41 research outputs found
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The effect of adding crystalline silicotitanate on the durability, liquidus, and viscosity of simulated high-level waste glasses at Savannah River Site
This report provides a summary of the results obtained for a limited variability study for glasses containing Crystalline Silicotitanate (CST), Monosodium Titanate (MST), and either simulated Purex or HM sludge. Twenty-two glasses containing Purex sludge and three glasses containing HM sludge were fabricated and tested. The fabricated glasses were tested for durability using the 7-day Product Consistency Test (PCT) and characterized by measuring the viscosity at 1,150 C and by determining an approximate, bounding liquidus temperature. The current models used by Defense Waste Processing Facility (DWPF) for predicting durability, viscosity, and liquidus temperature were applied to all 25 glasses. The goal of this work was to identify any major problems from a glass perspective, within the scope of this effort, which could potentially preclude the use of CST at DWPF
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Basic data report: Canister penetration system with relative humidity and pressure sensors
This work originates from a task assignment. This basic data report is for design and fabrication of a canister penetration system for use in these experiments. The basic system was designed and fabricated as a result of a previous task assignment and three associated task plans. The new system, which will be used on canistered waste forms produced during the DWPF Start up Test Program, will be a modification of the previous systems. Hence the seven items identified in the next paragraph have been previously designed, fabricated, and tested but will be required as part of the overall system. The canister penetration system to be designed and fabricated shall consist of (1) a device which can penetrate the canister above the glass line while preventing the mixing of the air within the canister with the air in the environment, (2) a sensor for measuring the relative humidity and dew point of the air within the canister, (3) a sensor for detecting the pressure of the system before penetration and the pressure of the canister and system after penetration, (4) a vacuum system for evacuating the canister penetration system, (5) a connecting port to a mass spectrometer for on line analysis of the air within the free volume, (6) a number of valves and joints (fittings) which make up the interconnecting plumbing, and (7) a calibrated container for use in measuring the free volume. All of these items are deliverables. The major focus of this design task is to modify six canisters, prior to glass filling, in order to provide for linkage with the above system after glass filling. This linkage shall not involve welding or drilling. The modification of the canister shall be such that it does not interfere with normal operations
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Compliance with the Nevada Test Site`s waste acceptance criteria for vitrified cesium-loaded crystalline silicotitanates
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/m{sup 3}. 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
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Effect of CST ion exchange loading on the volume of glass produced during the vitrification demonstration at SRTC
ORNL and SRTC have a joint project in which 25,000 gallons of supernate waste from the Melton Valley Storage Tanks at Oak Ridge will be treated by passage through a crystalline silicotitanate (CST) ion exchange medium. The CST was designed to sorb cesium, the primary radionuclide (Cs-137) in the supernate of the Melton Valley tanks. A smaller amount of strontium will also be sorbed. At least one drum of the loaded sorbent will then be shipped to SRTC where it will be mixed with glass formers and fed as an aqueous slurry to an 1,150 C joule-heated melter within the SRTC Shielded Cells. The molten glass will be poured into 500 ml stainless steel beakers. The original plan was to place the 500 ml beakers in 30 gallon drums for shipment to and disposal at the Nevada Test Site (NTS). A recent scope change included provisions to dispose of the vitrified waste at SRS. This report addresses requirements for disposal at either NTS or SRS. Current efforts in formulation experimentation will define the CST loading for the demonstration. The glass waste form must meet durability requirements, RCRA metal release limits, and viscosity. Liquidus, and redox requirements for processing. As indicated, higher waste loadings will reduce the processing time required, thus, reducing the overall costs. An added benefit, of course, is the reduction of total waste volume provided by higher loadings, leading to less waste disposal
Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.
BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
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Development of an Initial Simulant for the Idaho Tank Farm Solids
The goal of this task was to develop the methodology for producing a suitable simulant for waste solids and the fabrication of an initial simulant for use in the demonstrations and testing performed as part of the down-select process for disposition of INTEC tank waste. The analytical results from WM-182 and WM-183 tank samples were used as the basis for this work
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Measurement of DWPF glass viscosity - Final Report
This report details the results of a scoping study funded by the Defense Waste Processing Facility (DWPF) for the measurement of melt viscosities for simulated glasses representative of Macrobatch 2 (Tank 42/51 feed)
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Glass formulation requirements for DWPF coupled operations using crystalline silicotitanates
The design basis DWPF flowsheet couples the vitrification of two waste streams: (1) a washed sludge and (2) a hydrolyzed sodium tetraphenylborate precipitate product, PHA. The PHA contains cesium-137 which had been precipitated from the tank supernate with sodium tetraphenylborate. Smaller amounts of strontium and plutonium adsorbed on sodium titanate are also present with the PHA feed. Currently, DWPF is running a sludge-only flowsheet while working towards solutions to the problems encountered with In Tank Precipitation (ITP). The sludge loading for the sludge-only flowsheet and for the anticipated coupled operations is 28 wt% on an oxide basis. For the coupled operation, it is essential to balance the treatment of the two waste streams such that no supernate remains after immobilization of all the sludge. An alternative to ITP and sodium titanate is the removal of Cs-137, Sr-90, and plutonium from the tank supernate by ion exchange using crystalline silicotitanate (CST). This material has been shown to effectively sorb these elements from the supernate. It is also known that CST sorbs plutonium. The loaded CST could then be immobilized with the sludge during vitrification. It has recently been demonstrated that CST loadings approaching 70 wt% for a CST-only glass can be achieved using a borosilicate glass formulation which can be processed by the DWPF melter. Initial efforts on coupled waste streams with simulated DWPF sludge show promise that a borosilicate glass formulation can incorporate both sludge and CST. This paper presents the bases for research efforts to develop a glass formulation which will incorporate sludge and CST at loadings appropriate for DWPF operation
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Glass formulation requirements for Hanford coupled operations using crystalline silicotitanates (CST)
The U.S. Department of Energy (DOE) through the Richland Operations Office has requested proposals from the private sector for the treatment of waste from the Hanford Waste Tanks. Phase I of this privatization initiative may include a demonstration for treatment and immobilization of both low activity and high-level waste. If the demonstration includes high-level waste, then the Cs-137 waste stream most likely will be combined with the high-level waste sludge to produce a coupled feed for immobilization (most likely vitrification using a borosilicate glass). It appears that pretreatment will involve the removal of cesium (and perhaps strontium and some transuranic radionuclides) from the supernate using an ion exchange material such as crystalline silicotitanate (CST). The ion exchange sorbent (or the eluted Cs-137) can then be combined with the sludge and vitrified in a coupled operation similar to the DWPF process. Alternatively, the cesium-loaded ion exchange sorbent can be vitrified directly to produce a separate glass waste form. SRTC has been involved in an Office of Science and Technology (EM-50) funded project to determine if Cs-137 loaded CST can be successfully incorporated into glass at significant levels. 1 For a waste form which would include only Cs-137 loaded CST, concentrations up to 60 wt% of CST in glass have been achieved. 2 The glass produced from this demonstration is both processable and durable. This CST-only waste form could be used at Hanford if the cesium-loaded CST is vitrified in a separate melter. For coupled feed operations, the CST would be mixed with high-level radioactive sludge from the Hanford tanks. This report provides the basis and the path forward for SRTC`s efforts at developing a glass frit formulation which will incorporate both Hanford sludge and cesium-loaded CST for a coupled flowsheet. The goal of this work is to demonstrate the feasibility of vitrification as a method for immobilization of coupled feed (specifically, Cs-137-loaded CST). (Abstract Truncated