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At least 847 records · Page 47

Blend Pump Mixing in Tank 27 Evaluation

For future waste disposal operations, Savannah River Mission Completion (SRMC) plans to operate Tank 27 as a blend tank. It is desirable to avoid additional worker exposure by using the planned commercial submersible mixing pump (CSMP) installations in Risers B2 and B4 to function as the blend pumps for prolonged blend tank operations. The purpose of this task is to evaluate the impacts to mixing across a range of pump installation heights from 1 to 201 inches. Specifications include: A maximum pump diameter of 22.5 inches, dual nozzles placed tangentially opposed with nominal inside diameter of 2 inches, a total flow range (both nozzles combined) of 500 to 1950 gallons per minute (gpm) and a maximum revolutions per minute (RPM) of 1800. Tank 27 is expected to have maximum fill height of 360 inches.

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Results for the September Bimonthly Calendar Year 2022 Tank 50 Salt Solution Sample

In this Technical Report, the chemical and radionuclide contaminant results from the 2022 September bimonthly sample of Tank 50 salt solution are presented in tabulated form. The information from this characterization will be used by Savannah River Mission Completion (SRMC) for the transfer of aqueous waste from Tank 50 to the Saltstone Production Facility (SPF), where the waste will be treated and disposed in the Saltstone Disposal Facility. This Technical Report compares results, where applicable, to SPF Waste Acceptance Criteria (WAC) LIMITS and TARGETS that were established at the time the Tank 50 sample was obtained. The chemical and radionuclide contaminant results from the characterization of the 2022 September bimonthly sampling of Tank 50 were requested by SRMC personnel via a Task Technical Request (TTR). Details of the testing are presented in the Savannah River National Laboratory (SRNL) Task Technical and Quality Assurance Plan (TTQAP). This Technical Report is the TTR deliverable relating Salt Solution Analysis from the SRMC request. The following facts pertaining to the WAC are drawn from the analytical results, including analytical uncertainty, provided in this report. 1) WAC LIMITS and TARGETS were met for all analyzed chemical and radioactive contaminants for which the detection limits are below the WAC LIMITS and TARGETS; 2) Measured average concentrations of nitrate, nitrite and total mercury are approximately 24%, 9% and 12% of the WAC LIMITS, respectively; 3) Measured average concentrations of Tc-99 and I-129 are approximately 19% and 20% of the WAC LIMITS, respectively; 4) All other radionuclide average concentrations are at 4% or less of the WAC LIMITS and TARGETS.

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Analysis of Thermal-Protection Systems for Space-Vehicle Cryogenic-Propellant Tanks

Analytical techniques are presented that permit the calculation of heat-transfer rates with various thermal-protection systems for liquid-cryogenic-propellant tanks subjected to on-board, solar, and planetary heat fluxes. The thermal-protection systems considered include using closely spaced reflective surfaces (foils) and widely spaced reflective surfaces (shadow shields), insulation, arrangement of vehicle components, orientation with respect to radiant heating sources, and coatings for the control of solar absorptivity. The effectiveness of these thermal-protection systems in reducing propellant heating is shown both for ideal heat-transfer models and for a simplified hydrogen-oxygen terminal stage on a Mars mission. The proper orientation of a space-vehicle cryogenic tank with respect to the Sun is one of the more beneficial methods of reducing the heating effect of solar flux. Shadow shields can be extremely effective in reducing the propellant heating due to both solar and on-board fluxes. However, low-altitude planet orbits can result in high propellant heating rates due to planetary radiation reflected from the shields. For low-altitude orbits of more than a few days, foils appear to be desirable for all cryogenic-tank surfaces. Foils are also effective in reducing the on-board heating. A choice of shadow shields or foils cannot be made until a particular vehicle and a particular mission are chosen. The thermal conductivity of insulation materials would have to be lower by about two orders of magnitude with no increase in density before insulation could compete with reflective surfaces for use in long-duration thermal protection of cryogenic tanks in space. To demonstrate the application of the methods devised, thermal-protection systems are developed for a hydrogen-oxygen terminal stage for typical Mars missions.

SPACE VEHICLE↗

Thermal Desktop Modeling of the 2016 CRYOTE-2 Tank Chill and Fill Tests

The storing and transfer of cryogenic propellants is an enabling technology for NASA as it moves to expand future missions into low Earth orbit (LEO) and beyond. The transfer of cryogenic propellants is of particular interest because it has never been successfully demonstrated in microgravity. Several ground tests have been conducted in past decades examining various tank chilldown and fill methods. Creating accurate models using these historical datasets is a vital step toward developing appropriate modeling tools to form pre-test predictions for eventual flight and ground tests of various novel injector concepts. The goal of this work was to create a working model in Thermal Desktop using data from the CRYOTE-2 experiments whose purpose was to demonstrate the chill and fill process in a spherical receiver tank parametrically examining the effect of injection method, receiver tank initial wall temperature and initial state, supply pressure, and mass flow rate on the NVF process. These tests were conducting using liquid nitrogen with different injectors with different injection patterns. The focus of the current work is on one particular spray nozzle. The pressure rise inside the tank, the fill level, and the change in the outside wall temperature were all tracked and compared with test data. The Thermal Desktop model was able to accurately predict each of these metrics for this nozzle within 11.0%, 22.0%, and 7.0%, respectively.

Cryogenic Tank Chilldown↗

Thermal Desktop Modeling of 2016 CRYOTE-2 Tank Chill and Fill Testing

The storing and transfer of cryogenic propellants is an enabling technology for NASA and industry as civilization moves to expand future missions into low Earth orbit and beyond. Several ground propellant transfer tests have been conducted in past decades examining various tank chilldown and fill methods. Creating accurate models using these historical datasets is a vital step toward developing appropriate modeling tools to form pre-test predictions for subsequent ground and flight propellant transfers. This paper presents model validation of Thermal Desktop using data from the 2016 CRYOTE-2 liquid nitrogen transfer experiments whose purpose was to demonstrate the chill and fill process in a spherical receiver tank. Tank pressure, fill level, and wall temperature were all modeled and compared with 8 test cases using two modeling methods, Mass Controlled, and Pressure Controlled. This test series is the hardest Thermal Desktop tank chill and fill validation case to-date, yet the model was able to accurately predict each of these metrics for the 2016 tests within 28%, 10%, 20% respectively, for pressure, fill level, and wall temperature using the Mass Controlled model, and 29%, 79%, and 12%, respectively for the Pressure Controlled model.

Cryogenic Tank Chilldown↗

Performance Testing of Liquid Hydrogen Tanks

Testing the performance of liquid hydrogen in tanks brings many unique challenges. Often methods used even for liquid nitrogen need to be modified to be able to address the details required to fully understand the performance of the tank. During the development and characterization of many novel insulation systems both for in-space and ground applications, NASA has tested many liquid hydrogen tanks where performance was a key outcome. Over the course of analyzing the performance of multiple different hydrogen tests, including several with both hydrogen and nitrogen, differences in the details of test data interpretation become clear. One of these key details is the thermal stratification of the tank and what it can tell you about the heat load dispersion.

Liquid Hydrogen↗

Blending of Radioactive Salt Solutions in Million Gallon Tanks - 13002

Research was completed at Savannah River National Laboratory (SRNL) to investigate processes related to the blending of radioactive, liquid waste, salt solutions in 4920 cubic meter, 25.9 meter diameter storage tanks. One process was the blending of large salt solution batches (up to 1135 - 3028 cubic meters), using submerged centrifugal pumps. A second process was the disturbance of a settled layer of solids, or sludge, on the tank bottom. And a third investigated process was the settling rate of sludge solids if suspended into slurries by the blending pump. To investigate these processes, experiments, CFD models (computational fluid dynamics), and theory were applied. Experiments were performed using simulated, non-radioactive, salt solutions referred to as supernates, and a layer of settled solids referred to as sludge. Blending experiments were performed in a 2.44 meter diameter pilot scale tank, and flow rate measurements and settling tests were performed at both pilot scale and full scale. A summary of the research is presented here to demonstrate the adage that, 'One good experiment fixes a lot of good theory'. Experimental testing was required to benchmark CFD models, or the models would have been incorrectly used. In fact, CFD safety factors were established by this research to predict full-scale blending performance. CFD models were used to determine pump design requirements, predict blending times, and cut costs several million dollars by reducing the number of required blending pumps. This research contributed to DOE missions to permanently close the remaining 47 of 51 SRS waste storage tanks. (authors)

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Methods for Heel Retrieval for Tanks C-101, C-102, and C-111 at the Hanford Site - 13064

The purpose of this paper is to evaluate the prospects of using bulk waste characteristics to determine the most appropriate heel retrieval technology. If the properties of hard to remove heels can be determined before bulk retrieval, then a heel retrieval technology can be selected before bulk retrieval is complete. This would save substantially on sampling costs and would allow the deployment of the heel retrieval technology immediately after bulk retrieval. The latter would also accelerate the heel removal schedule. A number of C-farm retrievals have been fully or partially completed at the time of this writing. Thus, there is already substantial information on the success of different technologies and the composition of the heels. There is also substantial information on the waste types in each tank based on historical records. Therefore, this study will correlate the performance of technologies used so far and compare them to the known waste types in the tanks. This will be used to estimate the performance of future C Farm heel retrievals. An initial decision tree is developed and employed on tanks C-101, C-102, and C 111. An assumption of this study is that no additional characterization information would be available, before or after retrieval. Note that collecting additional information would substantially increase the probability of success. Deploying some in-situ testing technologies, such as a water lance or an in-situ Raman probe, might substantially increase the probability of successfully selecting the process conditions without having to take samples from the tanks for laboratory analysis. (authors)

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Tank 48 Chemical Destruction - 13237

Small tank copper-catalyzed peroxide oxidation (CCPO) is a potentially viable technology to facilitate the destruction of tetraphenylborate (TPB) organic solids contained within the Tank 48H waste at the Savannah River Site (SRS). A maturation strategy was created that identified a number of near-term development activities required to determine the viability of the CCPO process, and subsequent disposition of the CCPO effluent. Critical activities included laboratory scale validation of the process and identification of forward transfer paths for the CCPO effluent. The technical documentation and the successful application of the CCPO process on simulated Tank 48 waste confirm that the CCPO process is a viable process for the disposition of the Tank 48 contents. (authors)

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Properties of selected non-pertechnetate species relevant to Hanford Tank Waste - 15019

Among radioactive constituents present in the Hanford tank waste technetium-99 (Tc) poses a multitude of problems associated with its radiotoxicity, unique and relatively poorly understood chemistry, and high mobility in the environment. Technetium is one of the most difficult contaminants to be addressed at the U.S. Department of Energy (DOE) Hanford Site because of its complex chemical behavior in tank waste and limited incorporation in the glass waste forms during mid- to high-temperature immobilization processes. The majority of Tc exists in the supernatant and salt cake fractions of both single- and double-shell tanks as pertechnetate TcO{sub 4}{sup -} (oxidation state +7) and in the reduced forms (oxidation state < +7) collectively known as non-pertechnetate (non-TcO{sub 4}{sup -}) species. Our research program is aimed at gaining understanding of the behavior of non-pertechnetate species in various oxidation states including such phenomena as redox speciation, hydrolysis, oligomerization, coordination of small organic ligands present in the tank supernatant, and solubility of the complex species. This paper describes our current results on the characterization and properties of the non-pertechnetate species. (authors)

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Improving high level waste solids mobilization and transfer through Hanford double-shell tanks - 15099

The Hanford Tank Operations Contractor (TOC) and the Hanford Waste Treatment and Immobilization Plant (WTP) contractor are both engaged in demonstrating mixing, sampling, and transfer system capabilities using simulated Hanford High-Level Waste (HLW) formulations. Efficient and effective handling of solid radioactive waste is essential to the successful completion of River Protection Project (RPP) mission and the Department of Energy's Hanford site. The TOC ust transfer over 416 million liters (110 million gallons) of HLW slurry through a complex system of 28 double shell tanks (DSTs) of approximately 3.8 million liters (1 million gallons) each as it is staged and delivered to the WTP. Through the use of scaled tanks and non-radioactive simulants, the TOC has identified operational methodologies for mixer pumps that enhance the movement of the solids through the DST system which will minimize the amount of solids remaining for final tank closeout. (authors)

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Investigations for improved tank characterization and cleaning - 15454

In the process of tank closure, significant waste characterization and chemical cleaning occur. Costly characterization is performed at numerous processing stages. A need exists for new strategies and technologies to understand, optimize, scale, and speed up tank waste characterization with the end goal of reducing costs through implementation of programmatic changes that accelerate tank waste processing and tank closure schedules. This paper will explore a possible alternative to waste characterization methodologies and cleaning technologies to reduce costs and improve processing efficiency. (authors)

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Progress in Defining the UK Highly Active Storage Tanks POCO Strategy - 16134

In the UK Highly Active (HA) waste is stored in stainless steel tanks prior to encapsulation in glass in one of three operating vitrification plants. Significant progress has been made in recent years towards the reduction in the volume of HA Liquor (HAL) stored in these tanks and a number of the tanks are now operating at heel levels. As a result, a strategy is being developed to carry out Post Operational Clean Out (POCO) of some tanks while reprocessing operations continue, thus enabling accelerated and more cost effective clean-up of these HA facilities. This paper, and subsequent conference presentation, will highlight some of the key aspects of this strategy, including a description of the challenges and progress made so far to help facilitate the clean-up mission without having a detrimental effect on ongoing reprocessing operations. (authors)

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Pursuing Cost Effective Tank Waste Characterization at the Savannah River Site - 16172

The U. S. Department of Energy Office of Environmental Management has tasked the Savannah River National Laboratory (SRNL) with developing strategies and technologies to understand, optimize, scale, and speed up tank waste characterization. This scope is part of a multi-year project with the end goal of implementing programmatic changes that accelerate tank waste processing and tank closure schedules, and at the same time reduce characterization costs, while maintaining data integrity. The project is currently in its second year. During the first year of the project, SRNL completed a series of activities focused on understanding the range of current characterization practices, needs, gaps, risks, and potential alternative approaches. Based on the results, conclusions were drawn regarding aspects of the programs that are most costly and time consuming; particular waste constituents that drive costs, schedule, and program risks; alternative characterization approaches (other than sampling and analysis) that are less expensive and more rapid; new laboratory methods holding the greatest promise for reducing characterization costs and schedule; and in whole, the primary areas where current characterization practices can be improved. SRNL's current scope is focusing on three primary activities: 1) development of a technical basis/strategy for improving the cost effectiveness and schedule of SRNL's tank closure characterization program; 2) design/assembly of hardware, plumbing, and software for automating select radiochemical separation and waste removal processes; and 3) development and testing of alternative radiochemical separation protocols most likely to improve high resource demand/time consuming analysis methods (such as Ra-226, Pa-231, Tc-99/I-129, and/or Y/trivalent actinide separations). (authors)

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Development of Inspection Tools for the AY-102 Double-Shell Tank at the Hanford DOE Site - 16383

Florida International University (FIU) has been developing inspection tools to assist in identifying the location of the leak in the primary tank of AY-102. This effort has led to the development of a magnetic miniature rover and a pneumatic pipe crawler. The rover will travel through the refractory cooling channels and the crawler will travel through the air supply lines to the central plenum underneath the primary tank. Both tools will provide visual feedback and potentially identify the location of the leak. The magnetic miniature tool is a remote controlled rover with four wheels driven by independent micro DC motors. The rover will have to navigate through over 40 feet of channel that vary in width from 1.5 to 3.0 inches with four 90 deg. turns to reach the center of the tank. To avoid debris in the channel, the device will travel upside down magnetically attached to the bottom of the primary tank. The pneumatic pipe crawler is a worm type robot with a modular design, composed of interchangeable cylindrical modules connected with flexible links. The design is an evolution of previous peristaltic crawlers developed at FIU, and uses pneumatic actuators to emulate the contractions of the peristaltic movement. The crawler must travel approximately 100 feet through three and four inch piping and traverse through vertical risers, elbows and reducers to reach the central plenum. Prototypes for both the rover and the crawler have been designed and manufactured. Initial bench scale testing has validated the design concepts, demonstrating their ability to navigate through complex geometries. Future work will include full scale testing and evaluation of the systems' reliability. (authors)

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NitroJet{sup R}'s Verification Test of Contaminated Water Storage Tank Decontamination in Fukushima Daiichi Nuclear Power Plant - 16489

After the Fukushima Daiichi nuclear disaster, much radioactively contaminated water has generated and has been stored into tanks in the site. Therefore, these contaminated water storage tanks (flange-type) are severely required to be decontaminated in order to be dismantled or to be reused to store cleaner water with less radioactive liquid waste and exposure of workers. Then, IHI Corporation (hereinafter, IHI) have verified that NitroJet{sup R} had capability to decontaminate these tanks under governmental grant (the Validation of technologies for contaminated water management project in the FY2013 Supplementary Budget). For this verification, IHI achieved acquiring DF (decontamination factor) by fabricating radioactive partial mock-ups with Rb-86. Moreover, IHI have demonstrated remote operation of decontamination work by using tank's partially full-scale mock up. (authors)

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Flowsheet Definition for the Tank Side Cesium Removal Unit and the Importance of Early Communication - 19142

The U.S. Department of Energy (DOE) tank operations contractor Washington River Protection Solutions, LLC (WRPS) is working toward the start of low-activity waste (LAW) treatment in direct feed mode as soon as 2022. WRPS is responsible for providing the pre-treated feed for this direct feed mode and had originally planned to use the Low Activity Waste Pretreatment System (LAWPS) to supply the initial feed in 2021. In September 2017, in response to a DOE-sponsored LAWPS program review, a new system was proposed to provide the initial feed during direct feed mode until a supplemental pretreatment capability is ready to begin processing feed. This system, known as the Tank Side Cesium Removal (TSCR) system, is based on the Savannah River Tank Closure Cesium Removal (TCCR) system and technology used to separate cesium out of reactor water at Fukushima. A preliminary flowsheet was needed to form the initial basis for future decisions and allow discussions between operations, project management, and the customer. The main goal of the TSCR flowsheet was to form a process flow diagram, process description, and much of the preliminary information to be used to help inform future decisions. When flowsheet development first began, little to no information was readily known and what was known needed to be compiled in one place and digestible by several audiences. The impacts of various parameters on the system also needed a vehicle for clear communication to varying audiences. While a more complicated model was being completed, a model of the process was created using Microsoft Excela which could have several parameters changed while maintaining basic logical requirements (such as treated waste volume cannot exceed the volume of the Interim LAW Storage Tank [ILST], must shutdown for so many days for column changeout, etc.). This program allowed the unit downtime, start dates, treatment rates, and several other variables to be modified and reflect the ILST storage volume as a function of mission progression. The model with several different parameters gathered from the various groups was combined into an early flowsheet of the TSCR process and created one of the first citable documents about TSCR implementation at Hanford. (authors)

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Development of a Semi-autonomous Miniature Rover for Inspection of Double Shell Tank Floors - 19575

Leaks in the primary liner of double-shell tank (DST) 241-AY-102 at Hanford have prompted the need for the development of inspection tools that are able to access confined spaces around and underneath the tanks. Last year, Florida International University (FIU) has continued to improve inspection tools that were developed in the previous years, to ensure that the resultant tools are able to overcome the challenges posed by the DSTs. Experimental testing conducted last year at the full-scale sectional mock-up of the DST's refractory slots revealed some shortcomings of the miniature rover, particularly in traversing over weld seams of different heights. The weld seams are the results of welded steel plate-joints for the DST. It was advised by the site engineers that the weld seams height could range from 6.35 mm - 9.525 mm (1/4 to 3/8 inches), and with 12.7 mm (1/2 inches) width. As the rover traverses over a weld seam, the gap between the rover's magnets and tank surface increases, causing the adhesive force to drop. The rover loses its surface contact if this adhesive force drops below its weight, jeopardizing the inspection tasks. In this paper, we present the numerical studies to calculate the minimum magnetic force required for the miniature rover to traverse over weld seams with different heights and the corresponding modifications to the rover design. Initial bench scale tests were conducted using a steel bar with 5 welds of varying heights. The testing validated the results from the simulation studies and established the rover's capability in traversing weld seams. Another challenge for the miniature rover is the use of a joystick or keypad for manual control. Utilizing these controls will likely be difficult for the operators due to the tight channels underneath the tank. Having a semi-autonomous navigational capability would alleviate the complexity of the inspection tasks and allow the operator to focus on the channel inspection. The goal is to implement lane-keeping capability, akin to that of a driverless car, for the inspection tool, so that it will maintain its relative position with respect to the wall of the channels. Am image processing pipeline has been developed using both the Robot Operating System (ROS) and OpenCV to process the image stream coming from the onboard camera, for the purpose of lane identification. Additionally, a PID controller has been implemented to navigate the miniature rover along the central location of the detected lane, while allowing the operator to control the tool's forward and backward motion. (authors)

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