Comparison of different experimental and analytical measures of the thermal annealing response of neutron-irradiated RPV steels (open access)

Comparison of different experimental and analytical measures of the thermal annealing response of neutron-irradiated RPV steels

The thermal annealing response of several materials as indicated by Charpy transition temperature (TT) and upper-shelf energy (USE), crack initiation toughness, K{sub Jc}, predictive models, and automated-ball indentation (ABI) testing are compared. The materials investigated are representative reactor pressure vessel (RPV) steels (several welds and a plate) that were irradiated for other tasks of the Heavy-Section Steel Irradiation (HSSI) Program and are relatively well characterized in the unirradiated and irradiated conditions. They have been annealed at two temperatures, 343 and 454 C (650 and 850 F) for varying lengths of time. The correlation of the Charpy response and the fracture toughness, ABI, and the response predicted by the annealing model of Eason et al. for these conditions and materials appears to be reasonable. The USE after annealing at the temperature of 454 C appears to recover at a faster rate than the TT, and even over-recovers (i.e., the recovered USE exceeds that of the unirradiated material).
Date: May 1, 1997
Creator: Iskander, S. K.; Sokolov, M. A. & Nanstad, R. K.
System: The UNT Digital Library
A comparison of two aluminizing methods for corrosion protection in the wet seal of molten carbonate fuel cells (open access)

A comparison of two aluminizing methods for corrosion protection in the wet seal of molten carbonate fuel cells

Examination of set 1 and 2 samples reveals an initially serrated interface that consists of iron aluminides. Resolvable, changes in the bulk microstructure occurred after about 500 h. No corrosion layer growth was observed, but some of the aluminum deposit formed Fe-Al phases in both coupons.
Date: May 1, 1997
Creator: Bloom, I.; Indacochea, J.E.; Krumpelt, M. & Benjamin, T.G.
System: The UNT Digital Library
Computerized materials protection, control, and accountability (open access)

Computerized materials protection, control, and accountability

The proliferation of nuclear weapons, along with the technical knowledge and materials needed to make these weapons, is an enduring problem of international urgency. Current international nuclear nonproliferation efforts are aimed at deterring, detecting, and responding to proliferation of weapons of mass destruction. These safeguards efforts are being implemented by applying preeminent science and technology to the management and control of nuclear materials. By strengthening systems of nuclear material protection, control, and accountability (MPC and A), one can reduce the threat of nuclear weapons proliferation. Two major programs of international cooperation are now underway to achieve this goal. The first is between the US Department of Energy (DOE) and the Institutes of the Russian Federation (Laboratory-to-Laboratory Program), and the second is between the US Government and Governments of the former Soviet Republics (Government-to-Government Program). As part of these programs, the DOE is working with facilities to assist them in implementing computerized MPC and A systems. This work is a collaboration between computer scientists and safeguards experts in both the US and the new Republics. The US is making available technology and expertise to enable Russian experts to build on computerized MPC and A software developed in the US. This paper …
Date: May 1, 1997
Creator: Whiteson, R.; Seitz, S.; Landry, R. P.; Hadden, M. L. & Painter, J. A.
System: The UNT Digital Library
Computing Models of CDF and D0 in Run II (open access)

Computing Models of CDF and D0 in Run II

The next collider run of the Fermilab Tevatron, Run II, is scheduled for autumn of 1999. Both experiments, the Collider Detector at Fermilab (CDF) and the D0 experiment are being modified to cope with the higher luminosity and shorter bunch spacing of the Tevatron. New detector components, higher event complexity, and an increased data volume require changes from the data acquisition systems up to the analysis systems. In this paper we present a summary of the computing models of the two experiments for Run II.
Date: May 1, 1997
Creator: Lammel, S.
System: The UNT Digital Library
Condensation enhancement on a pool surface caused by a submerged liquid jet (open access)

Condensation enhancement on a pool surface caused by a submerged liquid jet

One advanced nuclear reactor design has a residual heat removal (RHR) pipe connected to the bottom of a steam generator outlet plenum. The water in the plenum can become thermally stratified during postulated loss of coolant accidents. Cold water injected through the RHR pipe has the potential effect of increasing the steam condensation on the pool surface due to the stirring action of the jet. The amount of increase depends on a number of factors, including the jet velocity and the pool height above the jet injection point. Prediction of steam condensation rates, before and after the jet breaks the pool surface, is the topic of this paper. Data and correlations exist for pre surface breakthrough and a method has been developed for post breakthrough. The models have been incorporated into the reactor safety analysis computer software known as RELAP5. Comparisons of predictions against data are presented.
Date: May 1997
Creator: Shumway, R. W.
System: The UNT Digital Library
The conflict of interest problem in EIS preparation (open access)

The conflict of interest problem in EIS preparation

The National Environmental Policy Act (NEPA) requires that federal agencies prepare environmental impact statements (EISs) on proposals for major Federal action significantly affecting the quality of the human environment. The Council on Environmental Quality (CEQ) regulations require that EISs be prepared directly by the lead agency or a contractor it selects. EIS contractors must execute a disclosure statement specifying that they have ``no financial or other interest`` in the outcome of the project. The intent of the ``conflict of interest`` prohibition is to ensure that the EIS is defensible, free of self-serving bias, and credible to the public. Those coming to the federal government for money, permits, or project approvals must not be placed in the position of analyzing the environmental consequences of their own proposals. This paper analyzes the conflict of interest problem faced by government contractors who maintain and operate government-owned or-controlled facilities for which EISs are required. In the US Department of Energy (DOE) system, these are referred to as ``M and O`` contractors. It also examines organizational conflicts presented by current or prospective government contractors who have a financial or other interest in the outcome of a project or program for which an EIS is prepared. …
Date: May 1, 1997
Creator: Hansen, R. P.; Wolff, T. A. & McCold, L. N.
System: The UNT Digital Library
Conjugate fracture pairs in the Molina Member of the Wasatch Formation, Piceance basin, Colorado: Implications for fracture origins and hydrocarbon production/exploration (open access)

Conjugate fracture pairs in the Molina Member of the Wasatch Formation, Piceance basin, Colorado: Implications for fracture origins and hydrocarbon production/exploration

The sandstones of the Molina Member of the Wasatch Formation in the Piceance basin of northwestern Colorado contain a suite of fractures that have a conjugate-pair geometry. The fractures are vertical and intersect at an acute angle of between 20 and 40 degrees. Although direct evidence of shear is rare, the fracture surfaces commonly display small steps. The fracture geometries suggest that the maximum compressive stress during fracturing was in the plane of the acute angle of the conjugate fractures: the steps are interpreted as broken-face manifestations of very low angle en echelon fractures, formed within exceptionally narrow zones of incipient shear. In contrast to the highly anisotropic permeability enhancement created by subparallel vertical extension fractures in the underlying Mesaverde Formation, the conjugate pairs in the Molina sandstones should create a well connected and relatively isotropic mesh of fracture conductivity. Increases in stress magnitudes and anisotropy during production drawdown of reservoir pressures should cause shear offsets along the fractures, initially enhancing permeability.
Date: May 1, 1997
Creator: Lorenz, J.C.
System: The UNT Digital Library
Control of longitudinal collective behavior in the Muon Collider rings (open access)

Control of longitudinal collective behavior in the Muon Collider rings

The longitudinal bunch collective effects in a Muon Collider ring are theoretically examined. The situation involves an intense bunch, a short bunch, a small momentum compaction, a rather large impedance compared with the stability threshold criterion, and luminosity life time limited by muon decay to a thousand turns. Qualitative descriptions of stability are given and a scaling law for the instability threshold is derived. Numerical simulation results for the impedance-related instabilities are given for two cases of current interest - a 250 GeV x 250 GeV demonstration machine and a 2 TeV x 2 TeV high energy machine. The results of these simulations are in good agreement with the predictions of the scaling law and show that the longitudinal collective effects are controllable with a proper choice of parameters (viz. rf voltage, rf frequency, linear and non-linear longitudinal chromaticity).
Date: May 1, 1997
Creator: Cheng, Wen-Hao; Sessler, A. M. & Turner, W. C.
System: The UNT Digital Library
Cost avoidance techniques through the Fernald controlled area trash segregation program and the RIMIA solid waste reduction program (open access)

Cost avoidance techniques through the Fernald controlled area trash segregation program and the RIMIA solid waste reduction program

The Fernald Environmental Management Project is a Department of Energy owned facility that produced high quality uranium metals for military defense. The Fernald mission has changed from one of production to remediation. Remediation is intended to clean up legacy (primary) waste from past practices. Little opportunity is available to reduce the amount of primary waste. However, there is an opportunity to reduce secondary waste generation, primarily through segregation. Two programs which accomplish this are the Controlled Area Trash Segregation Program and the RIMIA Solid Waste Reduction Program. With these two programs now in place at the FEMP, it has been estimated that a 60% reduction has been achieved in unnecessary clean waste being disposed as Low Level Waste at the Nevada Test Site. The cost savings associated with these programs (currently 79,000 cubic feet, $428,000) could easily run into the millions of dollars based on the upcoming restoration activities to be undertaken. The segregation of non-radiological waste in the radiologically Controlled Area not only establishes a firm commitment to send only low-level radioactive waste to the Nevada Test Site, but also results in substantial cost avoidance.
Date: May 14, 1997
Creator: Menche, C.E.
System: The UNT Digital Library
A coupled-bunch ion instability in the SLC electron damping ring (open access)

A coupled-bunch ion instability in the SLC electron damping ring

Under abnormally poor vacuum conditions in the electron damping ring, described in a companion paper at this conference, an emittance blowup was observed related to a transverse instability. The instability was only observed with two bunches in the ring, and could not be seen with single bunch operation, even at the same total beam current as for the two bunches. Measurements of the transverse Beam Transfer Function indicate strong coupling between the two bunches when ions are present. This is described in terms of a simple model where the oscillating ion cloud provides the coupling between the two bunches. The frequency shift due to coupling can also cause the ion cloud to become unstable, and disappear, when the betatron tune of the electron bunch is just below the 1/2 integer.
Date: May 1, 1997
Creator: Krejcik, P.
System: The UNT Digital Library
CP violation in neutral kaon decays (open access)

CP violation in neutral kaon decays

A brief review of the theoretical status of CP violation in decays of neutral kaons is presented. We focus on three important topics: {epsilon}, {epsilon}`/{epsilon} and K{sub L}{yields}{pi}{sup 0}{nu}{anti {nu}}.
Date: May 1, 1997
Creator: Buchalla, G.
System: The UNT Digital Library
Criticality measurements for control and accountability of fissile materials on critical assemblies (open access)

Criticality measurements for control and accountability of fissile materials on critical assemblies

Operational critical assemblies are subject to the same standards of materials control and accountability (MC and A) as other fissile materials. Typically these assemblies are not easily dismantled and the fuel components cannot be inventoried by traditional methods of destructive or non-destructive materials assay. Because of the large mass or unusual geometry of the fuel components these parts are often categorized as difficult-to-measure (DTM) items. The use of criticality to infer fissile inventory, in conjunction with physical security and two-person control procedures, provides accurate and cost-effective MC and A for these large critical assembly components. This method is being implemented at the Los Alamos Critical Experiments Facility (LACEF) and at several national nuclear research centers in Russia.
Date: May 1, 1997
Creator: Paternoster, R.; Kompaniets, G. & Polyakov, D.
System: The UNT Digital Library
Criticality parameters for tank waste evaluation (open access)

Criticality parameters for tank waste evaluation

Nuclear criticality parameters were developed as a basis for evaluating criticality safety for waste stored in the high-level waste tank farms on the Hanford Site in Washington State. The plutonium critical concentration and critical mass were calculated using a conservative waste model (CWM). The primary requirement of a CWM is that it have a lower neutron absorption than any actual waste. Graphs are provided of the critical mass as a function of plutonium concentration for spheres and for uniform slab layers in a 22.9-m-diameter tank. Minimum subcritical absorber-to-plutonium mass rates were calculated for waste components selected for their relative abundance and neutron absorption capacity. Comparison of measured absorber-to-plutonium mass ratios in their corresponding subcritical limit mass ratios provides a means of assessing whether criticality is possible for waste of the measured composition. A comparison is made between the plutonium critical concentrations in CWM solids and in a postulated real waste. This comparison shows that the actual critical parameters are likely to be significantly larger than those obtained using the CWM, thus providing confidence that the margin of safety obtained to the criticality safety evaluation is conservative.
Date: May 19, 1997
Creator: Rogers, C. A.
System: The UNT Digital Library
The Criticality Safety Information Resource Center at Los Alamos National Laboratory (open access)

The Criticality Safety Information Resource Center at Los Alamos National Laboratory

The mission of the Criticality Safety Information Resource Center (CSIRC) at Los Alamos National Laboratory (LANL) is the preservation of primary documentation supporting criticality safety. In many cases, but not all, this primary documentation consists of experimentalists` logbooks. Experience has shown that the logbooks and other primary information are vulnerable to being discarded. Destruction of these logbooks results in a permanent loss to the criticality safety community.
Date: May 1, 1997
Creator: Henderson, Barbara D.; Meade, Roger A. & Pruvost, Norman L.
System: The UNT Digital Library
Crossed elliptical polarization undulator (open access)

Crossed elliptical polarization undulator

The first switching of polarization direction is possible by installing two identical helical undulators in series in a same straight section in a storage ring. By setting each undulator in a circular polarization mode in opposite handedness, one can obtain linearly polarized radiation with any required polarization direction depending on the modulator setting between two undulators. This scheme can be used without any major degradation of polarization degree in any low energy low emittance storage ring.
Date: May 1997
Creator: Sasaki, Shigemi
System: The UNT Digital Library
A CsI(Na) based radiation detector for high resolution imaging studies using iodine 125 in small animal research (open access)

A CsI(Na) based radiation detector for high resolution imaging studies using iodine 125 in small animal research

The authors report on the development of a high resolution radiation imaging system which is capable of detecting and imaging the coincident gamma and X-ray emissions of the radioisotope iodine 125 ({sup 125}I). Iodine 125 is commonly available as a radioactive label to tag molecular biology probes. Iodine 125 decays via electron capture emitting a 35 keV gamma-ray with the prompt emission of several 27-32 keV X-rays. A coincidence condition can be set to detect the {sup 125}I decays thus reducing background radiation contribution to the image. They are testing the use of arrays of CsI(Na) crystal scintillators coupled to position sensitive photomultiplier tubes for this application. Laboratory studies have thus far been done on mice using a prototype of the detector which is intended to be used to image gene expression in live mice to advance research in neurobiology.
Date: May 1, 1997
Creator: Weisenberger, A.; Bradley, E.; Majewski, S. & Saha, and M.
System: The UNT Digital Library
Data analysis using wavelets (open access)

Data analysis using wavelets

This paper describes the use of wavelet transform techniques to analyze typical data found in industrial applications. A way of detecting system changes using wavelet transforms is described. The results of applying this method are described for several typical applications. The wavelet technique is compared with the use of Fourier transform methods.
Date: May 1, 1997
Creator: Fryer, M.O.
System: The UNT Digital Library
Decline curve analysis of vapor-dominated reservoirs (open access)

Decline curve analysis of vapor-dominated reservoirs

Geothermal Program activities at the INEEL include a review of the transient and pseudosteady state behavior of production wells in vapor-dominated systems with a focus on The Geysers field. The complicated history of development, infill drilling, injection, and declining turbine inlet pressures makes this field an ideal study area to test new techniques. The production response of a well can be divided into two distinct periods: transient flow followed by pseudo-steady state (depletion). The transient period can be analyzed using analytic equations, while the pseudo-steady state period is analyzed using empirical relationships. Yet by reviewing both periods, a great deal of insight can be gained about the well and reservoir. An example is presented where this approach is used to determine the permeability thickness product, kh, injection and production interference, and estimate the empirical Arps decline parameter b. When the production data is reinitialized (as may be required by interference effects), the kh determined from the new transient period is repeatable. This information can be used for well diagnostics, quantification of injection benefits, and the empirical estimation of remaining steam reserves.
Date: May 1, 1997
Creator: Faulder, D. D.
System: The UNT Digital Library
Decoherence bounds on the capabilities of cold trapped ion quantum computers (open access)

Decoherence bounds on the capabilities of cold trapped ion quantum computers

Using simple physical arguments we investigate the capabilities of a quantum computer based on cold trapped ions of the type recently proposed by Cirac and Zoller. From the limitations imposed on such a device by decoherence due to spontaneous decay, laser phase coherence times, ion heating and other possible sources of error, we derive bounds on the number of laser interactions and on the number of ions that may be used. As a quantitative measure of the possible performance of these devices, the largest number which may be factored using Shor`s quantum factoring algorithm is determined for a variety of species of ion.
Date: May 1, 1997
Creator: James, D.F.V.; Hughes, R.J. & Knill, E.H.
System: The UNT Digital Library
Decontamination and decommissioning of the JANUS reactor at the Argonne National Laboratory-East site (open access)

Decontamination and decommissioning of the JANUS reactor at the Argonne National Laboratory-East site

Argonne National Laboratory has begun the decontamination and decommissioning (D&D) of the JANUS Reactor Facility. The project is managed by the Technology Development Division`s D&D Program personnel. D&D procedures are performed by sub-contractor personnel. Specific activities involving the removal, size reduction, and packaging of radioactive components and facilities are discussed.
Date: May 1, 1997
Creator: Fellhauer, C. R. & Garlock, G. A.
System: The UNT Digital Library
Density of topological defects after a quench (open access)

Density of topological defects after a quench

We present results of numerical studies of the Landau-Ginzburg dynamics of the order parameter in one-dimensional models inspired by the condensed matter analogues of cosmological phase transitions. The main goal of our work is to show that, as proposed by one of us, the density of the frozen-out topological defects is set by the competition between the quench rate - the rate at which the phase transition is taking place - and the relaxation rate of the order parameter. In other words, the characteristic domain size, which determines the typical separation of topological defects in the new broken symmetry phase, is of the order of the correlation length at the instant at which the relaxation timescale of the order parameter equals the time remaining to the phase transition. In estimating the size of topological domains, this scenario shares with the original Kibble mechanism the idea that topological defects will form along the boundaries of independently selected regions of the new broken symmetry vacuum. However, it derives the size of such domains from non-equilibrium aspects of the transition (quench rate), as opposed to Kibble`s original proposal in which their size was estimated from the Ginzburg temperature above which thermally activated symmetry …
Date: May 13, 1997
Creator: Laguna, P. & Zurek, W.H.
System: The UNT Digital Library
Deploying innovative technologies to improve DOE D&D project baselines (open access)

Deploying innovative technologies to improve DOE D&D project baselines

The insertion of innovative technologies to replace baseline technologies used in cost estimation and planning of DOE D&D projects is considered a high risk endeavor by project and programmatic decision makers. It is almost always considered safer to go with the {open_quotes}devil you know{close_quotes} than use a new or untried technology, methodology or system. The decision on the specific technology to be utilized to remediate a problem is often made months or years in advance of execution, and the highly proscriptive documentation of agreements necessary to obtain stakeholder and regulator approval of remedial plans is often counterproductive to considering improved technologies.
Date: May 1, 1997
Creator: Rose, R. W.
System: The UNT Digital Library
Design and fabrication of a traveling-wave muffin-tin accelerating structure at 90 GHz (open access)

Design and fabrication of a traveling-wave muffin-tin accelerating structure at 90 GHz

A prototype of a muffin-tin accelerating structure operating at 32 times the SLAC frequency (2.856 GHz) was built for research in high gradient acceleration. A traveling-wave design with single input and output feeds was chosen for the prototype which was fabricated by wire electrodischarge machining. Features of the mechanical design for the prototype are described. Design improvements are presented including considerations of cooling and vacuum.
Date: May 1, 1997
Creator: Chou, P.J.; Bowden, G.B.; Copeland, M.R.; Menegat, A.; Siemann, R.H. & Henke, H.
System: The UNT Digital Library
A design and performance analysis tool for superconducting RF systems (open access)

A design and performance analysis tool for superconducting RF systems

Superconducting rf systems are usually operated with continuous rf power or with rf pulse lengths exceeding 1 ms to maximize the overall wall plug power efficiency. Typical examples are CEBAF at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) and the TESLA Test Facility at DESY. The long pulses allow for effective application of feedback to stabilize the accelerating field in presence of microphonics, Lorentz force detuning, and fluctuations of the beam current. In this paper the authors describe a set of tools to be used with MATLAB and SIMULINK, which allow to analyze the quality of field regulation for a given design. The tools include models for the cavities, the rf power source, the beam, sources of field perturbations, and the rf feedback system. The rf control relevant electrical and mechanical characteristics of the cavity are described in form of time-varying state space models. The power source is modeled as a current generator and includes saturation characteristics and noise.An arbitrary time structure can be imposed on the beam current to reflect a macro-pulse structure and bunch charge fluctuations. For rf feedback several schemes can be selected: Traditional amplitude and phase control as well as I/Q control. The choices for …
Date: May 1, 1997
Creator: Schilcher, T.; Simrock, S. N.; Merminga, L. & Wang, D. X.
System: The UNT Digital Library