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Creep Rupture in the Presence of a Fast Neutron Flux

Description: Possible mechanisms for creep rupture during irradiation are examined. Evidence that the rupture occurs by grain boundary sliding alone, or by vacancy condensation, is compared. It is observed that vacancy condensation is the more probable mechanism, and that this mechanism predicts a reduction in creep rupture life for metals exposed to a fast neutron flux (neglecting effects of radiation annealing). (T.F.H.)
Date: January 14, 1959
Creator: Gregory, D. P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Inherently safe nuclear-driven internal combustion engines

Description: A family of nuclear driven engines is described in which nuclear energy released by fissioning of uranium or plutonium in a prompt critical assembly is used to heat a working gas. Engine performance is modeled using a code that calculates hydrodynamics, fission energy production, and neutron transport self-consistently. Results are given demonstrating a large negative temperature coefficient that produces self-shutoff of energy production. Reduced fission product inventory and the self-shutoff … more
Date: June 14, 1991
Creator: Alesso, P.; Chow, Tze-Show; Condit, R.; Heidrich, J.; Pettibone, J. & Streit, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Evaluation of Buried Conduits as Personnel Shelters

Description: Supersedes ITR-1421. Twelve large-diameter buried conduit sections of various shapes were tested in the 60- to l49-psi overpressure region of Burst Priscilla to make an empirical determination of the degree of personnel protection afforded by commercially available steel and concrete conduits at depths of burial of 5, 7.5, and 10 feet below grade. Essentially, it was desired to assure that Repartment of Defense Class I, 100psi and comparable radiations, and Class II, 50-psi and comparable radia… more
Date: July 14, 1960
Creator: Albright, G. H.; LeDoux, J. C. & Mitchell, R. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Capture cross section and gamma-ray spectrum calculations for medium-weight nuclei. [Double-peak, energy-dependent Breit-Wigner model]

Description: A double-peak, energy-dependent Breit-Wigner model of the E1 gamma-ray strength function was applied to nuclei from As to Rh, to predict their neutron capture cross sections and capture gamma-ray spectra. A consistent set of model parameters was obtained in this mass region to describe the step in the low-energy tail of the E1 strength function. This step allows agreement with photonuclear data at high energies, the correct GAMMA/sub gamma/ to be obtained for agreement with neutron capture cros… more
Date: November 14, 1979
Creator: Gardner, M. A. & Gardner, D. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Germanium: From Its Discovery to SiGe Devices

Description: Germanium, element No.32, was discovered in 1886 by Clemens Winkler. Its first broad application was in the form of point contact Schottky diodes for radar reception during WWII. The addition of a closely spaced second contact led to the first all-solid-state electronic amplifier device, the transistor. The relatively low bandgap, the lack of a stable oxide and large surface state densities relegated germanium to the number 2 position behind silicon. The discovery of the lithium drift process, … more
Date: June 14, 2006
Creator: Haller, E.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Preliminary Evaluation of a Portable Handheld Combined Gamma and Neutron Directional Isotopic Identifying Detector

Description: Purpose: To simulate the performance of a portable dual gamma and neutron identification detector array with dual directional detection capability for preliminary algorithm evaluation. Experimental procedures: Monte Carlo N-Particle (MCNP) analysis on a compact array of borated polyvinyl toluene light pipes and photomultiplier tubes, standard spectral histogramming, and directional detection capability simulations. Results: Results demonstrate that the detector system is fully capable of correc… more
Date: February 14, 2008
Creator: Hayes, Robert
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A Time Projection Chamber for precision 239Pu(n,f) cross section measurement

Description: High precision measurements of the {sup 239}Pu(n,f) cross section have been identified as important for the Global Nuclear Energy Partnership (GNEP) and other programs. Currently the uncertainty on this cross section is of the order 2-3% for neutron energies below 14 MeV and the goal is to reduce this to less than 1%. The Time Projection Chamber (TPC) has been identified as a possible tool to make this high precision measurement.
Date: January 14, 2008
Creator: Heffner, M
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Multivariate Time Series Method for Monte Carlo Reactor Analysis

Description: A robust multivariate time series method has been established for the Monte Carlo calculation of neutron multiplication problems. The method is termed Coarse Mesh Projection Method (CMPM) and can be implemented using the coarse statistical bins for acquisition of nuclear fission source data. A novel aspect of CMPM is the combination of the general technical principle of projection pursuit in the signal processing discipline and the neutron multiplication eigenvalue problem in the nuclear engine… more
Date: August 14, 2008
Creator: Ueki, Taro
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Integrated system of production of neutronics and photonics calculational constants. Volume 21, Part A. Maxwell-averaged reaction rates (sigma v-bar) for selecteed reactions between ions with atomic mass less than or equal to 11

Description: Maxwell-averaged reaction rates (sigma v-bar) are presented for 24 interactions between /sup 1/H, /sup 2/H, /sup 3/H, /sup 3/He, /sup 4/He, /sup 6/Li, /sup 7/Li, /sup 10/B, and /sup 11/B ions. The reactions rates are calculated by use of the evaluated data of the LLL Evaluated Nuclear Data Library (ENDL). 5 figures, 5 tables.
Date: February 14, 1979
Creator: Howerton, Robert J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Personnel neutron monitoring developments at LLL. [Development and calibration of various types of neutron detectors and monitors]

Description: Approximately 40 employees at LLL work in areas where personnel neutron monitoring is necessary. The dose rate in these areas is low, rarely exceeding 0.5 rem per year. However, the wide variety of neutron environments (dt neutron generators; a 3 MW pool type reactor; a 100 MeV electron Linac; and a number of vaults and glove boxes where alpha, n and spontaneous fission sources are stored) makes the neutron monitoring task difficult. As a result, we have been studying potential developments in … more
Date: November 14, 1978
Creator: Griffith, R.V.; Fisher, J.C.; Hankins, D.E. & Miller, D.E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Small-Angle Neutron-Proton Scattering at 90 and 290 Mev

Description: From abstract: "The relative differential neutron-proton scattering cross section has been measured in the range of center-of-mass angles from 5.1° to 36.0° for approximately 90-Mev neutrons and from 10.7° to 37.8° for approximately 290-Mev neutrons."
Date: September 14, 1954
Creator: Easley, James Warren
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

CASIM input parameters for various materials

Description: During the past year, the computer program CASIM has been placed in a common area from which copies can be obtained by a wide array of users. The impetus for this arrangement was the need to have a standard code that could be maintained and transported to other platforms. In addition, an historical record would be kept of each version as the program evolved. CASIM requires a series of parameters (input by the user) that describe the medium in which the cascade develops. Presently a total of 9 m… more
Date: July 14, 1994
Creator: Malensek, A. J. & Elwyn, A. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The Bragg Reflection of Neutrons by a Single Crystal

Description: From cover page: This document has been assigned the above MDDC (Manhattan District Declassification) number, as given in the List of Declassified Documents issued semi-monthly by the Research Division, Manhattan District. In the case of Los Alapnos reports, LADC (Los Alamos Declassification) numbers are listed on the title page if known. This declassified document may differ materially from the original classified document by reason of deletions necessary to accomplish declassification. Hence,… more
Date: June 14, 1946
Creator: Zinn, Walter H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Final Technical Report

Description: Over the past year, our group here at the University of Texas has continued to focus primarily on analysis of data from the Sudbury Neutrino Observatory (SNO), in particular on a push to lower the energy threshold used in solar neutrino analyses and on a search for short time-scale astrophysical phenomena in the neutrino data set. We have in addition begun R and D and simulation work on a new direct search for dark matter as part of the DEAP/CLEAN collaboration, as well as an effort associated … more
Date: September 14, 2008
Creator: Klein, Joshua R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Event-by-event study of neutron observables in spontaneous and thermal fission

Description: The event-by-event fission model FREYA is extended to spontaneous fission of actinides and a variety of neutron observables are studied for spontaneous fission and fission induced by thermal neutrons with a view towards possible applications for SNM detection. We have shown that event-by-event models of fission, such as FREYA, provide a powerful tool for studying fission neutron correlations. Our results demonstrate that these correlations are significant and exhibit a dependence on the fission… more
Date: September 14, 2011
Creator: Vogt, R & Randrup, J
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The prediction of Neutron Elastic Scattering from Tritium for E(n) = 6-14 MeV

Description: In a recent report Navratil et al. evaluated the angle-integrated cross section and the angular distribution for 14-MeV n+T elastic scattering by inferring these cross sections from accurately measured p+3He angular distributions. This evaluation used a combination of two theoretical treatments, based on the no-core shell model and resonating-group method (NCSM/RGM) and on the R-matrix formalism, to connect the two charge-symmetric reactions n+T and p+{sup 3}He. In this report we extend this tr… more
Date: June 14, 2010
Creator: Anderson, J. D.; Dietrich, F. S.; Luu, T.; McNabb, D. P.; Navratil, P. & Quaglioni, S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A GREEN'S FUNCTION APPROACH FOR DETERMINING DOSE RATES FOR SMALL GRAM QUANTITIES IN SHIPPING PACKAGINGS

Description: The Small Gram Quantity (SGQ) concept is based on the understanding that small amounts of hazardous materials, in this case radioactive materials (RAM), are significantly less hazardous than large amounts of the same materials. This paper describes a methodology designed to estimate an SGQ for several neutron and gamma emitting isotopes that can be shipped in a package in compliance with 10 CFR Part 71 external radiation level limits regulations. The neutron and photon sources were calculated u… more
Date: June 14, 2012
Creator: Nathan, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Reactivity capacity of NPR control systems

Description: The reactivity control capacity of the N-reactor control systems has been calculated by methods which take into account the absorption of epithermal as well as thermo neutrons. Earlier calculations were made using a method which is satisfactory in control calculations for the existing Hanford reactors but which largely neglects the epithermal absorption. The new calculations were undertaken because of recent evidence that the epithermal absorption is more important to the NPR control strength a… more
Date: July 14, 1960
Creator: Simpson, D. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Historical Evaluation of Film Badge Dosimetry Y-12 Plant: Part 2–Neutron Radiation ORAUT-OTIB-0045

Description: A summary of the major neutron sources involved in radiation exposures to Y-12 workers is presented in this TIB. Graphical methods are used to evaluate available neutron dose data from quarterly exposures to Y-12 workers and to determine how the data could be used to derive neutron-to-gamma dose ratios for dose reconstruction purposes. This TIB provides estimates of neutron-to-gamma dose ratios for specific departments and a default value for the neutron-to-gamma dose ratio based on the pooled … more
Date: December 14, 2009
Creator: Kerr, G. D.; Frome, E. L.; Watkins, J. P. & Tankersley, W. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A Concept for a Low Pressure Noble Gas Fill Intervention in the IFE Fusion Test Facility (FTF) Target Chamber

Description: An engineering evaluation has been initiated to investigate conceptual engineering methods for implementing a viable gas shield strategy in the Fusion Test Facility (FTF) target chamber. The employment of a low pressure noble gas in the target chamber to thermalize energetic helium ions prior to interaction with the wall could dramatically increase the useful life of the first wall in the FTF reactor1. For the purpose of providing flexibility, two target chamber configurations are addressed: a … more
Date: January 14, 2010
Creator: C.A. Gentile, W.R. Blanchard, T.A. Kozub, M. Aristova, C. McGahan, S. Natta, K. Pagdon, J. Zelenty
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

NEUTRON ACTIVATION ANALYSIS APPLICATIONS AT THE SAVANNAH RIVER SITE USING AN ISOTOPIC NEUTRON SOURCE

Description: NAA using {sup 252}Cf is used to address important areas of applied interest at SRS. Sensitivity needs for many of the applications are not severe; analyses are accomplished using a 21 mg {sup 252}Cf NAA facility. Because NAA allows analysis of bulk samples, it offers strong advantages for samples in difficult-to-digest matrices when its sensitivity is sufficient. Following radiochemical separation with stable carrier addition, chemical yields for a number methods are determined by neutron acti… more
Date: August 14, 2006
Creator: Diprete, D; C Diprete, C & Raymond Sigg, R
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Vadose Zone Contaminant Fate and Transport Analysis for the 216-B-26 Trench

Description: The BC Cribs and Trenches, part of the 200 TW 1 OU waste sites, received about 30 Mgal of scavenged tank waste, with possibly the largest inventory of 99Tc ever disposed to the soil at Hanford and site remediation is being accelerated. The purpose of this work was to develop a conceptual model for contaminant fate and transport at the 216-B-26 Trench site to support identification and development and evaluation of remediation alternatives. Large concentrations of 99Tc high above the water table… more
Date: October 14, 2004
Creator: Ward, Andy L.; Gee, Glendon W.; Zhang, Z. F. & Keller, Jason M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Improved Gamma Bang Time Measurements on Omega and Implications for the National Ignition Facility

Description: The time of peak fusion reactivity with respect to the impingement of laser light on an ICF capsule is known as Bang Time (BT). This is an essential parameter in the understanding of ICF implosions. Traditionally, BT has been determined through temporal measurements of 14 MeV fusion neutrons. Because the neutron energy spectrum is Doppler broadened, the detector must be positioned close to target-chamber center in order to minimize the neutron temporal spreading which can compromise such a meas… more
Date: September 14, 2007
Creator: Miller, Edward K.; Hermann, H. W.; Caldwell, S. E.; Evans, S. C.; Mack, J. M.; Shanch, P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Characterization of a Tunable Quasi-Monoenergetic Neutron Beamfrom Deuteron Breakup

Description: A neutron irradiation facility is being developed at the88-Inch Cyclotron at Lawrence Berkeley National Laboratory for thepurposes of measuring neutron reaction cross sections on radioactivetargets and for radiation effects testing. Applications are of benefit tostockpile stewardship, nuclear astrophysics, next generation advancedfuel reactors, and cosmic radiation biology and electronics in space. Thefacility will supply a tunable, quasi-monoenergetic neutron beam in therange of 10-30 MeV or a… more
Date: December 14, 2006
Creator: Bleuel, D. L.; McMahan, M. A.; Ahle, L.; Barquest, B. R.; Cerny, J.; Heilbronn, L. H. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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