Chemical species of plutonium in Hanford radioactive tank waste (open access)

Chemical species of plutonium in Hanford radioactive tank waste

Large quantities of radioactive wastes have been generated at the Hanford Site over its operating life. The wastes with the highest activities are stored underground in 177 large (mostly one million gallon volume) concrete tanks with steel liners. The wastes contain processing chemicals, cladding chemicals, fission products, and actinides that were neutralized to a basic pH before addition to the tanks to prevent corrosion of the steel liners. Because the mission of the Hanford Site was to provide plutonium for defense purposes, the amount of plutonium lost to the wastes was relatively small. The best estimate of the amount of plutonium lost to all the waste tanks is about 500 kg. Given uncertainties in the measurements, some estimates are as high as 1,000 kg (Roetman et al. 1994). The wastes generally consist of (1) a sludge layer generated by precipitation of dissolved metals from aqueous wastes solutions during neutralization with sodium hydroxide, (2) a salt cake layer formed by crystallization of salts after evaporation of the supernate solution, and (3) an aqueous supernate solution that exists as a separate layer or as liquid contained in cavities between sludge or salt cake particles. The identity of chemical species of plutonium in …
Date: October 22, 1997
Creator: Barney, G. S.
System: The UNT Digital Library
Development of a ceramic form for immobilization of excess plutonium (open access)

Development of a ceramic form for immobilization of excess plutonium

Between 8 and 50 metric tonnes of excess plutonium are currently planned to be immobilized in a glass or ceramic waste form in the US. The immobilized Pu would then be encased in HLW glass (the can-in-canister alternative), which would provide a radiation barrier to enhance the proliferation resistance of the material. Associated with the plutonium are about 15 metric tonnes of uranium primarily {sup 238}U and a variety of other impurities (primarily Ga, Mo, Al, Mg, Si, and Cl) totaling about 1 metric tonne or less. Immobilization of this material is complicated by the fact that the uranium content in the various feed streams varies widely, from 0 to about 95%. The proposed ceramic form is composed of about 90% zirconolite (CaZrTi{sub 2}O{sub 7}) and/or pyrochlore (CaPuTi{sub 2}O{sub 7}) with about 10% other phases, typically hollandite (BaAl{sub 2}Ti{sub 6}O{sub 16}) and rutile (TiO{sub 2}). The form is a variation of Synroc-C, which contains nominally 30% zirconolite, 30% perovskite, 30% hollandite, and 10% rutile and noble metal alloys. Zirconolite and perovskite are the actinide host phases in Synroc-C with zirconolite being the more durable phase. The pyrochlore structure is closely related to zirconolite and forms at higher actinide loadings. Thus, …
Date: April 22, 1997
Creator: Van Konynenburg, R.; Ebbinghaus, B.; Ryerson, F.; Shaw, H. & Curtis, P.
System: The UNT Digital Library
Comparison of neutron lifetimes as predicted by MCNP and DANTSYS (open access)

Comparison of neutron lifetimes as predicted by MCNP and DANTSYS

The prompt removal lifetime algorithm used in the latest version of MCNP was modified to conform with the neutron-balance definitions described by Spriggs et al. In accordance with the neutron-balance theory, the non-adjoint-weighted removal lifetime is given by where {Phi} is the angular neutron flux, v is the neutron velocity, {Sigma}{sub a} is the macroscopic absorption cross section, E is neutron energy, {Omega} is angle, and r is a spatial vector. The numerator in this expression represents the total neutron population in the system, N, and the denominator represents the total loss rate due to leakage and absorption.
Date: January 22, 1997
Creator: Hendricks, J.S.; Parsons, D.K. & Spriggs, G.D.
System: The UNT Digital Library
Mechanical behavior of ultrahigh strength ultrahigh carbon steel wire and rod (open access)

Mechanical behavior of ultrahigh strength ultrahigh carbon steel wire and rod

Ultrahigh-carbon steels (UHCSS) can achieve very high strengths in wire or rod form. These high strengths result from the mechanical work introduced during wire and rod processing. These strengths have been observed to increase with carbon content. In wire form, tensile strengths approaching 6000 MPa are predicted for UHCS containing 1. 8%C. In this paper, we will discuss the influence of processing (including rapid transformation during wire patenting) and micros ct- ure on the mechanical behavior of UHCS wire. The tensile properties of as- extruded rods are described as a function of extrusion temperature and composition. For spheroidized steels, yield and ultimate tensile strength are a function of grain size, interparticle spacing and particle size. For pearlitic steels, yield and ultimate strength were found to be functions of colony size, carbide size and plate spacing and orientation. Alloying additions (such as C, Cr, Si, Al and Co) can influence the effect of processing on these microstructural features. For spheroidized steels, fracture was found to be a function of the size of coarse carbides and of composition.
Date: July 22, 1997
Creator: Lesuer, D. R.; Syn, C. K.; Sberby, O. D. & Whittenherger, W. D.
System: The UNT Digital Library
Non-equilibrium many body dynamics (open access)

Non-equilibrium many body dynamics

This Riken BNL Research Center Symposium on Non-Equilibrium Many Body Physics was held on September 23-25, 1997 as part of the official opening ceremony of the Center at Brookhaven National Lab. A major objective of theoretical work at the center is to elaborate on the full spectrum of strong interaction physics based on QCD, including the physics of confinement and chiral symmetry breaking, the parton structure of hadrons and nuclei, and the phenomenology of ultra-relativistic nuclear collisions related to the up-coming experiments at RHIC. The opportunities and challenges of nuclear and particle physics in this area naturally involve aspects of the many body problem common to many other fields. The aim of this symposium was to find common theoretical threads in the area of non-equilibrium physics and modern transport theories. The program consisted of invited talks on a variety topics from the fields of atomic, condensed matter, plasma, astrophysics, cosmology, and chemistry, in addition to nuclear and particle physics. Separate abstracts have been indexed into the database for contributions to this workshop.
Date: September 22, 1997
Creator: Creutz, M. & Gyulassy, M.
System: The UNT Digital Library
PHENIX On-Line Distributed Computing System Architecture (open access)

PHENIX On-Line Distributed Computing System Architecture

PHENIX is one of the two large experiments at the Relativistic Heavy Ion Collider (RHIC) currently under construction at Brookhaven National Laboratory. The detector consists of 11 sub-detectors, that are further subdivided into 29 units (``granules``) that can be operated independently, which includes simultaneous data taking with independent data streams and independent triggers. The detector has 250,000 channels and is read out by front end modules, where the data is buffered in a pipeline while awaiting the level trigger decision. Zero suppression and calibration is done after the level accept in custom built data collection modules (DCMs) with DSPs before the data is sent to an event builder (design throughput of 2 Gb/sec) and higher level triggers. The On-line Computing Systems Group (ONCS) has two responsibilities. Firstly it is responsible for receiving the data from the event builder, routing it through a network of workstations to consumer processes and archiving it at a data rate of 20 MB/sec. Secondly it is also responsible for the overall configuration, control and operation of the detector and data acquisition chain, which comprises the software integration for several thousand custom built hardware modules. The software must furthermore support the independent operation of the above …
Date: May 22, 1997
Creator: Desmond, Edmond; Haggerty, John; Kehayias, Hyon Joo; Purschke, Martin L.; Witzig, Chris & Kozlowski, Thomas
System: The UNT Digital Library
Establishing an appropriate baseline for assessing environmental impacts (open access)

Establishing an appropriate baseline for assessing environmental impacts

An important consideration in assessing environmental impacts for the National Environmental Policy Act (NEPA) is to establish a baseline from which to evaluate potential changes associated with a proposed action. For some assessments, establishment of the baseline is straightforward because the proposed action is located in an undeveloped area which has been negligibly affected by human activity. For other assessments, however, the baseline may be more difficult to determine because the proposed action may occur in an area where human activities have affected the environment and, in essence, have established a new (and often changing) baseline. Frequently, appreciable degradation has occurred on the proposed site itself. For such cases, the question arises as to whether the unperturbed condition or the present condition is more appropriate to use as the baseline. This paper argues that a proposed action in a previously disturbed area should not be assessed merely in relation to the new baseline. Rather, a more comprehensive evaluation should be given that compares potential environmental effects with both the unperturbed condition and the present condition and consequently presents a more balanced approach to the assessment. Furthermore, the sponsoring federal agency should take the opportunity offered by the proposed action to …
Date: May 22, 1997
Creator: Miller, R. L.
System: The UNT Digital Library
Mapping and inspection of damage and artifacts in large-scale optics (open access)

Mapping and inspection of damage and artifacts in large-scale optics

We have developed tools for accurately and economically mapping and inspecting damage and artifacts in the bulk as well as on the surface of meter-sized optics intended for use on large-scale lasers such as Beamlet and NIF. Optics are illuminated by white light through the optic edge or externally at grazing incidence using linear fiber- optics arrays. The mega-pixel camera records a digital map of the entire optic with precise addresses of highlighted artifacts. From these coordinated, artifacts are located and digitally recorded with resolution of less than 5 microns using a long-working-distance microscope. Total internal reflection of edge illumination efficiency couples light into the entire optic to inspect for bulk artifacts, such as bubbles, inclusions, edge-cladding flaws and laser- induced damage as well as surface scratches and pits which propagate into the substrate. Surface contamination such as dust, fingerprints, coating flaws, and cleaning flaws are highlighted by external grazing illumination. The procedures permit accurate recording of the evolution of damage after many laser shots as well as correlation of damage from one optic to the next in a laser chain.
Date: December 22, 1997
Creator: Rainer, F.
System: The UNT Digital Library
The integrated water conservation program at Sandia National Laboratories (open access)

The integrated water conservation program at Sandia National Laboratories

Sandia National Laboratories (SNL), located on Kirkland Air Force Base (KAFB) in Albuquerque, NM, is implementing a comprehensive water conservation program. Because the average rainfall in this metropolitan area of 500,000 is approximately 8 inches per year, conservation of this precious resource is critical to the economic health of the city and state, and the continued operations at SNL/NM. To address this need, SNL/NM is taking a systematic, comprehensive approach to water conservation. The approach is to estimate the water consumption for all of SNL/NM by type of consumption. For each type of water consumption, all cost effective measures for reducing, reclaiming, and/or recycling that usage will be ranked. These water conservation measures range from the simple such as retrofitting plumbing fixtures with low cost devices to reduce water required to flush toilets to the very complex. As an example of the very complex, a Microelectronics Development Laboratory (MDL) lab will implement a near zero water discharge from clean room wet benches. Deionized (DI) water can be sent back to the DI water input generation stream when the DI water is not being used for rinsing wafers. This paper discusses completed, ongoing and proposed projects at SNL/NM to reduce water …
Date: August 22, 1997
Creator: Rogers, D.
System: The UNT Digital Library