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At least 1,153 records · Page 64

High power handling digitizer using photonics

Devices, methods for analog-to-digital converters (ADCs) that perform high-dynamic range measurements based on optical techniques are disclosed. In one example aspect, an optical encoder includes a polarization rotator configured to receive a train of optical pulses, and an electro-optic (EO) modulator coupled to an output of the polarization rotator. The EO modulator is configured to receive a radio frequency (RF) signal and to produce a phase modulated signal in accordance with the RF signal. The optical encoder also includes a polarizing beam splitter coupled to the output of the EO modulator; and an optical hybrid configured to receive two optical signals from the polarizing beam splitter and to produce four optical outputs that are each phase shifted with respect to one another.

DeVore, Peter Thomas Setsuda↗

Lessons Learned Converting A Commercial Enclosure to a Uranium Handling Glovebox

This presentation highlights the conversion of a commercial Directed Energy Deposistion machine to a radiological glovebox. An overview of some of the advanced manufacturing capabilities at INL is outlined along with some definitions and facts of additive manufacturing. The upgrades to the commercially purchased Optomec LENS MR-7 and the difficulties with qualifying it as a radiological glovebox are presented.

3-D Printing↗

Handling gait disturbances with asynchronous timing

An example method may include i) detecting a disturbance to a gait of a robot, where the gait includes a swing state and a step down state, the swing state including a target swing trajectory for a foot of the robot, and where the target swing trajectory includes a beginning and an end; and ii) based on the detected disturbance, causing the foot of the robot to enter the step down state before the foot reaches the end of the target swing trajectory.

Blankespoor, Kevin↗

Uncertainty analysis of densities and isotopics: Handling correlations

This paper discusses two cases of correlated parameters in uncertainty analyses: (1) the case of measured mass, density, and volume or spatial dimension correlations; and (2) the case of measured material isotopics, where increasing one atom fraction must cause the others to decrease. In the first case, an equation is derived that has a term due to uncertain density, a term due to uncertain dimensions, and a term due to the correlation between density and dimensions. In a numerical test problem, this equation gives the same result as the standard equation that treats mass and dimensions independently. In the case of isotopics, an equation is derived relating the uncertainty due to uncertain isotopic fractions to the sensitivities to isotopic densities, which are easier to calculate. The equation is verified in a test problem. (authors)

97 MATHEMATICS AND COMPUTING↗

Handling of Ammonium Nitrate Mother-Liquid Radiochemical Production - 13089

The aim of the work is to develop a basic technology of decomposition of ammonium nitrate stock solutions produced in radiochemical enterprises engaged in the reprocessing of irradiated nuclear fuel and fabrication of fresh fuel. It was necessary to work out how to conduct a one-step thermal decomposition of ammonium nitrate, select and test the catalysts for this process and to prepare proposals for recycling condensation. Necessary accessories were added to a laboratory equipment installation decomposition of ammonium nitrate. It is tested several types of reducing agents and two types of catalyst to neutralize the nitrogen oxides. It is conducted testing of modes of the process to produce condensation, suitable for use in the conversion of a new technological scheme of production. It is studied the structure of the catalysts before and after their use in a laboratory setting. It is tested the selected catalyst in the optimal range for 48 hours of continuous operation. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Potential application of curium neutron detection in the high reliability safeguards approach for remotely handled nuclear facilities

The study presented in this paper is part of a series of quantitative modeling efforts to characterize the neutron flux for the major subsystems in a pyroprocessing facility. An MCNPX model has established the electroreduction process, in which uranium oxide is converted into a metal product by electrochemical methods. This process is important because the electroreduction stage is the earliest point in the system where a diversion attempt could occur. This paper will present neutron flux for a commercial batch size. The intent of this study is to determine if the magnitude of the flux is sufficiently high as to affect facility design. (author)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

The Reactor Graphite Handling. Problems and Solutions - 17208

The problem of industrial uranium-graphite reactors and NPP units decommissioning is one of the urgent tasks that require efficient and cost-effective solutions. To date, only Russia has already shut down and subject to decommissioning more than 120 objects. World-wide, more than 260,000 ton of irradiated graphite have arisen from the commercial nuclear power operations, research reactors, and defense production reactors. Under the circumstances the problem to develop cost-effective methods of the irradiated graphite management has appeared. Alternative disposal options for the irradiated graphite were discussed for at least 25-30 years. To date, various methods of irradiated graphite reprocessing have been proposed. They are based on the application of different physical and chemical processes, most of which involve incineration of the entire mass of graphite. However, they all have disadvantages, and do not solve the whole complex of problems. The primary goal of the research presented here was to carry out a study aimed at the development of a more simple technology (as compared to the incineration of the entire mass of graphite) that would provide for the graphite purification and allow the possibility of its transfer to the less hazardous waste category followed by the disposal of it in a near-surface repository. To achieve it is proposed to consider two directions, each of them reducing the cost of graphite reprocessing and the waste volume disposed of in the repository. The first alternative is based on the principle of partitioning radionuclides of different nature from the graphite, thus allowing to transfer it into the LLW category and minimize the volume of secondary waste products. The second option to change the reprocessing technology is the idea to use reactor graphite as the starting material to produce stable final waste form compositions intended for the long-term storage of radioactive waste including transuranic elements. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Regulatory inspection of the provision of disposability assessment and waste packaging advice in the UK to provide confidence that higher activity waste stored on licensed sites will be suitable for safe handling, transport and disposal - 15088

Radioactive Waste Management Limited (RWM), the developer and future operator of a geological disposal facility (GDF) in the United Kingdom, operates a disposability assessment process to minimise the risk that current conditioning and packaging of higher activity wastes (HAW) will result in packages incompatible with geological disposal in the future. Specialists in nuclear and environmental safety from the Office for Nuclear Regulation (ONR) and the Environment Agency (EA) in 2013/14 completed an inspection of the RWM's process of disposability assessment. The inspection gave the regulators confidence that RWM has in place a systematic process to provide an important means of reducing risks associated with waste packaging in advance of an operational GDF and that the process of disposability assessment is providing the necessary information for licensees to assure future HAW disposal to the GDF. This work forms part of our continuing programme to review RWM's work related to geological disposal of higher activity radioactive waste (HAW). (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Decommissioning costs - some international perspectives and initiatives. Presentation for Panel discussion. Session No. 024: 'Getting a Handle on Decommissioning Costs - a Global Perspective'

Financing for decommissioning: Are the cost estimates valid? Are the financing arrangements suitable? Are the fund management systems appropriate? Cost estimates are estimated, analysed and updated on a regular basis, but cost comparisons are not straight-forward. There is an incomplete understanding of variability between estimates. Multiple internal and external factors impact estimates: Institutional, legal and policy, purpose, Strategies and plans, overall context, Facility characteristics and history Contingencies and risk, Limited actual cost data. The financing arrangements: there exists a range of systems in place for the implementation of Funding Policy and Strategy, but there are Considerable variations in: Calculating funding requirements, contributions/provisions, Allocating risks and requirements for securities Managing funds and accounting, adjusting the system, Managing disbursements, Reporting and supervision. All cost estimates for future decommissioning activities include considerable uncertainties. These uncertainties will gradually diminish with growing experience from current and planned projects. Different costing methods have different data requirements. Their reliability depends on the extent to which various data are available and applicable to the specific case being considered. Independent of the assessment method, some uncertainty is inevitable in all estimates of future costs. Analysis of the costing method may be useful in order to locate the key uncertainties in each specific estimate. NEA's Decommissioning Cost Estimation Group (DCEG) was Created in 2008 to foster the exchange of information and experience. It Aims to enhance the credibility, reliability, and auditability of the cost estimation process. It Helps define international good practices in decommissioning cost estimation. However, some major challenges remain. Weaknesses in: Understanding relations between estimates and actual costs, Lack of relevant cost data, sharing data. How might be addressed: Improved sharing of cost data, Systematic analyses of estimates and actual costs, Developing benchmarking approaches.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Mercury Speciation in Savannah River Site High-Level Waste: Determination and Implications for Waste Handling and Disposal - 16178

As part of a larger program to address mercury issues at the Savannah River Site, a number of samples from across the salt processing flowsheet have been collected and analyzed for several mercury species. The results indicate the presence of organomercury species, predominately methylmercury cation. This result was not expected, and it represents a significant paradigm shift in the understanding of mercury chemistry in high-level tank waste. Concentrations of total and soluble mercury have been measured as high as 0.5 g/L with methylmercury concentrations of at least fifty percent of that value. The distribution of mercury species being observed have ramifications to waste processing strategies. In particular, the mercury behavior across the cesium solvent extraction process has been examined. Leachates, from toxicity testing of the cementitious waste form used for decontaminated salt waste at Savannah River, have been tested and shows methylmercury as the dominant extractable species. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Daher-TLI UCSC Wash Process - Lessons Learned from Handling a Legacy Cylinder - 16506

The Daher-TLI UF{sub 6} Cylinder Service Center (UCSC) began operation in 2013 and functions as a dedicated wash, re-certification, storage and disposal facility for 122 cm uranium hexafluoride (UF{sub 6}) cylinders. The primary purpose of the facility is to provide cylinder cleaning and re--certification services to the UF{sub 6} industry for cylinders that previously contained natural or depleted UF6. The facility also has the ability to recover most of the uranium in the form of uranyl peroxide (UO{sub 4}) or triuranium octoxide (U{sub 3}O{sub 8}). Small residues of UF{sub 6} (commonly referred to as a heel) from natural cylinders are removed and treated in a patented three-step purification process that recovers U{sub 3}O{sub 8} that meets the ASTM specification. The wastewater ordinarily contains a mixture of sodium salts (77% sodium sulfate, 23% sodium nitrate) along with minute traces of uranium (1 - 2 mg/L) and fluoride (10 - 20 mg/L). Over a period of 6 months, lab analyses were performed on the filtrate from a legacy cylinder in an attempt to separate uranium and fluoride from this stream. These pilot results established near quantitative recovery of uranium (< 1 mg/L) and near complete separation of fluorides (5 - 15 mg/L). This paper follows the efforts of the Daher-TLI UCSC to process the abnormal heeled UF{sub 6} cylinder. This paper also documents the lessons learned from this experience and how those lessons were used to improve the UCSC wash process. These modifications served to recover 99.87% of the input uranium as UO{sub 4} while simultaneously creating a waste stream with only trace amounts of impurities. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Panel Session 111: Nuclear Power Plant Onsite SNF storage, ISFSIs and Failed Fuel Handling Issues

This panel session provided updates on several issues seen in developing, operating independent spent fuel storage installations (ISFSIs), Damaged Fuel and aging management recent activities. Presentations proposed include: 1 - Spent Nuclear Fuel Management Activities at Holtec (Myron Kaczmarsky, Holtec International (USA)); 2 - INL Spent Fuel Management: Challenges and Path Forward for Dry Storage (Josh Jarrell, Idaho National Laboratory (USA))

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Handling Iterative Solvers in an Algorithmic Differentiation Framework Using Implicit Methods

Differentiable programming is a powerful concept as it enables the seemly propagation of gradients through functions, algorithms, and/or whole physics simulations. These gradients are useful for a wide variety of applications, including sensitivity studies and machine learning, but one of particular interest is optimization. Gradient-based optimization, enabled through automatic/algorithmic differentiation (AD), can be used on predictive physical models to efficiently optimize a set of design variables. AD methods are a particularly promising approach to complex physics simulations because they can be shown to scale well with an increasing number of design variables; however, care must be taken when coupling between different models or different states of a single model.

algorithmic differentiation↗

Revolutionizing Waste Management: AI-Powered Real-Time Characterization for Efficient Handling of Non-Recyclable Municipal Solid Waste

According to EPA, -300 MM tons of municipal solid waste (MSW) was available in the US as of 2018. Of that total material, nearly 50% was landfilled resulting in a significant loss for the potential to convert its energy value into cost effective and sustainable biofuels. Redirecting this material away from the landfill and into conversion ready feedstock for energy generation can directly address DOE's selling price < $2.50/GGE while securing the US national energy independence [1]. However, the paramount challenges in any rational fuel conversion strategy are understanding the chemical makeup, quality and associated calorific value of the MSW. Understanding these parameters is critical in achieving any acceptable fuel conversion and requires rapid characterization followed by accurate separation technologies. Therefore, we are proposing to address the rapid characterization by building a non-invasive, rapid, and highly accurate Artificial Intelligence (AI)-enabled spectrometric/optical approach augmented with multi-sensory information for advanced characterization of domestic heterogeneous MSW. North Carolina State University (NCSU) and the National Renewable Energy Laboratory (NREL), in partnership with strong support from the Town of Cary and IBM, Inc., will closely work together to implement this ground-breaking technology for the effective characterization of MSW for sustainable and affordable production of conversion-ready feedstocks, while solving the environment issue of planetary proportions.

artificial intelligence↗