Search Results

Approximate Models for Distributed-Parameter Heat-Transfer Systems

Description: Summary: The use of dimensionless-parameter frequency response diagrams to determine accuracies of lumped-parameter approximations is demonstrated by two examples: calculation of the heat flux at the surface of a semi-infinite solid due to temperature fluctuations of an adjacent fluid; and the response of a counterflow heat exchanger to inlet fluid temperature perturbations. Dimensionless system parameters make it possible to use general-purpose plots to find the error in particular approximations as a function of the frequency of perturbation. Such plots are directly applicable to control-system stability problems, where the highest frequency of interest is usually apparent.
Date: August 20, 1963
Creator: Ball, S. J.

Asymptotic Neutron Spectra in Multiplying Media

Description: Asymptotic low energy neutron spectra have been measured for two multiplying systems. The reentrant hold spectrum (scalar flux) and the surface leakage spectrum were obtained for both assemblies using the pulsed-source chopper technique at the RPI linear accelerator.
Date: November 1963
Creator: Slovacek, R. E.; Fullwood, R. R.; Gaerttner, Erwin Rudolf, 1911- & Bach, D. R.

Automatic Exit Steam Quality Control for Boiling Water Reactors

Description: From American Nuclear Society Meeting, New York, Nov. 1963. The need for control of the flow distribution and/or steam quality in boiling reactors is discussed. A quality control device is being developed which consists of an entrance venturi and an exit venturi for measuring the flow rates into and out of the channel, means for comparing the two flow rate signals, and a value for regulating the flow rate. This device can be used either as a constant quality device or as a controlled-quality device. Results are given of air-water studies of two-phase flow in a vertical venturi.
Date: November 1963
Creator: Gall, D. A. & Doyle, E. F.

Behavior of Irradiated Metallic Fuel Elements Exposed to Nuclear Excursion in TREAT

Description: In fast reactor safety studies, it is imperative to know the effects of temperature excursions on the fuel elements. Previous controlled out-of-pile experiments on the behavior of uranium fuel elements under meltdown or near-meltdown conditions have been performed using direct electrical resistance heating or furnace heating. As a step toward obtaining more complete information on reactivity effects accompanying fuel meltdown, the behavior of irradiated EBR II and Fermi A samples under transient nuclear heating in TREAT has been studied. The experiment results obtained indicate that effects of prior irradiation can produce significant effects upon reactivity changes produced by meltdown of metallic fast reactor fuel pins.
Date: November 1963
Creator: Monaweck, J. H.; Dickerman, Charles Edward, 1932- & Sowa, E. S.

Beta Radiation Processing at Rigorous Conditions

Description: Introduction: The literature reflects ever expansive studies of radiation chemistry over the past twenty years However, in the application of radiation processing to chemical reactions, in general and excepting a few isolated cases, the yield of useful products have been so low as to preclude practical utilization. Thus, for many reactions,radiation alone at ambient conditions is not a sufficient agent for economical production. Hence, we are led to the investigation of radiation effects on reactions at elevated temperatures and pressures where the thermodynamics favor more extensive reactions that may be induced by radiation. the probability of developing a successful practical radiation process is increased when applying radiation at rigorous conditions. To have a commercial advantage, a radiation process usually must replace an expensive catalyst system, generate a reaction at somewhat less rigorous conditions than is usually employed or yield a better or unique product of high value. In our investigations, we have examined only the potential of radiation as a replacement for contact catalyst. Results: We have worked with coal extract rather than coal because it can be melted or dissolved to facilitate pumping into the processing unit and, in general, permits easier handling than a solid. From numerous radiation runs with coat extract in the liquid phase, treated with 5000 psi of hydrogen pressure, temperatures up to 430 degree C, and total dose of up to 6 megarand, we have disappointingly but conclusively observed red that radiation does not induce hydrogenation beyond that obtain by thermal reaction alone.
Date: November 15, 1963
Creator: Yavorsky, P. M. & Gorin, E.

A Cladding Failure Monitor for Liquid Metal-Cooled Reactor Systems

Description: A cladding failure monitor using the principle of detection of rare gas fission products in the cover gas system of liquid metal-cooled reactors, was developed which efficiently discriminates against AR41. This discrimination is accomplished by electrostatic precipitation of the rare gas daughter nuclides; since K41, the daughter of Ar41, is not radioactive, the activity of the precipitation is chiefly due to decay of various Rb and Cs fission products. The monitor equipment is described. Results of monitor testing in EBR-1 are reported; a simulated fuel road failure experiment was made which shows that the charged-wire cover gas monitoring principle should be useful in other sodium-cooled fast reactors systems.
Date: October 1963
Creator: Smith, R. R. & Doe, B. B.

Control of the Dissolved Gases in the Moderator of the HWCTR

Description: The Heavy Water Components Test Reactor (HWCTR) is used to test prototype fuel elements for power reactors that are moderated with heavy water and fueled with natural or slightly enriched uranium. During the initial critical experiments in the HWCTR, it was observed that there were unexpected variations in nuclear reactivity. Investigations revealed that this effect was due to bubble of helium gas appearing and disappearing in the moderator. An examination of the expected operating conditions of the HWCTR and the solubility of helium in D2O showed that it was possible during normal operation for the helium content of the moderator to exceed saturation and thus for helium to appear as bubbles in the moderator. The possibility of helium bubbles appearing in the moderator because of solubility characteristics was eliminated by modifications to the process system so as to maintain the gas content of the moderator appreciably below saturation.
Date: September 20, 1963
Creator: Arnett, L. M.

Current-Carrying Capacity and Transition State of Superconducting Solenoids

Description: Montgomery and Chandrasekhar and Hulm suggested models for predicting Im and Hm of high-field superconducting solenoids. Montgomery's model for predicting the degradation effect of superconducting solenoids leads to a unique coil quenching characteristics if geometrically similar solenoids are considered. Experiments do not verify these predicted results. Chandrasekhar and Hulm's model leads to one unique coil quenching characteristic for all solenoids with identical wire type and turn distance; coils with identical load factor should display identical values im and Hm. An analysis of the surface currents in an ideal superconducting infinitely long solenoid demonstrated possible forms of shielding currents. Experiments with Pb coils with and without NbZr and compensation agree with results expected from this analysis, but contradict Chandrasekhar and Hulm's model. Measurements of individual turn resistances show behavior of a soft superconductor solenoid in the intermediate state.
Date: September 3, 1963
Creator: Gauster, W. F. & Coffey, D. L.

[Delta]I = 1/2 Rule for Non-Leptonic Strangeness-Changing Decay Processes

Description: Gell-Mann and Pais were the first to suggest that the non-leptonic decay processes of strange particles may be subject to an isospin selection rule, allowing only those decay transitions which involve a change [delta]I = 1/2 in to total isopin of the system. At present, however, there is really no theoretical framework for the description of weak interactions into which this selection rule fits in a natural and compelling way. The report includes sections on the 91) decay processes of the [caret] hyperon, (2) decay processes, (3) [complex conjugate] decay processes, and (6) K[pi]3 decay processes. We have considered the evidence on all of the known non-leeptonic non-radiative decay modes of strange particles. All of this evidence is in good qualitative accord with the [delta]I = 1/2 selection rule.
Date: December 2, 1963
Creator: Dalitz, R. H. (Richard Henry), 1925-2006.

Design Review and Safety Analysis of Experiments in ORNL Research Reactors

Description: Since 1943 when the oak Ridge Graphite Reactor was put into operation, literally thousands of individual irradiation have been performed in this reactor and in other ORNL research reactors. Over the years there have been many minor incidents caused by experiments. Such incidents have provided a basis cor continued improvement in experiment design review and safety-analysis procedures. The reports lists the Design Review and Safety Analysis (1) objectives, (2) principles and rules of design, and (3) limits of application of the review process. The report includes a review of 19 incidents at ORNL research reactors.
Date: October 1963
Creator: Stanford, L. E. & Costner, R. A., Jr.

Detection and Identification of a Ruptured Fuel Element at the SM-1 (APR-1) Nuclear Power Plant

Description: Summary. In October 1960, increases in the fission product activity of the primary coolant of the SM-1 power plant indicated that a fuel element failure had occurred. Low power tests were run first to determine the nature and magnitude of the defect. Flux tilting experiments were then performed to determine the general location of the failed element. Finally, the primary coolant flowing through each of the fuel elements was sampled at low reactor power for relative iodine activity to determine the exact location of the defective element.. The element was found and replaced. Upon return to power, the fission product activity dropped back to its normal full power value.
Date: 1961
Creator: Misenheimer, Leo J.; Purple, Robert A. & Brown, Paul S.

The Determination of k∞ From Measurements on a Small Test Sample in a Critical Assembly

Description: Abstract. The determination of the infinite multiplication factor, k∞ , from measurement son a small test sample was investigated by both theoretical and experimental techniques. Theoretical relations were developed to calculate the error in the measurement due to a mismatch between the flux ratios in the critical assembly and those of the test sample. Experiments were carried out at the Hanford Laboratory of the General Electric Company with the PCTR, to obtain values of the multiplication factor for comparison with the theoretical results. Calculations with two-group theory gave results that agreed with the experimental results when the test sample, with natural uranium fuel, was surrounded by a buffer region of the same material. When this buffer region was loaded with highly enriched fuel, the errors in the measured values were not predicted by the two-group theory. Three-group theory relations were derived which gave calculated values in agreement with the experimental values and indicated that a mismatch of the epithermal neutron group leads to the measured differences in the value of k∞ for the two buffer types.
Date: November 1963
Creator: Lanning, David Dayton

Development and Evaluation of Large Volume Scintillation Detectors and Their Application to Radioisotope Process Control

Description: Preliminary phases of this investigation that have been completed include basic studies to determine optimum detector engineering characteristics and static tests of a number of designs. A pilot system for dynamic testing of the detectors in simulated process control applications is presently in operation.
Date: November 1963
Creator: Perry, J. Kent

Development of Fueled Graphite Containing Pyrolytic-Carbon Coated Carbide Particles for Nonpurged, Gas-Cooled Reactor Systems

Description: Abstract: Progress is reported in several areas of development of fueled graphite containing coated particles for nonurged gas-cooled reactor systems. The sol-gel process has been modified for making spherical particles of both thorium-uranium carbide and thorium-uranium oxide suitable for coating. Equipment has been assembled and methods have been developed for deposition of pyrolytic-carbon coating under well-controlled conditions. Damage to coated particles during fabrication into a graphite matrix depends on the molding pressure and the volumetric content of coated particles. Vendor-supplied coated particles and fueled graphite spheres have been evaluated extensively in both in- and out-of-reactor tests. Duplex- and triplex-coasted particles have excellent fission-gas retention at 2050 degree F to burnups of 15 at. % burnup. Fueled graphite spheres containing coated particles have good irradiation performance, but the fission-gas release rates are somewhat higher than for unsupported coated particles. Fueled graphite spheres react with water vapor about as rapidly as do Speer Mod-2 and ATJ grades of graphite. The diffusion rates in pyrolytic carbon are the same for uranium, thorium, and protactinium. The diffusion rates in the direction parallel to the deposition plane are much higher than those in the perpendicular direction.
Date: November 1963
Creator: Carlsen, F. L., Jr.; Bomar, E. S. & Harms, W. O.

The Diffusion of Fast Neutrons

Description: From American Nuclear Society Meeting, New York, Nov. 1963. The use of the asymptotic solution to the one-velocity transport equation is considered. The angular distribution for fast neutron elastic scattering by heavy elements is discussed. An exponential angular distribution on is assumed to simplify the decay length calculation. The diffusion length of 1 to 15 Mev neutrons in iron is calculated, as well as the vector flux angular dependence. The asymptotic solution for an arbitrary angular distribution of a plane delta -function source is also found. An isotropic source is investigated, and some applications of the model are examined.
Date: November 1963
Creator: Francis, N. C.; Brooks, E. J. & Watson, R. A.

Diffusion Parameters of Water for Various Scattering Kernels

Description: Abstract. Some diffusion parameters of water are computed with various thermal-neutron scattering laws. It is found that the diffusion cooling coefficient, in particular, is reasonably sensitive to the scattering law, but that the diffusion cooling coefficients predicted by the Radkowsky and Nelkin kernels are in fortuitious agreement. The coefficients computed for the Nelkin kernel, when treated in a manner consistent with the way in which experimental data are treated, are in reasonable agreement with the results of a recent experiment.
Date: August 16, 1963
Creator: Calame, Gerald P.

The Education, Experience, Training, and Certification of Reactor Operators at AEC-Owned Reactors

Description: Results of a questionnaire survey are presented on reactor supervisor and operator education, experience, and training, and on certification procedures by reactor category. The questionnaires were obtained from 362 supervisors, 393 operators, 44 supervisor trainees, and 139 operator trainees.
Date: October 31, 1964
Creator: Wilgus, Walter S.; McCool, Whittie J. & Biles, Martin B.

Effect of Eddy Diffusion on Temperatures in a Fixed Bed, Particulate-Fueled Nuclear Reactor

Description: Abstract: To assess diffusion's importance, the temperature distribution in a cylindrical reactor is derived for a coolant with uniform properties and velocity, taking into account both radial and axial diffusion, for a cosine-J0 power distribution. The fractional temperature rise of the coolant is found to be [chemical formula] where E(z) = [sin(z) + sin(Z)]/2 sin(Z), z= π x/2′, x is the axial distance from the core center, -H and ′ are the core half-height and extrapolated half-height, -H≤x≤H; Fn = 1/J0(Pn)·[(Pn/2.405P)2-10, J1(Pn) = 0, P= R/R′ = core radius/extrapolated radius, ρ = r/R, r = radial distance from axis, 0≤r≤R; an = = βnH/Z, 2 Aβn + 1 =[1 + 4αβ(Pn/R)2]½, A = axial diffusivity /u, B = radial diffusivity /u, u = coolant axial velocity, and [chemical formula]. The expression is evaluated for a variety of values for all the parameters, and the results are discussed analytically and presented in tables and graphs. The effect is dependent upon the relative size of the diffusion eddies in comparison with the dimensions of the reactor. The eddy diffusivity is proportional to the size of the particles in the bed and is about ten times larger axially than radially. A small core with large fuel particles will be affected by eddy diffusion, thereby reducing hot spots, but a large core with small particles will not. For a core 8 ft in diameter cooled by sodium flowing at 2 ft/sec, the effect is perceptible with 2-in. particles, but not with 0.2-in. particles.
Date: November 1963
Creator: Barker, James J. & Benenati, Robert F.

Effect of Fluoride Ions on the Aqueous Corrosion of Zirconium Alloys

Description: Abstract. A review has been made of the effects of fluoride ions on the corrosion behavior of zirconium alloys in high-temperature water. Corrosion was found to occur as the result of contamination of the water or the zirconium surface. A major source of fluorides is undue delay in rinsing the HF-HNO3 pickling solution during surface preparation. The oxide on corrosion-resistant material has been found to contain up to 7600 ppm fluoride from this source. The threshold concentration of fluoride in the oxide film which produces poor corrosion resistance ranges from 8500 to 17,000 ppm. Accelerated corrosion from fluorides in water at 300 to 360 C occurs at about 100 ppm, although increased corrosion has been reported at 10 ppm fluoride in water at 300 C. Fluorocarbon plastics degrade and contribute fluorides to the high-temperature water or to the alloy surface when in direct contact with zirconium. Chlorides (1 to 10,000 ppm) and iodides (1270 ppm) do not adversely affect the corrosion behavior of zirconium alloys in water at 360 C. The mechanism of corrosion is not well understood but apparently is related to the formation of insoluble zirconium oxyfluorides during pickling and during exposure to fluoride-contaminated water.
Date: November 1963
Creator: Berry, Warren E., 1922-

Effect of Radiation on Mechanical Properties of CVTR Pressure Tube Material

Description: An essential part of establishing the acceptability of warm extruded Zircaloy-4 for the CVTR pressure tube application was the determination of irradiation effects on mechanical properties of the alloy. Representative specimens were irradiated in low temperature process water in the WTR for simulated two, three and five year exposure. The effects of this irradiation were then evaluated in terms of changes in tensile, impact and creep properties. The experiment results concluded that the irradiation-induced changes in mechanical proprieties will not introduce any operational hazard to the CVTR pressure tube under anticipated operating conditions.
Date: November 1963
Creator: Smalley, W. R.

Elastic Scattering of Atoms and Molecules in the Thermal Energy Range

Description: Abstract: the goal of research on elastic scattering of atomic (or molecular) beams is the elucidation of the interaction potential V(r). the present discussion is confined to thermal energy collisions ([less than]1 ev), sensitive primarily to the attractive part of the potential. Studies of the velocity dependence of the differential and total elastic scattering cross sections have yielded information as follows: (1) The functional form of the long-range attraction : V[tilde]-C/r6, from differential cross sections I(0), at low angles: I(0) oc 0-7/3. (2) The attractive potential constant C, from total cross sections: Q oc (C/v)2/5, (3) The depth of the potential well [epsilon], from the rainbow effect in I(0): 0r=f(1/2mv2/[epsilon). (4) The equilibrium separation rm, from de Broglie interference producing undulations in (I0). (5) the product [epsilon]rm, from extrema in Q(v), and thus rm (from absolute Q's). (6) Observations of m maxima in plots of vQ5/2 vx. v-1 (termed elastic impact spectra) implied the existence of at least m bound states (discrete vibrational levels of zero angular momentum for the composite system).
Date: 1963
Creator: Bernstein, Richard B. (Richard Barry), 1923-1990

An Electrochemical pH-STAT

Description: An apparatus has been developed which controls automatically the acidity of unbuffered solutions in the region from pH 4 to 10. A potentiostat is used to control the potential of an inert electrode on which the hydrogen gas-hydrogen ion reaction occurs in a solution saturated with hydrogen gas. The inert electrode acts as both a sensing element and a regulating electrode for the control of acidity. Current from the potentiostat passes through the inert electrode and an auxiliary polarizing electrode in an external compartment separated from the main cell by a salt bridge or porous plate. Transients which occur during the regulating action are presented and analyzed. The electrochemical pH-stat may be used to measure corrosion rates. Limitations of the device are discussed and a modification is proposed which makes use of a differential amplifier instead of a potentiostat.
Date: October 1963
Creator: Posey, F. A. (Franz Adrian), 1930-; Morozumi, T. & Kelly, E. J.

Electronic Data Processing an Application to Nuclear Materials Management

Description: Abstract: This report is concerned with the application of an electronic data processing system to the unique combination of scientific and commercial data processing requirement of nuclear materials management. The organization and flow of data from the plant through the data processing equipment to the final report is the principle topic of the report. Included in the discussion, however, are topics concerned with the impact of conversion to electronic data processing on personnel, materials management costs, and on other plant organizations. Portions of the report are devoted to programming systems and decision-making abilities of data processing equipment which make these systems readily adaptable to nuclear materials management.
Date: 1963
Creator: Hudson, J. F.