1,032 Matching Results

Search Results

Advanced search parameters have been applied.

TOUGH+/GasH20 study of the effects of a heat source buried in theMartian permafrost

Description: We use TOUGH+/GasH2O to study the effects of a heat sourceburied in the Martian permafrost to evaluate the possibility ofestablishing a wet zone of liquid water, in which terrestrialmicroorganisms could survive and multiply. Analysis of the problemindicates that (1) only a limited permafrost volume (not exceeding 0.35 min radius) is affected, (2) a "wet" zone with limited amounts of liquidwater de-velops (not exceeding 8 and 0.7 kg for a 250 W and a 62.5 Wsource, respectively), (3) the wet zone per-sists for a long time,becomes practically stationary after t = 20 sols because of venting intothe Martian atmosphere, and its thickness is limited and decreases slowlyover time, (4) a "dry" zone (where SG>0.9) evolves, continues toexpand (albeit slowly) with time, but its extent remains limited, and (5)the ice front surrounding the wet zone is self-sharpening. For a range ofinitial conditions investigated, evolution of the liquid water massoccurs at approximately the same rate, reaches roughly the same maximum,and occurs at about the same time (10 to 20 sols; 1 sol = 24.39hours).
Date: May 12, 2006
Creator: Moridis, George J. & Pruess, Karsten
Partner: UNT Libraries Government Documents Department

Prandtl Number Dependent Natural Convection with Internal Heat Sources

Description: Natural convection plays an important role in determining the thermal load from debris accumulated in the reactor vessel lower head during a severe accident. Recently, attention is being paid to the feasibility of external vessel flooding as a severe accident management strategy and to the phenomena affecting the success path for retaining the molten core material inside the vessel. The heat transfer inside the molten core material can be characterized by the strong buoyancy-induced flows resulting from internal heating due to decay of fission products. The thermo-fluid dynamic characteristics of such flow depend strongly on the thermal boundary conditions. The spatial and temporal variation of heat flux on the pool wall boundaries and the pool superheat are mainly characterized by the natural convection flow inside the molten pool. In general, the natural convection heat transfer phenomena involving the internal heat generation are represented by the modified Rayleigh number (Ra’), which quantifies the internal heat source and hence the strength of the buoyancy force. In this study, tests were conducted in a rectangular section 250 mm high, 500 mm long and 160 mm wide. Twenty-four T-type thermocouples were installed in the test section to measure temperatures. Four T-type thermocouples were used to measure the boundary temperatures. The thermocouples were placed in designated locations after calibration. A direct heating method was adopted in this test to simulate the uniform heat generation. The experiments covered a range of Ra' between 1.5x106 and 7.42x1015 and the Prandtl number (Pr) between 0.7 and 6.5. Tests were conducted with water and air as simulant. The upper and lower boundary conditions were maintained uniform. The results demonstrated feasibility of the direct heating method to simulate uniform volumetric heat generation. Particular attentions were paid to the effect of Pr on natural convection heat transfer within the rectangular pool.
Date: June 1, 2004
Creator: Lee, Kang Hee; Lee, Seung Dong; Suh, Kune Y.; Rempe, Joy L.; Cheung, Fan-Bill & Kim, Sang B.
Partner: UNT Libraries Government Documents Department

Artificial heart development program. Volume II. System support. Phase III summary report. Period covered: July 1, 1973--September 30, 1977

Description: Appendix A covers major activities of the Artificial Heart Development program that supported the design, fabrication, and test of the system demonstration units. Section A.1.0 provides a listing beyond that of the body of the report on the components needed for an implantation. It also presents glove box sterilization calibration results and results of an extensive mock circulation calibration. Section A.2.0 provides detail procedures for assembly, preparing for use, and the use of the system and major components. Section A.3.0 covers the component research and development activities undertaken to improve components of the existing system units and to prepare for a future prototype system. Section A.4.0 provides a listing of the top assembly drawings of the major systems variations fabricated and tested.
Date: January 1, 1977
Partner: UNT Libraries Government Documents Department

Artificial heart development program. Volume I. System development. Phase III summary report

Description: The report documents efforts and results in the development of the power system portions of a calf implantable model of nuclear-powered artificial heart. The primary objective in developing the implantable model was to solve the packaging problems for total system implantation. The power systems portion is physically that portion of the implantable model between the Pu-238 heat sources and the blood pump ventricles. The work performed had two parallel themes. The first of these was the development of an integrated implantable model for bench and animal experiments plus design effort on a more advanced model. The second was research and development on components of the system done in conjunction with the development of the implantable model and to provide technology for incorporation into advanced models plus support to implantations, at the University of Utah, of the systems blood pumping elements when driven by electric motor. The efforts and results of implantable model development are covered, mainly, in the text of the report. The research and development efforts and results are reported, primarily, in the appendices (Vol. 2).
Date: January 1, 1977
Partner: UNT Libraries Government Documents Department

Assessment of radioisotope heaters for remote terrestrial applications

Description: This paper examines the feasibility of using radioisotope byproducts for special heating applications at remote sites in Alaska and other cold regions. The investigation included assessment of candidate radioisotope materials for heater applications, identification of the most promising cold region applications, evaluation of key technical issues and implementation constraints, and development of conceptual heater designs for candidate applications. Strontium-90 (Sr-90) was selected as the most viable fuel for radioisotopic heaters used in terrestrial applications. Opportunities for the application of radioisotopic heaters were determined through site visits to representative Alaska installations. Candidate heater applications included water storage tanks, sludge digesters, sewage lagoons, water piping systems, well-head pumping stations, emergency shelters, and fuel storage tank deicers. Radioisotopic heaters for water storage tank freeze-up protection and for enhancement of biological waste treatment processes at remote sites were selected as the most promising applications.
Date: May 1, 1987
Creator: Uherka, K.L.
Partner: UNT Libraries Government Documents Department

Chemical and isotopic characteristics of the coso east flankhydrothermal fluids: implications for the location and nature of the heatsource

Description: Fluids have been sampled from 9 wells and 2 fumaroles fromthe East Flank of the Coso hydrothermal system with a view toidentifying, if possible, the location and characteristics of the heatsource inflows into this portion of the geothermal field. Preliminaryresults show that there has been extensive vapor loss in the system, mostprobably in response to production. Wells 38A-9, 51-16 and 83A-16 showthe highest CO2-CO-CH4-H2 chemical equilibration temperatures, rangingbetween 300-340oC, and apart from 38A-9, the values are generally inaccordance with the measured temperatures in the wells. Calculatedtemperatures for the fractionation of 13C between CO2 and CH4 are inexcess of 400oC in fluids from wells 38A-9, 64-16-RD2 and 51A-16,obviously pointing to equilibrium conditions from deeper portions of thereservoir. Given that the predominant reservoir rock lithologies in theCoso system are relatively silicic (granitic to dioritic), the isotopicsignatures appear to reflect convective circulation and equilibrationwithin rocks close to the plastic-brittle transition. 3He/4He signatures,in conjunction with relative volatile abundances in the Coso fluids,point to a possibly altered mantle source for the heat sourcefluids.
Date: January 8, 2007
Creator: Christenson, B.W.; Kennedy, B.M.; Adams, M.C.; Bjornstad, S.C. & Buck, C.
Partner: UNT Libraries Government Documents Department

Memorandum on Chemical Reactors and Reactor Hazards

Description: Two important problems in the investigation of reactor hazards are the chemical reactivity of various materials employed in reactor construction and the chracteristics of heat transfer under transient conditions, specifically heat transfer when driven by an exponentially increasing heat source (exp t/T). Although these problems are independent of each other, when studied in relation to reactor hazards they may occur in a closely coupled sequence. For example the onset of a dangerous chemical reactor may be due to structural failure of various reactor components under an exponentially rising heat source originating with a runaway nuclear reactor. For this reason, these two problems should eventually be studied together after an exploratory experimental survey has been made in which they are considered separately.
Date: July 5, 1951
Creator: Mills, M.M.; Pearlman, H.; Ruebsamen, W. & Steele, G., Chrisney, J.
Partner: UNT Libraries Government Documents Department

Frozen plasma within the flow from a metal plate hit by an electron beam pulse

Description: When a pulsed electron beam hits a metal plate with sufficient energy a volume of the metal becomes hot fluid that subsequently sprays out of the plate. A portion of this flow is ionized. This report describes a fluid that expands so rapidly into a vacuum that the ionized portion of the flow departs from local thermodynamic equilibrium. This cold supersonic exhaust will have a much higher degree of ionization, and of higher electron temperature, than would be expected from a gas in thermodynamic equilibrium at the local temperature of the neutral flow. This report presents a continuation of the work described in reference (1). My aim is to develop as simple a model as will reasonably predict the speed and density of neutral flow, and the temperature and density of plasma. I use simplifying assumptions and mathematical approximations to develop convenient formulas, and I test them by comparing specific examples to experimental data and computations by DeVolder and other Los Alamos scientists (2). The phenomenon of sudden expansion of a gas cloud into vacuum is described in several sections of the two-volume work by ZelUdovich and Raizer (3). The criterion I use for estimating the point in the flow where plasma ceases to be in equilibrium is in principle that proposed by Bray (4), (5), and discussed extensively by Vincenti and Kruger (6). The immediate concern motivating this work is how to design a metal target that accurately converts an electron beam pulse train into a radiation pulse train for use in the high-speed radiography of implosion hydrodynamics experiments. In the radiography application, either the electron beam must be swept magnetically along the metal target more quickly than the spread of the debris plume, or the metal plate must move laterally past a fixed point of impact, carrying its ...
Date: November 1, 1997
Creator: Garcia, M., LLNL
Partner: UNT Libraries Government Documents Department

Iron/potassium perchlorate pellet burn rate measurements

Description: A burn rate test having several advantages for low gas-producing pyrotechnic compacts has been developed. The technique involves use of a high speed video motion analysis system that allows immediate turnaround and produces all required data for rate computation on magnetic tape and becomes immediately available on the display screen. The test technique provides a quick method for material qualification along with data for improved reliability and function. Burn rate data has been obtained for both UPI and Eagle Pitcher Iron/Potassium Perchlorate blends. The data obtained for the UPI blends cover a range of composition, pellet density, and ambient (before ignition) pellet temperature. Burn rate data for the E-P blends were extended to include surface conditions or particle size as a variable parameter.
Date: January 25, 1995
Creator: Reed, J.W. & Walters, R.R.
Partner: UNT Libraries Government Documents Department

Design and performance of a vacuum-bottle solid-state calorimeter

Description: EG and G Mound Applied Technologies calorimetry personnel have developed a small, thermos-bottle solid-state calorimeter, which is now undergoing performance testing at Los Alamos National Laboratory. The thermos-bottle solid-state calorimeter is an evaluation prototype for characterizing the heat output of small heat standards and other homogeneous heat sources. The current maximum sample size is 3.5 in. long with a diameter of 0.8 in. The overall size of the thermos bottle and thermoelectric cooling device is 9.25 in. high by 3.75 in. diameter and less than 3 lb. Coupling this unit with compact electronics and a laptop computer makes this calorimeter easily hand carried by a single individual. This compactness was achieved by servo controlling the reference temperature below room temperature and replacing the water bath used in conventional calorimeter design with the thermos-bottle insulator. Other design features will also be discussed. The performance of the calorimeter will be presented.
Date: November 1, 1997
Creator: Bracken, D.S.; Biddle, R. & Cech, R.
Partner: UNT Libraries Government Documents Department

Electromagnetic Heating Methods for Heavy Oil Reservoirs

Description: The most widely used method of thermal oil recovery is by injecting steam into the reservoir. A well-designed steam injection project is very efficient in recovering oil, however its applicability is limited in many situations. Simulation studies and field experience has shown that for low injectivity reservoirs, small thickness of the oil-bearing zone, and reservoir heterogeneity limits the performance of steam injection. This paper discusses alternative methods of transferring heat to heavy oil reservoirs, based on electromagnetic energy. They present a detailed analysis of low frequency electric resistive (ohmic) heating and higher frequency electromagnetic heating (radio and microwave frequency). They show the applicability of electromagnetic heating in two example reservoirs. The first reservoir model has thin sand zones separated by impermeable shale layers, and very viscous oil. They model preheating the reservoir with low frequency current using two horizontal electrodes, before injecting steam. The second reservoir model has very low permeability and moderately viscous oil. In this case they use a high frequency microwave antenna located near the producing well as the heat source. Simulation results presented in this paper show that in some cases, electromagnetic heating may be a good alternative to steam injection or maybe used in combination with steam to improve heavy oil production. They identify the parameters which are critical in electromagnetic heating. They also discuss past field applications of electromagnetic heating including technical challenges and limitations.
Date: May 1, 2000
Creator: Sahni, A.; Kumar, M. & Knapp, R.B.
Partner: UNT Libraries Government Documents Department

Utilization of sensitivity coefficients to guide the design of a thermal battery

Description: Equations are presented to describe the sensitivity of the temperature field in a heat-conducting body to changes in the volumetric heat source and volumetric heat capacity. These sensitivity equations, along with others not presented, are applied to a thermal battery problem to compute the sensitivity of the temperature field to 19 model input parameters. Sensitivity coefficients, along with assumed standard deviation in these parameters, are used to estimate the uncertainty in the temperature prediction. From the 19 parameters investigated, the battery cell heat source and volumetric heat capacity were clearly identified as being the major contributors to the overall uncertainty in the temperature predictions. The operational life of the thermal battery was shown to be very sensitive to uncertainty in these parameters.
Date: August 1, 1998
Creator: Blackwell, B.F.; Dowding, K.J.; Cochran, R.J. & Dobranich, D.
Partner: UNT Libraries Government Documents Department

Spreader beam analysis for the CASTOR GSF cask

Description: The purpose of this report is to document the results of the 150% rated capacity load test performed by DynCorp Hoisting and Rigging on the CASTOR GSF special cask lifting beams. The two lifting beams were originally rated and tested at 20,000kg (44,000lb) by the cask manufacturer in Germany. The testing performed by DynCorp rated and tested the lifting beams to 30,000 kg (66,000 lb) +0%, -5%, for Hanford Site use. The CASTOR GSF cask, used to transport isotopic Heat Sources (canisters), must be lifted with its own designed lifting beam system (Figures 1, 2, and 3). As designed, the beam material is RSt 37-2 (equivalent to American Society for Testing and Materials [ASTM] A-570), the eye plate is St 52-2 (equivalent to ASTM A-516), and the lifting pin is St 50 (equivalent to ASTM A-515). The beam has two opposing 58 mm (2.3 in.) diameter by 120 mm(4.7 in.) length, high grade steel pins that engage the cask for lifting. The pins have a manual locking mechanism to prevent disengagement from the casks. The static, gross weight (loaded) of the cask 18,640 kg (41,000 lb) on the pins prevents movement of the pins during lifting. This is due to the frictional force of the cask on the pins when lifting begins.
Date: April 7, 1997
Creator: Clements, E.P.
Partner: UNT Libraries Government Documents Department

A conceptual design for an electron beam

Description: This report is a brief description of a model electron beam, which is meant to serve as a pulsed heat source that vaporizes a metal fleck into an ''under-dense'' cloud. See Reference 1. The envelope of the electron beam is calculated from the paraxial ray equation, as stated in Reference 2. The examples shown here are for 5 A, 200 keV beams that focus to waists of under 0.4 mm diameter, within a cylindrical volume of 10 cm radius and length. The magnetic fields assumed in the examples are moderate, 0.11 T and 0.35 T, and can probably be created by permanent magnets.
Date: February 15, 1999
Creator: Garcia, M
Partner: UNT Libraries Government Documents Department

Thermal Analysis of a H1616-1 Shipping container in Hypothetical Accident conditions

Description: The thermal response of the H1616 transport container is simulated to demonstrate compliance with the Federal regulations for performance during hypothetical accident conditions (HAC). The goal is to show that tests conducted for the certification of the H1616 shipping container provide conservatively high estimates of temperatures at key regions within the container. A one-dimensional computational model is developed to simulate the thermal response of the shipping container in cylindrical coordinates. The model assumes the container is axisymmetric and allows for variable thermal properties. The model is calibrated using temperature data obtained from two experimental thermal tests and is then used to evaluate the thermal response of the shipping container to several different scenarios that meet or exceed the Federal regulations. A pre-heating technique, which is used to simulate the thermal effects of a radioactive heat source within the container, is also evaluated.
Date: November 2002
Creator: Hollenshead, Jeromy T.
Partner: UNT Libraries Government Documents Department

ORNL isotopic power fuels quarterly report for period ending December 31, 1973

Description: Heat soak periods were completed on the remaining 49 couples of the compatibility matrix which was put on test in May 1973. Examination of the 18 couples which were taken off test in August 1973 was completed. The planned short-term ceramic compatibiliiy matrix exposures were completed, and optical microscope examinations were done. Experiments were started to develop fabrication techniques for preparation of an 11-couple compatibility matrix scheduled for FY 1974. The design of this matrix was finalized, and component procurement was started. Free energy calculations were made for the reactions of Cm/sub 2/O/sub 3/ fuel with Haynes 188, Ta-10% W, and TZM alloys and with beryllium. Measurements of the helium release characteristics of hot-pressed / sup 244 Cm/sub 2/O/sub 3/ were started at 500, 650, and 800 deg C. A vapor pressu re determination was run on curium metal in the temperature range from 900 to 1800 deg C. Vapor pressure measurements of/sup 244/Cm/sub 2/O/sub 3/ in the range from 1200 to 1600 deg C were begun these will continue next quarter. Examinations by x-ray diffraction were made on materials resulting from exposures of/sup 244/Cm/sub 2/O/sub 3/ to flowing seawater, boiling scawater, and dry air as well as on/sup 244/Cm/sub 2/O/sub 3/ sam ples taken at various stages in the fuel forming process. The equipment which will be used for emissivity measurements was improved and checked with nonradioactive samples. Observations of two 25-W//sup 244/Cm/sub 2/O/sub 3/ pellets stored in argon ond one 25-W/sup 244/Cm/sub 2/O/sub 3/ pellet stored in dry air continued. A /sup 244/Cm/sub 2/O/ sub 3/ pellet was leac hed with boiling distilled water and the rate of/sup 244/ Cm loss measured. Calculational studies of /sup 244/Cm yields and isotopic abundances from various types of reactor operations were continued. A study of the potentinl fur criticality problems in/sup ...
Date: February 1, 1974
Creator: Lamb, E.
Partner: UNT Libraries Government Documents Department

Savannah River Laboratory monthly report: {sup 238}Pu fuel form processes

Description: In direct-strike {sup 238}PuO{sub 2}, agglomeration occurs in the oxalate precipitate and is unaffected by washing agent or calcining temperature. The evaluation of an automatic pulverizer-classifier for the PuFF Facility was begun. Difference between the mini-hot press at SRL and the LASL full-scale hot press require higher pressures to be used at SRL to obtain the density specified for PPO. Hot-pressed density was found to vary with applied pressure and, to a lesser extent, with size of feed. The new contained metallograph has been installed. A wire saw has been placed in containment for precise cutting of PPO pellets. The scanning microscope was mounted within the glove boxes.
Date: April 1, 1974
Partner: UNT Libraries Government Documents Department