An Electronic Speckle pattern interferometer (ESPI) was constructed which performs full-field surface displacement measurements. This measurement technique when combined with a single-point measurement known as laser vibrometry, can completely determine the vibrational characteristics of complex structures. This information can, in turn, be used for nondestructive testing as well as for modal analysis. One NDT E technique is to vibrationally excite the object and evaluate the time averaged interferograms from the ESPI and the vibration spectra from the vibrometer. Anomalies in the interferograms can be related to subsurface defects such as defective weld joints, internal cracks, voids, etc. All of this can be accomplished in a noncontacting and nonintrusive manor. In many instances, a finite element analysis in concert with this approach can be useful in interpreting the results. Since ESPI is analogous to optical holography, other methods equivalent to real-time and double-pulse holography may also be easily applied. As in holography, EXSPI is sensitive to out-of-plane surface displacements. Other optical arrangements can be implemented with the same equipment to give in-plane displacements which would give results similar to Moire interferometry without the need to apply gratings to the object under test. The advantage of this method over holographic interferometry is …

The acceptable operating limits of a nuclear reactor are set to prevent fuel cladding damage. Critical Heat Flux (CHF) is the limiting criterion for the high pressure systems such as the BWRs (6.9 MPa) and the PWRs (13.8 MPa). However, the Onset of Flow Instability (OFI) is the limiting criterion of the low pressure system such as the existing Savannah River Site (SRS) production reactors (0.2 MPa). The physical basis of this difference is presented. 3 refs.

The radioactive waste glass melter used at Savannah River Site (SRS) is a liquid slurry feed joule-heated ceramic melter. The physical nature of a joule-heated meter is complex and involves interactions between electric, thermal, and flow fields. These interactions take place through strongly temperature-dependent glass properties, natural convection, advection, diffusion, and volumetrically distributed joule heating sources. The cold feed on top of heated glass distabilizes the flow field and develops unsteady asymmetric flow motions underneath. Thus waste glass modeling requires solving a full 3-D, unsteady, momentum, energy, and electric equation with temperature-dependent properties. Simulation of noble metal deposit process requires an additional mass diffusion equation that is coupled to the momentum equation through mass advection term. The objective of this paper is to identify critical issues anticipated in the Defense Waste Process Facility (DWPF) melter operation and address how these issues can be resolved with current state-of-the-art mathematical modeling techniques.

The results of this analysis quantified the uncertainty associated with monitoring the Axial Power Shape (APS) in the Savannah River Reactors. Thermocouples at each assembly flow exit map the radial power distribution and are the primary means of monitoring power in these reactors. The remaining uncertainty in power monitoring is associated with the relative axial power distribution. The APS is monitored by seven sensors that respond to power on each of nine vertical Axial Power Monitor (APM) rods. Computation of the APS uncertainty, for the reactor power limits analysis, started with a large database of APM rod measurements spanning several years of reactor operation. A computer algorithm was used to randomly select a sample of APSs which were input to a code. This code modeled the thermal-hydraulic performance of a single fuel assembly during a design basis Loss-of Coolant Accident. The assembly power limit at Onset of Significant Voiding was computed for each APS. The output was a distribution of expected assembly power limits that was adjusted to account for the biases caused by instrumentation error and by measuring 7 points rather than a continuous APS. Statistical analysis of the final assembly power limit distribution showed that reducing reactor power …

Accountability and nuclear safety concerns arising from uncertainties in Pu-239 loadings of a number of waste containers at SRS were investigated by in situ neutron and gamma-ray measurements and an assessment of risk stemming from past waste analysis and packaging practices. The neutron and gamma measurements largely confirmed the correctness of original waste analysis and accountability, while the risk assessment and measurement implications suggested no present or foreseeable nuclear safety problems.

The computer codes used at Brookhaven National Laboratory to compute BWR safety parameters are the Engineering Plant Analyzer (EPA) and RAMONA-3B/MOD1. Both codes have the same methodology for modeling thermal hydraulic phenomena: drift-flux formulation, two-phase multipliers for the wall friction and form losses calculations, and the momentum integral approach for spatial integration of the loop momentum equations. Both codes use explicit integration methods for solving ordinary differential equations. It is concluded that both the codes are capable of modelling the instability problems for a BWR. The accuracy of thermohydraulics codes predictions was assessed by modelling oscillatory FRIGG tests. Nodalizations studies showed that 24 axial nodes were sufficient for a converged solution, 12 axial nodes produced an error of 4.4% in the gain of the power to flow transfer function. The code predicted consistently the effects of power and inlet subcooling on gain and system resonance frequency. The comparisons showed that the code predicted the peak gains with a mean difference from experiments of 7% {plus minus} 30% for all the tests modeled. The uncertainty in the experimental data is {minus}11% to +12%. The mean difference in the predicted frequency at the peak gain is {minus}6% {plus minus} 14%.

Specialized miniature low cost video equipment has been effectively used in a number of remote, radioactive, and contaminated environments at the Savannah River Site (SRS). The equipment and related techniques have reduced the potential for personnel exposure to both radiation and physical hazards. The valuable process information thus provided would not have otherwise been available for use in improving the quality of operation at SRS.

The chemical decomposition of aqueous alkaline solutions of sodium tetraphenylborate, NaTPB, has been investigated. The focus of the investigation is on the determination of components which influence NaTPB decomposition. Copper(II) ions, solution temperature, and solution pH (hydroxide ion concentration) have all been demonstrated to affect NaTPB stability. Their relationship with each other and the stability of NaTPB has been determined. Based upon this knowledge, a method for stabilizing NaTPB was determined. Decomposition of a NaTPB solution was delayed with the addition of sodium hydroxide. In additional work, the elimination of oxygen from the reaction environment did not prevent NaTPB decomposition in the presence of copper(II) ions but did, however, affect the course of decomposition.

The Savannah River Site has conducted a study to statistically quantify differences in metals concentrations as a function of sampling device and filter treatment. Twelve wells screened in unconsolidated coastal plain sediments were sampled for the study. All wells had histories of detectable toxic metals concentrations. Unfiltered and filtered (using 10 and 0.45 micron filters) samples were collected from all wells to evaluate the effects of filtering. To compare the effects of sampling device, the wells were sampled twice, once with a bladder pump and once with a centrifugal pump. An analysis of covariance (ANCOVA) method was used to assess the effects of sampling device and filtration on metals concentrations considering the variation in pH, conductivity, and turbidity among samples. This study demonstrates that when controlled sampling techniques are employed, differences in toxic metals concentrations between filtered and unfiltered samples are not statistically significant. However, variations in sampling devices yield samples with statistically different metals concentrations. The centrifugal pumps, which cause more agitation of the sample and the screened zone than bladder pumps, yield samples with statistically higher metals concentrations.

An innovative environmental restoration technology, in situ air stripping, has been demonstrated at the US Department of Energy (DOE) Savannah River Site (SRS) in South Carolina. This process, using horizontal wells, is designed to concurrently remediate unsaturated-zone soils and ground water containing Volatile Organic Compounds (VOC). In situ technologies have the potential to substantially reduce costs and time required for remediation as well as improve effectiveness of remediation. Horizontal wells were selected to deliver and extract fluids from the subsurface because their geometry can maximize the efficiency of a remediation system and they have great potential for remediating contaminant sources under existing facilities. The first demonstration of this new technology was conducted for a period of twenty weeks. A vacuum was first drawn on the vadose zone well until a steady-state removal of VOCs was obtained. Air was then injected at three different rates and at two different temperatures. An extensive characterization program was conducted at the site and an extensive monitoring network was installed prior to initiation of the test. Significant quantities of VOCs have been removed from the subsurface (equivalent to an eleven-well, 500-gpm, pump-and-treat system at the same site). Concentrations of VOCs in the ground water have …

A review of the Savannah River Site production reactor systems was initiated in 1980 and led to implementation of the Reactor Materials Program in 1984 to assess reactor safety and reactor service life. The program evaluated performance of the reactor tanks, primary coolant piping, and thermal shields, components of welded construction that were fabricated from Type 304 stainless steel. The structural integrity analysis of the primary coolant system has shown that the pressure boundary is not susceptible to gross rupture, including a double ended guillotine break or equivalent large area bank. Residual service life is potentially limited by two material degradation modes, irradiation damage and intergranular stress corrosion cracking. Analysis of the structural integrity of the tanks and piping has shown that continued safe operation of the reactors for several additional decades is not limited by the material performance of the primary coolant system. Although irradiation damage has not degraded material behavior to an unacceptable level, past experience has revealed serious difficulties with repair welding on irradiated stainless steel. Stress corrosion can be mitigated by newly identified limits on impurity concentrations in the coolant water and by stress mitigation of weld residual stresses. Work continues in several areas: the effects …

The Reversatron 2 RFP (R/a=50cm/8cm) has been operated with interchangeable shells to investigate resistive wall modes. Shell penetration times are 610, 100, and 4 {mu}sec (no shell). With the 610 {mu}sec shell, the plasma current is {le} 65 kA and the duration {le} 550 {mu}sec. With no shell, helium discharges are more resistive and hydrogen discharges cannot be sustained. An m=1, n=-6 mode resonant on axis grows to a relative amplitude of 20% during the setting-up phase. With the 100{mu}sec shell, deuterium discharges can be sustained but are degraded due to a broad spectrum of modes. The increased plasma resistance can be correlated with the flux intersecting the wall. 21 refs., 12 figs.

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Changes in perspectives on fast reactor safety have occurred over the past ten years due both to technical progress and to the course of events. The major aspect of these changes is that they relate to basic design decisions that are largely, but not exclusively, related to safety considerations. Among the topics discussed are inherent safety, choice of fuel between metal and oxide, choice of reactor configuration between pool and loop, impact of size on safety characteristics and modularity, containment options, and treatment of the hypothetical core disruptive accident.

The main thrust of this talk is to review and discuss various topics in both perturbative and non-perturbative QCD that are, by and large, model independent. This inevitably means that we shall rely heavily on the renormalization group and asymptotic freedom. Although this usually means that one has to concentrate on high energy phenomena, there are some physical processes even involving bound states which are certainly highly non-perturbative, where one can make some progress without becoming overly model independent. Experience with the EMC effect, where there are about as many explanations'' as authors, has surely taught us that it may well be worth returning to basics'' and thinking about general properties of QCD rather than guessing, essentially arbitrarily, what we think is its low energy structure. No doubt we shall have to await further numerical progress or for some inspired theoretical insight before we can, with confidence, attack these extremely difficult problems. So, with this in mind, I shall review a smattering of problems which do have a non-perturbative component and where some rather modest progress can actually be made; I emphasize the adjective modest''

For a number of years, the authors have been studying the application of advanced ceramic fabric materials to spacecraft heat rejection systems. Their studies indicated that significant mass and launch volume savings could be realized through such application, but concrete evidence to support this contention was lacking. Last year they presented preliminary test data that supported their claims (Antoniak and Webb 1989). Recent pressure, heat transfer, and wicking tests and analyses confirm the earlier results.

Light-weight drum choppers rotating at 15 Hz have been in use on the IPNS powder diffractometers for several years, where they serve to eliminate the delayed-neutron background from much of the spectral region of interest. Monte Carlo simulations indicate that a similar chopper operated at 15 Hz should do an excellent job of delayed-neutron removal in the new small-angle diffractometer being designed at IPNS. The simulations also show that when the same chopper is operated at 7.5 Hz it performs quite successfully as a frame-elimination chopper, effectively eliminating neutrons from alternate pulses and allowing extension of the useful wavelength range of the instrument to {approximately}28 {Angstrom}. Thus the incorporation of such a chopper should add considerably to the range and flexibility of the new instrument. 7 refs., 9 figs.

The importance of small-angle neutron scattering (SANS) in biological, chemical, physical, and engineering research mandates that all intense neutron sources be equipped with SANS instruments. Four existing instruments are described, and the general differences between pulsed-source and reactor-based instrument designs are discussed. The basic geometries are identical, but dynamic range is achieved by using a broad band of wavelengths (with time-of-flight analysis) rather than by moving the detector. This allows a more optimized collimation system. Data acquisition requirements at a pulsed source are more severe, requiring large, fast histogramming memories. Data reduction is also more complex, as all wave length-dependent and angle-dependent backgrounds and non-linearities must be accounted for before data can be transformed to intensity vs Q. A comparison is shown between the Los Alamos pulsed instrument and D-11 (Institute Laue-Langevin), and examples from the four major topics of the conference are shown. The general conclusion is that reactor-based instruments remain superior at very low Q or if only a narrow range of Q is required, but that the current generation of pulsed-source instruments is competitive at moderate Q and may be faster when a wide range of Q is required. In principle, a user should choose which facility …

Tunneling measurements are reported for Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{minus}y} (NCCO) and Ba{sub 1{minus}x}K{sub x}BiO{sub 3} (BKBO) using the point-contact technique with a Au or Nb tip. The junctions display very low zero-bias conductance values of <1% for BKBO and {approximately}10% for NCCO, and show sharp conductance peaks at eV = {plus minus} {Delta}. In the case of BKBO, the normalized conductance can be fit with a BCS density of states with thermal smearing only. The energy gaps are in good agreement with optical measurements and lead to values of 2{Delta}k{Tc} in the range of 3.5--4.0 for both compounds implying moderate coupling strength. The tunneling conductance data at high bias voltages display reproducible structures which are characteristic of phonon effects as found in conventional superconductors. We have obtained the Eliashberg functions, {alpha}{sup 2}F({omega}), and the resulting values of {lambda} determined from this analysis are consistent with the measured values of the strong-coupling ratio, 2{Delta}/k{Tc}. We conclude that the pairing mechanism in both materials is principally phonon mediated. 12 refs., 6 figs., 1 tab.

In this paper we present the design of the two dimensional coil and iron cross section, referred to as DSX201/W6733, for the 50 mm aperture dipole magnet being built at the Brookhaven National Laboratory for the Superconducting Super Collider (SSC). The computed values of the allowed field harmonics as a function of current, the quench performance predictions, the stored energy calculations, the effect of random errors on the coil placement and the Lorentz forces on the coil will be presented. The yoke has been optimized to reduce iron saturation effects on the field harmonics. We shall present the summary of this design which will include the expected overall performance of this cross section. 4 refs., 8 figs., 12 tabs.

The need for realistic computational models of neural microarchitecture is growing increasingly apparent. While traditional neural networks have made inroads on understanding cognitive functions, more realism (in the form of structural and connectivity constraints) is required to explain processes such as vision or motor control. A highly detailed computational model of mammalian cerebellum has been developed. It is being compared to physiological recordings for validation purposes. The model is also being used to study the relative contributions of each component to cerebellar processing. 28 refs., 4 figs.

We summarize activities concerning the Fermilab polarized beams. They include a brief description of the polarized-beam facility, measurements of beam polarization by polarimeters, asymmetry measurements in the {pi}{degree} production at high p{sub {perpendicular}} and in the {Lambda} ({Sigma}{degree}), {pi}{sup {plus minus}}, {pi}{degree} production at large x{sub F}, and {Delta}{sigma}{sub L}(pp, {bar p}p) measurements. 20 refs., 5 figs.

The use of general circulation models (GCMs) to provide climate data for regional assessments of the impacts of changing climate on water resources stretches the limits of what the models were designed for. Problems that must be addressed include disagreement on a regional scale among GCMs and between the modeled and observed climate; coarse spatial resolution of the models; and simplistic representation of surface hydrology. It is important that continued progress be made in developing the methodology for using GCM output in climate-impact assessments. 18 refs.

The heart of each time-of-flight neutron scattering instrument is its complement of detectors and the associated encoding and counting electronics. Currently there are ten fully-scheduled neutron scattering instruments in operation at IPNS, with three more instruments under development. Six of these instruments use position-sensitive neutron detectors (PSDs) of various types. These PSDs include a 30 cm {times} 30 cm, {approximately}3 mm resolution, neutron Anger camera area PSD with {sup 6}Li-glass scintillator; a 2.5 cm dia, {approximately}0.7 mm resolution, microchannel-plate area PSD with {sup 6}Li-glass scintillator; a 20 cm {times} 20 cm, {approximately}5 mm resolution, {sup 3}He proportional counter area PSD; a 40 cm {times} 40 cm, {approximately}4 mm resolution, {sup 3}He proportional counter area PSD; a flat 25 cm long, {approximately}1.6 mm resolution, {sup 3}He proportional counter linear PSD; and 160 cylindrical {sup 3}He proportional counter linear PSDs, each of which is 1.27 cm in dia and 60 cm long and has {approximately}14 mm resolution. In addition to these PSDs, {approximately}750 standard cylindrical {sup 3}He proportional counters of various sizes are utilized on IPNS instruments, and {approximately}20 BF{sub 3} pulsed ion chambers are in use as beam monitors. This paper discusses these various detectors and associated electronics, with emphasis on …