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Severe accident core heatup transients in modular high temperature gas-cooled reactors without operating Reactor Cavity Cooling Systems
The ultimate decay heat removal system for the current Modular High Temperature Gas-Cooled reactors is a completely passive natural convection air cooling loop. This paper considers an extremely remote accident scenario, where even this passive system fails, and heat rejection is only via a layer of thermal insulation to the reactor silo structure and the surrounding soil. The results show that even in this case the peak fuel temperatures remain well within safe limits. However, vessel and concrete temperatures can - under extreme circumstances and after several weeks - reach temperature levels at which structural failure becomes possible.
Date:
January 1, 1988
Creator:
Kroeger, P. G.
Object Type:
Article
System:
The UNT Digital Library
Characterization of low-level waste from the industrial sector, and near-term projection of waste volumes and types
A telephone survey of low-level waste generators has been carried out in order to make useful estimates of the volume and nature of the waste which the generators will be shipping for disposal when the compacts and states begin operating new disposal facilities. Emphasis of the survey was on the industrial sector, since there has been little information available on characteristics of industrial LLW. Ten large industrial generators shipping to Richland, ten shipping to Barnwell, and two whose wastes had previously been characterized by BNL were contacted. The waste volume shipped by these generators accounted for about two-thirds to three-quarters of the total industrial volume. Results are given in terms of the categories of LLW represented and of the chemical characteristics of the different wastes. Estimates by the respondents of their near-term waste volume projections are presented.
Date:
January 1, 1988
Creator:
MacKenzie, D.R.
Object Type:
Article
System:
The UNT Digital Library
A benchmark-problem specification and calculation using SENSIBL, a one- and two-dimensional sensitivity and uncertainty analysis code of the AARE system
The lack of suitable benchmark problems makes it difficult to test sensitivity codes with a covariance library. A benchmark problem has therefore been defined for one- and two-dimensional sensitivity and uncertainity analysis codes and code systems. The problem, representative of a fusion reactor blanket, has a simple, three-zone )tau)-z geometry containing a D-T fusion neutron source distributed in a central void region surrounded by a thick /sup 6/LiH annulus. The response of interest is the /sup 6/Li tritium production per source neutron, T/sub 6/. The calculation has been performed with SENSIBL using other codes from the AARE code system as a test of both SENSIBL and the linked, modular system. The caluclation was performed using the code system in the standard manner with a covariance data library in the COVFILS-2 format but modified to contain specifically tailored covariance data for H and /sup 6/Li (Path A). The calculation was also performed by a second method which uses specially perturbed H and Li cross sections (Path B). This method bypasses SENSIBL and allows a hand calculation of the benchmark T/sub 6/ uncertainties. The results of Path A and Path B were total uncertainties in T/sub 6/ of 0.21% and 0.19%, respectively. …
Date:
January 1, 1988
Creator:
Muir, D. W.; Davidson, J. W.; Dudziak, D. J.; Davierwalla, D. M.; Higgs, C. E. & Stepanek, J.
Object Type:
Article
System:
The UNT Digital Library
Operating experience and procedures at the tritium systems test assembly
Operating procedures are important for the safe and efficient operation of the Tritium Systems Test Assembly (TSTA). TSTA has been operating for four years with tritium in a safe and efficient manner. The inventory of tritium in the process loop is 100 grams and several milestone runs have been completed. This paper describes the methods used to operate TSTA. 3 refs., 1 fig.
Date:
January 1, 1988
Creator:
Carlson, R.V.; Binning, K.E.; Cole, S. P.; Jenkins, E. M.; Wilhelm, R. C. & Cole, S. P.
Object Type:
Article
System:
The UNT Digital Library
Plutonium scrap recovery at Savannah River: Past, present, and vision of the future
As a result of the changing requirement, plus environmental and regulatory commitments, SRP now has essentially completed its paradigm shift. SRP has been transformed from primarily a reprocessor of irradiated uranium targets to primarily a reprocessor of non-specification plutonium. This is the mission which will carry SRP into the 21st Century. Accomplishment of the defined goals for the three-pronged RandD program will achieve several objectives: exploit new processes for recovering low-grade scraps; enhance SRP's position to incorporate pyrochemical processes where they are attractive or beneficial to plant scrap recovery; provide SRL/SRP with a capability to develop compatible aqueous pyrochemical processes; identify material compatibility requirements for the incorporation of pyrochemical processes at SRP; promote development and demonstration of improved NDA instrumentation to accurately measure plutonium holdups in solid residues; identify and implement the technology required for reagent preparation and atmospheric quality control; provide a means to compare economic options for emerging new processes; and as a result, identify process steps which will also put SRP in a position to readily adapt to changing plutonium missions.
Date:
January 1, 1988
Creator:
Gray, Leonard W.; Gray, John H.; Blancett, Allen L.; Lower, William M. & Rudisill, Tracy S.
Object Type:
Article
System:
The UNT Digital Library
Current drive and heating systems based on high-energy (1- to 3-MeV) negative ion beams
This paper describes a concept for a current drive system based on negative ions with beam energy > 1 MeV. Preliminary physics calculations show that the core current necessary for stability enhancement can best be achieved by beams with energy ranging from 1 to 4 MeV. Further study and experiments will better define the optimum energy. Work under way at Oak Ridge National Laboratory (ORNL) and at collaborating institutes in Canada and the Federal Republic of Germany is defining a system, its elements, a configuration and operational scenarios deemed appropriate for such devices as ITER and other future steady-state tokamaks, and the requisite research and development to provide such a system. 7 refs., 2 figs.
Date:
January 1, 1988
Creator:
Becraft, W. R.; Akerman, M. A.; Haselton, H. H.; Murphy, B. D.; Lousteau, D. C.; Ryan, P. M. et al.
Object Type:
Article
System:
The UNT Digital Library
Generation of radiation by intense plasma and e. m. undulators
This program involves the generation of short wavelength optical radiation by intense plasma and e.m. undulators. In this concept a relativistic electron beam is wiggled by either the oscillating electric field of an intense plasma wave, or by a laser beam causing it to radiate. For both types of undulators the designed parameters are a{sub w} > 0.1, N {approximately} 100 and {lambda}{sub w} = 100 {mu}m for plasma wave or 10.6 {mu}m for laser light. This progress report describes the work to-date on generating such intense short wavelength undulators. We have successfully generated up to 200 GW of CO{sub 2} radiation in a 200 ps long pulse. A uniform plasma source, {Theta}-pinch, has been constructed and it's density diagnosed using holographic interferometry. Using about 20 GW of laser radiation at two frequencies, 10.27 {mu}m and 9.56 {mu}m, relativistic plasma wave has been excited using the beat wave'' technique. The amplitude of this plasma wave has been inferred to be n{sub 1}/n{sub 0} {approx lt} 1%. The plasma wave width is thought to be about 2--3 wavelengths. A 1.5 MeV, 9 GHz linac has been procurred using funds from another contract and diagnosed. The electron beam emittance as it exits …
Date:
January 1, 1988
Creator:
Joshi, C.
Object Type:
Report
System:
The UNT Digital Library
Pseudorapidity distributions and correlations in central sup 16 O interactions at 200 A GeV
Whether or not adequate energy densities for a transition to the Quark-Gluon Plasma (QGP) phase are possible in {sup 16}O and {sup 32}S induced reactions is still an open question. Before unambiguous signals can be identified it is necessary to understand the background upon which the expected QGP signatures can be sought. An important aim of early experiments in this new energy density regime is thus to understand the process of hadronization in a nuclear environment. In any discussion of high energy nucleus-nucleus collisions formation time is an important feature. If, for example, the final state particles are produced instantaneously in a bound hadron-nucleon collision, all these particles will have a chance to reinteract inside the nuclear medium. If, on the other hand, the formation time is long, i.e., longer than the nuclear diameter, the energy flux will stay together as a unit throughout its passage through the target nucleus. While these extreme cases are clearly unrealistic, one expects interaction parameters such as the multiplicity and pseudorapidity distributions to be sensitive functions of the formation time. Here we present results on charged hadron production in an experiment using tracking detectors with the highest possible spatial resolution: emulsion chambers. A sample …
Date:
January 1, 1988
Creator:
Wilkes, R. J.
Object Type:
Article
System:
The UNT Digital Library
Preliminary assessment of tree mortality near F- and H-area seepage basins
A preliminary assessment was conducted to evaluate factors that may have been responsible for the vegetation damage that has occurred in groundwater seeps downslope from the F- and H-area seepage basins. The factors that were considered included altered hydrology, toxicity from hazardous chemical constituents associated with seepage basin operation, and toxicity from non-hazardous constituents associated with basin operation. It was concluded that the observed damage was not likely to have resulted from altered hydrologic conditions or hazardous constituents associated with basin operation. Insufficient information is currently available to determine definitively which of the non-hazardous constituents, alone or in concert, were responsible for the observed vegetation damage. The most likely explanation, however, is that elevated Na, pH, and conductivity is outcropping seep water are responsible for tree mortality. All three of these factors will return to ambient levels over a period of several years when basin operation ceases. Faster remediation can be achieved using lime at the seep line.
Date:
January 28, 1988
Creator:
Loehle, C & Gladden, J
Object Type:
Report
System:
The UNT Digital Library
A theoretical prediction of critical heat flux in subcooled pool boiling during power transients
Understanding and predicting critical heat flux (CHF) behavior during steady-state and transient conditions are of fundamenatal interest in the design, operation, safety of boiling and two-phase flow devices. This paper discusses the results of a comprehensive theoretical study made specifically to model transient CHF behavior in subcooled pool boiling. This study is based upon a simplified steady-state CHF model in terms of the vapor mass growth period. The results obtained from this theory indicate favorable agreement with the experimental data from cylindrical heaters with small radii. The statistical nature of the vapor mass behavior in transient boiling also is considered and upper and lower limits for the current theory are established. Various factors that affect the discrepancy between the data and the theory are discussed.
Date:
January 1, 1988
Creator:
Pasamehmetoglu, K. O.; Nelson, R. A. & Gunnerson, F. S.
Object Type:
Article
System:
The UNT Digital Library
A semi-analytical method for heat sweep calculations in fractured reservoirs
An analytical approximation is developed for purely conductive heat transfer from impermeable blocks of rock to fluids sweeping past the rocks in fractures. The method was incorporated into a multi-phase fluid and heat flow simulator. Comparison with exact analytical solutions and with simulations using a multiple interacting continua approach shows very good accuracy, with no increase in computing time compared to porous medium simulations. 14 refs., 3 figs., 5 tabs.
Date:
January 1, 1988
Creator:
Pruess, K. & Wu, Y.S.
Object Type:
Article
System:
The UNT Digital Library
Nuclear plant-aging research on reactor protection systems
This report presents the rsults of a review of the Reactor Trip System (RTS) and the Engineered Safety Feature Actuating System (ESFAS) operating experiences reported in Licensee Event Reports (LER)s, the Nuclear Power Experience data base, Nuclear Plant Reliability Data System, and plant maintenance records. Our purpose is to evaluate the potential significance of aging, including cycling, trips, and testing as contributors to degradation of the RTS and ESFAS. Tables are presented that show the percentage of events for RTS and ESFAS classified by cause, components, and subcomponents for each of the Nuclear Steam Supply System vendors. A representative Babcock and Wilcox plant was selected for detailed study. The US Nuclear Regulatory Commission's Nuclear Plant Aging Research guidelines were followed in performing the detailed study that identified materials susceptible to aging, stressors, environmental factors, and failure modes for the RTS and ESFAS as generic instrumentation and control systems. Functional indicators of degradation are listed, testing requirements evaluated, and regulatory issues discussed.
Date:
January 1, 1988
Creator:
Meyer, L.C.
Object Type:
Report
System:
The UNT Digital Library
Detection of plasma equilibrium shifts with fiber optic sensing of image currents
The radial equilibrium position of Reverse Field Pinch experiments is determined by the j x B force on the plasma. The current density is that of the toroidal plasma current and the B field is the vertical magnetic field which is present in the plasma. This magnetic field is the result of several components. The main field, generated by the toroidal current windings, is corrected by adjustable trim windings to achieve a desired equilibrium position. There is an additional component to the field due to induced image currents in the close fitting conducting shell which encircles the plasma. These currents vary in time due to the finite L/R time of the conducting shell. It is the object of this paper to investigate the possibility of measuring these shell currents accurately using fiber optics so as to provide an analog signal to the equilibrium feedback circuit. 7 refs., 7 figs.
Date:
January 1, 1988
Creator:
Forman, P.R.; Jahoda, F.C. & Miller, G.
Object Type:
Article
System:
The UNT Digital Library
Sources of polarized ions and atoms
In this presentation we discuss methods of producing large quantities of polarized atoms and ions (Stern-Gerlach separation, optical pumping, and spin-exchange) as well as experimental methods of measuring the degree of polarization of atomic systems. The usefulness of polarized atoms in probing the microscopic magnetic surface properties of materials will also be discussed. 39 refs., 5 figs., 2 tabs.
Date:
January 1, 1988
Creator:
Cornelius, W.D.
Object Type:
Article
System:
The UNT Digital Library
Coarse-node computations with an adaptive node structure
The analysis with COMMIX of liquid metal reactor (LMR) intermediate heat exchanger (IHX) transients that are characterized by low flows, and especially imbalanced low flows, shows that if a coarse-node structure is used the predicted temperatures are significantly different than those given by a fine-node structure. If a fine-node structure is used, for problems that involve a large part of the plant, the computation time becomes excessive. This paper presents an improved version of an adaptive node structure. At this stage this version has been applied only to one-dimensional problems.
Date:
January 1, 1988
Creator:
Tzanos, C.P.
Object Type:
Article
System:
The UNT Digital Library
Transient thermal analysis of three fast-charging latent heat storage configurations for a space-based power system
A space-based thermal storage application must accept large quantities of heat in a short period of time at an elevated temperature. A model of a lithium hydride phase change energy storage system was used to estimate reasonable physical dimensions for this application which included the use of a liquid metal heat transfer fluid. A finite difference computer code was developed and used to evaluate three methods of enhancing heat transfer in the PCM energy storage system. None of these three methods, inserting thin fins, reticulated nickel, or liquid lithium, significantly improved the system performance. The use of a 95% void fraction reticulated nickel insert was found to increase the storage capacity (total energy stored) of the system slightly with only a small decrease in the system energy density (energy storage/system mass). The addition of 10% liquid lithium was found to cause minor increases in both storage density and storage capacity with the added benefit of reducing the hydrogen pressure of the lithium hydride. 9 refs., 7 figs., 2 tabs.
Date:
January 1, 1988
Creator:
Stovall, T. K. & Arimilli, R. V.
Object Type:
Article
System:
The UNT Digital Library
Full-wave calculations in flux coordinates for toroidal geometry
A new 2-D full-wave code, HYPERION, employing a poloidal and toroidal mode expansion and including the toroidal terms arising in the wave equation has been developed. It is based on the existing modules developed for the MHD stability codes and uses as input the tokamak equilibria calculated with the RSTEQ code. At present the plasma response is described by the collisionally broadened cold plasma conductivity. However, the code is written in straight field line coordinates, this permits the accurate representation of k /sub /parallel// and as a consequence allows the incorporation of the plasma Z functions. This code also retains the E/sub /parallel// component of the electric field which will allow the study of the low density region of the plasma. We have done detailed benchmarking of the HYPERION code in the cold plasma limit with the existing finite difference ORION full-wave code. The agreement is very good.
Date:
January 1, 1988
Creator:
Carreras, B. A.; Lynch, V. E.; Jaeger, E. F. & Batchelor, D. B.
Object Type:
Article
System:
The UNT Digital Library
Hyperdeformed nuclei and the residual pseudo-SU(3) symmetry
The author discusses superdeformed and hypothetical hyperdeformed nuclei. Quadrupole deformations characteristic of these types of nuclei are defined. Symmetry features are also discussed. The characteristic cycle dependence of shell structures as functions of the deformation gives rise to chains of the deformed shell closures. Such a chain structure applies to moderately-, super- and hyper-deformed nuclei as well. The resulting total energy calculations give a systematic variation of super- and hyperdeformations with, e.g., increasing N at fixed Z, thus predicting the way nuclei deviate from the simple a:b = 2:1 and a:b = 3:1 symmetries.
Date:
January 1, 1988
Creator:
Dudek, J. & Werner, T.
Object Type:
Article
System:
The UNT Digital Library
Passive safety and the advanced liquid metal reactors
Advanced Liquid Metal Reactors being developed today in the USA are designed to make maximum use of passive safety features. Much of the LMR safety work at Argonne National Laboratory is concerned with demonstrating, both theoretically and experimentally, the effectiveness of the passive safety features. The characteristics that contribute to passive safety are discussed, with particular emphasis on decay heat removal systems, together with examples of Argonne's theoretical and experimental programs in this area.
Date:
January 1, 1988
Creator:
Hill, D.J.; Pedersen, D.R. & Marchaterre, J.F.
Object Type:
Article
System:
The UNT Digital Library
Ultraviolet imaging of hydrogen flames
We have assembled an ultraviolet-sensitive intensified camera for observing hydrogen combustion by imaging the OH, A/sup 2/..sigma.. - X/sup 2//Pi/ bandhead emissions near 309 nm. The camera consists of a quartz and CaF achromat lense-coupled to an ultraviolet image intensifier which is in turn fiber-coupled to a focus projection scan (FPS) vidicon. The emission band is selected with interference filters which serve to discriminate against background. The camera provides optical gain of 100 to 1000 and is capable of being shuttered at nanosecond speeds and of being framed at over 600 frames per second. We present data from observations of test flames in air at standard RS-170 video rates with varying background conditions. Enhanced images using background subtraction are presented. Finally, we discuss the use of polarizaton effects to further discrimination against sky background. This work began as a feasibility study to investigate ultraviolet technology to detect hydrogen fires for the NASA space program. 6 refs., 7 figs, 2 tabs.
Date:
January 1, 1988
Creator:
Yates, G. J.; Wilke, M. & King, N.
Object Type:
Article
System:
The UNT Digital Library
Methods and techniques of NDA (nondestructive assay)
Nondestructive assay (NDA) refers to techniques and instruments developed to measure nuclear materials in the many forms in which they occur throughout the fuel cycle. These techniques were first developed to support nuclear safeguards inspections and nuclear material accountability; they are also used extensively for process and quality control. Most accountability measurements are based on analytical chemistry and require that a sample be drawn and analyzed destructively. Destructive analysis can not be applied to many of the product materials found in the fuel cycle, such as fuel rods and assemblies, because of their high monetary value. Also, many waste and scrap materials can not be adequately sampled for destructive analysis because of their heterogenous nature. This situation led to the development of nondestructive analysis techniques. This paper presents an overview of the major NDA techniques and instrumentation in use today. The instrumentation described below is now used frequently by safeguards inspectors and facility operators alike. 19 refs., 18 figs., 4 tabs.
Date:
January 1, 1988
Creator:
Reilly, T. D.
Object Type:
Article
System:
The UNT Digital Library
Development and process evaluation of improved Fischer-Tropsch slurry catalysts
The objective of this contract is to develop a consistent technical data base on the use of iron-based catalysts in Fischer-Tropsch (FT) synthesis reactions. This data base will be developed to allow the unambiguous comparison of the performance of these catalysts with each other and with state-of-the-art iron catalyst comparisons. Particular attention will be devoted to generating reproducible kinetic and selectivity data and to developing reproducible improved catalyst compositions.
Date:
January 1, 1988
Creator:
Withers, H.P. (Air Products and Chemicals, Inc., Allentown, PA (United States)); Bukur, D.B. & Rosynek, M.P. (Texas A and M Univ., College Station, TX (United States))
Object Type:
Report
System:
The UNT Digital Library
Benefits of vertical and horizontal seismic isolation for LMR (liquid metal reactor) nuclear reactor units
Seismic isolation has been shown to be able to reduce transmitted seismic force and lower response accelerations of a structure. When applied to nuclear reactors, it will minimize seismic influence on the reactor design and provide a design which is less site dependent. In liquid metal reactors where components are virtually at atmospheric pressure but under severe thermal conditions, thin-walled structures are generally used for primary systems. Thin-walled structures, however, have little inherent seismic resistance. The concept of seismic isolation therefore offers a viable and effective approach that permits the reactor structures to better withstand thermal and seismic loadings simultaneously. The majority of published work on seismic isolation deals with use of horizontal isolation system only. In this investigation, however, local vertical isolation is also provided for the primary system. Such local vertical isolation is found to result in significant benefits for major massive components, such as the reactor cover, designed to withstand vertical motions and loadings. Preliminary estimations on commodity savings of the primary system show that, with additional local vertical isolation, the savings could be twice that estimated for horizontal isolation only. The degree of effectiveness of vertical isolation depends on the diameter of the reactor vessel. As …
Date:
January 1, 1988
Creator:
Wu, Ting-shu; Chang, Y. W. & Seidensticker, R. W.
Object Type:
Article
System:
The UNT Digital Library
Tritium module for ITER/Tiber system code
A tritium module was developed for the ITER/Tiber system code to provide information on capital costs, tritium inventory, power requirements and building volumes for these systems. In the tritium module, the main tritium subsystems/emdash/plasma processing, atmospheric cleanup, water cleanup, blanket processing/emdash/are each represented by simple scaleable algorithms. 6 refs., 2 tabs.
Date:
January 1, 1988
Creator:
Finn, P. A.; Willms, S.; Busigin, A. & Kalyanam, K. M.
Object Type:
Article
System:
The UNT Digital Library