Underground Corrosion of Activated Metals in an Arid Vadose Zone Environment (open access)

Underground Corrosion of Activated Metals in an Arid Vadose Zone Environment

The subsurface radioactive disposal site located at the Idaho National Engineering and Environmental Laboratory contains neutron-activated metals from nonfuel nuclear-reactor- core components. A long-term corrosion test is being conducted to obtain site-specific corrosion rates to support efforts to more accurately estimate the transfer of activated elements in an arid vadose zone environment. The tests use nonradioactive metal coupons representing the prominent neutron-activated material buried at the disposal location, namely, Type 304L stainless steel, Type 315L stainless steel, nickel-chromium alloy (UNS NO7718), beryllium, aluminum 6061-T6, and a zirconium alloy, (UNS R60804). In addition, carbon steel (the material presently used in the cask disposal liners and other disposal containers) and a duplex stainless steel (UNS S32550) (the proposed material for the high- integrity disposal containers) are also included in the test program. This paper briefly describes the test program and presents the early corrosion rate results after 1 year and 3 years of underground exposure.
Date: October 24, 2001
Creator: Adler Flitton, M. K.; Mizia, R. E. & Bishop, C. W.
Object Type: Article
System: The UNT Digital Library
Neutrino Observations From the Sudbury Neutrino Observatory (open access)

Neutrino Observations From the Sudbury Neutrino Observatory

The Sudbury Neutrino Observatory (SNO) is a water imaging Cherenkov detector. Its usage of 1000 metric tons of D{sub 2}O as target allows the SNO detector to make a solar-model independent test of the neutrino oscillation hypothesis by simultaneously measuring the solar {nu}{sub e} flux and the total flux of all active neutrino species. Solar neutrinos from the decay of {sup 8}B have been detected at SNO by the charged-current (CC) interaction on the deuteron and by the elastic scattering (ES) of electrons. While the CC reaction is sensitive exclusively to {nu}{sub e}, the ES reaction also has a small sensitivity to {nu}{sub {mu}} and {nu}{sub {tau}}. In this paper, recent solar neutrino results from the SNO experiment are presented. It is demonstrated that the solar flux from {sup 8}B decay as measured from the ES reaction rate under the no-oscillation assumption is consistent with the high precision ES measurement by the Super-Kamiokande experiment. The {nu}{sub e} flux deduced from the CC reaction rate in SNO differs from the Super-Kamiokande ES results by 3.3{sigma}. This is evidence for an active neutrino component, in additional to {nu}{sub e}, in the solar neutrino flux. These results also allow the first experimental determination …
Date: September 24, 2001
Creator: Ahmad, Q. R.; Allen, R. C.; Andersen, T. C.; Anglin, J. D.; Barton, J. C.; Beier, E. W. et al.
Object Type: Article
System: The UNT Digital Library
Laboratory Directed Research and Development FY 2000 Annual Report (open access)

Laboratory Directed Research and Development FY 2000 Annual Report

This Annual Report provides an overview of the FY2000 Laboratory Directed Research and Development (LDRD) Program at Lawrence Livermore National Laboratory (LLNL) and presents a summary of the results achieved by each project during the year.
Date: May 24, 2001
Creator: Al-Ayat, R
Object Type: Report
System: The UNT Digital Library
Ion Temperature Measurements in SSPX (open access)

Ion Temperature Measurements in SSPX

The Ion Doppler Spectrometer instrument on the Sustained Spheromak Physics experiment is described, along with background about it's operation. Results are presented from recent experimental runs, and the data is compared to the results of simple statistical models of heat exchange in two species gasses.
Date: August 24, 2001
Creator: Auerbach, D W; Hill, D N & McLean, H S
Object Type: Report
System: The UNT Digital Library
Scale-Up of Palladium Powder Production Process for Use in the Tritium Facility at Westinghouse, Savannah River, SC/Summary of FY99-FY01 Results for the Preparation of Palladium Using the Sandia/LANL Process (open access)

Scale-Up of Palladium Powder Production Process for Use in the Tritium Facility at Westinghouse, Savannah River, SC/Summary of FY99-FY01 Results for the Preparation of Palladium Using the Sandia/LANL Process

Palladium used at Savannah River (SR) for process tritium storage is currently obtained from a commercial source. In order to understand the processes involved in preparing this material, SR is supporting investigations into the chemical reactions used to synthesize this material. The material specifications are shown in Table 1. An improved understanding of the chemical processes should help to guarantee a continued reliable source of Pd in the future. As part of this evaluation, a work-for-others contract between Westinghouse Savannah River Company and Ames Laboratory (AL) was initiated. During FY98, the process for producing Pd powder developed in 1986 by Dan Grove of Mound Applied Technologies, USDOE (the Mound muddy water process) was studied to understand the processing conditions that lead to changes in morphology in the final product. During FY99 and FY00, the process for producing Pd powder that has been used previously at Sandia and Los Alamos National Laboratories (the Sandia/LANL process) was studied to understand the processing conditions that lead to changes in the morphology of the final Pd product. During FY01, scale-up of the process to batch sizes greater than 600 grams of Pd using a 20-gallon Pfaudler reactor was conducted by the Iowa State University …
Date: August 24, 2001
Creator: Baldwin, David P.; Zamzow, Daniel S.; Vigil, R. Dennis & Pikturna, Jesse T.
Object Type: Report
System: The UNT Digital Library
A Comparative experimental study of media access protocols for wireless radio networks (open access)

A Comparative experimental study of media access protocols for wireless radio networks

We conduct a comparative experimental analysis of three well known media access protocols: 802.11, CSMA, and MACA for wireless radio networks. Both fixed and ad-hoc networks are considered. The experimental analysis was carried out using GloMoSim: a tool for simulating wireless networks. The main focus of experiments was to study how (i) the size of the network, (ii) number of open connections, (iii) the spatial location of individual connections, (iv) speed with which individual nodes move and (v) protocols higher up in the protocol stack (e,g. routing layer) affect the performance of the media access sublayer protocols. The performance of the protocols was measured w.r.t. three important parameters: (1) number of received packets, (2) average latency of each packet, and (3) throughput. The following general qualitative conclusions were obtained; some of the conclusions reinforce the earlier claims by other researchers. (1) Although 802.11 performs better than the other two protocols with respect to fairness of transmission, packets dropped, and latency, its performance is found to (i) show a lot of variance with changing input parameters and (ii) the overall performance still leaves a lot of room for improvement. (2) CSMA does not perform too well under the fairness criteria, however, …
Date: May 24, 2001
Creator: Barrett, C. L. (Christopher L.); Drozda, M. (Martin) & Marathe, M. V. (Madhav V.)
Object Type: Article
System: The UNT Digital Library
Applications of Crystal Plasticity in Multiscale Modeling (open access)

Applications of Crystal Plasticity in Multiscale Modeling

Multiscale modeling with crystal plasticity constitutive relations is used to determine the average response of a polycrystal. The measured crystallographic texture of a copper shaped charge liner is used in a crystal plasticity model to construct a yield surface that exhibits normal-shear coupling. Simulations with this yield surface model demonstrate the spinning behavior observed in the spin formed copper shaped charges.
Date: September 24, 2001
Creator: Becker, R.; Busche, M.; Schwartz, A. J. & Kumar, M.
Object Type: Article
System: The UNT Digital Library
Calculation of Fragmentation Functions in Two-Hadron Semi-Inclusive Processes. (open access)

Calculation of Fragmentation Functions in Two-Hadron Semi-Inclusive Processes.

We investigate the properties of interference fragmentation functions arising from the emission of two leading hadrons inside the same jet for inclusive lepton-nucleon deep inelastic scattering. Using an extended spectator model for the mechanism of the hadronization, we give a complete calculation and numerical estimates for the examples of a proton-pion pair produced with invariant mass on the Roper resonance, and of two pions produced with invariant mass close to the {rho} mass. We discuss azimuthal angular dependence of the leading order cross section to point up favourable conditions for extracting transversity from experimental data.
Date: April 24, 2001
Creator: Bianconi, A.; Boffi, S.; Boer, D.; Jakob, R. & Radici, M.
Object Type: Article
System: The UNT Digital Library
Radionuclide Releases During Normal Operations for Ventilated Tanks (open access)

Radionuclide Releases During Normal Operations for Ventilated Tanks

This calculation estimates the design emissions of radionuclides from Ventilated Tanks used by various facilities. The calculation includes emissions due to processing and storage of radionuclide material.
Date: September 24, 2001
Creator: Blunt, B.
Object Type: Report
System: The UNT Digital Library
Methods for Addressing Uncertainty and Variability to Characterize Potential Health Risk from Trichloroethylene-Contaminated Ground Water at Beale Air Force Base in California:Integration of Uncertainty and Variability in Pharmacokinetics and Dose-Response (open access)

Methods for Addressing Uncertainty and Variability to Characterize Potential Health Risk from Trichloroethylene-Contaminated Ground Water at Beale Air Force Base in California:Integration of Uncertainty and Variability in Pharmacokinetics and Dose-Response

Traditional estimates of health risk are typically inflated, particularly if cancer is the dominant endpoint and there is fundamental uncertainty as to mechanism(s) of action. Risk is more realistically characterized if it accounts for joint uncertainty and interindividual variability within a systematic probabilistic framework to integrate the joint effects on risk of distributed parameters of all (linear as well as nonlinear) risk-extrapolation models involved. Such a framework was used to characterize risks to potential future residents posed by trichloroethylene (TCE) in ground water at an inactive landfill site on Beale Air Force Base in California. Variability and uncertainty were addressed in exposure-route-specific estimates of applied dose, in pharmacokinetically based estimates of route-specific metabolized fractions of absorbed TCE, and in corresponding biologically effective doses estimated under a genotoxic/linear (MA{sub G}) vs. a cytotoxic/nonlinear (MA{sub c}) mechanistic assumption for TCE-induced cancer. Increased risk conditional on effective dose was estimated under MA{sub G} based on seven rodent-bioassay data sets, and under MA{sub c} based on mouse hepatotoxicity data. Mean and upper-bound estimates of combined risk calculated by the unified approach were <10{sup -6} and 10{sup -4}, respectively, while corresponding estimates based on traditional deterministic methods were >10{sup -5} and 10{sup -4}, respectively. It …
Date: May 24, 2001
Creator: Bogen, K T
Object Type: Report
System: The UNT Digital Library
Decommissioning the Brookhaven National Laboratory Building 830 Gamma Irradiation Facility (open access)

Decommissioning the Brookhaven National Laboratory Building 830 Gamma Irradiation Facility

The Building 830 Gamma Irradiation Facility (GIF) at Brookhaven National Laboratory (BNL) was decommissioned because its design was not in compliance with current hazardous tank standards and because its cobalt-60 sources were approaching the end of their useful life. The facility contained 354 stainless steel encapsulated cobalt-60 sources in a pool, which provided shielding. Total cobalt-60 inventory amounted to 24,000 Curies (when the sources were shipped for disposal). The decommissioning project included packaging, transport and disposal of the sources and dismantling and disposing of all other equipment associated with the facility. Worker exposure was a major concern in planning for the packaging and disposal of the sources. These activities were planned carefully according to ALARA (As Low As Reasonably Achievable) principles. As a result, the actual doses experienced during the work were lower than anticipated. Because the sources were sealed, most of the remaining equipment was not contaminated; therefore disposal was straightforward, as scrap metal and construction debris. However, disposal of the pool water involved addressing environmental concerns, since the planned method was to discharge the slightly contaminated water to the BNL sewage treatment plant.
Date: February 24, 2001
Creator: Bowerman, B.; Sullivan, P. T. & Moore, D.
Object Type: Article
System: The UNT Digital Library
MULTI-PHASE Cr-BASED ALLOYS FOR AGGRESSIVE HIGH TEMPERATURE ENVIRONMENTS (open access)

MULTI-PHASE Cr-BASED ALLOYS FOR AGGRESSIVE HIGH TEMPERATURE ENVIRONMENTS

Attractive high-temperature mechanical properties and oxidation/hot corrosion resistance have been achieved in a new family of Cr{sub 2}Ta-reinforced Cr alloys. However, inadequate room-temperature toughness remains a key challenge, with the best Cr-Cr{sub 2}Ta alloys exhibiting only modest toughness in the range of 12-14 MPa m{sup 1/2}. The addition of MgO has been shown to significantly improve the room-temperature mechanical properties of unalloyed Cr and was investigated as a means for improving the room-temperature mechanical properties of the Cr-Cr{sub 2}Ta alloys. Microstructural analysis of a series of Cr and Cr-6MgO base alloys was used to investigate the proposed ductilization mechanism of nitrogen gettering by a MgCr{sub 2}O{sub 4} spinel phase, which forms during consolidation of Cr and MgO powders. Nitride and related impurity precipitates have been linked to reduced ductility in Cr at room-temperature. Surprisingly, nitride (and carbide) impurity precipitates were found i n hot-pressed Cr-6 MgO base alloys despite room-temperature tensile ductility of 5%. These precipitates were found adjacent to MgO/MgCr{sub 2}O{sub 4} particles and were somewhat more blunt than those observed in unalloyed Cr. The addition of TiO{sub 2} to unalloyed Cr resulted in similar morphological changes to the nitride and carbide impurity precipitates; however, the TiO{sub 2} dispersed …
Date: August 24, 2001
Creator: Brady, MP
Object Type: Article
System: The UNT Digital Library
The Science Manager's Guide to Case Studies (open access)

The Science Manager's Guide to Case Studies

This guide takes the science manager through the steps of planning, implementing, validating, communicating, and using case studies. It outlines the major methods of analysis, describing their relative merits and applicability while providing relevant examples and sources of additional information. Well-designed case studies can provide a combination of rich qualitative and quantitative information, offering valuable insights into the nature, outputs, and longer-term impacts of the research. An objective, systematic, and credible approach to the evaluation of U.S. Department of Energy Office of Science programs adds value to the research process and is the subject of this guide.
Date: September 24, 2001
Creator: Branch, Kristi M.; Peffers, Melissa S.; Ruegg, Rosalie T. & Vallario, Robert W.
Object Type: Report
System: The UNT Digital Library
Predicting and Evaluating the Effectiveness of Ocean Carbon Sequestration by Direct Injection (open access)

Predicting and Evaluating the Effectiveness of Ocean Carbon Sequestration by Direct Injection

Direct injection of CO{sub 2} into the ocean is a potentially effective carbon sequestration strategy. Therefore, we want to understand the effectiveness of oceanic injection and develop the appropriate analytic framework to allow us to compare the effectiveness of this strategy with other carbon management options. Here, after a brief review of direct oceanic injection, we estimate the effectiveness of ocean carbon sequestration using one dimensional and three dimensional ocean models. We discuss a new measure of effectiveness of carbon sequestration in a leaky reservoir, which we denote sequestration potential. The sequestration potential is the fraction of global warning cost avoided by sequestration in a reservoir. We show how these measures apply to permanent sequestration and sequestration in leaky reservoirs, such as the oceans, terrestrial biosphere, and some geologic formations. Under the assumptions of a constant cost of carbon emission and a 4% discount rate, injecting 900 m deep in the ocean avoids {approx}90% of the global warming cost associated with atmospheric emission; an injection 1700 m deep would avoid > 99 % of the global warming cost. Hence, for discount rates in the range commonly used by commercial enterprises, oceanic direct injection may be nearly as economically effective as …
Date: April 24, 2001
Creator: Caldeira, K; Herzog, H J & Wickett, M E
Object Type: Article
System: The UNT Digital Library
PHASE II CALDERON PROCESS TO PRODUCE DIRECT REDUCED IRON RESEARCH AND DEVELOPMENT PROJECT (open access)

PHASE II CALDERON PROCESS TO PRODUCE DIRECT REDUCED IRON RESEARCH AND DEVELOPMENT PROJECT

This project was initially targeted to the making of coke for blast furnaces by using proprietary technology of Calderon in a phased approach, and Phase I was completed. The project was then re-directed to the making of iron units. U.S. Steel teamed up with Calderon for a joint effort which will last 30 months to produce directly reduced iron with the potential of converting it into molten iron (hot metal) consistent with the Roadmap recommendations of 1998 prepared by the Steel Industry in cooperation with the Department of Energy. The work which is labeled as Phase II will take place at two levels; namely, the bench scale level and the process development unit (PDU) level. The bench scale work is being divided into two parts; the construction and operation of Bench Scale No.1 to make hot metal direct as one part and the construction and operation of Bench Scale No.2 to make DRI with its conversion to hot metal as the second part. The work at the PDU consists of getting the PDU which exists ready for advancing the activities from bench scale to PDU level.
Date: October 24, 2001
Creator: Calderon, Albert
Object Type: Report
System: The UNT Digital Library
Supervised and unsupervised discretization methods for evolutionary algorithms (open access)

Supervised and unsupervised discretization methods for evolutionary algorithms

This paper introduces simple model-building evolutionary algorithms (EAs) that operate on continuous domains. The algorithms are based on supervised and unsupervised discretization methods that have been used as preprocessing steps in machine learning. The basic idea is to discretize the continuous variables and use the discretization as a simple model of the solutions under consideration. The model is then used to generate new solutions directly, instead of using the usual operators based on sexual recombination and mutation. The algorithms presented here have fewer parameters than traditional and other model-building EAs. They expect that the proposed algorithms that use multivariate models scale up better to the dimensionality of the problem than existing EAs.
Date: January 24, 2001
Creator: Cantú-Paz, Erick
Object Type: Article
System: The UNT Digital Library
Neutral Beam Ion Confinement in NSTX (open access)

Neutral Beam Ion Confinement in NSTX

Neutral-beam (NB) heating in the National Spherical Torus Experiment (NSTX) began in September 2000 using up to 5 MW of 80 keV deuterium (D) beams. An initial assessment of beam ion confinement has been made using neutron detectors, a neutral particle analyzer (NPA), and a Faraday cup beam ion loss probe. Preliminary neutron results indicate that confinement may be roughly classical in quiescent discharges, but the probe measurements do not match a classical loss model. MHD activity, especially reconnection events (REs) causes substantial disturbance of the beam ion population.
Date: July 24, 2001
Creator: Darrow, D. S.; Fredrickson, E. D.; Kaye, S. M.; Medley, S. S. & Roquemore, A. L.
Object Type: Report
System: The UNT Digital Library
A Stochastic Method for Estimating the Effect of Isotopic Uncertainties in Spent Nuclear Fuel (open access)

A Stochastic Method for Estimating the Effect of Isotopic Uncertainties in Spent Nuclear Fuel

This report describes a novel approach developed at the Oak Ridge National Laboratory (ORNL) for the estimation of the uncertainty in the prediction of the neutron multiplication factor for spent nuclear fuel. This technique focuses on burnup credit, where credit is taken in criticality safety analysis for the reduced reactivity of fuel irradiated in and discharged from a reactor. Validation methods for burnup credit have attempted to separate the uncertainty associated with isotopic prediction methods from that of criticality eigenvalue calculations. Biases and uncertainties obtained in each step are combined additively. This approach, while conservative, can be excessive because of a physical assumptions employed. This report describes a statistical approach based on Monte Carlo sampling to directly estimate the total uncertainty in eigenvalue calculations resulting from uncertainties in isotopic predictions. The results can also be used to demonstrate the relative conservatism and statistical confidence associated with the method of additively combining uncertainties. This report does not make definitive conclusions on the magnitude of biases and uncertainties associated with isotopic predictions in a burnup credit analysis. These terms will vary depending on system design and the set of isotopic measurements used as a basis for estimating isotopic variances. Instead, the report …
Date: August 24, 2001
Creator: DeHart, M.D.
Object Type: Report
System: The UNT Digital Library
Average Total Neutron Cross Section OF 233U, 235U AND 239Pu from ORELA Transmission Measurements and Statistical Analysis of the Data (open access)

Average Total Neutron Cross Section OF 233U, 235U AND 239Pu from ORELA Transmission Measurements and Statistical Analysis of the Data

The average total neutron cross sections of {sup 233}U, {sup 235}U, and {sup 239}Pu were obtained from transmission measurements in the unresolved resonance region up to several hundred keV neutron energy. The method used for the calculation of the self-shielding effect is described. A statistical model analysis of the results was performed and the s-, p- and d-wave neutron strength functions were obtained.
Date: August 24, 2001
Creator: Derrien, H.
Object Type: Article
System: The UNT Digital Library
LLNL PuPS Weld Qualification Plan (open access)

LLNL PuPS Weld Qualification Plan

This plan ensures the quality of the Lawrence Livermore National Laboratory (LLNL) DOE 3013 Standard Plutonium Packaging System (PuPS) can welds meet the requirements stipulated in the DOE Standard 3013-00 ''Stabilization, Packaging, and Storage of Plutonium-Bearing Materials'' (Reference 1) and G-ESR-G-00035, Revision 1 dated July 26, 2000, ''Savannah River Site Stabilization and Packaging Requirements for Plutonium Bearing Materials for Storage.'' (Reference 2) This plan also meets the requirements for a weld qualification plan as stipulated in the G-ESR-G-00035. The Outer Can weld must meet ASME VIII & IX. The Outer Can welds will be evaluated initially and during production. The initial evaluation will be done by performing the following: ASME IX welding procedure qualification, ASME IX operator qualification, and a 25 can Dummy Outer Can (DOC) verification run. During production, product cans and DOCs will be evaluated. Product cans will be evaluated by a combination of visual examination of the weld faces and the use of helium leak checking. The DOCs will be examined by visual examination, leak check, radiographic examination and metallographic examination. Appendix 2 summarizes the requirements of each of these evaluations. The Inner Can weld must meet the leak tightness requirements of DOE 3013. The Inner Can …
Date: August 24, 2001
Creator: Dodson, K E & Riley, D
Object Type: Report
System: The UNT Digital Library
The Kestrel interface to the NEOS server. (open access)

The Kestrel interface to the NEOS server.

The NEOS Server provides access to optimization solvers through the Internet with a suite of interfaces. In particular, the Kestrel interface enables the remote solution of optimization problems within the AMPL and GAMS modeling languages. Problem generation, including the run-time detection of syntax errors, occurs on the local machine using any available modeling language facilities. Solution takes place on a remote machine, with the result returned in the native modeling language format for further processing. No significant differences exist between local and remote solutions. A byproduct of the Kestrel interface is the ability to solve in parallel multiple problems generated by a modeling language.
Date: July 24, 2001
Creator: Dolan, E. D. & Munson, T. S.
Object Type: Report
System: The UNT Digital Library
A Monte Carlo Approach to Calculate Probability Tables for the Unresolved-Resonance Region Using the AMPX Cross-Section Processing System (open access)

A Monte Carlo Approach to Calculate Probability Tables for the Unresolved-Resonance Region Using the AMPX Cross-Section Processing System

A new module, PURM (Probability tables for the Unresolved Region using Monte Carlo), has been developed for the AMPX-2000 cross-section processing system. PURM uses a Monte Carlo approach to calculate probability tables on an evaluator-defined energy grid in the unresolved-resonance region. For each probability table, PURM samples a Wigner spacing distribution for pairs of resonances surrounding the reference energy. The resonance distribution is sampled for each spin sequence (i.e., {ell}-J pair), and PURM uses the {Delta}{sub 3}-statistics test to determine the number of resonances to sample for each spin sequence. For each resonance, PURM samples the resonance widths from a Chi-square distribution for a specified number of degrees of freedom. Once the resonance parameters are sampled, PURM calculates the total, capture, fission and scatter cross sections at the reference energy using the single-level Breit-Wigner formalism with appropriate treatment for temperature effects. Probability tables have been calculated and compared with NJOY. The probability tables and cross-section values that are calculated by PURM and NJOY are in agreement, and the verification studies with NJOY establish the computational capability for generating probability tables using the new AMPX module PURM.
Date: August 24, 2001
Creator: Dunn, M. E.
Object Type: Article
System: The UNT Digital Library
Fiscal Year 2001 Status Report for the Investigation of Reactivity Effects Due to Perturbations in Cross-Section Temperature (open access)

Fiscal Year 2001 Status Report for the Investigation of Reactivity Effects Due to Perturbations in Cross-Section Temperature

The objective of the current work is to calculate changes in system multiplication due to perturbations in cross-section temperature. Moreover, the study is intended to investigate cross-section perturbations using ENDF/B-VI data which are the most up-to-date cross-section information currently available in the United States. The purpose of this letter report is to document the work that has been completed during the 2001 fiscal year. In addition, the report provides the current status of the temperature-effects study. During the fiscal year, the majority of effort has focused on the development of a 238-group ENDF/B-VI library using the AMPX cross-section processing system. At this point, 340 ENDF/B-VI evaluations have been processed (i.e., 15 thermal and 325 nonthermal evaluations), and a prototypic 238-group library has been developed. Efforts are currently in progress to test the cross-section library for accuracy. Once the library is determined to be suitable for radiation transport calculations, the library will be used to perform reactivity calculations to assess the impact of cross-section temperature perturbations. Regarding the temperature perturbation studies, a FORTRAN program (CRCREAD) has been developed to read the CRCbenchmark models (i.e., MCNP input files) and search for the 130 different isotopes that have been designated by the YMP …
Date: October 24, 2001
Creator: Dunn, M.E.
Object Type: Report
System: The UNT Digital Library
Materials Selection for the HFIR Cold Neutron Source (open access)

Materials Selection for the HFIR Cold Neutron Source

In year 2002 the High Flux Isotope Reactor (HFIR) will be fitted with a source of cold neutrons to upgrade and expand its existing neutron scattering facilities. The in-reactor components of the new source consist of a moderator vessel containing supercritical hydrogen gas moderator at a temperature of 20K and pressure of 15 bar, and a surrounding vacuum vessel. They will be installed in an enlarged beam tube located at the site of the present horizontal beam tube, HB-4; which terminates within the reactor's beryllium reflector. These components must withstand exceptional service conditions. This report describes the reasons and factors underlying the choice of 6061-T6 aluminum alloy for construction of the in-reactor components. The overwhelming considerations are the need to minimize generation of nuclear heat and to remove that heat through the flowing moderator, and to achieve a minimum service life of about 8 years coincident with the replacement schedule for the beryllium reflector. 6061-T6 aluminum alloy offers the best combination of low nuclear heating, high thermal conductivity, good fabricability, compatibility with hydrogen, superior cryogenic properties, and a well-established history of satisfactory performance in nuclear environments. These features are documented herein. An assessment is given of the expected performance of …
Date: August 24, 2001
Creator: Farrell, K.
Object Type: Report
System: The UNT Digital Library