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Small Column Ion Exchange Analysis For Removal Of Cesium From Srs Low Curie Salt Solutions Using Crystalline Silicotitanate Cst Resin
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Book Synopsis Small Column Ion Exchange Analysis for Removal of Cesium from SRS Low Curie Salt Solutions Using Crystalline Silicotitanate (CST) Resin by :
Download or read book Small Column Ion Exchange Analysis for Removal of Cesium from SRS Low Curie Salt Solutions Using Crystalline Silicotitanate (CST) Resin written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Savannah River Technology Center (SRTC) researchers modeled ion exchange removal of cesium from dissolved salt waste solutions. The results assist in evaluating proposed configurations for an ion exchange process to remove residual cesium from low curie waste streams. A process for polishing (i.e., removing small amounts) of cesium may prove useful should supernate draining fail to meet the Low Curie Salt (LCS) target limit of 0.1 Ci of Cs-137 per gallon of salt solution. Cesium loading isotherms and column breakthrough curves for Low Curie dissolved salt solutions were computed to provide performance predictions for various column designs.
Book Synopsis Small-Column Ion-Exchange Alternative to Remove 137Cs from Low-Curie Salt Waste by : Walker, JR. (J. F.)
Download or read book Small-Column Ion-Exchange Alternative to Remove 137Cs from Low-Curie Salt Waste written by Walker, JR. (J. F.) and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A Small-Column Ion-Exchange (SCIX) system is being evaluated for removing cesium from the Type 2 and/or Type 3 dissolved saltcake wastes at the Savannah River Site (SRS) to ensure that the dissolved saltcake meets the waste acceptance criteria at the Saltstone Facility. Both crystalline silicotitanate (CST) and IONSIV{trademark} IE-96 zeolite were evaluated as the ion-exchange media. The accelerated alternative, using CST in the SCIX, could save as much as $3 billion in operating and storage costs and {approx}20 years in processing time compared to the current baseline. With its proven high cesium-loading capacity for the expected dissolved saltcake compositions and temperatures, CST is the preferred sorbent for SCIX. The low-cost alternative sorbent, zeolite, greatly increases the volume of sorbent required because of its much lower cesium-loading capacity. Thus, zeolite greatly increases the cost for the alternative, mainly because of the increased number of Defense Waste Processing Facility canisters required to dispose of the loaded sorbent (potentially over 7000 for zeolite, compared with
Book Synopsis Modeling of Crystalline Silicotitanate Ion Exchange Columns by :
Download or read book Modeling of Crystalline Silicotitanate Ion Exchange Columns written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-elutable ion exchange is being considered as a potential replacement for the In-Tank Precipitation process for removing cesium from Savannah River Site (SRS) radioactive waste. Crystalline silicotitanate (CST) particles are the reference ion exchange medium for the process. A major factor in the construction cost of this process is the size of the ion exchange column required to meet product specifications for decontaminated waste. To validate SRS column sizing calculations, SRS subcontracted two reknowned experts in this field to perform similar calculations: Professor R.G. Anthony, Department of Chemical Engineering, Texas A & 038;M University, and Professor S.W. Wang, Department of Chemical Engineering, Purdue University. The appendices of this document contain reports from the two subcontractors. Definition of the design problem came through several meetings and conference calls between the participants and SRS personnel over the past few months. This document summarizes the problem definition and results from the two reports.
Book Synopsis Small Column Ion Exchange Design and Safety Strategy by :
Download or read book Small Column Ion Exchange Design and Safety Strategy written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Small Column Ion Exchange (SCIX) is a transformational technology originally developed by the Department of Energy (DOE) Environmental Management (EM-30) office and is now being deployed at the Savannah River Site (SRS) to significantly increase overall salt processing capacity and accelerate the Liquid Waste System life-cycle. The process combines strontium and actinide removal using Monosodium Titanate (MST), Rotary Microfiltration, and cesium removal using Crystalline Silicotitanate (CST, specifically UOP IONSIV{reg_sign}IE-911 ion exchanger) to create a low level waste stream to be disposed in grout and a high level waste stream to be vitrified. The process also includes preparation of the streams for disposal, e.g., grinding of the loaded CST material. These waste processing components are technically mature and flowsheet integration studies are being performed including glass formulations studies, application specific thermal modeling, and mixing studies. The deployment program includes design and fabrication of the Rotary Microfilter (RMF) assembly, ion-exchange columns (IXCs), and grinder module, utilizing an integrated system safety design approach. The design concept is to install the process inside an existing waste tank, Tank 41H. The process consists of a feed pump with a set of four RMFs, two IXCs, a media grinder, three Submersible Mixer Pumps (SMPs), and all supporting infrastructure including media receipt and preparation facilities. The design addresses MST mixing to achieve the required strontium and actinide removal and to prevent future retrieval problems. CST achieves very high cesium loadings (up to 1,100 curies per gallon (Ci/gal) bed volume). The design addresses the hazards associated with this material including heat management (in column and in-tank), as detailed in the thermal modeling. The CST must be size reduced for compatibility with downstream processes. The design addresses material transport into and out of the grinder and includes provisions for equipment maintenance including remote handling. The design includes a robust set of nuclear safety controls compliant with DOE Standard (STD)-1189, Integration of Safety into the Design Process. The controls cover explosions, spills, boiling, aerosolization, and criticality. Natural Phenomena Hazards (NPH) including seismic event, tornado/high wind, and wildland fire are considered. In addition, the SCIX process equipment was evaluated for impact to existing facility safety equipment including the waste tank itself. SCIX is an innovative program which leverages DOE's technology development capabilities to provide a basis for a successful field deployment.
Book Synopsis Thermal and Chemical Stability of Baseline and Improved Crystalline Silicotitanate by :
Download or read book Thermal and Chemical Stability of Baseline and Improved Crystalline Silicotitanate written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Savannah River Site (SRS) has been evaluating technologies for removing radioactive cesium (137Cs) from the supernate solutions stored in the high-level waste tanks at the site. Crystalline silicotitanate (CST) sorbent (IONSIV IE-911{reg_sign}, UOP LLC, Des Plaines, IL), which is very effective at removing cesium from high-salt solutions, was one of three technologies that were tested. Because of the extremely high inventory of 137Cs expected for the large columns of CST that would be used for treating the SRS supernate, any loss of flow or cooling to the columns could result in high temperatures from radiolytic heating. Also, even under normal operating conditions, the CST would be exposed to the supernates for up to a year before being removed. Small-scale batch and column tests conducted last year using samples of production batches of CST showed potential problems with CST clumping and loss of cesium capacity after extended contact with the simulant solutions. Similar tests-using samples of a baseline and improved granular CST and the CST powder used to make both granular samples-were performed this year to compare the performance of the improved CST. The column tests, which used recirculating supernate simulant, showed that the baseline CST generated more precipitates of sodium aluminosilicate than the improved CST. The precipitates were particularly evident in the tubing that carried the simulant solution to and from the column, but the baseline CST also showed higher concentrations of aluminum on the CST than were observed for the improved CST. Recirculating the simulant through just a section of the tubing (no contact with CST) also produced small amounts of precipitate, similar to the amounts seen for the improved CST column. The sodium aluminosilicate formed bridges between the CST granules, causing clumps of CST to form in the column. Clumps were visible in the baseline CST column after 1 month of operation and in the improved CST column after 2 months, For the baseline CST column, the clumps were routinely dispersed by backwashing the column with simulant. After 96 days of operation, a thin hard layer of CST formed on the bottom screen of the baseline column that restricted flow through the column. The bottom cap was removed and the CST was scraped from the screen to restore the column to normal operation. After 3 months of operation, the improved CST column was completely clumped together and could not be dispersed by backwashing. The pressure drop through the column was still relatively low, so the test was continued until the pressure drop increased to>15 psig after 105 days of operation. The column was then disassembled, and the CST was physically removed from the column and broken up. These results show that both the baseline and improved CST, when contacted with the supernate simulant, have the potential for forming clumps that can restrict the flow through the small columns used in these tests. The cesium capacity of the CST samples from the column tests with recirculating simulant decreased slightly as the run time increased. Most of this decrease could be attributed to the weight of cancrinite (a sodium aluminosilicate) on the CST samples. Tests conducted last year using production batch samples of CST showed a more pronounced drop in cesium capacity under comparable conditions. A column test using the improved CST and once-through simulant showed few problems during 5 months of operation. The pressure drop through the column remained low; however, when the final samples were taken after 5 months of operations, the CST in the column had clumped together. The final sample taken from the top 1 cm of the column showed a 65% drop in cesium capacity compared with all the other samples from this column. This sample also contained the highest concentration of cancrinite, but the weight of cancrinite could account for only a small fraction of the drop in cesium capacity by simple dilution of the CST. The CST in the batch tests stored at elevated temperatures in average simulant formed clumps, but this occurred at a slower rate than that observed last year during comparable tests using production batch samples of CST. Storage at elevated temperatures caused a gradual decrease in cesium capacity as the storage time increased, with a loss in capacity of up to 20% after 5 to 6 months at 80 C. The results for the baseline and improved CST samples were essentially the same for these batch tests.
Book Synopsis Preliminary Ion Exchange Modeling for Removal of Cesium from Hanford Waste Using Hydrous Crystalline Silicotitanate Material by :
Download or read book Preliminary Ion Exchange Modeling for Removal of Cesium from Hanford Waste Using Hydrous Crystalline Silicotitanate Material written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the current pretreatment facility design of the River Protection Project (RPP) Waste Treatment Plant (WTP), the removal of cesium from low activity waste (LAW) is achieved by ion-exchange technology based on SuperLig(R) 644 resin. Due to recent concerns over potential radiological and chemical degradation of SuperLig(R) 644 resin and increased pressure drops observed during pilot-scale column studies, an increased interest in developing a potential backup ion-exchanger material has resulted. Ideally, a backup ion-exchanger material would replace the SuperLig(R) 644 resin and have no other major impacts on the pretreatment facility flowsheet. Such an ideal exchanger has not been identified to date. However, Crystalline Silicotitanate (CST) ion-exchanger materials have been studied for the removal of cesium from a variety of DOE wastes over the last decade. CST ion-exchanger materials demonstrate a high affinity for cesium under high alkalinity conditions and have been under investigation for cesium removal specifically at Hanford and SRS during the last six years. Since CST is an inorganic based material (with excellent properties in regard to chemical, radiological, and thermal stability) that is considered to be practically non-elutable (while SuperLig(R) 644 is an organic based elutable resin), the overall pretreatment facility flowsheet would be impacted in various ways. However, the CST material is still being considered as a potential backup ion-exchanger material. The performance of a proposed backup ion-exchange column using IONSIV IE-911 (CST in its engineered-form) material for the removal of cesium from Hanford high level radioactive alkaline waste is discussed. This report focuses attention on the ion-exchange aspects and addresses the loading phase of the process cycle.
Book Synopsis Design of a Carousel Process for Removing Cesium from SRS Waste Using Crystalline Silicotitanate Ion Exchanger by :
Download or read book Design of a Carousel Process for Removing Cesium from SRS Waste Using Crystalline Silicotitanate Ion Exchanger written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Designs of a three-column carousel process based on crystalline silicotitanate (CST) ion exchanger have been developed for removing radioactive 137Cs+ from Savannah River Site's (SRS) nuclear wastes. A multicomponent ion exchange equilibrium model (Zheng et al., 1997) from Texas A & M University, which is based on batch data obtained from CST powder, is used to generate cesium loading data at different cesium concentrations for various types of SRS wastes. These loading data are fit to the Langmuir equation to obtain effective single-component cesium isotherm parameters. The predictions are in reasonable agreement with batch test data obtained from CST powder, an early CST pellet batch (38B), and a later batch (IE911) using two SRS waste simulants. The ratios between experimental cesium distribution coefficients and predicted values are between 0.56 and 1.0. The variation appears to be due to inadequate equilibration time in some of the batches. Mass transfer parameters are estimated by analyzing column data of a simulated SRS waste and Melton Valley Storage Tank W29 (MVST-W29) waste. The intraparticle diffusivity estimated for the two wastes can be well correlated by means of the Stokes-Einstein equation. Simulations are performed to determine the length of the mass transfer zone for given feed compositions, Cs+ concentrations, and linear velocities. In order to ensure high column utilization during both the transient and cyclic steady state periods, the length of a single segment in the carousel process is chosen to be the mass transfer zone length after the concentration wave achieves a constant pattern. Analysis of the dimensionless groups in the differential mass balance equations reveals that the normalized mass transfer zone length is linearly proportional to the particle Peclet number. The proportionality constant is a function of the waste composition and the Cs+ concentration in the waste. The higher the effective Cs+ capacity and the higher the Cs+ concentration, the smaller the proportionality constant. This dimensionless group analysis allows one to easily adjust designs for variations in particle size, linear velocity, and intraparticle diffusivity.
Book Synopsis MODELING OF ION-EXCHANGE FOR CESIUM REMOVAL FROM DISSOLVED SALTCAKE IN SRS TANKS 1-3, 37 AND 41 by :
Download or read book MODELING OF ION-EXCHANGE FOR CESIUM REMOVAL FROM DISSOLVED SALTCAKE IN SRS TANKS 1-3, 37 AND 41 written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents an evaluation of the expected performance of engineered Crystalline Silicotitanate (CST) and spherical Resorcinol-Formaldehyde (RF) ion exchange resin for the removal of cesium from dissolved saltcake in SRS Tanks 1-3, 37 and 41. The application presented in this report reflects the expected behavior of engineered CST IE-911 and spherical RF resin manufactured at the intermediate-scale (approximately 100 gallon batch size; batch 5E-370/641). It is generally believed that scale-up to production-scale in RF resin manufacturing will result in similarly behaving resin batches whose chemical selectivity is unaffected while total capacity per gram of resin may vary. As such, the predictions provided within this report should provide reasonable estimates of production-scale column performance. Two versions of the RF cesium isotherm were used. The older version provides a conservative estimate of the resin capacity while the newer version more accurately fits the most recent experimental data.
Book Synopsis Small-Scale Ion Exchange Removal of Cesium and Technetium from Hanford Tank 241-AN-103 by :
Download or read book Small-Scale Ion Exchange Removal of Cesium and Technetium from Hanford Tank 241-AN-103 written by and published by . This book was released on 2000 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The pretreatment process for BNFL, Inc.'s Hanford River Protection Project is to provide decontaminated low activity waste and concentrated eluate streams for vitrification into low activity and high level waste glass, respectively. The pretreatment includes sludge washing, filtration, precipitation, and ion exchange processes to remove entrained solids, cesium, transuranics, technetium, and strontium. The ion exchange removal of cesium (Cs) and technetium (Tc) ions is accomplished by using SuperLig 644, and 639 resins from IBC Advanced Technologies, American Fork, Utah. The resins were shown to selectively remove cesium and technetium (as pertechnetate), from alkaline salt solutions. The efficiency of ion exchange column loading and elution is a complex function involving feed compositions, equilibrium and kinetic behavior of ion exchange resins, diffusion, and the ionic strength and pH of the aqueous solution. A previous experimental program completed at the Savannah River Technology Center demonstrated the conceptualized flow sheet parameters with a similar Hanford tank sample (241-AW-101). Those experiments included determination of Cs and Tc batch distribution coefficients by SuperLig 644 and 639 resins and demonstration of small-scale column breakthrough and elution. The experimental findings were used in support of preliminary design bases and pretreatment flow sheet development by BNFL, Inc.
Book Synopsis Cesium Removal Using Crystalline Silicotitanate. Innovative Technology Summary Report by :
Download or read book Cesium Removal Using Crystalline Silicotitanate. Innovative Technology Summary Report written by and published by . This book was released on 1999 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: Approximately 100 million gallons of radioactive waste is stored in underground storage tanks at the Hanford Site, Idaho National Engineering and Environmental Laboratory (INEEL), Oak Ridge Reservation, and Savannah River Site (SRS). Most of the radioactivity comes from 137Cs, which emits high-activity gamma radiation. The Cesium Removal System is a modular, transportable, ion-exchange system configured as a compact processing unit. Liquid tank waste flows through columns packed with solid material, called a sorbent, that selectively adsorbs cesium and allows the other materials to pass through. The sorbent is crystalline silicotitanate (CST), an engineered material with a high capacity for sorbing cesium from alkaline wastes. The Cesium Removal System was demonstrated at Oak Ridge using Melton Valley Storage Tank (MVST) waste for feed. Demonstration operations began in September 1996 and were completed during June 1997. Prior to the demonstration, a number of ion-exchange materials were evaluated at Oak Ridge with MVST waste. Also, three ion-exchange materials and three waste types were tested at Hanford. These bench-scale tests were conducted in a hot cell. Hanford's results showed that 300 times less sorbent was used by selecting Ionsiv IE-911 over organic ion-exchange resins for cesium removal. This paper gives a description of the technology and discusses its performance, applications, cost, regulatory and policy issues and lessons learned.
Book Synopsis Thermal and Chemical Stability of Crystalline Silicotitanate Sorbent by :
Download or read book Thermal and Chemical Stability of Crystalline Silicotitanate Sorbent written by and published by . This book was released on 2000 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Savannah River Site (SRS) is evaluating technologies for removing radioactive cesium (137Cs) from the supernate solutions stored in the high-level waste tanks at the site. Crystalline silicotitanate sorbent (IONSIV IE-911,{reg_sign} UOP LLC, Des Plaines, IL), which is very effective at removing cesium from high-salt solution, is one of three technologies currently being tested. Because of the extremely high inventory of 137Cs expected for the large columns of crystalline silicotitanate (CST) that would be used for treating the SRS supernate, any loss of flow or cooling to the columns could result in high temperatures from radiolytic heating. Also, even for normal operation, the CST would be exposed to the supernates for up to a year before being removed. Small-scale tests using simulant solutions were used to determine the long-term stability of the CST to the solutions at various temperatures. In the tests performed in this study, the cesium capacity of the CST decreased significantly (76%) as the temperature of the simulant and CST during loading was increased from 23 to 80 C. CST exposed to recirculating SRS average simulant solution at room temperature in a column test showed a slow decrease in cesium loading capacity (measured at 23 C), with a drop of 30% for CST from the top of the bed and 13% for CST from the bottom of the bed after a 12-month period of exposure. A similar column test using a high-pH salt solution did not show any change in the cesium capacity of the CST. An increase was noted in pressure drop through the column using average simulant, but no change was observed for the column using high-pH salt solution.
Book Synopsis An Optimal Ion Exchange Design for Removal of Cesium from Hanford Waste by :
Download or read book An Optimal Ion Exchange Design for Removal of Cesium from Hanford Waste written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-elutable crystalline silicotitanate (CST) ion-exchanger materials have been studied for removing cesium from a variety of radioactive wastes at several U.S. DOE sites over the last decade. For the current pretreatment facility design of the River Protection Project (RPP) Waste Treatment Plant (WTP) in Hanford, the removal of cesium from low activity waste (LAW) is achieved by ion-exchange technology based on SuperLig(R) 644 resin. However, due to concerns over potential radiological and chemical degradation of SuperLig(R) 644 resin, IONSIV IE-911 (CST in its engineered form) material is being proposed as a backup ion-exchange material for the removal of cesium from Hanford radioactive waste. This paper discusses the methodology used to determine the optimal CST ion-exchange column size to process all 16 separate batches of feeds from the ten targeted Hanford waste tanks. The optimal design ensures the best utilization of CST material and therefore results in a minimum amount of spent CST.
Book Synopsis Modeling of Crystalline Silicotitanate Ion Exchange Columns Using Experimental Data from SRS Simulated Waste by :
Download or read book Modeling of Crystalline Silicotitanate Ion Exchange Columns Using Experimental Data from SRS Simulated Waste written by and published by . This book was released on 1999 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-elutable ion exchange using crystalline silicotitanate is being considered for removing cesium from Savannah River Site radioactive waste. The construction cost of this process depends strongly on the size of the ion exchange column required to meet product specifications.
Book Synopsis Ion Exchange Kinetics of Cesium for Various Reaction Designs Using Crystalline Silicotitanate, UOP IONSIV IE-911 by : Sung Hyun Kim
Download or read book Ion Exchange Kinetics of Cesium for Various Reaction Designs Using Crystalline Silicotitanate, UOP IONSIV IE-911 written by Sung Hyun Kim and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Through collaborative efforts at Texas A & M University and Sandia National Laboratories, a crystalline silicotitanate (CST), which shows extremely high selectivity for radioactive cesium removal in highly concentrated sodium solutions, was synthesized. The effect of hydrogen peroxide on a CST under cesium ion exchange conditions has been investigated. The experimental results with hydrogen peroxide showed that the distribution coefficient of cesium decreased and the tetragonal phase, the major component of CST, slowly dissolved at hydrogen peroxide concentrations greater than 1 M.A simple and novel experimental apparatus for a single-layer ion exchange column was developed to generate experimental data for estimation of the intraparticle effective diffusivity. A mathematical model is presented for estimation of effective diffusivities for a single-layer column of CST granules. The intraparticle effective diffusivity for Cs was estimated as a parameter in the analytical solution. By using the least square method, the effective diffusivities of 1.56 ł 0.14 x 10-11 m2/s and 0.68 ł 0.09x 10-11 m2/s, respectively, were obtained. The difference in the two values was due to the different viscosities of the solutions. A good fit of the experimental data was obtained which supports the use of the homogeneous model for this system. A counter-current ion exchange (CCIX) process was designed to treat nuclear waste at the Savannah River Site. A numerical method based on the orthogonal collocation method was used to simulate the concentration profile of cesium in the CCIX loaded with CST granules. To maximize cesium loading onto the CST and minimize the volume of CST, two design cases of a moving bed, where the fresh CST is pulsed into the column at certain periods or at certain concentration of cesium, were investigated. Simulation results showed that cesium removal behavior in the pilot-scale test of CCIX experiment, where the column length is 22 ft and the CST is pulsed 1 ft in every 24 hours, was well predicted by using the values of the effective diffusivities of 1.0 to 6.0 x 10-11 m2/s.
Book Synopsis Small-Scale Ion Exchange Removal of Cesium and Technetium from Hanford Tank 241-AN-102 by :
Download or read book Small-Scale Ion Exchange Removal of Cesium and Technetium from Hanford Tank 241-AN-102 written by and published by . This book was released on 2000 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The pretreatment process for BNFL, Inc.'s Hanford River Protection Project is to provide decontaminated low activity waste and concentrated eluate streams for vitrification into low and high activity waste glass, respectively. The pretreatment includes sludge washing, filtration, precipitation, and ion exchange processes to remove entrained solids, cesium, transuranics, technetium, and strontium. The cesium (Cs-137) and technetium (Tc-99) ion exchange removal is accomplished by using SuperLig 644, and 639 resins from IBC Advanced Technologies, American Fork, Utah. The resins were shown to selectively remove cesium and technetium (as anionic pertechnetate) from alkaline salt solutions. The efficiency of ion exchange column loading and elution is a complex function involving feed compositions, equilibrium and kinetic behavior of ion exchange resins, diffusion, and the ionic strength and pH of the aqueous solution. A previous experimental program completed at the Savannah River Tech nology Center2 demonstrated the conceptualized flow sheet parameters with an Envelope C sample from Hanford Tank 241-AN-107. Those experiments also included determination of Cs and Tc batch distribution coefficients by SuperLig 644 and 639 resins and demonstration of small-scale column breakthrough and elution. The experimental findings were used in support of preliminary design bases and pretreatment flow sheet development by BNFL, Inc.
Book Synopsis THERMAL PERFORMANCE ANALYSIS FOR SMALL ION-EXCHANGE CESIUM REMOVAL PROCESS. by :
Download or read book THERMAL PERFORMANCE ANALYSIS FOR SMALL ION-EXCHANGE CESIUM REMOVAL PROCESS. written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The In-Riser Ion Exchange program focuses on the development of in-tank systems to decontaminate high level waste (HLW) salt solutions at the Savannah River Site (SRS) and the Hanford Site. Small Column Ion Exchange (SCIX) treatment for cesium removal is a primary in-riser technology for decontamination prior to final waste immobilization in Saltstone. Through this process, radioactive cesium from the salt solution is adsorbed onto the ion exchange media which is packed within a flow-through column. Spherical Resorcinol-Formaldehyde (RF) is being considered as the ion exchange media for the application of this technology at both sites. A packed column loaded with media containing radioactive cesium generates significant heat from radiolytic decay. Under normal operating conditions, process fluid flow through the column can provide adequate heat removal from the columns. However, in the unexpected event of loss of fluid flow or fluid drainage from the column, the design must be adequate to handle the thermal load to avoid unacceptable temperature excursions. Otherwise, hot spots may develop locally which could degrade the performance of the ion-exchange media or the temperature could rise above column safety limits. Data exists which indicates that performance degradation with regard to cesium removal occurs with RF at 65C. In addition, the waste supernate solution will boil around 130C. As a result, two temperature limits have been assumed for this analysis. An additional upset scenario was considered involving the loss of the supernate solution due to inadvertent fluid drainage through the column boundary. In this case, the column containing the loaded media could be completely dry. This event is expected to result in high temperatures that could damage the column or cause the RF sorbent material to undergo undesired physical changes. One objective of these calculations is to determine the range of temperatures that should be evaluated during testing with the RF media. Although, the safety temperature limit is based on the salt solution boiling point which does not apply in the air-filled case (because there is no liquid), this same limit (130C) is used as a measure for the evaluation of this condition as well. The primary objective of the present work is to develop models to simulate the thermal performance of the RF column design when the media is fully loaded with radioactive cesium and the central cooling tube is excluded. Previous analysis led to the consideration of this design simplification for RF, since the baseline column design with center cooling was developed assuming that CST media would be used for cesium removal which has a higher volumetric heat load. Temperature distributions and maximum temperatures across the column during SCIX process operations and upset conditions were conducted with a focus on SCIX implementation at Hanford. However, a feed composition and cesium loading were assumed which were known to be considerably higher than would typically be observed at Hanford. In order to evaluate the impact of this potentially highly conservative assumption, fractionally-reduced loading cases were also considered. A computational modeling approach was taken to include conservative, bounding estimates for key parameters so that the results would provide the maximum temperatures achievable under the design configurations.
Book Synopsis Ion Exchange Modeling of Crystalline Silicotitanate (IONSIV(R) IE-911) Column for Cesium Removal from Argentine Waste by :
Download or read book Ion Exchange Modeling of Crystalline Silicotitanate (IONSIV(R) IE-911) Column for Cesium Removal from Argentine Waste written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The U.S. Department of Energy (DOE) and the Nuclear Energy Commission of Argentina (CNEA) have a collaborative project to separate cesium/strontium from waste resulting from the production of Mo-99. The Pacific Northwest National Laboratory (PNNL) is assisting DOE on this joint project by providing technical guidance to CNEA scientists. As part of the collaboration, PNNL staff works with staff at the Savannah River Technology Center (SRTC) to run the VERSE-LC model for removal of cesium from the Mo-99 waste using the crystalline silicotitanate (CST) material (IONSIV(R) IE-911, UOP LLC, DesPlaines, IL) based on technical data provided by CNEA. This report discusses the VERSE-LC ion-exchange-column model and the predicted results of CNEA test cases.
