Download or read book Compliance with the Nevada Test Site s Waste Acceptance Criteria for Vitrified Cesium loaded Crystalline Silicotitanates written by and published by . This book was released on 1997 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: As part of a joint project between the Oak Ridge National Laboratory (ORNL) and the Savannah River Technology Center (SRTC), Cs-137 loaded crystalline silicotitanate (CST) sorbent will be vitrified in a joule-heated melter. Glass formulation development for this CST sorbent is discussed in an accompanying abstract for this conference. One of the objectives for this project was to ensure that the vitrified waste form could be disposed of at the Nevada Test Site (NTS). To accomplish this objective, the waste form must meet the NTS Waste Acceptance Criteria (WAC). This paper presents SRTC's efforts at ensuring that the glass waste form produced as a result of vitrification of CST will meet all of the criteria of the WAC. The producer must demonstrate that the waste is neither TRU nor mixed, and that the glass has a radionuclide content which is less than the Class C limit of 4,600 Ci/m3. The impact of this requirement on the CST loading in the glass is discussed along with the benefits to the producer which result if greater than Class C waste is accepted by NTS since this limit may be relaxed in the near future. This paper demonstrates that vitrification leads to a waste form which meets all of the criteria of the NTS WAC.

Download or read book Compliance with the Nevada Test Site s Waste Acceptance Criteria for Vitrified Cesium loaded Crystalline Silicotitanate CST written by and published by . This book was released on 1997 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oak Ridge National Laboratory (ORNL) and Savannah River Technology Center (SRTC) are involved in a joint project for immobilization of radionuclides from the Melton Valley Storage Tanks (MVST) at Oak Ridge (OR). The supernate from Tank W-29 of the MVST will be treated by passage through a crystalline silicotitanate (CST) ion exchange medium. The CST was designed to sorb cesium, the primary radio nuclide (Cs-137) in the supernate of MVST's. A smaller amount of strontium (Sr-90) will also be sorbed. This demonstration will be performed by ORNL. One column volume of cesium-loaded CST ((approximately)10 gallons or 38 liters) will then be shipped to SRTC where it will be mixed with glass formers and fed as an aqueous slurry to a joule-heated melter within the SRTC Shielded Cells. A borosilicate glass formulation which will incorporate the CST has been developed as part oft SRTC's role in this project. The molten glass ((approximately)1150°C) will be poured into 500 ml stainless steel beakers which in turn will be placed in 30 gallon drums for disposal. An import & f part of this project is to demonstrate that the glass waste form produced will meet the Waste Acceptance Criteria (WAC) for disposal at the Nevada Test Site (NTS). If vitrification of the cesium-loaded CST is implemented as the immobilization method for all of the MVST supernate, then it is essential to demonstrate that the waste can be disposed of at an acceptable disposal facility. NTS accepts low-level radioactive waste as long as it is not TRU and not hazardous. This paper documents the efforts in the development stage of this work to integrate the requirements of NTS into the formulation and processing efforts. This work is funded by the Tank Focus Area with additional funding for ORNL provided by EM-30 at OR.

Download or read book The Office of Environmental Management Technical Reports A Bibliography written by and published by DIANE Publishing. This book was released on 2001 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Office of Environmental Management's (EM) technical reports bibliography is an annual publication that contains information on scientific and technical reports sponsored by the Office of Environmental Management added to the Energy Science and Technology Database from July 1, 1994 through June 30, 1995. This information is divided into the following categories: Focus Areas, Cross-Cutting Programs, and Support Programs. In addition, a category for general information is included. EM's Office of Science and Technology sponsors this bibliography.

Download or read book EM written by and published by . This book was released on 1997 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vitrification of Cesium loaded Crystalline Silicotitanate CST in the Shielded Cells Melter written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Through the Tanks Focus Area, the Savannah River Technology Center (SRTC) and the Oak Ridge National Laboratory participated in a joint project in which supernate waste from the Melton Valley Storage Tanks at Oak Ridge was treated by passage through a crystalline silicotitanate (CST) ion exchange column. CST was designed to sorb Cs- 137, Sr-90 and several other radionuclides from highly alkaline solutions containing large quantities of sodium. 2 After demonstrating the effectiveness of CST as an ion exchange medium, ORNL shipped some of the loaded sorbent to SRTC where it was mixed with glass formers and processed in a joule-heated melter within the SRTC Shielded Cells. This report details the results of the melter run, along with the preparations that were required to complete the campaign.

Download or read book New Silicotitanate Waste Forms Development and Characterization written by and published by . This book was released on 1999 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this program is to identify new waste forms and disposal strategies specific to crystalline silicotitanate (CST) secondary waste that is generated from cesium and strontium ion exchange processes. In particular, in situ heat treatment of CSTs to produce an alternative waste form is being examined. Waste forms that are developed in this work will offer an alternative to current disposal plans, which call for recombining the separated cesium, strontium-loaded CST into the high-activity waste (HAW) streams, then dissolving it in borosilicate glass. The goals of the program are to reduce the costs associated with CST waste disposal, minimize the risk of contamination to the environment during CST processing, and provide DOE with technical alternatives for CST disposal. Because there is uncertainty in repository availability and in waste acceptance criteria, it is likely that cesium and strontium-loaded ion exchangers will require short-term storage at Hanford or t hat new scenarios for long-term storage or disposal of nuclides with relatively short half-lives (such as 137Cs and 90Sr) will arise. Research activities in this program will generate information on the durabilities and stabilities of thermally consolidated CSTs so that the potential of these options as viable storage or disposal scenarios can be evaluated. The technical objectives of the proposed work are to fully characterize the phase relationships, structures, and thermodynamic and kinetic stabilities of crystalline silicotitanate waste forms and to establish a sound technical basis for understanding key waste form properties, such as melting temperatures and aqueous durability, based on an in-depth understanding of waste form structures and thermochemistry.

Download or read book Performance of Crystalline Silicotitanates for Cesium Removal from Hanford Tank Waste Simulants written by and published by . This book was released on 1994 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new class of inorganic ion exchangers, called crystalline silicotitanates (CSTs), has been prepared at Sandia National Laboratories and Texas A & M University. CSTs have been determined to have high selectivity for the adsorption of Cs and Sr, and several other radionuclides from highly alkaline, high-sodium supernate solutions such as those found at Westinghouse Hanford (WHC). Continuous flow, ion-exchange columns are expected to be used to remove Cs and other radionuclides from the Hanford tank supernate. The proposed application for the CST would be Cs removal from highly alkaline salt solutions in a single pass process with interim storage of the Cs loaded CST until the glass vitrification plant is operational. This paper presents test results which address material requirements relevant for Hanford radwaste processing. This paper also discusses the integrated experimental and modeling approach being developed to establish the performance of the CST materials for the range of solution compositions and processing conditions which are expected to occur. The status on the commercialization of the CST material is also discussed.

Download or read book Cesium Removal from Simulated SRS High Level Waste Using Crystalline Silicotitanate written by and published by . This book was released on 1998 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study measured the adsorption of cesium from simulated Savannah River Site liquid waste onto crystalline silicotitanate (CST) in equilibrium (Kd) and ion exchange column tests.

Download or read book Glass Formulation Development for the Vitrification of Oak Ridge Tank Waste written by and published by . This book was released on 1998 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crystalline silicotitanate (CST) is a highly specific ion exchange material for cesium. In particular, CST has been successfully demonstrated with both simulants and actual supernates from Savannah River and Hanford tank wastes. As a disposal option, vitrification of the cesium-loaded CST coupled with High-Level Waste (HLW) has been proposed. However, the CST sorbent contains significant quantities of titanium which historically have been difficult to incorporate into the glass structure. Therefore, nonradioactive tests using CST coupled with simulated HLW were performed to develop a glass formulation that would be both processable and durable. The results of the simulated crucible melts were verified using radioactive waste and cesium-loaded CST. This paper will detail the results of the formulation efforts.

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

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.

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.

Download or read book Ceramicrete trademark Stabilization of CST Resin written by and published by . This book was released on 1998 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Ceramicrete{trademark} waste form is a magnesium phosphate hydrate, which sets as the result of an acid-base reaction between KH2PO4 and MgO in the presence of water. Based on the results of this feasibility study, this low temperature ceramic waste form is acceptable for stabilization of cesium loaded crystalline silicotitanate (CST) resin. The performance objective of CST stabilization is to convert a friable powdered resin into a monolithic form to improve handling and storage and to reduce the waste mobility. Advantages of this type of the CST-Ceramicrete{trademark} waste form include: room temperature processing of a fluid slurry, limited off gas, flexible mix designs, rapid setting, no free liquids, temperature tolerant and durable up to at least 90 degrees C. The Ceramicrete/220 waste form can be processed by in-container mixing or by batch mixing. Since a trace amount of free water will be associated with the wet resin in the CST-Ceramicrete{trademark} waste form, radiolysis of the free water may cause pressurization of the containers. Leaching tests were conducted to evaluate the CST-Ceramicrete{trademark} waste form performance relative to high-level waste glass. Results were very encouraging given that only one waste loading (50 wt. percent resin) was tested and that the leaching procedures were not fully optimized for a non-glass waste form. In general, the cesium leachability per the PCT test of the CST-Ceramicrete{trademark} waste was about 2X more than that of the ARM glass and about 200X more than the EA glass. For monolithic samples (MCC-1 test), the CST-Ceramicrete{trademark} waste form leached 4X to7X more cesium than the ARM glass. (The EA glass is not suited to monolithic leaching.) The CST-Ceramicrete{trademark} leaching results appear to be independent of curing temperature over the range 24 to 90 degrees C.

Download or read book Ion exchange Performance of Crystalline Silico titanates for Cesium Removal from Hanford Tank Waste Simulants written by and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Clumping Behaviour and Cesium Loading Results for Crystalline Silicotitanate and Zeolite in SRS Dissolved Salt Simulants written by P. A. Taylor and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Initial Evaluation of Sandia National Laboratory written by Lane A. Bray and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: