[en] This report documents material balance calculations for the Americium/Curium vitrification process and describes the basis used to make the calculations. The material balance calculations reported here start with the solution produced by the Am/Cm pretreatment process as described in ``Material Balance Calculations for Am/Cm Pretreatment Process (U)'', SRT-AMC-99-0178 [1]. Following pretreatment, small batches of the product will be further treated with an additional oxalic acid precipitation and washing. The precipitate from each batch will then be charged to the Am/Cm melter with glass cullet and vitrified to produce the final product. The material balance calculations in this report are designed to provide projected compositions of the melter glass and off-gas streams. Except for decanted supernate collected from precipitation and precipitate washing, the flowsheet neglects side streams such as acid washes of empty tanks that would go directly to waste. Complete listings of the results of the material balance calculations are provided in the Appendices to this report

[en] The objectives of this multi-organizational research are to develop new real-time sensors for characterizing glass melts in high level waste (HLW) and low activity waste (LAW) melters, and to understand the scientific basis and to bridge the gap between glass melt model data and melter performance

[en] SpeedUp trademark has been used to model a continuous counter-current solvent extraction process designed to remove cesium from a waste stream at the Savannah River Site. The SpeedUp software from ASPEN Technology, Inc. is an equation-based dynamic chemical process modeling package that has been found particularly convenient to use. SpeedUp allows the user to readily develop unique models of process unit operations that can be combined into a system flowsheet and solved in a time dependent form. Since many of the unit operations at the Savannah River Site are unique this framework is particularly convenient for their modeling needs. The material balance model described in this report was used to evaluate solvent extraction as a method for cesium removal from a radioactive waste stream. If cesium can be efficiently removed, the decontaminated waste stream can be disposed of as low-level radioactive waste in the existing Saltstone grouting facility at the site. The raffinate stream from the solvent extraction process containing the concentrated cesium in an aqueous solution would be sent to the high-level waste vitrification facility which has been operating at the site since 1995. Here the cesium would be incorporated into borosilicate glass with other high-level radioactive waste materials and poured into steel canisters along for permanent disposal. The solvent extraction process is modeled as a series of equilibrium stages. Within each stage, the distribution coefficients that partition dissolved materials between the aqueous and organic phases are user specified parameters. As an enhancement, the basic solvent extraction model was modified to include carryover of the aqueous phase into the organic stream and carryover of the organic phase into the aqueous stream. This version of the model was run to simulate the TRUEX process and model results were found to compare favorablywith those reported in the literature. The SpeedUp formulation is easy to extend to handle additional modifications such as solvent cleanup or direct linking to pre- and post-processing steps used to treat the radioactive waste streams. The SpeedUp code is also very compact using just a generalized model of a single extraction stage and a macro that creates separate units (extraction, scrubbing and stripping) in the extraction process. The macro automatically builds each unit using as many stages as are specified in the operation section of the code

[en] This report documents material balance calculations for the pretreatment steps required to prepare the Americium/Curium solution currently stored in Tank 17.1 in the F-Canyon for vitrification. The material balance uses the latest analysis of the tank contents to provide a best estimate calculation of the expected plant operations during the pretreatment process. The material balance calculations primarily follow the material that directly leads to melter feed. Except for vapor products of the denitration reactions and treatment of supernate from precipitation and precipitate washing, the flowsheet does not include side streams such as acid washes of the empty tanks that would go directly to waste. The calculation also neglects tank heels

[en] This report documents material balance calculations for the Americium/Curium vitrification process and describes the basis used to make the calculations

[en] This report documents material balance calculations for the pretreatment steps required to prepare the Americium/Curium solution currently stored in Tank 17.1 in the F-Canyon for vitrification. The material balance uses the latest analysis of the tank contents to provide a best estimate calculation of the expected plant operations during the pretreatment process. The material balance calculations primarily follow the material that directly leads to melter feed. Except for vapor products of the denitration reactions and treatment of supernate from precipitation and precipitate washing, the flowsheet does not include side streams such as acid washes of the empty tanks that would go directly to waste. The calculation also neglects tank heels. This report consolidates previously reported results, corrects some errors found in the spreadsheet and provides a more detailed discussion of the calculation basis

[en] A computer model is in development to provide a dynamic simulation of batch operations within the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). The DWPF will chemically treat high level waste materials from the site tank farm and vitrify the resulting slurry into a borosilicate glass for permanent disposal. The DWPF consists of three major processing areas: Salt Processing Cell (SPC), Chemical Processing Cell (CPC) and the Melt Cell. Separate models have been developed for each of these process units using the SPEEDUP trademark software from Aspen Technology. Except for glass production in the Melt Cell, all of the chemical operations within DWPF are batch processes. Since the SPEEDUP software is designed for dynamic modeling of continuous processes, considerable effort was required to devise batch process algorithms. This effort was successful and the models are able to simulate batch operations and the dynamic behavior of the process. In this paper, we will describe the SPC model in some detail and present preliminary results from a few simulation studies

[en] The evidence for relativistic beam compression being the source of pulses from pulsars is discussed. The properties of the radio pulses, self-absorption in the infrared and the role of the pulsar magnetosphere are considered. It is concluded that the relativistic beaming theory gives a fairly good description of the high energy particle motions that lead to the radiation. (U.K.)

[en] A computer model has been developed for the dynamic simulation of batch process operations within the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). The DWPF chemically treats high level waste materials from the site tank farm and vitrifies the resulting slurry into a borosilicate glass for permanent disposal. The DWPF consists of three major processing areas: Salt Processing Cell (SPC), Chemical Processing Cell (CPC) and the Melt Cell. A fully integrated model of these process units has been developed using the SPEEDUP trademark software from Aspen Technology. Except for glass production in the Melt Cell, all of the chemical operations within DWPF are batch processes. Since SPEEDUP is designed for dynamic modeling of continuous processes, considerable effort was required to device batch process algorithms. This effort was successful and the model is able to simulate batch operations and the dynamic behavior of the process. The model also includes an optimization calculation that maximizes the waste content in the final glass product. In this paper, we will describe the process model in some detail and present preliminary results from a few simulation studies

[en] This report documents preliminary versions of the models that include the components of the offgas systems from the melters through the exhaust stacks and the vessel ventilation systems. The models consider only the two major chemical species in the offgas stream: air and steam or water vapor. Model mass and energy balance calculations are designed to show the dynamic behavior of gas pressure and flow throughout the offgas systems in response to transient driving forces