702 Matching Results

Search Results

Advanced search parameters have been applied.

Assessing the RELAPS-3D Heat Conduction Enclosure Model

Description: Three heat conduction problems that have exact solutions are modeled with RELAP5-3D using the conduction enclosure model. These comparisons are designed to be used in the RELAP5-3D development assessment scheduled to be completed in 2009. It is shown that with proper input choices and adequate model detail the exact solutions can be matched. In addition, this analysis identified an error and the required correction in the cylindrical and spherical heat conductor models in RELAP5-3D which will be corrected in a future version of RELAP5-3D.
Date: September 30, 2008
Creator: McCann, Larry D.
Partner: UNT Libraries Government Documents Department

RADTRAN 5 user guide.

Description: This User Guide for the RADTRAN 5 computer code for transportation risk analysis describes basic risk concepts and provides the user with step-by-step directions for creating input files by means of either the RADDOG input file generator software or a text editor. It also contains information on how to interpret RADTRAN 5 output, how to obtain and use several types of important input data, and how to select appropriate analysis methods. Appendices include a glossary of terms, a listing of error messages, data-plotting information, images of RADDOG screens, and a table of all data in the internal radionuclide library.
Date: July 1, 2003
Creator: Kanipe, Frances L. & Neuhauser, Karen Sieglinde
Partner: UNT Libraries Government Documents Department

RECOG: pattern recognition analysis of generalized data sets. A user's manual

Description: Pattern recognition is a developing branch of artificial intelligence that has shown great promise in providing a general approach to solutions of a large class of data analysis problems in such diverse areas as medical diagnosis, environmental protection, materials science, production control, and the experimental physical sciences. The computer program RECOG is described. (MOW)
Date: December 1, 1973
Creator: Pritchard, R. H. & Bender, C. F.
Partner: UNT Libraries Government Documents Department

User`s manual for the radioactive decay and accumulation code RADAC

Description: The RADAC computer code calculates radioactive decay and accumulation of decayed products using an algorithm based on the direct use of the Bateman equations and referred to here as the yield factor method. This report explains the yield factor method, gives an overview of the various modules in the RADAC code system, and describes the decay and accumulation code in detail. The RADAC code has capacity for two waste types and can accommodate up to 60 years of annual waste inputs. Decay times as high as 1 million years can be calculated. The user supplies the undecayed composition and radioactivity of the waste placed in storage each year. The code calculates the decayed composition, radioactivity, and thermal power of the accumulated waste at the end of each year and gives the results in terms of grams and curies of individual radionuclides. Calculations can be made for up to 19 waste storage sites in a single run. For each site and each waste type, calculations can be made by 1-year steps up to 60 years, by 10-year steps to 160 years, and by 6 discrete steps to 1 million years. Detailed outputs can be printed for each waste site and each time step by individual radionuclides. Summarized outputs are also available. Excluding data-preparation time, RADAC requires about 2 min to run 19 waste sites with two types of transuranic waste at each site, using a 486 DX computer with a clock speed of 33 MHz. Because RADAC uses a preselected set of decay times and does not make in-reactor calculations, it should not be viewed as a substitute for ORIGEN2. RADAC is intended for use in applications in which accumulations at the decay times provided by the code are sufficient for the user`s purposes.
Date: November 1, 1995
Creator: Salmon, R.; Loghry, S.L. & Ashline, R.C.
Partner: UNT Libraries Government Documents Department

Expected residence time model

Description: The Transportation Technology Department of Sandia National Laboratories develops analytical and computational tools for the US Department of Energy to assess the radiological consequences and risks from the transportation of radioactive materials by all modes. When large quantities of materials are to be transported movements may occur over an extended period of time in what is collectively referred as a ``shipping campaign``. Since the routes over which the shipments occur often remain the same, cumulative exposure to individuals inhabiting the population zones adjacent to the transport links must be estimated. However, individuals do not remain in the same residences throughout their lifetimes and, in fact, move quite often. To appropriately allocate exposures among populations over extended periods of time, perhaps years, requires a model that accounts for three population categories; (1) the original populations residing in the areas adjacent to the transport links, (2) individuals moving out and (3) individuals moving into residences in the designated areas. The model described here accounts for these conditions and will be incorporated as a user option in the RADTRAN computer code for transportation consequence and risk analysis (Reference 1). RADTRAN is a computer code for estimating the consequences and risks associated with the transport of radioactive materials.
Date: March 1, 1996
Creator: Smith, J.D.; Neuhauser, K.S. & Kanipe, F.L.
Partner: UNT Libraries Government Documents Department

Numerical simulations of Hurricane Bertha using a mesoscale atmospheric model

Description: The Regional Atmospheric Model System (RAMS) has been used to simulate Hurricane Bertha as it moved toward and onto shore during the period July 10--12, 1996. Using large-scale atmospheric data from 00 UTC, 11 July (Wednesday evening) to initialize the model, a 36-hour simulation was created for a domain centered over the Atlantic Ocean east of the Florida coast near Jacksonville. The simulated onshore impact time of the hurricane was much earlier than observed (due to the use of results from the large-scale model, which predicted early arrival). However, the movement of the hurricane center (eye) as it approached the North Carolina/South Carolina coast as simulated in RAMS was quite good. Observations revealed a northerly storm track off the South Carolina coast as it moved toward land. As it approached landfall, Hurricane Bertha turned to the north-northeast, roughly paralleling the North Carolina coast before moving inland near Wilmington. Large-scale model forecasts were unable to detect this change in advance and predicted landfall near Myrtle Beach, South Carolina; RAMS, however, correctly predicted the parallel coastal movement. For future hurricane activity in the southeast, RAMS is being configured to run in an operational model using input from the large-scale pressure data in hopes of providing more information on predicted hurricane movement and landfall location.
Date: August 1, 1996
Creator: Buckley, R.L.
Partner: UNT Libraries Government Documents Department

RADON reconstruction in longitudinal phase space

Description: Longitudinal particle motion in circular accelerators is typically monitoring by one dimensional (1-D) profiles. Adiabatic particle motion in two dimensional (2-D) phase space can be reconstructed with tomographic techniques, using 1-D profiles. A computer program RADON has been developed in C++ to process digitized mountain range data and perform the phase space reconstruction for the AGS, and later for Relativistic Heavy Ion Collider (RHIC).
Date: July 1, 1997
Creator: Mane, V.; Peggs, S. & Wei, J.
Partner: UNT Libraries Government Documents Department

A new assessment of RELAP5-3D using a General Electric level swell problem

Description: The RELAP5-3D (version bt) computer program was used to assess a GE level swell experiment. The primary goal of the new assessment models was to faithfully represent the experimental facility and instrumentation. In developing the new models, a non-physical representation of the vessel heads in a previous assessment was found. This distortion resulted in predictions that closely matched the experimental data, but were in error. The new assessment also highlighted an instability in the calculation of interfacial drag. To explore this issue, analyses were performed using three different interfacial drag correlations appropriate for large diameter pipes and/or vessels. The results of this study show that the Kataoka-Ishii correlation, which is currently used in RELAP5-3D, compares most favorably with the experimental data. Additionally, a numerical instability was uncovered with the analysis performed using the Gardner correlation and was traced to the calculation of bubble diameter in the bubbly flow regime.
Date: September 1, 2000
Creator: Aumiller, D.L.; Tomlinson, E.T. & Clarke, W.G.
Partner: UNT Libraries Government Documents Department


Description: We discuss using the inherent grid manipulation capability within a Continuously Adaptive Mesh Refinement hydrodynamics code, RAGE, to implement parallel, automated, self-contained grid generation. We show how arbitrarily complex 3D geometries specified in any unambiguous form can be used. The RAGE computational environment is any of several massively parallel computers being developed under the Department Of Energy's Accelerated Strategic Computing Initiative. A typical 3D RAGE analysis may contain 100 million cells and occupy 2000 processors for several weeks. RAGE grid generation is embarrassingly parallel. The RAGE computational grid is an octree decomposition of the model space. The problem domain is subdivided into as many subdomains as the number of processors assigned to the problem. The grid for each subdomain is then generated independently, except for occasional adjustments. Geometry used for initial grid generation includes CSG combinations of NURBS-based boundary representation models, stereo lithography (STL) files, implicit surfaces, and functionally perturbed surfaces.
Date: June 1, 2000
Creator: Oakes, W.R.; Henning, P.J.; Gittings, M.L. & Weaver, R.P.
Partner: UNT Libraries Government Documents Department

Automated analysis of failure event data

Description: This paper focuses on fully automated analysis of failure event data in the concept and early development stage of a semiconductor-manufacturing tool. In addition to presenting a wide range of statistical and machine-specific performance information, algorithms have been developed to examine reliability growth and to identify major contributors to unreliability. These capabilities are being implemented in a new software package called Reliadigm. When coupled with additional input regarding repair times and parts availability, the analysis software also provides spare parts inventory optimization based on genetic optimization methods. The type of question to be answered is: If this tool were placed with a customer for beta testing, what would be the optimal spares kit to meet equipment reliability goals for the lowest cost? The new algorithms are implemented in Windows{reg_sign} software and are easy to apply. This paper presents a preliminary analysis of failure event data from three IDEA machines currently in development. The paper also includes an optimal spare parts kit analysis.
Date: March 27, 2000
Partner: UNT Libraries Government Documents Department

Residual radioactivity guidelines for the heavy water components test reactor at the Savannah River Site

Description: Guidelines were developed for acceptable levels of residual radioactivity in the Heavy Water Components Test Reactor (HWCTR) facility at the conclusion of its decommissioning. Using source terms developed from data generated in a detailed characterization study, the RESRAD and RASRAD-BUILD computer codes were used to calculate derived concentration guideline levels (DCGLs) for the radionuclides that will remain in the facility. The calculated DCGLs, when compared to existing concentrations of radionuclides measured during a 1996 characterization program, indicate that no decontamination of concrete surfaces will be necessary. Also, based on the results of the calculations, activated concrete in the reactor biological shield does not have to be removed, and imbedded radioactive piping in the facility can remain in place. Viewed in another way, the results of the calculations showed that the present inventory of residual radioactivity in the facility (not including that associated with the reactor vessel and steam generators) would produce less than one millirem per year above background to a hypothetical individual on the property. The residual radioactivity is estimated to be approximately 0.04 percent of the total inventory in the facility as of March, 1997. According to the results, the only radionuclides that would produce greater than 0.0.1-millirem per year are Am-241 (0.013 mrem/yr at 300 years), C-14 (0.022 mrem/yr at 1000 years) and U-238 (0.034 mrem/yr at 6000 years). Human exposure would occur only through the groundwater pathways, that is, from water drawn from, a well on the property. The maximum exposure would be approximately one percent of the 4 millirem per year ground water exposure limit established by the U.S. Environmental Protection Agency. 11 refs., 13 figs., 15 tabs.
Date: April 1, 1997
Creator: Owen, M.B. Smith, R. & McNeil, J.
Partner: UNT Libraries Government Documents Department

RELAP5 analyses of two hypothetical flow reversal events for the Advanced Neutron Source Reactor

Description: The reactor design features 4 independent cooling loops (3 active, 1 standby), each containing a main circulation pump (with battery powered pony motor), heat exchanger, an accumulator, and a check valve. The first transient assumes one of these pumps fails, and also that the check valve in that loop remains stuck open. This accident is considered extremely unlikely. Flow reverses in this loop, reducing core flow because much of the coolant is diverted from the intact loops back through the failed loop. The second transient examines a 102-mm-dia instantaneous pipe break near the core inlet (worst break location). A break is assumed to occur 90 s after a total loss-of-offsite power. Core flow reversal occurs because accumulator injection overpowers the diminishing pump flow. Safety margins are evaluated against 4 thermal limits: T{sub wall} = T{sub sat}, incipient boiling, onset of significant void, and critical heat flux. For the first transient, results show that these limits are not exceeded (at 95% non-exceedance probability level) if the pony motor battery lasts 30 minutes (present design value). For the second transient, the closest approach of the fuel surface temperature to local saturation temperature during core flow reversal is about 39 C, so the fuel remains cool during this transient. Although this work is for the ANSR geometry and operating conditions, the general conclusion may be applicable to other highly subcooled reactor systems.
Date: December 31, 1995
Creator: Chen, N.C.J.; Wendel, M.W. & Yoder, G.L. Jr.
Partner: UNT Libraries Government Documents Department

Verification of RADTRAN

Description: This document presents details of the verification process of the RADTRAN computer code which was established for the calculation of risk estimates for radioactive materials transportation by highway, rail, air, and waterborne modes.
Date: December 31, 1995
Creator: Kanipe, F.L. & Neuhauser, K.S.
Partner: UNT Libraries Government Documents Department

Investigation of RADTRAN Stop Model input parameters for truck stops

Description: RADTRAN is a computer code for estimating the risks and consequences as transport of radioactive materials (RAM). RADTRAN was developed and is maintained by Sandia National Laboratories for the US Department of Energy (DOE). For incident-free transportation, the dose to persons exposed while the shipment is stopped is frequently a major percentage of the overall dose. This dose is referred to as Stop Dose and is calculated by the Stop Model. Because stop dose is a significant portion of the overall dose associated with RAM transport, the values used as input for the Stop Model are important. Therefore, an investigation of typical values for RADTRAN Stop Parameters for truck stops was performed. The resulting data from these investigations were analyzed to provide mean values, standard deviations, and histograms. Hence, the mean values can be used when an analyst does not have a basis for selecting other input values for the Stop Model. In addition, the histograms and their characteristics can be used to guide statistical sampling techniques to measure sensitivity of the RADTRAN calculated Stop Dose to the uncertainties in the stop model input parameters. This paper discusses the details and presents the results of the investigation of stop model input parameters at truck stops.
Date: March 1, 1996
Creator: Griego, N.R.; Smith, J.D. & Neuhauser, K.S.
Partner: UNT Libraries Government Documents Department

On implementing MPI-IO portably and with high performance.

Description: We discuss the issues involved in implementing MPI-IO portably on multiple machines and file systems and also achieving high performance. One way to implement MPI-IO portably is to implement it on top of the basic Unix I/O functions (open, seek, read, write, and close), which are themselves portable. We argue that this approach has limitations in both functionality and performance. We instead advocate an implementation approach that combines a large portion of portable code and a small portion of code that is optimized separately for different machines and file systems. We have used such an approach to develop a high-performance, portable MPI-IO implementation, called ROMIO. In addition to basic I/O functionality, we consider the issues of supporting other MPI-IO features, such as 64-bit file sizes, noncontiguous accesses, collective I/O, asynchronous I/O, consistency and atomicity semantics, user-supplied hints, shared file pointers, portable data representation, file preallocation, and some miscellaneous features. We describe how we implemented each of these features on various machines and file systems. The machines we consider are the HP Exemplar, IBM SP, Intel Paragon, NEC SX-4, SGI Origin2000, and networks of workstations; and the file systems we consider are HP HFS, IBM PIOFS, Intel PFS, NEC SFS, SGI XFS, NFS, and any general Unix file system (UFS). We also present our thoughts on how a file system can be designed to better support MPI-IO. We provide a list of features desired from a file system that would help in implementing MPI-IO correctly and with high performance.
Date: November 30, 1998
Creator: Thakur, R.; Gropp, W. & Lusk, E.
Partner: UNT Libraries Government Documents Department

An Integrated RELAP5-3D and Multiphase CFD Code System Utilizing a Semi Implicit Coupling Technique

Description: An integrated code system consisting of RELAP5-3D and a multiphase CFD program has been created through the use of a generic semi-implicit coupling algorithm. Unlike previous CFD coupling work, this coupling scheme is numerically stable provided the material Courant limit is not violated in RELAP5-3D or at the coupling locations. The basis for the coupling scheme and details regarding the unique features associated with the application of this technique to a four-field CFD program are presented. Finally, the results of a verification problem are presented. The coupled code system is shown to yield accurate and numerically stable results.
Date: June 21, 2001
Creator: Aumiller, D.L.; Tomlinson, E.T. & Weaver, W.L.
Partner: UNT Libraries Government Documents Department

Accelerator waveform synthesis and longitudinal beam dynamics in a small induction recirculator

Description: A recirculating induction accelerator requires accelerating waveforms that produce current amplification and provide bunch length control throughout the acceleration process. Current amplification occurs because of both an increase in the beam velocity and a shortening of the length of the beam bunch. The pulsed acceleration and control waveforms seen by the beam change in time as the pulse duration shortens. For one acceleration cycle of the small recirculator, each accelerating gap is driven by a burst of 15 pulses. As the beam gains velocity, the time interval between pulses shortens from approximately 20 to 10 {mu}sec. A zero-dimensional design code REC is used to develop the accelerator wave forms. An envelope/fluid code CIRCE and a 3-D particle code WARP3d are used to confirm the REC design and study the effects of errors. The authors find that acceleration errors can lead to space-charge waves launched at the bunch ends that strongly affect or even destroy the current pulse shape. The relation between the rate of longitudinal compression and the velocity of space charge waves is studied.
Date: April 1995
Creator: Fessenden, T.J.; Grote, D.P. & Sharp, W.M.
Partner: UNT Libraries Government Documents Department