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Title: KEY ELEMENTS OF CHARACTERIZING SAVANNAH RIVER SITE HIGH LEVEL WASTE SLUDGE INSOLUBLES THROUGH SAMPLING AND ANALYSIS

Abstract

Characterization of HLW is a prerequisite for effective planning of HLW disposition and site closure performance assessment activities. Adequate characterization typically requires application of a combination of data sources, including process knowledge, theoretical relationships, and real-waste analytical data. Consistently obtaining high quality real-waste analytical data is a challenge, particularly for HLW sludge insolubles, due to the inherent complexities associated with matrix heterogeneities, sampling access limitations, radiological constraints, analyte loss mechanisms, and analyte measurement interferences. Understanding how each of these complexities affects the analytical results is the first step to developing a sampling and analysis program that provides characterization data that are both meaningful and adequate. A summary of the key elements impacting SRS HLW sludge analytical data uncertainties is presented in this paper, along with guidelines for managing each of the impacts. The particular elements addressed include: (a) sample representativeness; (b) solid/liquid phase quantification effectiveness; (c) solids dissolution effectiveness; (d) analyte cross contamination, loss, and tracking; (e) dilution requirements; (f) interference removal; (g) analyte measurement technique; and (h) analytical detection limit constraints. A primary goal of understanding these elements is to provide a basis for quantifying total propagated data uncertainty.

Authors:
;
Publication Date:
Research Org.:
SRS
Sponsoring Org.:
USDOE
OSTI Identifier:
908211
Report Number(s):
LWO-PIT-2007-00061
TRN: US0703626
DOE Contract Number:
DE-AC09-96SR18500
Resource Type:
Conference
Resource Relation:
Conference: Materials Science and Technology 2007
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; SAVANNAH RIVER PLANT; HIGH-LEVEL RADIOACTIVE WASTES; SAMPLING; CHEMICAL ANALYSIS; PLANNING; RADIOACTIVE WASTE DISPOSAL; SLUDGES; RECOMMENDATIONS

Citation Formats

Reboul, S, and Barbara Hamm, B. KEY ELEMENTS OF CHARACTERIZING SAVANNAH RIVER SITE HIGH LEVEL WASTE SLUDGE INSOLUBLES THROUGH SAMPLING AND ANALYSIS. United States: N. p., 2007. Web.
Reboul, S, & Barbara Hamm, B. KEY ELEMENTS OF CHARACTERIZING SAVANNAH RIVER SITE HIGH LEVEL WASTE SLUDGE INSOLUBLES THROUGH SAMPLING AND ANALYSIS. United States.
Reboul, S, and Barbara Hamm, B. Thu . "KEY ELEMENTS OF CHARACTERIZING SAVANNAH RIVER SITE HIGH LEVEL WASTE SLUDGE INSOLUBLES THROUGH SAMPLING AND ANALYSIS". United States. doi:. https://www.osti.gov/servlets/purl/908211.
@article{osti_908211,
title = {KEY ELEMENTS OF CHARACTERIZING SAVANNAH RIVER SITE HIGH LEVEL WASTE SLUDGE INSOLUBLES THROUGH SAMPLING AND ANALYSIS},
author = {Reboul, S and Barbara Hamm, B},
abstractNote = {Characterization of HLW is a prerequisite for effective planning of HLW disposition and site closure performance assessment activities. Adequate characterization typically requires application of a combination of data sources, including process knowledge, theoretical relationships, and real-waste analytical data. Consistently obtaining high quality real-waste analytical data is a challenge, particularly for HLW sludge insolubles, due to the inherent complexities associated with matrix heterogeneities, sampling access limitations, radiological constraints, analyte loss mechanisms, and analyte measurement interferences. Understanding how each of these complexities affects the analytical results is the first step to developing a sampling and analysis program that provides characterization data that are both meaningful and adequate. A summary of the key elements impacting SRS HLW sludge analytical data uncertainties is presented in this paper, along with guidelines for managing each of the impacts. The particular elements addressed include: (a) sample representativeness; (b) solid/liquid phase quantification effectiveness; (c) solids dissolution effectiveness; (d) analyte cross contamination, loss, and tracking; (e) dilution requirements; (f) interference removal; (g) analyte measurement technique; and (h) analytical detection limit constraints. A primary goal of understanding these elements is to provide a basis for quantifying total propagated data uncertainty.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu May 24 00:00:00 EDT 2007},
month = {Thu May 24 00:00:00 EDT 2007}
}

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  • This paper describes the results of the analyses of High Level Waste (HLW) sludge slurry samples and of the calculations necessary to decay the radionuclides to meet the reporting requirement in the Waste Acceptance Product Specifications (WAPS) [1]. The concentrations of 45 radionuclides were measured. The results of these analyses provide input for radioactive decay calculations used to project the radionuclide inventory at the specified index years, 2015 and 3115. This information is necessary to complete the Production Records at Savannah River Site's Defense Waste Processing Facility (DWPF) so that the final glass product resulting from Macrobatch 5 (MB5) canmore » eventually be submitted to a Federal Repository. Five of the necessary input radionuclides for the decay calculations could not be measured directly due to their low concentrations and/or analytical interferences. These isotopes are Nb-93m, Pd-107, Cd-113m, Cs-135, and Cm-248. Methods for calculating these species from concentrations of appropriate other radionuclides will be discussed. Also the average age of the MB5 HLW had to be calculated from decay of Sr-90 in order to predict the initial concentration of Nb-93m. As a result of the measurements and calculations, thirty-one WAPS reportable radioactive isotopes were identified for MB5. The total activity of MB5 sludge solids will decrease from 1.6E+04 {micro}Ci (1 {micro}Ci = 3.7E+04 Bq) per gram of total solids in 2008 to 2.3E+01 {micro}Ci per gram of total solids in 3115, a decrease of approximately 700 fold. Finally, evidence will be given for the low observed concentrations of the radionuclides Tc-99, I-129, and Sm-151 in the HLW sludges. These radionuclides were reduced in the MB5 sludge slurry to a fraction of their expected production levels due to SRS processing conditions.« less
  • The Savannah River Site F-Tank Farm Closure project has successfully performed Mechanical Sludge Removal (MSR) using the Waste on Wheels (WOW) system for the first time within one of its storage tanks. The WOW system is designed to be relatively mobile with the ability for many components to be redeployed to multiple waste tanks. It is primarily comprised of Submersible Mixer Pumps (SMPs), Submersible Transfer Pumps (STPs), and a mobile control room with a control panel and variable speed drives. In addition, the project is currently preparing another waste tank for MSR utilizing lessons learned from this previous operational activity.more » These tanks, designated as Tank 6 and Tank 5 respectively, are Type I waste tanks located in F-Tank Farm (FTF) with a capacity of 2,840 cubic meters (750,000 gallons) each. The construction of these tanks was completed in 1953, and they were placed into waste storage service in 1959. The tank's primary shell is 23 meters (75 feet) in diameter, and 7.5 meters (24.5 feet) in height. Type I tanks have 34 vertically oriented cooling coils and two horizontal cooling coil circuits along the tank floor. Both Tank 5 and Tank 6 received and stored F-PUREX waste during their operating service time before sludge removal was performed. DOE intends to remove from service and operationally close (fill with grout) Tank 5 and Tank 6 and other HLW tanks that do not meet current containment standards. Mechanical Sludge Removal, the first step in the tank closure process, will be followed by chemical cleaning. After obtaining regulatory approval, the tanks will be isolated and filled with grout for long-term stabilization. Mechanical Sludge Removal operations within Tank 6 removed approximately 75% of the original 95,000 liters (25,000 gallons). This sludge material was transferred in batches to an interim storage tank to prepare for vitrification. This operation consisted of eleven (11) Submersible Mixer Pump(s) mixing campaigns and multiple intraarea transfers utilizing STPs from July 2006 to August 2007. This operation and successful removal of sludge material meets requirement of approximately 19,000 to 28,000 liters (5,000 to 7,500 gallons) remaining prior to the Chemical Cleaning process. Removal of the last 35% of sludge was exponentially more difficult, as less and less sludge was available to mobilize and the lighter sludge particles were likely removed during the early mixing campaigns. The removal of the 72,000 liters (19,000 gallons) of sludge was challenging due to a number factors. One primary factor was the complex internal cooling coil array within Tank 6 that obstructed mixer discharge jets and impacted the Effective Cleaning Radius (ECR) of the Submersible Mixer Pumps. Minimal access locations into the tank through tank openings (risers) presented a challenge because the available options for equipment locations were very limited. Mechanical Sludge Removal activities using SMPs caused the sludge to migrate to areas of the tank that were outside of the SMP ECR. Various SMP operational strategies were used to address the challenge of moving sludge from remote areas of the tank to the transfer pump. This paper describes in detail the Mechanical Sludge Removal activities and mitigative solutions to cooling coil obstructions and other challenges. The performance of the WOW system and SMP operational strategies were evaluated and the resulting lessons learned are described for application to future Mechanical Sludge Removal operations.« less
  • The SRS sludge that was to become a major fraction of Sludge Batch 5 (SB5) for the Defense Waste Processing Facility (DWPF) contained a large fraction of H-Modified PUREX (HM) sludge, containing a large fraction of aluminum compounds that could adversely impact the processing and increase the vitrified waste volume. It is beneficial to reduce the non-radioactive fraction of the sludge to minimize the number of glass waste canisters that must be sent to a Federal Repository. Removal of aluminum compounds, such as boehmite and gibbsite, from sludge can be performed with the addition of NaOH solution and heating themore » sludge for several days. Preparation of SB5 involved adding sodium hydroxide directly to the waste tank and heating the contents to a moderate temperature through slurry pump operation to remove a fraction of this aluminum. The Savannah River National Laboratory (SRNL) was tasked with demonstrating this process on actual tank waste sludge in our Shielded Cells Facility. This paper evaluates some of the impacts of aluminum dissolution on sludge washing and DWPF processing by comparing sludge processing with and without aluminum dissolution. It was necessary to demonstrate these steps to ensure that the aluminum removal process would not adversely impact the chemical and physical properties of the sludge which could result in slower processing or process upsets in the DWPF.« less
  • The Savannah River Site F-Tank Farm Closure project has successfully performed Mechanical Sludge Removal (MSR) using the Waste on Wheels (WOW) system for the first time within one of its storage tanks. The WOW system is designed to be relatively mobile with the ability for many components to be redeployed to multiple waste tanks. It is primarily comprised of Submersible Mixer Pumps (SMPs), Submersible Transfer Pumps (STPs), and a mobile control room with a control panel and variable speed drives. In addition, the project is currently preparing another waste tank for MSR utilizing lessons learned from this previous operational activity.more » These tanks, designated as Tank 6 and Tank 5 respectively, are Type I waste tanks located in F-Tank Farm (FTF) with a capacity of 2,840 cubic meters (750,000 gallons) each. The construction of these tanks was completed in 1953, and they were placed into waste storage service in 1959. The tank's primary shell is 23 meters (75 feet) in diameter, and 7.5 meters (24.5 feet) in height. Type I tanks have 34 vertically oriented cooling coils and two horizontal cooling coil circuits along the tank floor. Both Tank 5 and Tank 6 received and stored F-PUREX waste during their operating service time before sludge removal was performed. DOE intends to remove from service and operationally close (fill with grout) Tank 5 and Tank 6 and other HLW tanks that do not meet current containment standards. Mechanical Sludge Removal, the first step in the tank closure process, will be followed by chemical cleaning. After obtaining regulatory approval, the tanks will be isolated and filled with grout for long-term stabilization. Mechanical Sludge Removal operations within Tank 6 removed approximately 75% of the original 95,000 liters (25,000 gallons). This sludge material was transferred in batches to an interim storage tank to prepare for vitrification. This operation consisted of eleven (11) Submersible Mixer Pump(s) mixing campaigns and multiple intra-area transfers utilizing STPs from July 2006 to August 2007. This operation and successful removal of sludge material meets requirement of approximately 19,000 to 28,000 liters (5,000 to 7,500 gallons) remaining prior to the Chemical Cleaning process. Removal of the last 35% of sludge was exponentially more difficult, as less and less sludge was available to mobilize and the lighter sludge particles were likely removed during the early mixing campaigns. The removal of the 72,000 liters (19,000 gallons) of sludge was challenging due to a number factors. One primary factor was the complex internal cooling coil array within Tank 6 that obstructed mixer discharge jets and impacted the Effective Cleaning Radius (ECR) of the Submersible Mixer Pumps. Minimal access locations into the tank through tank openings (risers) presented a challenge because the available options for equipment locations were very limited. Mechanical Sludge Removal activities using SMPs caused the sludge to migrate to areas of the tank that were outside of the SMP ECR. Various SMP operational strategies were used to address the challenge of moving sludge from remote areas of the tank to the transfer pump. This paper describes in detail the Mechanical Sludge Removal activities and mitigative solutions to cooling coil obstructions and other challenges. The performance of the WOW system and SMP operational strategies were evaluated and the resulting lessons learned are described for application to future Mechanical Sludge Removal operations. (authors)« less
  • The Savannah River Plant routinely samples its high level radioactive waste tank supernatants for analysis of major components. These results are important in maintaining proper levels of corrosion inhibiters for protection of the tank walls. Because the tank ambient temperature is elevated, the sample is heated to 70/sup 0/C prior to removing aliquots for use in a variety of analytical methods. Typical analyses include density, pH, OH/sup -/, NO/sub 3//sup -/, and NO/sub 2//sup -/, with occasional requests for Al(OH)/sub 4//sup -/, CO/sub 3//sup =/, PO/sub 4//sup =/, SO/sub 4//sup =/, and various radionuclides.