Bettis Atomic Power Laboratory is a U.S. Government-owned research and development facility operated by Bechtel Marine Propulsion Corporation and located in the Pittsburgh suburb of West Mifflin, Pennsylvania. It solely focuses on the design and development of nuclear power for the U.S. Navy and was one of the leaders in creating the "nuclear navy". The laboratory was founded in 1949 on the site of the former Bettis Field and is named after Cyrus Bettis. It covers approximately 207 acres and is operated for the Department of Energy by Bechtel Marine Propulsion Corporation, a wholly owned subsidiary of the Bechtel Corporation. Bechtel won the contract to run the laboratory on September 19, 2008 and assumed operation on February 1, 2009; Prior to that the Lab was operated by another Bechtel subsidiary, Bechtel Bettis, Inc. From the Lab's founding until 1998, it was run by Westinghouse Electric Corporation.The laboratory's work is part of the Naval Nuclear Propulsion Program, which is a joint U.S Navy-DOE program responsible for the research, design, construction, operation and maintenance of U.S. nuclear-powered warships.The laboratory developed Oak Ridge National Laboratory's original design of the pressurized water reactor for operational naval use. It built the nuclear propulsion plants for the first U.S. nuclear submarines and surface ships including the USS Nautilus , the USS George Washington , the USS Long Beach , and the USS Enterprise .Westinghouse's Nuclear Power Division adapted the PWR design for commercial use and built the first commercial nuclear power plant in the United States, the Shippingport Power Plant in the west hills of Pittsburgh.The laboratory has two computers listed on the 26th TOP500 List of supercomputers in the world. Ranked 97 is a 1,090 processor Opteron system and ranked 405 is a 536 processor Itanium 2 system.The laboratory is also home to the U.S. Navy's Bettis Reactor Engineering School. The school provides a post-graduate certificate program in Nuclear Engineering with a focus on nuclear reactor design, construction, and operations. It is open only to Naval personnel and Bettis engineers.The laboratory had been chosen to develop the Project Prometheus nuclear power source for the JIMO project, however, funding for this program was cancelled in the fall of 2005. Wikipedia.
Griesheimer D.P.,Bettis Atomic Power Laboratory |
Millman D.L.,University of North Carolina at Chapel Hill |
Willis C.R.,University of Texas at Austin
Journal of Quantitative Spectroscopy and Radiative Transfer | Year: 2011
A generalized probability density function (PDF) describing the distribution of inter-inclusion distances in finite, isotropic, binary stochastic materials with fixed diameter inclusions has been developed and tested. The new probability density function explicitly accounts for edge effects present in finite two- and three-dimensional stochastic materials. The generalized PDF is shown to include factors that are dependent on both the geometry of the material region as well as the statistical properties of the material. A discussion of the properties and application of this newly developed PDF is provided along with supporting numerical results for case studies in one- and two-dimensions. These numerical results demonstrate the ability of the newly derived PDF to correctly account for edge effects in finite stochastic materials, while still reproducing the expected distribution within the bulk material region. © 2010.
Neuberger B.W.,University of Maryland College Park |
Oberson P.G.,Bettis Atomic Power Laboratory |
Ankem S.,Bettis Atomic Power Laboratory
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2011
Much interest has developed in the near-α titanium alloy Ti-5Al-1Sn-1V-1Zr-0.8Mo (Ti-5111) for naval applications. When gas tungsten arc welded with filler metal that has the same chemical composition as the base metal, however, the weld FZ tends to be harder and less ductile than the base metal, which may make the weld susceptible to failure. This behavior may be attributed to the presence of oxygen impurities and the large prior-β grain size in the weld. In this investigation, the addition of a small amount of yttrium to the weld filler metal can decrease hardening and increase the ductility of Ti-5111 welds, which is beneficial for weld performance. Microstructural and chemical analyses of unmodified and yttrium-modified Ti-5111 welds are presented along with results from mechanical testing of the welds. © 2010 The Minerals, Metals & Materials Society and ASM International.
Pounders J.M.,Georgia Institute of Technology |
Pounders J.M.,Bettis Atomic Power Laboratory |
Rahnemat F.,Georgia Institute of Technology
Nuclear Science and Engineering | Year: 2014
A new solution technique is derived for the time-dependent transport equation. This approach extends the steady-state coarse-mesh transport method that is based on global-local decompositions of large (i.e.,full-core) neutron transport problems. The new method is based on polynomial expansions of the space, angle, and time variables in a response-based formulation of the transport equation. The local problem (coarse-mesh) solutions, which are entirely decoupled from each other, are characterized by space-, angle-, and time-dependent response functions. These response functions are, in turn, used to couple an arbitrary sequence of local problems to form the solution of a much larger global problem. In the current work, the local problem (response function) computations are performed using the Monte Carlo method, while the global (coupling) problem is solved deterministically. The spatial coupling is performed by orthogonal polynomial expansions of the partial currents on the local problem surfaces, and similarly, the time-dependent response of the system (i.e., the time-varying flux) is computed by convolving the time-dependent surface partial currents and time-dependent volumetric sources against precomputed time-dependent response kernels.
Hall Jr. M.M.,Bettis Atomic Power Laboratory |
Flinn J.E.,Argonne National Laboratory
Journal of Nuclear Materials | Year: 2010
Irradiation creep constitutive equations, which were developed in Part I, are used here to analyze in-reactor creep and swelling data obtained ca. 1977-1979 as part of the US breeder reactor program. The equations were developed according to the principles of incremental continuum plasticity for the purpose of analyzing data obtained from a novel irradiation experiment that was conducted, in part, using Type 304 stainless steel that had been previously irradiated to significant levels of void swelling. Analyses of these data support an earlier observation that all stress states, whether tensile, compressive, shear or mixed, can affect both void swelling and interactions between irradiation creep and swelling. The data were obtained using a set of five unique multiaxial creep-test specimens that were designed and used for the first time in this study. The data analyses demonstrate that the constitutive equations derived in Part I provide an excellent phenomenological representation of the interactive creep and swelling phenomena. These equations provide nuclear power reactor designers and analysts with a first-of-its-kind structural analysis tool for evaluating irradiation damage-dependent distortion of complex structural components having gradients in neutron damage rate, temperature and stress state.
Kimball K.J.,Knolls Atomic Power Laboratory |
Clementoni E.M.,Bettis Atomic Power Laboratory
Proceedings of the ASME Turbo Expo | Year: 2012
The Knolls Atomic Power Laboratory (KAPL) and Bettis Atomic Power Laboratory are testing a supercritical carbon dioxide (S-CO2) Brayton power cycle system. The 100 kWe Integrated System Test (IST) is a two shaft recuperated closed Brayton cycle with a variable speed turbine driven compressor and a constant speed turbine driven generator using S-CO2 as the working fluid. The IST was designed to demonstrate operational, control and performance characteristics of an S-CO2 Brayton power cycle over a wide range of conditions. The IST design includes a comprehensive instrumentation and control system incorporating results of turbomachinery operational testing performed at Barber Nichols Inc (BNI) in the Sandia National Laboratory's DOE test loop. A detailed dynamic performance model was used both to predict IST performance and to evaluate the testing completed at BNI. The IST construction was completed in mid 2011 and is currently undergoing shakedown testing. Results of testing completed to date and future testing plans will be summarized. Copyright © 2012 by ASME.
Meholic M.J.,Bettis Atomic Power Laboratory |
Aumiller Jr. D.L.,Bettis Atomic Power Laboratory |
Cheung F.-B.,Pennsylvania State University
Nuclear Technology | Year: 2013
A mechanistic droplet deposition model has been developed to quantify the direct-contact heat transfer present in dispersed flow film boiling. Lagrangian subscale trajectory calculations utilizing realistic velocity and temperature distributions in the momentum boundary layer are used to determine the number of dispersed droplets able to achieve contact with the heated wall. Coupling the droplet deposition model with a physical directcontact heat transfer coefficient model allows the total direct-contact heat transfer to be determined based upon the local vapor mass flux, wall superheat, and vapor superheat. Comparisons to the existing models highlight the more mechanistic nature of the proposed model.
Zerkle M.L.,Bettis Atomic Power Laboratory
ICNC 2015 - International Conference on Nuclear Criticality Safety | Year: 2015
Following the Fukushima Daiichi accident a need arose to perform defense-in-depth analyses to assess the effect of seawater immersion on the reactivity of nuclear fuel. This paper derives a composition for Standard Seawater based on the Reference Composition using the International Thermodynamic Equation of Seawater - 2010 (TEOS-10). The Reference Composition for seawater is based on measurements of the Atlantic surface seawater and assumes no organic or inorganic material is entrained in the seawater. Using the Reference Composition, a methodology for determining the composition of seawater as a function of temperature, pressure and salinity is developed. These seawater compositions may be used in nuclear criticality safety analyses to determine the effect of seawater immersion on reactivity. Results of a sensitivity study are presented that illustrate the effect of seawater immersion and salinity on the reactivity of a representative low-enriched uranium critical assembly, LEU-COMP-THERM-002.
Densmore J.D.,Bettis Atomic Power Laboratory
Journal of Computational and Theoretical Transport | Year: 2013
We present an extension of our recent examination of the method of moments when moments are computed on a spatial grid instead of through integration over the entire domain to include time dependence. For the problem we consider, we show that (i) the flux-weighted average of x remains equal to its initial value but (ii) the flux-weighted average of (x — xa)2 differs from its initial value by an additional error term when moments are determined in this manner, where x is the spatial variable and xa is an arbitrary point. We also present numerical examples that confirm the accuracy of our results. © Taylor & Francis Group, LLC.
Griesheimer D.P.,Bettis Atomic Power Laboratory |
Nease B.R.,Bettis Atomic Power Laboratory
Physics of Reactors 2016, PHYSOR 2016: Unifying Theory and Experiments in the 21st Century | Year: 2016
This paper presents an improvement for traditional weight window variance reduction in coupled radiation Monte Carlo transport calculations. The improved technique automatically adjusts the number of secondary particles created at each collision in order to ensure that the birth weight of each secondary particle falls within the weight window limits for the type, energy, direction, and location of the emitted radiation. The proposed technique simplifies the process for defining, applying, and optimizing radiation-specific space/energy importance definitions in coupled-radiation problems. Testing on a simplified problem demonstrates that the proposed adaptive-yield technique is effective even for deep-penetration coupled-radiation calculations that include many generations of secondary radiation.
Fore L.B.,Bettis Atomic Power Laboratory
Measurement Science and Technology | Year: 2010
Cross-correlation, whether by a direct or spectral calculation, remains the most common analysis method for digital particle image velocimetry. Gaussian sub-pixel interpolation likewise remains a common method for achieving measurement resolution at fractional pixel displacements. Specific to the use of Gaussian sub-pixel interpolation, the particular form of the cross-correlation function is shown to affect the peak-locking or mean-bias error that increases the probability of the measurement occurring at integer pixel displacements. The main effect is from nonzero mean image intensities that cause a shift in the amplitude of the cross-correlation function away from zero and introduce a bias error into the Gaussian interpolation formula. A simple, but not universal, method of reducing this error is to use the covariance function, often calculated in a single step after calculation of the cross-correlation function. This effectively shifts the amplitude back toward zero and reduces the bias that originates in the interpolation formula. Examples are shown using synthetic particle image simulations and experimental water jet PIV images from the 2003 PIV Challenge. © 2010 IOP Publishing Ltd.