30 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Neutron Flux"  
Results: 1 - 24 next
open access

Use of additional fission sources or scattering sources to model inward axial leakages in fast-reactor analysis

Description: When calculations of flux are done in less than three dimensions, bucklings are normally used to model leakages (flows) in the dimensions for which the flux is not calculated. If the net leakage for a given energy group is outward (positive), the buckling is positive, and buckling methods work well. However, if the new leakage for a given energy group is inward (negative), the buckling is negative and can lead to numerical instabilities (oscillations in the iterative flux calculation). This rep… more
Date: October 1, 1981
Creator: Grimm, K. N. & Meneghetti, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

LOCA simulation in the NRU reactor: materials test-1

Description: A simulated loss-of-coolant accident was performed with a full-length test bundle of pressurized water reactor fuel rods. This second experiment of the program produced peak fuel cladding temperatures of 1148K (1607/sup 0/F) and resulted in six ruptured fuel rods. Test data and initial results from the experiment are presented here in the form of photographs and graphical summaries. These results are also compared with the preceding prototypic thermal-hydraulic test results and with computer mo… more
Date: October 1, 1981
Creator: Russcher, G. E.; Marshall, R. K.; Hesson, G. M.; Wildung, N. J. & Rausch, W. N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

COROPT heterogeneous flux model

Description: The PHYSICS module of COROPT calculates the power and flux distributions, power fractions, required fissile enrichment, and fuel mass balances. Sufficiently accurate data are clearly necessary for the results of the thermal hydraulic and fuel pin and assembly performance analysis to be acceptable. The smooth flux and power distribution model developed for the homogeneous core COROPT application has been shown to be accurate for homogeneous cores in the range of interest. However, this model and… more
Date: September 1, 1981
Creator: Bailey, H.S. & Alexander, C.N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Los Alamos benchmarks: calculations based on ENDF/B-V data

Description: The new and revised benchmark specifications for nine Los Alamos National Laboratory critical assemblies are used to compute the entire set of parameters that were measured in the experiments. A comparison between the computed and experimental values provides a measure of the adequacy of the specifications, cross sections, and physics codes used in the calculations.
Date: November 1, 1981
Creator: Kidman, R. B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Use of Additional Fission Sources or Scattering Sources to Model Inward Axial Leakages in Fast-Reactor Analysis

Description: When calculations of flux are done in less than three dimensions, bucklings are normally used to model leakages (flows) in the dimensions for which the flux is not calculated. If the net leakage for a given energy group is outward (positive), the buckling is positive, and buckling methods work well. However, if the new leakage for a given energy group is inward (negative), the buckling is negative and can lead to numerical instabilities (oscillations in the iterative flux calculation). This rep… more
Date: October 1981
Creator: Grimm, K. N. & Meneghetti, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Comparison of calculations with neutron dosimetry measurements performed at the Oak Ridge Poolside Facility

Description: The Oak Ridge Poolside Facility (PSF), like the Pool Critical Assembly (PCA), is used for benchmark dosimetry measurements which can serve to validate the transport methods used in calculating the high-energy neutron fluences (> 0.1 MeV) in LWR pressure vessels required to estimate the neutron damage to the pressure vessels in the form of embrittlement. The PSF consists of an arrangement of two water gaps of 4 and 12 cm thickness separated by a simulated thermal shield and followed by a simulat… more
Date: January 1, 1981
Creator: Maerker, R.E. & Williams, M.L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Neutron attenuation in the laser ducts of an inertial-confinement fusion reactor

Description: This report deals with the problem of neutron streaming through the laser beam ducts of an inertial confinement fusion power plant. The neutron flux through these ducts must be attenuated by a factor of 10/sup 12/ to meet radiological safety limits. The problem is dealt with by using mirrors to bend the path of the laser beam while cutting off a line of sight path for neutrons. The Monte Carlo Code MCNP was used to analyze the two mirror SOLASE design, which only attenuated the neutron flux by … more
Date: November 1, 1981
Creator: Augustine, F., Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Review of measurement techniques for the neutron radiative-capture process

Description: The experimental techniques applied in measurements of the neutron capture process are reviewed. The emphasis is on measurement techniques used in neutron capture cross section measurements. The activation technique applied mainly in earlier work has still its use in some cases, specifically for measurements of technologically important cross sections (/sup 238/U and /sup 232/Th) with high accuracy. Three major prompt neutron radioactive capture detection techniques have evolved: the total gamm… more
Date: July 1, 1981
Creator: Poenitz, W.P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Depth-charge static and time-dependence perturbation/sensitivity system for nuclear reactor core analysis. [LMFBR]

Description: This report provides the background theory, user input, and sample problems required for the efficient application of the DEPTH-CHARGE system - a code block for both static and time-dependence perturbation theory and data sensitivity analyses. The DEPTH-CHARGE system is of modular construction and has been implemented within the VENTURE-BURNER computational system at Oak Ridge National Labortary. The DEPTH-CHARGE system provides, for the first time, a complete generalized first-order perturbati… more
Date: September 1, 1981
Creator: White, J.R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Neutronics code VALE for two-dimensional triagonal (hexagonal) and three-dimensional geometries

Description: This report documents the computer code VALE designed to solve multigroup neutronics problems with the diffusion theory approximation to neutron transport for a triagonal arrangement of mesh points on planes in two- and three-dimensional geometry. This code parallels the VENTURE neutronics code in the local computation system, making exposure and fuel management capabilities available. It uses and generates interface data files adopted in the cooperative effort sponsored by Reactor Physics RRT … more
Date: August 1, 1981
Creator: Vondy, D.R. & Fowler, T.B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Cosmic-ray-induced radiation environment and dose to man for low-orbit space applications

Description: Neutrons and photons resulting from the interaction of galactic cosmic rays with the material of an orbiting satellite or an orbiting space station at an altitude of some few hundreds of kilometers, and below the level of the radiation belts, have been calculated as a function of geomagnetic latitude and solar activity level. The photon and neutron leakage currents from the top of the atmosphere have been computed. The radiation dose-equivalent rate to an unshielded astronaut has also been calc… more
Date: September 1, 1981
Creator: Sandmeier, H. A.; Hansen, G. E.; Battat, M. E. & O'Brien, K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Source-to-incident-flux relation in a tokamak blanket module

Description: The next-generation tokamak experiments, including the Tokamak Fusion Test Reactor (TFTR), will utilize small blanket modules to measure performance parameters such as tritium breeding profiles, power deposition profiles, and neutron flux profiles. Specifically, a neutron calorimeter (simply a neutron moderating blanket module) which allows one to infer the incident 14 MeV flux based on measured temperature profiles has been proposed for TFTR. The problem addressed here is how to relate this to… more
Date: January 1, 1981
Creator: Imel, G.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Bounded limit for the Monte Carlo point-flux-estimator

Description: In a Monte Carlo random walk the kernel K(R,E) is used as an expected value estimator at every collision for the collided flux phi/sub c/ r vector,E) at the detector point. A limiting value for the kernel is derived from a diffusion approximation for the probability current at a radius R/sub 1/ from the detector point. The variance of the collided flux at the detector point is thus bounded using this asymptotic form for K(R,E). The bounded point flux estimator is derived. (WHK)
Date: January 1, 1981
Creator: Grimesey, R.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Collocation method for the solution of the neutron transport equation with both symmetric and asymmetric scattering

Description: A collocation method is developed for the solution of the one-dimensional neutron transport equation in slab geometry with both symmetric and polarly asymmetric scattering. For the symmetric scattering case, it is found that the collocation method offers a combination of some of the best characteristics of the finite-element and discrete-ordinates methods. For the asymmetric scattering case, it is found that the computational cost of cross-section data processing under the collocation approach … more
Date: January 1, 1981
Creator: Morel, J.E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

MIT LMFBR blanket research project. Quarterly progress report, October 1, 1980-December 31, 1980

Description: Information on heterogeneous assembly evaluation is presented concerning ringed moderator description and flux trap description; cross section generation; ringed moderator results; effects of heterogeneous moderation; sodium void worth breakdown; flux trap configuration; flux trap results; the effects of stoichiometric variation in the moderator; and the effects of lattice representation. Also discussed is the engineering compatibility of heterogeneous assembly designs.
Date: March 26, 1981
Creator: Driscoll, M.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Materials Selection for the US INTOR Divertor Collector Plate

Description: The divertor collector plate in the INTOR reactor will be subjected to high heat, particle, and neutron fluxes, making it the most severely damaged torus component. The collector plate is composed of a protection plate, which is directly exposed to the particle flux, and a heat sink which provides support for the protection plate and carries the water coolant. The high-Z refractory metals have been considered for use as the protection plate material, and austenitic stainless steels and copper a… more
Date: January 1, 1981
Creator: Mattas, R. F.; Misra, B.; Smith, D. L.; Morgan, G. D.; Delaney, M. & Gold, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Effect of irradiation induced structural material deformations on core restraint design

Description: A summary of the major considerations in the design of LMFBR core restraint systems is presented. A discussion of these considerations is given using the design features and environment of the Clinch River Breeder Reactor Plant core restraint system design. A comparison of core restraint performance with an alternate concept is provided. Conclusions are drawn on the direction of current and future core restraint system designs.
Date: January 1, 1981
Creator: Kalinowski, J.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Long-time behavior of a nuclear reactor

Description: A fundamental problem of reactor physics is the determination of the long-time behavior of the neutron population in a nuclear reactor. In particular, one is interested in the question whether the total neutron density has a purely exponential behavior as t ..-->.. infinity. We formulate this problem as an abstract Cauchy problem, show that the solution is given by a semigroup, and investigate the asymptotic behavior of the semigroup.
Date: January 1, 1981
Creator: Kaper, H.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Thermal neutron absorption cross section of sulfur and the 252-californium nubar problem

Description: The thermal neutron absorption cross section for natural sulfur was measured to be 513 +- 15 mb. Any discrepancy between MnSO/sub 4/-bath and liquid scintillator measurements of /sup 252/Cf(anti ..nu..) cannot be attributed to a discrepancy in this cross section value.
Date: January 1, 1981
Creator: Jurney, E. T.; Raman, S. & Spencer, R. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Neutron-irradiation facilities at the intense pulsed-neutron source

Description: Among the accelerator-based neutron sources presently in operation, the highest-flux source is the Intense Pulsed Neutron Source (IPNS), a user facility at Argonne. Neutrons in this source are produced by the interaction of 500-MeV protons from a synchrotron with either of two /sup 238/U target systems. In the Radiation Effects Facility (REF), the /sup 238/U target is surrounded by Pb for neutron generation and reflection. The REF has three separate irradiation thimbles. Two thimbles provide ir… more
Date: January 1, 1981
Creator: Birtcher, R. C.; Blewitt, T. H.; Kirk, M. A.; Scott, T. L.; Brown, B. S. & Greenwood, L. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Neutron-source characterization and radiation-damage calculations for material studies

Description: In our quest to understand radiation damage in materials, it is vital that we characterize radiation sources in terms of neutron flux and spectra as well as the more-fundamental displacement damage, gas production, and transmutation rates. Such data are crucial to correlations of materials-property changes in different environments and to predictions of materials performance in inaccessible environments, such as fusion reactors. Dosimetry techniques have been developed to measure the neutron fl… more
Date: November 9, 1981
Creator: Greenwood, L.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Neutron-source characterization for fusion-materials studies

Description: Neutron-flux and energy-spectrum measurements are conducted for all major fusion-materials irradiation facilities, including fission reactors and accelerators. Dosimetry-characterization experiments and integral cross section measurements have been performed. Multiple activation and helium-production measurements are performed routinely to provide materials experimenters with neutron-exposure parameters including fluence, spectrum, displacements, gas production, and transmutation with typical a… more
Date: June 1, 1981
Creator: Greenwood, L.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
Back to Top of Screen