MELCOR Code Development Status
A presentation giving a current status of the various tasks for the MELCOR code development is provided, including some recently corrected code issues.
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
SEARCH · Engineering Papers
Results for “Code”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Modeling Constituent Redistribution in U-Pu-Zr Metallic Fuel Using the Advanced Fuel Performance Code BISON
The Advanced Fuels Campaign (AFC) metallic fuels currently being tested have higher zirconium and plutonium concentrations than those tested in the past in EBR reactors. Current metal fuel performance codes have limitations and deficiencies in predicting AFC fuel performance, particularly in the modeling of constituent distribution. No fully validated code exists due to sparse data and unknown modeling parameters. Our primary objective is to develop an initial analysis tool by incorporating state-of-the-art knowledge, constitutive models and properties of AFC metal fuels into the MOOSE/BISON (1) framework in order to analyze AFC metallic fuel tests.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Decoding and optimized implementation of SECDED codes over GF(q)
A plurality of columns for a check matrix that implements a distance d linear error correcting code are populated by providing a set of vectors from which to populate the columns, and applying to the set of vectors a filter operation that reduces the set by eliminating therefrom all vectors that would, if used to populate the columns, prevent the check matrix from satisfying a column-wise linear independence requirement associated with check matrices of distance d linear codes. One of the vectors from the reduced set may then be selected to populate one of the columns. The filtering and selecting repeats iteratively until either all of the columns are populated or the number of currently unpopulated columns exceeds the number of vectors in the reduced set. Columns for the check matrix may be processed to reduce the amount of logic needed to implement the check matrix in circuit logic.
97 MATHEMATICS AND COMPUTING↗
Development of FESTR: a new spectroscopic modeling and analysis code
The FESTR code solves the radiation transport equation to model LTE and NLTE plasmas. Motivation, implementation, examples, and future work regarding the code are presented in a series of slides.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Beam Dynamics in an Electron Lens with the Warp Particle-in-cell Code
Electron lenses are a mature technique for beam manipulation in colliders and storage rings. In an electron lens, a pulsed, magnetically confined electron beam with a given current-density profile interacts with the circulating beam to obtain the desired effect. Electron lenses were used in the Fermilab Tevatron collider for beam-beam compensation, for abort-gap clearing, and for halo scraping. They will be used in RHIC at BNL for head-on beam-beam compensation, and their application to the Large Hadron Collider for halo control is under development. At Fermilab, electron lenses will be implemented as lattice elements for nonlinear integrable optics. The design of electron lenses requires tools to calculate the kicks and wakefields experienced by the circulating beam. We use the Warp particle-in-cell code to study generation, transport, and evolution of the electron beam. For the first time, a fully 3-dimensional code is used for this purpose.
43 PARTICLE ACCELERATORS↗
QPhiX Code Generator
A simple code-generator to generate the low level code kernels used by the QPhiX Library for Lattice QCD. Generates Kernels for Wilson-Dslash, and Wilson-Clover kernels. Can be reused to write other optimized kernels for Intel Xeon Phi(tm), Intel Xeon(tm) and potentially other architectures.
Joo, Balint↗
Non-uniform Neutron Source Approximation for Iterative Reconstruction of Coded Source Images
X-ray and neutron optics both lack ray focusing capabilities. An x-ray source can be made small and powerful enough to facilitate high-resolution imaging while providing adequate flux. This is not yet possible for neutrons. One remedy is to employ a computational imaging technique such as magnified coded source imaging. The greatest challenge associated with successful reconstruction of high-resolution images from such radiographs is to precisely model the flux distribution for complex non-uniform neutron sources. We have developed a framework based on Monte Carlo simulation and iterative reconstruction that facilitates high- resolution coded source neutron imaging. In this paper, we define a methodology to empirically measure and approximate the flux profile of a non-uniform neutron source, and we show how to incorporate the result within the forward model of an iterative reconstruction algorithm. We assess improvement in image quality by comparing reconstructions based respectively on the new empirical forward model and our previous analytic models.
Gregor, Jens↗
Code Analysis and Refactoring with Clang Tools, Version 0.1
Code Analysis and Refactoring with Clang Tools is a small set of example code that demonstrates techniques for applying tools distributed with the open source Clang compiler. Examples include analyzing where variables are used and replacing old data structures with standard structures.
Kelley, Timothy M.↗
Update on the Code Intercomparison and Benchmark for Muon Fluence and Absorbed Dose Induced by an 18 GeV Electron Beam After Massive Iron Shielding
In 1974, Nelson, Kase and Svensson published an experimental investigation on muon shielding around SLAC high-energy electron accelerators [1]. They measured muon fluence and absorbed dose induced by 14 and 18 GeV electron beams hitting a copper/water beamdump and attenuated in a thick steel shielding. In their paper, they compared the results with the theoretical models available at that time. In order to compare their experimental results with present model calculations, we use the modern transport Monte Carlo codes MARS15, FLUKA2011 and GEANT4 to model the experimental setup and run simulations. The results are then compared between the codes, and with the SLAC data.
Fasso, A.↗
Studies of EMP generation using a Lienard-Wiechert formulation, and progress toward a 3-D EMP code
Here, we describe studies of the generation of electro-magnetic pulse (EMP) fields under the idealized conditions of a delta-function gamma pulse, a spherical cap of Compton electrons located at a common radius from the burst, and the absence of the conduction current. Various processes (geomagnetic rotation, drag, and scattering) contribute to the time derivative of the Compton current density, which appears as the source term in the Lienard–Wiechert expression for the radiation field. These processes are considered separately and in combination, and their influences on the waveform of the EMP assessed. Using a separate computational approach, different numerical models of multiple scattering are tested, in an effort to assess the validity of existing codes and earlier results. We also describe plans for and progress toward a comprehensive 3-D EMP code, which is to employ recently developed numerical methods and is to offer a variety of models, including the Lienard–Wiechert formulation described here.
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
EMPulse, a new 3-D simulation code for EMP formation and propagation
EMPulse is a comprehensive and modern 3-D simulation code for electro-magnetic pulse (EMP) formation and propagation studies, being developed at LLNL under a Laboratory Directed R&D (LDRD) initiative that was launched in the fall of 2014. Furthermore, EMPulse builds upon the open-source Warp particle-in-cell code framework which was developed by members of this team and collaborators at other institutions. Our goal of this endeavor is a new tool, using methods different from those in common use, and enabling the detailed and self-consistent study of multidimensional effects in geometries that have typically been treated only approximately. We describe the underlying Warp framework and its capabilities; the models that have been or are being newly developed and incorporated into EMPulse, tests of these models, and number of approaches to increased computational efficiency that we are studying.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Efficient convolutional sparse coding
Computationally efficient algorithms may be applied for fast dictionary learning solving the convolutional sparse coding problem in the Fourier domain. More specifically, efficient convolutional sparse coding may be derived within an alternating direction method of multipliers (ADMM) framework that utilizes fast Fourier transforms (FFT) to solve the main linear system in the frequency domain. Such algorithms may enable a significant reduction in computational cost over conventional approaches by implementing a linear solver for the most critical and computationally expensive component of the conventional iterative algorithm. The theoretical computational cost of the algorithm may be reduced from O(M.sup.3N) to O(MN log N), where N is the dimensionality of the data and M is the number of elements in the dictionary. This significant improvement in efficiency may greatly increase the range of problems that can practically be addressed via convolutional sparse representations.
97 MATHEMATICS AND COMPUTING↗
Development of Hexagonal Nodal Diffusion Codes at National Tsing-Hua University
The development of nodal methods for hexagonal geometry reactors at National Tsing-Hua University is reviewed. In particular, the development of the Hybrid Nodal Green's Function Method in hexagonal geometry is re-cast into the Direct-Coarse Mesh Finite Difference Method for efficient implementation with residual solution techniques such as GMRES. The method is further modified to include a rigorous treatment of non-physical terms that arise from the transverse integration procedure. The treatment follows the conformal mapping approach first developed by Y-A Chao and his co-workers. The overall development is implemented into a code written in C++ and tested on a number of well known benchmarks. The new code is shown to be very highly accurate while extremely efficient computationally.
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
Potential impacts of climate change on the built environment: ASHRAE climate zones, building codes and national energy efficiency
Statement of the Problem: ASHRAE releases updates to 90.1 “Energy Standard for Buildings except Low-Rise Residential Buildings” every three years resulting in a 3.7%-17.3% increase in energy efficiency for buildings with each release. This is adopted by or informs building codes in nations across the globe, is the National Standard for the US, and individual states elect which release year of the standard they will enforce. These codes are built upon Standard 169 “Climatic Data for Building Design Standards,” the latest 2017 release of which defines climate zones based on 8, 118 weather stations throughout the world and data from the past 8-25 years. This data may not be indicative of the weather that new buildings built today, will see during their upcoming 30-120 year lifespan. Methodology & Theoretical Orientation: Using more modern, high-resolution datasets from climate satellites, IPCC climate models (PCM and HadGCM), high performance computing resources (Titan) and new capabilities for clustering and optimization the authors briefly analyzed different methods for redefining climate zones. Using bottom-up analysis of multiple meteorological variables which were the subject matter, experts selected as being important to energy consumption, rather than the heating/cooling degree days currently used. Findings: We analyzed the accuracy of redefined climate zones, compared to current climate zones and how the climate zones moved under different climate change scenarios, and quantified the accuracy of these methods on a local level, at a national scale for the US. Conclusion & Significance: There is likely to be a significant annual, national energy and cost (billions USD) savings that could be realized by adjusting climate zones to take into account anticipated trends or scenarios in regional weather patterns.
New, Joshua Ryan↗
Regulations, Codes, and Standards (RCS) for Large-Scale Hydrogen Systems
Hydrogen has potential applications that require larger-scale storage, use, and handling systems than currently are employed in emerging-market fuel cell applications. These potential applications include hydrogen generation and storage systems that would support electrical grid systems. There has been extensive work evaluating regulations, codes, and standards (RCS) for the emerging fuel cell market, such as the infrastructure required to support fuel cell electric vehicles. However, there has not been a similar RCS evaluation and development process for these larger systems. This paper presents an evaluation of the existing RCS in the United States for large-scale systems and identifies potential RCS gaps. This analysis considers large-scale hydrogen technologies that are currently being employed in limited use but may be more widely used as large-scale applications expand. The paper also identifies areas of potential safety research that would need to be conducted to fill the RCS gaps. U.S. codes define bulk hydrogen storage systems but do not define large-scale systems. This paper evaluates potential applications to define a large-scale hydrogen system relative to the systems employed in emerging technologies such as hydrogen fuelling stations. These large-scale systems would likely be of similar size to or larger than industrial hydrogen systems.
08 HYDROGEN↗
Modeling Fission Gas Behaviour with the BISON Fuel Performance Code
The behavior of fission gases (Xe, Kr) is of critical importance to nuclear fuel performance, because it determines both the amount of fuel swelling and the quantity of fission gas released to the fuel rod plenum. It follows that accurate models of fission gas behavior need to be developed for the calculation of fission gas swelling and release in fuel performance codes, such as the BISON code developed at Idaho National Laboratory (INL). To this end, the fission gas behavior model included in BISON is being continually extended and improved. In the present contribution, we give an account of the most recent developments and results on modeling fission gas behavior in uranium dioxide fuel with BISON.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
New Release of Fuel Performance Code, FRAPCON-3.5 and FRAPTRAN-1.5
New versions of the USNRC fuel performance codes, FRAPCON-3 and FRAPTRAN are available to members of the code users group. FRAPCON-3.5 and FRAPTRAN-1.5 include model improvements to various material property models such as gaseous swelling, primary creep, pellet relocation, cladding models, cladding ballooning, and ID oxidation. Various new capabilities have been added such as increased numbers of time steps, axial nodes, and radial nodes. The ability to model pellet chamfers has been added. The ability to specify variable axial node lengths and specify different enrichment, gadolinia content, and central hole size in each axial node has been added. Finally the capability to model refabrication of a rodlet following irradiation of a full length rod has been added to FRAPCON-3.5. This paper will describe the changes made in the new versions of FRAPCON-3 and FRAPTRAN.
FRAPCON, FRAPTRAN↗
Using redundant transactions to verify the correctness of program code execution
In the described embodiments, a processor core (e.g., a GPU core) receives a section of program code to be executed in a transaction from another entity in a computing device. The processor core sends the section of program code to one or more compute units in the processor core to be executed in a first transaction and concurrently executed in a second transaction, thereby creating a “redundant transaction pair.” When the first transaction and the second transaction are completed, the processor core compares a read-set of the first transaction to a read-set of the second transaction and compares a write-set of the first transaction to a write-set of the second transaction. When the read-sets and the write-sets match and no transactional error condition has occurred, the processor core allows results from the first transaction to be committed to an architectural state of the computing device.
Gurumurthi, Sudhanva↗