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A focal plane assembly facilitates a molybdenum base plate being mounted to another plate made from aluminum. The molybdenum pin is an interference fit (press fit) in the aluminum base plate. An annular cut out area in the base plate forms two annular flexures.
Disclosed herein are atmospheric pressure pin-to-hole pulsed spark discharge devices and methods for creating plasma. The devices include a conduit for fluidically communicating a gas, a plasma, or both, therethrough, portion of the conduit capable of being connected to a gas supply, and a second portion of the conduit capable of emitting a plasma; a positive electrode comprising a sharp tip; and a ground plate electrode. Disclosed are methods for treating a skin ulcer using non-thermal plasma include flowing a gas through a cold spark discharge zone simultaneously with the creation of a pulsed spark discharge to give rise to a non-thermal plasma emitted from a conduit, the non-thermal plasma comprising NO; and contacting a skin ulcer with said non-thermal plasma for sufficient time and intensity to give rise to treatment of the skin ulcer.
Detecting diversion of spent fuel from Pressurized Water Reactors (PWR) by determining possible diversion including the steps of providing a detector cluster containing gamma ray and neutron detectors, inserting the detector cluster containing the gamma ray and neutron detectors into the spent fuel assembly through the guide tube holes in the spent fuel assembly, measuring gamma ray and neutron radiation responses of the gamma ray and neutron detectors in the guide tube holes, processing the gamma ray and neutron radiation responses at the guide tube locations by normalizing them to the maximum value among each set of responses and taking the ratio of the gamma ray and neutron responses at the guide tube locations and normalizing the ratios to the maximum value among them and producing three signatures, gamma, neutron, and gamma-neutron ratio, based on these normalized values, and producing an output that consists of these signatures that can indicate possible diversion of the pins from the spent fuel assembly.
The standard multigroup (MG) method for energy discretization of the transport equation can be sensitive to approximations in the weighting spectrum chosen for cross-section averaging. As a result, MG often inaccurately treats important phenomena such as self-shielding variations across a material. From a finite-element viewpoint, MG uses a single fixed basis function (the pre-selected spectrum) within each group, with no mechanism to adapt to local solution behavior. In this work, we introduce the Finite-Element-with-Discontiguous-Support (FEDS) method, whose only approximation with respect to energy is that the angular flux is a linear combination of unknowns multiplied by basis functions. A basis function is non-zero only in the discontiguous set of energy intervals associated with its energy element. Discontiguous energy elements are generalizations of bands and are determined by minimizing a norm of the difference between snapshot spectra and their averages over the energy elements. We begin by presenting the theory of the FEDS method. We then compare to continuous-energy Monte Carlo for one-dimensional slab and two-dimensional pin-cell problem. We find FEDS to be accurate and efficient at producing quantities of interest such as reaction rates and eigenvalues. Results show that FEDS converges at a rate that is approximately first-order in the number of energy elements and that FEDS is less sensitive to weighting spectrum than standard MG.
CTF is the modernized and improved version of the subchannel code, COBRA-TF. It has been adopted by the Consortium for Advanced Simulation for Light Water Reactors (CASL) for subchannel analysis applications and thermal hydraulic feedback calculations in the Virtual Environment for Reactor Applications Core Simulator (VERA-CS). CTF is now jointly developed by Oak Ridge National Laboratory and North Carolina State University. Until now, CTF has been used for pressurized water reactor modeling and simulation in CASL, but in the future it will be extended to boiling water reactor designs. This required development activities to integrate the code into the VERA-CS workflow and to make it more ecient for full-core, pin resolved simulations. Additionally, there is a significant emphasis on producing high quality tools that follow a regimented software quality assurance plan in CASL. Part of this plan involves performing validation and verification assessments on the code that are easily repeatable and tied to specific code versions. This work has resulted in the CTF validation and verification matrix being expanded to include several two-phase flow experiments, including the General Electric 3 3 facility and the BWR Full-Size Fine Mesh Bundle Tests (BFBT). Comparisons with both experimental databases is reasonable, but the BFBT analysis reveals a tendency of CTF to overpredict void, especially in the slug flow regime. The execution of these tests is fully automated, analysis is documented in the CTF Validation and Verification manual, and the tests have become part of CASL continuous regression testing system. This paper will summarize these recent developments and some of the two-phase assessments that have been performed on CTF.
A method for producing a long length high temperature superconductor wire, includes providing a substrate, having a surface with a length of at least 50 meters and a width. The surface supports a biaxially textured high temperature superconducting layer and the biaxially textured high temperature superconducting layer has a length and a width corresponding to the length and width of the surface of the substrate. The method includes irradiating the biaxially textured high temperature superconductor layer with an ion beam impinging uniformly along the length and across the width of the biaxially textured high temperature superconductor layer to produce a uniform distribution of pinning microstructures in the biaxially textured high temperature superconductor layer.
Disclosed herein are atmospheric pressure pin-to-hole pulsed spark discharge devices and methods for creating plasma. The devices include a conduit for fluidically communicating a gas, a plasma, or both, therethrough, portion of the conduit capable of being connected to a gas supply, and a second portion of the conduit capable of emitting a plasma; a positive electrode comprising a sharp tip; and a ground plate electrode. Disclosed are methods for treating a skin ulcer using non-thermal plasma include flowing a gas through a cold spark discharge zone simultaneously with the creation of a pulsed spark discharge to give rise to a non-thermal plasma emitted from a conduit, the non-thermal plasma comprising NO; and contacting a skin ulcer with said non-thermal plasma for sufficient time and intensity to give rise to treatment of the skin ulcer.
Automated fault prediction and diagnosis in HPC systems needs to be efficient for better system resilience. With increasing scalability required for exascale, accurate fault prediction aiding in quick remedy is hard. With changing supercomputer architectures, distilling fault data from the noisy raw logs requires substantial efforts. Predicting node failures in such voluminous system logs is challenging. To this end, we investigate an interesting way to pin-point node failures in such supercomputing systems. Our study on Cray system data with automated machine learning tools suggests that specific patterns of event messages on node unavailability can be indicator to node failures. This data extraction coupled with system and job data correlation helps in devising a methodology to predict node failures and their location over a specific time frame. This work aims to enable broader applicability for a generic fault prediction framework.
The mechanical strength of extrusion-based printed parts is often greatly reduced (25-50%) in the build direction (z-direction) compared to the in-plane strength due to poor bonding between successively deposited layers. This effect can be magnified (75-90% difference) when depositing fiber-reinforced materials or larger print areas with long layer times. Therefore, a patent-pending approach has been developed that deposits material into intentionally aligned voids in the zdirection, allowing continuous material to span multiple layers. The “z-pinning” approach can be applied to several concepts for improving the interlaminar strength of extrusion-based 3D printed parts as well as techniques for applying the technology across a broad spectrum of deposition platforms and material systems. Initial experimental results demonstrate a significant improvement (>3x) in mechanical strength and (>8x) toughness for fiber reinforced components.
The variational nodal method (VNM) as implemented in the VARIANT code has been widely employed to fast reactor cores, but much less so for thermal reactors. In what follows we report the initial phase of development of the PANX code (Purdue - Argonne - Northwestern - Xi'an) for three-dimensional pin resolved PWR transport calculations. In two dimensions, prototype modifications of VARIANT using finite elements to obtain heterogeneous nodes and quasi-reflected interface conditions to reduce the high angular-order interface conditions, have been successfully employed to the 2D C5G7 benchmark. In three dimensions, however, the polynomial interface conditions employed in VARIANT smear fuel and coolant at each axial interface, leading to lack of convergence as the axial mesh is refined. This problem is also encountered in the 2D/1D approximations in MOC based methods. The intent of this work is to eliminate these interface homogenization effects from VNM calculations. For clarity, in this work we examine these phenomena in diffusion theory. The next stage of development will incorporate spherical harmonic trial functions to achieve more accurate transport solutions. (authors)
The variational nodal method (VNM) as implemented in the VARIANT code has found wide application to fast reactor problems where fuel assembly homogenization does not result in unacceptable errors. The objective of this research is to generalize VNM for application to PWR problems, where homogenization even at the pin-cell level often results in unacceptable errors. To accomplish this, we are developing the PANX code (Purdue - Argonne - Northwestern - Xi'an) to implement a 2D/1D VNM transport method without spatial homogenization employing spherical harmonics and diffusion theory, respectively, in the radial and axial directions. In the preceding paper, we employed diffusion theory in conjunction with finite element methods to implement heterogeneous VNM nodes, in which the problem of fuel-coolant smearing at axial interfaces, found in existing 2D/1D approximations, is eliminated. In this work, we generalize the resulting VNM nodes to couple spherical harmonics in the x-y plane with axial diffusion theory. We then apply the method to the three-dimensional C5G7 benchmark problem. (authors)
Texas A and M University is conducting isothermal flow tests in a wire-wrapped, 61-pin hexagonal fuel bundle to support the research on advanced nuclear fuel development sponsored by the Department of Energy (DOE). The purpose of these tests is to produce high spatial- and temporal-resolution measurements of the flow and pressure measurements at different locations of the test bundle. The data resulting from these tests will be used to benchmark numerical simulations of the experiments using both industry-standard Reynolds-averaged Navier-Stokes (RANS) based Computation Fluid Dynamics (CFD) methods and a highly resolved Large Eddy Simulation (LES) computer code. This article described the main features of the experimental facility, its capabilities in producing experimental data of pressure drop and velocity fields at different axial locations and within different exterior and interior sub-channels, using advanced flow visualization techniques. Examples of experimental data outputs and typical locations of the measurements that will included in the research scope are also shown in this article. (authors)
Texas A and M University is conducting isothermal experiments in a wire-wrapped 61-pin hexagonal fuel bundle to support the research on advanced nuclear fuel development sponsored by the Department of Energy (DOE). The purpose of these experiments is to produce high spatial and temporal resolution measurements of the flow and pressure measurements at different locations of the test bundle. The experimental data will be used to benchmark numerical simulations of the experiments using both industry-standard Reynolds-averaged Navier-Stokes (RANS) based computational fluid dynamics (CFD) methods and highly resolved large eddy simulations (LES). (authors)
The Advanced Fuel Campaign’s Fission Accelerated Steady-state Testing (FAST) program uses metallic fuel pins with small diameters to reach a desired burnup more quickly. This enables accelerated testing of advanced fuel designs and decreases the time between idea conception and commercial usage. Post-irradiation examination is critical in this process, especially with respect to the fuel-cladding chemical interactions (FCCI). In this work, energy dispersive X-ray spectroscopy (EDS) is used to track how elements from the fuel and fission products have diffused through the cladding. Elemental redistribution along the fuel-cladding interface is mapped and FCCI region thicknesses are measured. The correlations between geometry, temperature, burnup, and FCCI thickness are presented.
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Topological insulators are of interest for many applications in electronics and optoelectronics, but harnessing their unique properties requires detailed understanding and control of charge injection at electrical contacts. Here we present large-scale ab initio calculations of the electronic properties of Au, Ni, Pt, Pd, and graphene contacts to Bi 2 Se 3 . We show that regardless of the metal, the Fermi level is located in the conduction band, leading to n-type Ohmic contact to the first quintuplet. Furthermore, we find strong charge transfer and band-bending in the first few quintuplets, with no Schottky barrier for charge injection even when the topoplogical insulator is undoped. Our calculations indicate that Au and graphene leave the spin-momentum locking mostly unaltered, but on the other hand, Ni, Pd, and Pt strongly hybridize with Bi 2 Se 3 and relax spin-momentum locking. In conclusion, our results indicate that judicious choice of the contact metal is essential to reveal the unique surface features of topological insulators.