications and task technical and quality assurance plan, was to estimate all the physical properties that are required to design the storage and transport facilities for the concentrated cesium and technetium eluates. Specifically, the scope of this study included: (1) modeling of the aqueous electrolyte chemistry of Tank 241-AN-107 Cs and Tc eluate evaporators, (2) process modeling of semi-batch and continuous evaporation operations, (3) determination of the operating vacuum and target endpoint of each evaporator, (4) calculation of the physical properties of the concentrated Cs and Tc eluate blend, and (5) development of the empirical correlations for the physical properties thus estimated.},
doi = {10.2172/782040},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jun 12 00:00:00 EDT 2001},
month = {Tue Jun 12 00:00:00 EDT 2001}
}
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Technical Report:
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DOI:  10.2172/782040
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  • Two bench-scale process simulations of the proposed cesium eluate evaporation process of concentrating eluate produced in the Hanford Site Waste Treatment Plant were conducted. The primary objective of these experiments was to determine the physical properties and the saturation concentration of the eluate evaporator bottoms while producing condensate approximately 0.50 molar HN03.

  • The baseline flowsheet for low activity waste (LAW) in the Hanford River Protection Project (RPP) Waste Treatment Plant (WTP) includes pretreatment of supernatant by removing cesium using ion exchange. When the ion exchange column is loaded, the cesium will be eluted with a 0.5M nitric acid (HNO3) solution to allow the column to be conditioned for re-use. The cesium eluate solution will then be concentrated in a vacuum evaporator to minimize storage volume and recycle HNO3. To prevent the formation of solids during storage of the evaporator bottoms, criteria have been set for limiting the concentration of the evaporator productmore » to 80 percent of saturation at 25 degrees C. A fundamental element of predicting evaporator product solubility is to collect data that can be used to estimate key operating parameters. The data must be able to predict evaporator behavior for a range of eluate concentrations that are evaporated to the point of precipitation. Parameters that were selected for modeling include solubility, density, viscosity, thermal conductivity, and heat capacity. Of central importance is identifying the effect of varying feed components on overall solubility. The point of solubility defines the upper limit for eluate evaporation operations and liquid storage. The solubility point also defines those chemical compounds that have the greatest effects on physical properties. Third, solubility behavior identifies intermediate points where physical property data should be measured for the database. Physical property data (density, viscosity, thermal conductivity, and heat capacity) may be an integral part of tracking evaporator operations as they progress toward their end point. Once the data have been collected, statistical design software can develop mathematical equations that estimate solubility and other physical properties.« less

  • The baseline flowsheet for low activity waste (LAW) in the Hanford River Protection Project (RPP) Waste Treatment Plant (WTP) includes pretreatment of supernatant by removing cesium using ion exchange. When the ion exchange column is loaded, the cesium will be eluted with a 0.5M nitric acid (HNO3) solution to allow the column to be conditioned for re-use. The cesium eluate solution will then be concentrated in a vacuum evaporator to minimize storage volume and recycle HNO3. To prevent the formation of solids during storage of the evaporator bottoms, criteria have been set for limiting the concentration of the evaporator productmore » to 80 percent of saturation at 25 degrees C. Prior work has collected fundamental data for predicting solubility and other physical property measurements. Other ongoing efforts have involved the development of a computer model to predict solubility and physical properties during evaporation. Evaporation experiments were conducted with cesium eluate simulant generated from a pilot scale experiment in the Thermal Fluids Lab (TFL) at the Savannah River Technology Center (SRTC). The data from the experiments will be used to validate the modeling data.« less

  • Major analytes expected to be present in the WTP cesium ion-exchange eluate solutions were identified from the available analytical data collected during radioactive bench-scale runs, and a test matrix of cesium eluate solutions was designed within the bounding concentration ranges of those major analytes. A computer model describing the semi-batch evaporation of cesium eluate solutions was built using the Environmental Simulation Program (ESP), licensed by OLI Systems, Inc., and was run to calculate the physical properties of each test matrix solution concentrated to the target endpoints of 80 percent and 100 percent bulk saturation. The calculated physical properties were thenmore » analyzed statistically and fitted into predetermined mathematical expressions for the bulk solubility, density, viscosity and heat capacity as a function of temperature and feed concentration of each species considered in the matrix. In addition, the volume reduction factor, which is defined as the ratio of total cumulative feed volume to that of the initial acid charge, was calculated and modeled for the 80 percent saturation case. The R2 of the resulting physical property models ranged from 0.89 to 0.99. Validation of these physical property models against the true experimental data was not part of the current work scope; instead, the results of model validation will be discussed later in another report, after all the necessary data for model validation have been collected and analyzed.« less

  • This work contained two objectives. To verify the mathematical equations developed for the physical properties of concentrated cesium eluate solutions against experimental test results obtained with simulated feeds. To estimate the physical properties of the radioactive AW-101 cesium eluate at saturation using the validated models. The Hanford River Protection Project (RPP) Hanford Waste Treatment and Immobilization Plant (WTP) is currently being built to extract radioisotopes from the vast inventory of Hanford tank wastes and immobilize them in a silicate glass matrix for eventual disposal at a geological repository. The baseline flowsheet for the pretreatment of supernatant liquid wastes includes removalmore » of cesium using regenerative ion-exchange resins. The loaded cesium ion-exchange columns will be eluted with nitric acid nominally at 0.5 molar, and the resulting eluate solution will be concentrated in a forced-convection evaporator to reduce the storage volume and to recover the acid for reuse. The reboiler pot is initially charged with a concentrated nitric acid solution and kept under a controlled vacuum during feeding so the pot contents would boil at 50 degrees Celsius. The liquid level in the pot is maintained constant by controlling both the feed and boilup rates. The feeding will continue with no bottom removal until the solution in the pot reaches the target endpoint of 80 per cent saturation with respect to any one of the major salt species present.« less