scholarly journals Development of an MCNP6-ANSYS FLUENT Multiphysics Coupling Capability

2016 ◽  
Author(s):  
William Gurecky ◽  
Erich Schneider
Keyword(s):  
State Of The Art ◽  
Radiation Transport ◽  
National Laboratory ◽  
Operating Conditions ◽  
Reactor Physics ◽  
Ansys Fluent ◽  
Oak Ridge ◽  
Deterministic Solution ◽  
Multiphysics Coupling ◽  
Full Power

This work presents a novel core multiphysics coupling method and its application to geometries and thermal hydraulic operating conditions typical of U.S. PWRs. Monte Carlo based radiation transport from the MCNP v6.1.0 package and finite volume thermal hydraulic (TH) packages provided by ANSYS-FLUENT v14.0 are combined to produce results with intra-pin resolved spatial resolution equivalent to state-of-the-art reactor physics and multi-physics suites. The Virtual Environment for Reactor Applications (VERA) whose development is spearheaded at Oak Ridge National Laboratory is one such example package. Results from the MCNP-FLUENT coupling framework are compared to a deterministic solution provided by the MPACT-COBRA-TF (MPACT-CTF) package available in VERA. Comparisons between the MCNP-FLUENT methodology and the MPACT-CTF solutions are provided for a single pin case. Good power and eigenvalue agreement (+/−4%, 352[pcm] respectively) is achieved at hot full power conditions.

scholarly journals Octane Index Applicability over the Pressure-Temperature Domain

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 607
Author(s):  
Tommy R. Powell ◽  
James P. Szybist ◽  
Flavio Dal Forno Chuahy ◽  
Scott J. Curran ◽  
John Mengwasser ◽  
...  
Keyword(s):  
High Efficiency ◽  
National Laboratory ◽  
Operating Conditions ◽  
Dominant Factor ◽  
Compression Ignition ◽  
Oak Ridge ◽  
Operating Modes ◽  
Wide Range ◽  
Thermodynamic Conditions ◽  
Si Engines

Modern boosted spark-ignition (SI) engines and emerging advanced compression ignition (ACI) engines operate under conditions that deviate substantially from the conditions of conventional autoignition metrics, namely the research and motor octane numbers (RON and MON). The octane index (OI) is an emerging autoignition metric based on RON and MON which was developed to better describe fuel knock resistance over a broader range of engine conditions. Prior research at Oak Ridge National Laboratory (ORNL) identified that OI performs reasonably well under stoichiometric boosted conditions, but inconsistencies exist in the ability of OI to predict autoignition behavior under ACI strategies. Instead, the autoignition behavior under ACI operation was found to correlate more closely to fuel composition, suggesting fuel chemistry differences that are insensitive to the conditions of the RON and MON tests may become the dominant factor under these high efficiency operating conditions. This investigation builds on earlier work to study autoignition behavior over six pressure-temperature (PT) trajectories that correspond to a wide range of operating conditions, including boosted SI operation, partial fuel stratification (PFS), and spark-assisted compression ignition (SACI). A total of 12 different fuels were investigated, including the Co-Optima core fuels and five fuels that represent refinery-relevant blending streams. It was found that, for the ACI operating modes investigated here, the low temperature reactions dominate reactivity, similar to boosted SI operating conditions because their PT trajectories lay close to the RON trajectory. Additionally, the OI metric was found to adequately predict autoignition resistance over the PT domain, for the ACI conditions investigated here, and for fuels from different chemical families. This finding is in contrast with the prior study using a different type of ACI operation with different thermodynamic conditions, specifically a significantly higher temperature at the start of compression, illustrating that fuel response depends highly on the ACI strategy being used.

scholarly journals The Local Seismoacoustic Wavefield of a Research Nuclear Reactor and Its Response to Reactor Power Level

2020 ◽  
Vol 92 (1) ◽  
pp. 378-387
Author(s):  
Omar E. Marcillo ◽  
Monica Maceira ◽  
Chengping Chai ◽  
Christine Gammans ◽  
Riley Hunley ◽  
...  
Keyword(s):  
Energy Transport ◽  
Nuclear Reactor ◽  
Power Level ◽  
National Laboratory ◽  
Reactor Power ◽  
Operational Conditions ◽  
Oak Ridge ◽  
Research Nuclear Reactor ◽  
Full Power ◽  
Power Operation

Abstract We describe the seismoacoustic wavefield recorded outdoors but inside the facility fence of the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (Tennessee). HFIR is a research nuclear reactor that generates neutrons for scattering, irradiation research, and isotope production. This reactor operates at a nominal power of 85 MW, with a full-power period between 24 and 26 days. This study uses data from a single seismoacoustic station that operated for 60 days and sampled a full operating reactor cycle, that is, full-power operation and end-of-cycle outage. The analysis presented here is based on identifying signals that characterize the steady, that is, full-power operation and end-of-cycle outage, and transitional, that is, start-up and shutdown, states of the reactor. We found that the overall seismoacoustic energy closely follows the main power cycle of the reactor and identified spectral regions excited by specific reactor operational conditions. In particular, we identified a tonal noise sequence with a fundamental frequency around 21.4 Hz and multiple harmonics that emerge as the reactor reaches 90% of nominal power in both seismic and acoustic channels. We also utilized temperature measurements from the monitoring system of the reactor to suggest links between the operation of reactor’s subsystems and seismoacoustic signals. We demonstrate that seismoacoustic monitoring of an industrial facility can identify and track some industrial processes and detect events related to operations that involve energy transport.

Long-Term Microturbine Exposure of an Advanced Alloy for Microturbine Primary Surface Recuperators

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Wendy J. Matthews ◽  
Karren L. More ◽  
Larry R. Walker
Keyword(s):  
Steady State ◽  
National Laboratory ◽  
Operating Conditions ◽  
Normal Operation ◽  
Operating Environment ◽  
Protective Oxide ◽  
Oak Ridge ◽  
Steady State Operation ◽  
Alloy Oxidation

Haynes alloy HR-120 (Haynes and HR-120 are trademarks of Haynes International, Inc.) forms a protective oxide scale when exposed to the harsh operating environment of a microturbine primary surface recuperator. Primary surface recuperators manufactured from HR-120 are currently in use on the Capstone C65 MicroTurbine (MicroTurbine is a registered trademark of Capstone Turbine Corporation). Long-term microturbine tests of this alloy are currently being conducted at an elevated turbine exit temperature (∼100°F higher than that in a normal operation) at Capstone Turbine Corporation. Alloy samples that have been tested under steady-state microturbine operating conditions are removed after predetermined exposure intervals for characterization by Capstone Turbine Corporation in collaboration with Oak Ridge National Laboratory. Such evaluations include the characterization of surface oxide scales and the associated alloy compositional changes following a steady-state operation ranging from 1800 h to 14,500 h. Results from the microstructural and compositional analyses of these long-term steady-state engine-tested HR-120 samples are used to illustrate the progression of alloy oxidation in the microturbine operating environment.

Cathodic Protection in Molten Fluoride Salts at 1200 F

CORROSION ◽  
1966 ◽  
Vol 22 (7) ◽  
pp. 194-197 ◽  
Author(s):  
L. K. MATSON ◽  
E. F. STEPHAN ◽  
P. D. MILLER ◽  
W. K. BOYD ◽  
R. P. MILFORD
Keyword(s):  
Cathodic Protection ◽  
Large Scale ◽  
National Laboratory ◽  
Reference Electrode ◽  
Operating Conditions ◽  
Oak Ridge ◽  
Polarization Characteristics ◽  
Molten Fluoride ◽  
Current Densities ◽  
Fluoride Salts

Abstract Corrosion is a major problem in the Fluoride Volatility Process for recovery of nuclear fuel. Relatively large scale pilot plant developments are under way by the Chemical Technology Division of the Oak Ridge National Laboratory. In this process fuel is dissolved by hydrogen fluoride in a molten bath consisting of mixtures of such salts as NaF-LiF-ZrF4. Usual operating temperatures are near 1200 F (649 C). Because metals such as stainless steel and zirconium are to be dissolved in this process it is obvious that the salt mixture must be quite corrosive. This is particularly true because HF is sparged through the bath continuously. Experiments were carried out at Battelle on a laboratory scale to determine the feasibility of using cathodic protection to reduce the attack in process vessels. Polarization curves were developed under simulated operating conditions for the materials of interest, i.e., Inor-8, Zircaloy and graphite. Polarization characteristics were obtained by use of a potentiostat using platinum as a reference electrode and graphite as an anode. Experiments using rectangularly shaped coupons were carried out to determine the amount of protection furnished by the impressed current technique in the most corrosive salt composition. Specimens were made cathodic at current densities ranging from 3 to 50 amp/ft2. Excellent protection was furnished to the submerged portions of the specimens. However, severe attack occurred at the interface at reasonable current densities.

Numerical and Experimental Investigation of the Flow in the SNS Jet Flow Target

2015 ◽  
Author(s):  
Charlotte Barbier ◽  
Mark Wendel ◽  
David Felde ◽  
Michael C. Daugherty
Keyword(s):  
Numerical Simulations ◽  
Radiation Transport ◽  
Fluid Dynamic ◽  
National Laboratory ◽  
Jet Flow ◽  
Numerical Approach ◽  
General Purpose ◽  
Temperature Fields ◽  
Beam Power ◽  
Oak Ridge

Computational Fluid Dynamic (CFD) numerical simulations were performed for the flow inside the Spallation Neutron Source jet-flow target vessel at Oak Ridge National Laboratory. Different flow rates and beam conditions were tested to cover all the functioning range of the target, but for brevity, only the nominal case with a mass flow rate of 185 kg/s and a beam power of 1.54MW is presented here. The heat deposition rate from the proton beam was computed using the general-purpose Monte Carlo radiation transport code MCNPX and the commercial CFD code ANSYS-CFX was used to determine the flow velocity in the mercury and the temperature fields in both the mercury and the stainless steel vessel. Boundary conditions, turbulence model and mesh effects are presented in depth. To validate the numerical approach, Particle Imagery Velocimetry (PIV) measurements on a water-loop setup with an acrylic jet-flow target mock-up were performed and compared to the numerical simulations. It was found that a sustained wall jet was developed across the whole length of the vulnerable surface, confirming the good design of the jet-flow target. Overall, good agreements were observed between the experiments and the simulations: the velocity contours and the shape of the recirculation zone near the side baffle are qualitatively similar. However, some differences were also observed that underlines the shortcomings of both the numerical simulations and the experimental measurements.

Commercialization Status of Ni3Al-Based Alloys

1996 ◽  
Vol 460 ◽  
Author(s):  
V. K. Sikka
Keyword(s):  
National Laboratory ◽  
Melting Process ◽  
Heat Treating ◽  
The United States ◽  
Operating Conditions ◽  
Current Status ◽  
Oak Ridge ◽  
Technical Developments ◽  
Property Data ◽  
Component Manufacturing

ABSTRACTThe Ni3Al-based alloys have been under development at the Oak Ridge National Laboratory (ORNL) and other research institutions in the United States and around the world for the last ten years. The incremental developments of composition, melting process, casting methods, property data, corrosion data, weldability development, and prototype component testing under production-like operating conditions have pushed the ORNL-developed Ni3Al-based alloys closer to commercialization. This paper will present the highlights of incremental technical developments along with the approach and current status of commercialization. It is concluded that cast components are the primary applications of Ni3Al-based alloys, and applications range from heat-treating fixtures to forging dies. It is also concluded that the commercialization process is accelerated when technology is licensed to an organization that can produce the alloy, has component manufacturing capability, and is also a user.

scholarly journals High-resolution neutron time-of-flight measurements for light water at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory

2020 ◽  
Vol 239 ◽  
pp. 14005
Author(s):  
Luiz Leal ◽  
Vaibhav Jaiswal ◽  
Alexander I. Kolesnikov
Keyword(s):  
Experimental Data ◽  
Neutron Source ◽  
National Laboratory ◽  
Operating Conditions ◽  
Spallation Neutron Source ◽  
Light Water ◽  
Oak Ridge ◽  
Oak Ridge National Laboratory ◽  
Thermal Scattering ◽  
Reactor Operating

Series of light water inelastic neutron scattering experiments have been made at the Oak Ridge National Laboratory (ORNL), Spallation Neutron Source (SNS) covering temperatures ranging from 295 K to 600 K and pressures of 1 bar and 150 bar. The temperatures and pressures ranges correspond to that of pressurized light water reactors. The inelastic scattering measurements will help the development of light water thermal scattering kernels, also known as S (α,β) thermal scattering law (TSL), in a consistent fashion given the amount and the quality of the measured data. Light water thermal scattering evaluations available in existing nuclear data libraries have certain limitations and pitfalls. This paper introduces the state of the art of the light water thermal scattering cross-section data not only for room temperature but as well as for reactor operating temperatures, i.e. 550 - 600 K. During the past few years there has been a renewed interest in re-investigating the existing TSL models and utilize the recent experimental data or perform molecular dynamics simulations. It should be pointed out that no single TSL evaluation is based entirely on experimental data and one has to rely on TSL models or a combination of both. New TOF measurement of light water at the SNS, with a detailed description of the experimental setup, measurement conditions, and the associated foreseen results is presented in this paper. The analysis of the experimental data would help in validating the existing approach based on old experimental data or based on molecular dynamic simulations using classical water models, knowledge of which is very important to generate TSL libraries at reactor operating conditions.

Accelerated Oxidation of Type 347 Stainless Steel Primary Surface Recuperators Operating Above 600°C

2007 ◽  
Author(s):  
Wendy J. Matthews ◽  
Karren L. More ◽  
Larry R. Walker
Keyword(s):  
Stainless Steel ◽  
Water Vapor ◽  
Stainless Steels ◽  
National Laboratory ◽  
Austenitic Stainless Steels ◽  
Operating Conditions ◽  
Accelerated Oxidation ◽  
Oak Ridge ◽  
Compositional Changes ◽  
Operating Temperatures

Type 347 stainless steel has traditionally been used in the manufacture of microturbine primary surface recuperators. It has been established during the past few years that the water vapor present in the microturbine exhaust gas causes accelerated oxidation of austenitic stainless steels at operating temperatures above ∼600°C (∼1110°F), which has resulted in the replacement of austenitic stainless steels with more highly alloyed Fe-based alloys and Ni-based alloys in microturbine recuperators. The effect of water vapor on type 347 stainless steel primary surface recuperators has been studied extensively by Capstone Turbine Corporation in collaboration with Oak Ridge National Laboratory. Several recuperators exposed in a Capstone C60 MicroTurbine™ under different steady-state and cyclic operating conditions, have been microstructurally characterized. Evaluation of surface oxide scale formation and associated compositional changes has been carried out on representative sections from recuperators with operating lives ranging from ∼2,000–15,000 hours. Results from the microstructural and compositional analyses of the engine-tested recuperators illustrate the progression of accelerated oxidation of type 347 stainless steel at recuperator operating temperatures above 600°C.

Performance Analysis of Integrated Active Desiccant Rooftop Air-Conditioning System Operating in Heating Mode

2005 ◽  
Author(s):  
Andrei Yu. Petrov ◽  
James R. Sand ◽  
Abdolreza Zaltash ◽  
John Fischer ◽  
Rick Mitchell ◽  
...  
Keyword(s):  
National Laboratory ◽  
Operating Mode ◽  
Operating Conditions ◽  
Vapor Compression ◽  
Performance Study ◽  
Air Conditioning System ◽  
Oak Ridge ◽  
Heating Capacity ◽  
Heating Mode ◽  
Analysis Of Performance

This investigation describes the performance study of a novel Integrated Active Desiccant-Vapor Compression Hybrid Rooftop (IADR) at Oak Ridge National Laboratory (ORNL) in heating mode. The tests were performed at two different ratios of outdoor/return air. Analysis of performance characteristics under each operating mode, including heating capacity and energy efficiency ratio, are given. Results of defrost cycle are also presented. Comparison between the experimental performance of IADR unit and the calculated performance of other commercially available heat pump systems at comparable operating conditions has been conducted.

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