Science.gov (United States)

An 80-K Joule-Thomson (J-T) cooling system designed for the Probe Infrared Laser Spectrometer (PIRLS) proposed for the Huygens Titan Probe of the Cassini Saturn orbiter mission is presented. The cryogenic cooling requirements of the PIRLS instrument are listed, and the cooler system design including details of a J-T cryostat, cold head, and dewar design is described along with the results of a thermal modeling effort and lab cooler performance testing. It is shown that by using active feedback temperature control of the cold head in combination with the self-regulating action of the J-T cryostat, a temperature stability of less than 0.1 mK/min is achieved by the cooler weighting 1.8 kg.

Science.gov (United States)

... If the MCAV is used in conjunction with a cooling system designed for the CVC air vest, the wearer would receive more cooling due entirely to the ...

Energy Technology Data Exchange (ETDEWEB)

A cost study is described which compared the economics of four dry/wet cooling systems to use at the existing Raft River Geothermal Plant. The results apply only at this site and should not be generalized without due consideration of the complete geothermal cycle. These systems are: the Binary Cooling Tower, evaporative condenser, Combin-aire, and a metal fin-tube dry cooling tower with deluge augmentation. The systems were evaluated using cooled, treated geothermal fluid instead of ground or surface water in the cooling loops. All comparisons were performed on the basis of a common plant site - the Raft River 5 MWe geothermal plant in Idaho. The Binary Cooling Tower and the Combin-aire cooling system were designed assuming the use of the isobutane/water surface condenser currently installed at the Raft River Plant. The ...

International Nuclear Information System (INIS)

Purpose: To obtain stabilized operation by preventing over heat in emergency cooling pumps upon accidents of flow regulators. Constitution: A pressure suppression chamber pool and a pressure vessel are communicated to each other with a pipeway and the water in the suppression pool is charged by a charging pump to the pipeway. The pipeway is interposed with an emergency cooling pump so as to feed water in the pipeway to the pressure vessel and a water source and the emergency cooling pumps are connected by way of a closed pipeway. Further, the closed pipeway and the pipeway interposed with the charging pump are communicated to each other by way of a connecting pipeway, to which are interposed an instrument for detecting the increase in the temperature of the emergency cooling pumps due to abnormality in the closed pipe (such as troubles in flow regulators) and outputting control ...

Energy Technology Data Exchange (ETDEWEB)

A large amount of industrial water is used for cooling the various process fluids in the petroleum purification factories as well as petroleum chemistry factories. Consequently, a lot of heat exchangers as the necessary constitutional instruments are made of carbon steel. Due to the most of the corrosions of the carbon steel occurring in such cooling water systems are pitting corrosions, the inhibition thereof is extremely important for the elongation of the life of the plants and the stable operation. In this paper, the influences of water quality fractions on pitting corrosion of carbon steel in cooling water circumstance are examined aiming at the fouling in the cooling water. The fouling in the cooling water does not only increase the amount of occurrence of pitting corrosion but also accelerates the progress of pitting corrosion enlarging the rust ...

Energy Technology Data Exchange (ETDEWEB)

Two methods to cool muon beams deeply below the limit conventionally established for the ionization cooling are proposed. In Phase Ionization Cooling (PIC), the beam is focused at wedge absorber plates each half of particle oscillation period by imposing a weak parametric resonance along the beam path. The resonance growth of particle amplitude is surmounted by the ionization cooling. At optimum, such arrangement results in reduction of each of two transverse emittances by an order of value in addition to the preceding 6D ionization cooling. Next, resonance focusing and transverse cooling can be continued in the regime of a fast Reverse Emittance Exchange (REMEX). Here, the sign of the absorber wedge is opposite to PIC while the dispersion increased. REMEX to be accompanied by the bunch lengthening and acceleration in order to maintain the relative energy spread ...

Energy Technology Data Exchange (ETDEWEB)

This report presents the thermal-hydraulic analysis of four Loss-of-Flow Accidents (LOFAs) in the first wall/blanket cooling system of the alternative SEAFP reactor design. The LOFAs considered result from a loss of electrical power for the recirculation pump in the primary cooling circuit. The analyses have been performed using the thermal-hydraulic system analysis code RELAP5/MOD3. In the analyses, special attention has been paid to the transient thermal-hydraulic behaviour of the cooling system and the temperature development in the first wall and blanket. For the LOFA without plasma shutdown, significant loss of heat removal due to dryout occurs at the midplane of the outboard first wall cooling pipes about 41 s after pump trip. For the three LOFA cases with emergency plasma shutdown that have been studied, the temperature increase in the Be-coating at the midplane of the ...

Science.gov (United States)

Cooling towers of power plants are used to dissipate waste heat into the atmosphere. If saline water is used for cooling, a saline aerosol known as drift is released into the atmosphere. Drift effects on vegetation are not well known. To simulate drift for a field study, cooling tower basin water was sprayed thirty separate times during a 46-day period in 1975 on Virginia pine (Pinus virginiana), flowering dogwood (Cornus florida), tulip tree (Liriodendron tulipfera), and California privet (Ligustrum ovalifolium), Norway spruce (Picea abies), and white ash (Fraxinus americana) were added in 1976 and all trees were sprayed 43 times during a 59-day period. Only dogwood leaves showed significant injury. Absence of injury on other species was probably due to the ability of their leaves to exclude, or reduce absorption of, toxic concentrations of the ions supplied.

CERN Document Server

An effect of laser-cooling of water was observed for the first time with a temperature decrease dT = -2.2 K after irradiation of liquid water surface by a powerful Ar-Xe pulse laser with a pulse energy of about 1 J and wavelength L = 1.73, 2.63 and 2.65 um. The discovered effect can apparently be ascribed to the optical excitation of vibrational states of H2O molecules followed by an endothermic consolidation of chemically active excited molecules into a quasi-stable cluster-like structure. The measured time dependences of the cooling effect show that a typical life time of the new state of water amounts to hours. It has also been shown that the life time of the excited vibrational molecular states due to a radiation trapping effect can be estimated to at least hundreds of seconds.

International Nuclear Information System (INIS)

Natural cooling conditions of the nuclear fuel in the channel type reactor after its shut down are commonly determined with relatively high uncertainty. This is not only to he lack of adequate measurements of thermal parameters i.e. the residual power generation, the coolant flow and temperatures, but also due to indeterminate model of convection mechanism. The numerical simulation of natural convection in multitube fuel assembly in the fuel channel leads to various convection modes including evidently chaotic behaviour. To determine the real cooling conditions in the MARIA research reactor a series of experiments has been performed with fuel assembly equipped with a set of thermocouples. After some forced cooling period (the shortest was half an hour after the reactor shut down) the reactor was left with the only natural convection. Two completely different cooling modes have been ...

International Nuclear Information System (INIS)

Purpose: To effectively cool the reactor core in a steam atmosphere by upwardly directing several of spray nozzles attached to a ring header thereby increasing the flying distance of the spray. Constitution: Ring headers in two upper and lower stages are disposed above the outer circumference of a reactor core and each of the ring headers is mounted with spray nozzles. Among the spray nozzles, at least several nozzles mounted to the ring header at the lower stage are directed such that the center axis for each of the nozzle is raised above the horizontal axis and other several nozzles are mounted with the nozzle center axis directed downwardly from the horizontal axis. Accordingly, even if collapsing phenomenon occurs in the jetting stream due to the condensation in the steams that forms the operation atmosphere of the reactor core spray cooling device, a sufficient amount of emergency cooling water can ...

International Nuclear Information System (INIS)

Object: To prevent coolant inventory within a cooling system loop in an atomic power plant from being varied depending on loads thereby relieving restriction of varied speed of coolant flow rate to lowering of a liquid surface due to short in coolant. Structure: Instruments such as a superheater, an evaporator, and the like, which constitute a cooling system loop in an atomic power plant, have a plurality of free liquid surface of coolant. Portions whose liquid surface is controlled and portions whose liquid surface is varied are adjusted in cross-sectional area so that the sum total of variation in coolant inventory in an instrument such as a superheater provided with an annulus portion in the center thereof and an inner cylindrical portion and a down-comer in the side thereof comes equal to that of variation in coolant inventory in an instrument such as an evaporator similar to the superheater. which is provided with an ...

British Library Electronic Table of Contents (United Kingdom)

The electrophysical characteristics of the electric cable?s transition into a state of a heterogenic polymer system due to a wire?s explosion were examined. Using cyclic heating-cooling of the composite, the changes in its topology were observed. The latter makes it possible to regulate the dielectric characteristics of the system.

International Nuclear Information System (INIS)

Purpose: To permit accurate detection of sodium leakage by distinguishing between variations in the overflow tank level due to changes in sodium temperature accompanying changes in the power level or operating state of a liquid metal sodium cooled fast breeder, and a reduction in power level due to duct leakage. Constitution: The volume of sodium in the primary cooling system is roughly estimated from the temperatures of hot and cold legs, and the duct leak preset level with respect to the sodium liquid level within an overflow tank when the plant is normal is varied according to the state of the plant. More particularly, the volume of sodium within the overflow tank is calculated on the basis of a signal representing the liquid level detected by a liquid level gauge in the overflow tank and a signal representing the temperature detected by hot leg and cold leg thermometers, thereby obtaining the preset ...

CERN Document Server

The confining effect of a spherical substrate inducing anchoring (normal to the surface) of rod-like liquid crystal molecules contained in a thin film spread over it has been investigated with regard to possible changes in the nature of the isotropic-to-nematic phase transition as the sample is cooled. The focus of these Monte Carlo simulations is to study the competing effects of the homeotropic anchoring due to the surface inducing orientational ordering in the radial direction and the inherent uniaxial order promoted by the intermolecular interactions. By adopting entropic sampling procedure, we could investigate this transition with a high temperature precision, and we studied the effect of the surface anchoring strength on the phase diagram for a specifically chosen geometry. We find that there is a threshold anchoring strength of the surface below which uniaxial nematic phase results, and above which the isotropic fluid ...

Science.gov (United States)

PMID:4423540

International Nuclear Information System (INIS)

This study deals with testing the capability of the code PARET to simulate natural convection cooling phenomena under different boundary conditions. In addition to applying and testing some new options related to simulation of the control rod movement and studying the reactivity effect of thermal expansion fuel elements. The experiments of the simple thermal hydraulic loop of Missouri university about natural cooling phenomena in two narrow paralled channels were used to validate the code. The study indicate good results regarding the distribution of coolant flux velocity and clad temperature. In particular the heat transfer coefficient of natural convection has been calculated in good agreement with the experiment. On the other hand, the core of MNSR reactor has been modelled to simulate the reactor dynamic behaviour under natural convection cooling conditions for different initial power level. The observed oscillation ...

International Nuclear Information System (INIS)

Cooling water is sprayed on the outer surface of an upper portion of a container, and a pool is formed by the cooling water flowing down while cooling the container. Further, the cooling water stored in the cooling water pool is recycled by a pump for spraying the cooling water on the outer surface of the upper portion of the container. Sufficient amount of cooling water is supplied for spraying the cooling water to the outer surface of the upper portion of the container so that the outer surface of the container is free from drying and a liquid membrane is formed on the entire surface. The amount of the cooling water is made greater than that of the cooling water evaporated when the entire amount of the heat generate in the reactor core of the reactor is transferred to the ...

International Nuclear Information System (INIS)

In a supercritical water-cooled reactor, property of water changes significantly around the critical point. It is expected that irradiation and change of water property will affect the chemistry and material corrosion. Deep understanding of interactions between supercritical water and materials under irradiation is important. However, comprehensive data on radiolysis, kinetics, corrosion and thermodynamics have not been obtained due to the severe experimental condition. To get such data by experiments and computer simulations, a national program funded by Ministry of Education, Culture, Sports, Science and Technology (MEXT) has been started since December 2002. (author)

International Nuclear Information System (INIS)

The commercial Modular High Temperature Gas-Cooled Reactor (MHTGR) achieves improved reactor safety performance and reliability by utilizing an integrated sequence of completely passive thermal storage and heat transfer mechanisms to reject decay heat in the event that all its active cooling systems fail to operate. During such events, the initial heatup transient in the core is followed by a quasi-steady state cooldown process which, if uninterrupted, can continue for several days. A buoyancy-driven natural convection cooling system called the RCCS facilitates the continuous heat removal by circulating ambient air through the reactor cavity, where it is heated and then exhausted to the outside environment. The peak thermal load on the RCCS occurs approximately at the time that the vessel reaches its highest temperature. To confirm the adequacy of the RCCS design, detailed analytical models were developed to simulate the ...

International Nuclear Information System (INIS)

The Wendelstein 7-X (W7-X) modular stellarator is under construction at the Max-Planck-Institut fuer Plasmaphysik in Greifswald, Germany. The W7-X magnet system contains 70 coils made up from helium cooled superconducting cables in aluminium alloy (EN AW-6063) jackets. Several hundred connections of the jacket to the cable joints are made by aluminium-to-aluminium welds. Due to geometrical and thermal boundary conditions these welds cannot be accomplished free from defects. Microscopic analyses of the welds show that a variety of small flaws such as cracks and pores develop during welding. The welds have thus to be dimensioned accordingly, and appropriate weld qualification, investigation and testing has to be done in order not to jeopardise the structural integrity and leak tightness. The weld is mechanically loaded during cool-down due to the difference in thermal contractions between the GRP ...

International Nuclear Information System (INIS)

Experimental and analytical studies in convection cooling and boiling cooling conditions have been performed on natural convection heat transfer with solidified crust formation in the molten metal pool. The present experimental results on the relationship between the Nusselt number and Rayleigh number in the molten metal pool were compared with existing correlations on Rayleigh-Bebard natural convection in an enclosure. A new correlation on the relationship between the Nusselt number and Rayleigh number in the molten metal pool with crust formation has been developed using the experimental data. The experimental results were verified by the analytical study. The experimental study has shown that the bottom surface temperature of the molten metal layer, in all experiments, is the major influential parameter in the crust formation, due to the natural convection flow. The Nusselt number of the case without a crust formation in ...

International Nuclear Information System (INIS)

The RESF is utilized for storage of spent fuel under emergency conditions as well as for testing of FM heads. It receives cooling supply from the PHT Pressurizing pumps and after removal of decay heat from the spent fuel it goes to the D2O Storage Tank. The geometry of the RESF system is such that it can not sustain the thermosyphon loop during SBO, due to high frictional forces. To achieve the sustained thermosyphon, modifications in the design were suggested viz., removal of the steam trap and the relief valve above it and replacement by a solenoid valve (SV-16). In the event of SBO, SV-16 will open on 'RESF channel temperature high' signal and connect to FT D2O tank. The tank, being at atmospheric pressure and at lower elevation, will provide higher cooling flow rate through the RESF channel. D2O is periodically removed from the FT D2O tank by operating a Class-II pump intermittently. The analysis was done for the ...

Energy Technology Data Exchange (ETDEWEB)

The stability of a forced-flow cooled superconducting coil is investigated by use of the numerical simulation. The numerical code to integrate the simultaneous partial differential system composed of the 1 D hydrodynamic equations and the 1 D thermal conduction equation has been developed and stability margins are evaluated as functions of coolant mass flow rate, operation current and imposed magnetic field. The results of computations show that the stability margin is multi-valued with respect to these operation parameters, as expected from the experimental results. It is also shown that the appearance of the first unstable regime is closely related to the existance of the stagnant region located at the upstream side of the heated zone and that the second stable regime appears because the heat transfer is appreciably enhanced by the induced backflow due to the thermal expansion of coolant. 13 refs., 13 figs., 1 tab.

International Nuclear Information System (INIS)

The Four years of the IMPACT, 'Integrated Modular Plant Analysis and Computing Technology', project Phase 1 have been completed. The verification study of Severe Accident Analysis Code SAMPSON prototype developed in Phase 1 was conducted in two steps. First, each analysis module was run independently and analysis results were compared and verified against separate-effect test data with good results. Second, with the Simulation Supervisory System, up to 11 analysis modules were executed concurrently in the parallel environment (currently, NUPEC uses IBM-SP2 with 72 process elements), to demonstrate the code capability and integrity. The target plant was Surry as a typical PWR and the initiation events were a 10-inch cold leg failure. The analysis is divided to two cases; one is in-vessel retention analysis when the gap cooling is effective (In-vessel scenario test), the other is analysis of phenomena event is extended to ex-vessel due to the ...

International Nuclear Information System (INIS)

Turbulent heat transfer performance of a fuel rod with three-dimensional trapezoidal spacer ribs for high temperature gas-cooled reactors was studied for various Reynolds numbers using an annular channel at the same coolant condition as the reactor operation, maximum outlet temperature of 1000 C and pressure of 4 MPa, and analytically by a numerical simulation using the k-#epsilon# turbulence model. The turbulent heat transfer coefficients of the fuel rod were 18-80% higher than those of a concentric smooth annulus at a region of Reynolds number exceeding 2000. On the other hand, the predicted average Nusselt number of the fuel rod agreed well with the empirical correlation obtained from the experimental data within a relative error of 10% with Reynolds number of more than 5000. It was verified that the numerical analysis results had sufficient accuracy. Furthermore, the numerical prediction could clarify quantitatively the effects of the heat transfer augmentation ...

International Nuclear Information System (INIS)

... Natural convection cooling of the channel type reactor performed with the fuel

International Nuclear Information System (INIS)

... [2] Hee Taek Chae, et al., "On the Natural Convection Cooling in HANARO;

British Library Electronic Table of Contents (United Kingdom)

The Wendelstein 7-X (W7-X) modular stellarator is under construction at the Max-Planck-Institut fur Plasmaphysik in Greifswald, Germany. The W7-X magnet system contains 70 coils made up from helium cooled superconducting cables in aluminium alloy (EN AW-6063) jackets. Several hundred connections of the jacket to the cable joints are made by aluminium-to-aluminium welds. Due to geometrical and thermal boundary conditions these welds cannot be accomplished free from defects. Microscopic analyses of the welds show that a variety of small flaws such as cracks and pores develop during welding. The welds have thus to be dimensioned accordingly, and appropriate weld qualification, investigation and testing has to be done in order not to jeopardise the structural integrity and leak tightness. The ...

International Nuclear Information System (INIS)

Test Blanket Modules (TBM) will be tested in ITER to verify the capability of tritium breeding and recovery and the extraction of thermal energy suitable for the production of electricity. A Helium Cooled Solid Breeder (HCSB) TBM has been developed in Korea to accomplish these goals. Reduced Activation Ferritic/Martensitic (RAFM) steel has been chosen as the primary candidate structural material for Korean TBM. Due to the complexity of the First wall (FW) and Side wall (SW), it is necessary to develop various joining technologies, such as Hot Isostatic Pressing (HIP), Electron Beam Welding (EBW) and Tungsten Inert Gas (TIG) welding, for the successful fabrication of TBM. In this study, the mechanical properties of TIG welded RAFM steel were investigated. Various mechanical tests of TIG-welded RAFM steel were performed to obtain the optimized TIG welding process for RAFM steel

Energy Technology Data Exchange (ETDEWEB)

Improving the performance of the Chinese B135 six-cylinder direct injection turbocharged and turbocompounded Low Heat Rejection Engine (LHRE) was based on experimental and analytical studies. The studies were primarily applied on a B1135 single-cylinder LHR engine and a conventional water-cooled B1135 single-cylinder engine. Performance of the B1135 LHRE was worse than that of the conventional B1135 due to a deterioration in the combustion process of the B1135 LHRE. The combustion process was improved and the fuel injection system was redesigned and applied to the B135 six-cylinder LHRE. The new design improved the performance of the LHRE and better fuel economy was realized by the thermal energy recovered from the exhaust gases by the turbocompounding system.

International Nuclear Information System (INIS)

We develop a large scale parallel viscous-elastic analysis program incorporating a mesoscopic self-consistent model developed by Laws. In the model, macroscopic elastic constants are treated as variables depending on the shape and statistical properties of pre-existing microscopic pores and change due to neutron irradiation. We apply this program to the visco-elastic analysis of nuclear graphite structures under neutron irradiation environment in High Temperature Gas-cooled Reactor (HTGR), as an example problem. Furthermore the calculated results by this parallel computational program are compared with those by one of commercial finite element analysis codes, FINAS, for validating elastic and thermal stress analysis function. (author)

British Library Electronic Table of Contents (United Kingdom)

This work is focused on effect of various cooling strategies on surface roughness and tool wear during computer aided milling of soft workpiece materials. These milling operations were selected as dry milling, cool air cooling milling and fluid cooling milling. A cool air cooling system was designed and produced to cool end milling tools. Cool air was produced by a vortex tube. Annealed AISI 1050 was used as the workpiece material and cutting tool material was selected as HSS-Co8 DIN 844/BN. Optimal cutting parameters were selected according to workpiece hardness from reference catalog and kept for all tests. Tool wear and surface quality were measured for three different cooling types changing from ten minute machining time to thirty minute machining time. As a result, the surface roughne...

Energy Technology Data Exchange (ETDEWEB)

During LOCA (Loss of Coolant Accident) in design bases accident (DBA), emergency core coolant supplements form a recirculation sump and cooled core and containment. When the double ended guillotine Break (DEGB) at the hot leg near steam generator, due to the jet impingement discharge flow, the debris could be potentially generated at pipe or wall nearby steam generator and be transported to the recirculation sump. Therefore, the debris, such as insulations and paint chips, could be accumulated and be clogged in the recirculation sump screen. If debris is blocked the sump strainer, the pressure drop is increased at the screen so as to increase the pressure loss of ECCS (Emergency Core Cooling System) pump NPSH (Net positive suction head). It is potentially influenced to decrease the long-term cooling capability of the recirculation sump. The recirculation sump screen clogging accident has happened in BWR ...

International Nuclear Information System (INIS)

Full text: Full text: The incomplete understanding of the complex mechanisms connected with the interaction between thermal-hydraulic and neutron kinetics still challenges the design and the operation of nuclear reactors and imposes the adoption of conservatism in the evaluation of safety limits. The recent availability of powerful computer and computational techniques together with the continuing increase in operational experience suggests the revisiting of those areas and the identification of design/operation requirements that can be relaxed. So far, almost all of the safety analyses of research reactors have been performed using conservative computational tools such as channel codes but, nowadays, the application of Best-Estimate (BE) methods constitutes a real necessity. The global aim of the current work is an attempt to apply the best-estimate system thermal-hydraulic code Relap5. For this purpose, the generic IAEA research reactor Benchmark problem is re-considered for proving ...

Energy Technology Data Exchange (ETDEWEB)

The further optimisation and improvement of the efficiency of internal combustion engines require the realisation of new technologies leading to a distinctively faster warm-up behaviour of the coolant and lubricants as well as of the engine components after a cold start. In order to achieve reduced fuel consumption and exhaust gas emissions with the help of heat management, the design criteria of innovative cooling systems need to be reflected and adapted to future requirements. The use of intelligent components within the cooling system, such as the 'Stand Alone Rotary Valve' as a thermostat's substitute or the use of coolant pumps with a rotary valve integrated into the pump's inlet chamber, offer new ways to realise in a decisively quicker and more flexible way the appropriate heating up and cooling down procedures at varying driving conditions. A description of both of the intelligent ...

Energy Technology Data Exchange (ETDEWEB)

Net heats of reaction were measured in an isothermal calorimeter for both single phase (organic) and two phase (organic and aqueous) TBP/HNO{sub 3} reacting solutions at temperatures above 100 C. The oxidation rate constant was determined to be 5.4E-4 min{sup {minus}1} at 110 C for an open ``vented`` system as compared to 1.33 E-3 min{sup {minus}1} in the closed system. The heat released per unit material oxidized was also reduced. The oxidation in both phases was found to be first order in nitric acid and pseudo-zero order in butylnitrate and water. The hydrolysis (esterification) rate constant determined by Nichols` (1.33E-3 min{sup {minus}1}) fit the experimental data from this work well. Forced evaporation of the volatile components by the product gases from oxidation resulted in a cooling mechanism which more than balanced the heat from the oxidation reaction in the two-phased systems. Rate expressions were derived and rate constants determined for both the ...

Energy Technology Data Exchange (ETDEWEB)

Desiccant cooling is a potentially environmentally friendly technology that can be used to condition the internal environment of buildings. Unlike conventional air conditioning systems, which rely on electrical energy to drive the cooling cycle, desiccant cooling is a heat-driven cycle. This paper follows on from an initial study by the authors, and uses real meteorological data to evaluate the potential in the United Kingdom of using solar energy to drive the desiccant cooling cycle. Through the use of parametric studies, the paper investigates the energy consumption and costs associated with desiccant cooling. (author)

International Nuclear Information System (INIS)

Purpose: To prevent structure material meltdown upon rupture of cooling pipeways in a impurity remover by preventing the coolants from flowing into the vacuum vessel while continuing the supply of coolants to other portions to be cooled. Constitution: Dual cooling pipeway systems are disposed to the neutralizing plates of the impurity remover. A rupture detector (pressure gage) is mounted to each of the cooling pipeways and flow rate control valves to be opened and closed by the signal from the detector are disposed to the upstream and downstream of the cooling pipeway. In this constitution if the cooling pipes should be ruptured, the coolant supply is stopped to the ruptured system in which the flow rate valve is closed by the signal from the rupture detector. However, since the coolant is kept to be supplied to the other system of the ...

Energy Technology Data Exchange (ETDEWEB)

This thesis details the first direct ultrafast measurements of the dynamic thermal expansion of a surface and the temperature dependent surface thermal diffusivity using a two-color reflection transient grating technique. Studies were performed on p-type, n-type, and undoped GaAs(100) samples over a wide range of temperatures. By utilizing a 90 fs ultraviolet probe with visible excitation beams, the effects of interband saturation and carrier dynamics become negligible; thus lattice expansion due to heating and subsequent contraction caused by cooling provided the dominant influence on the probe. At room temperature a rise due to thermal expansion was observed, corresponding to a maximum net displacement of {approximately} 1 {Angstrom} at 32 ps. The diffracted signal was composed of two components, thermal expansion of the surface and heat flow away from the surface, thus allowing a determination of the rate of expansion as ...

Energy Technology Data Exchange (ETDEWEB)

The thermal performance of an automotive radiator plays an important role in the performance of an automobile's cooling system and all other associated systems. For a number of years, this component has been given little attention with very little changing in its manufacturing cost, operation and geometry. As opposed to the old tubular heat exchanger configurations used in automotive radiators, plate heat exchangers currently form the backbone of today's process industry with their advanced performance reaching levels the designers of tubular heat exchangers can only dream of. The aluminium roll-bonding technique widely used in manufacturing the cooling compartments for domestic refrigeration units is one of the cheapest methods for heat exchanger manufacturing. Using this technique, it is possible to manufacture a wide range of heat exchanger configurations that can help augment heat transfer whilst reducing pressure drops. ...

Science.gov (United States)

Magmatic sulfide deposits are the most significant source of platinum-group elements (PGE) in the world. Key to understanding their genesis is determining the processes and timing of sulfide saturation, metal enrichment and crustal contamination. In this study, we have identified droplets of magmatic sulfide from the Platreef, South Africa, where droplets of sulfide have been trapped in the earliest crystallising phase, chromite. Due to their early entrapment at high temperatures, metal concentrations and ratios that they display are indicative of a very early-stage sulfide liquid in the system, as they will have cooled and fractionated within an essentially closed system, unlike interstitial blebs that crystallise in an open system as the magma cools. Analysis of these droplets in an opaque mineral like chromite by LA-ICP-MS is problematic as some of the fractionated inclusion is necessarily lost during cutting and ...

International Nuclear Information System (INIS)

Norway is a member of Annex 29, 'Ground-Source Heat Pump Systems Overcoming Technical and Market Barriers' (2004-2006), organized under the umbrella of the International Energy Agency (IEA) and the IEA Heat Pump Programme (HPP). The 7 participating countries are Austria (Operating Agent), Canada, Japan, Norway, Spain, Sweden and the USA. The Norwegian participation is financed by ENOVA SF, and SINTEF Energy Research is responsible for planning and carrying out the Norwegian activities. This report provides a status for ground-source heat pump (GSHP) systems in Norway with regard to state-of-the-art technology, installation examples, geological data, costs and market opportunities. A Norwegian Internet home page for ground-source heat pump systems (www.energy.sintef.no/prosjekt/Annex29) is also presented. GSHP systems in Norway are classified as direct systems (groundwater and soil/ground) and indirect closed-loop systems (vertical-rock and horizontal-soil/ground). The vast majority of ...

Science.gov (United States)

We report the existence of a previously unsuspected peak in the [sup 1]H magic angle spinning spectrum of commercially available HZSM-5 samples. At 298 K, this resonance is a broad shoulder on the downfield side of the Bronsted acid signal at 4.3 ppm. Cooling the sample caused the line to narrow, and a clear peak at 6.9 ppm was visible at 123 K. This technique resulted in selective broadening of the 4.3 and 6.9 ppm resonances as a result of conflicting averaging of the [sup 1]H-[sup 27]Al dipolar coupling. We conclude that the 6.9 ppm resonance corresponds to a novel aluminum-containing site in zeolite HZSM-5 and is not an artifact due to exchange with the Bronsted site or an aluminum-rich impurity phase. A possible interpretation of these results is a second Bronsted site for the zeolite. 49 refs., 8 figs.

Energy Technology Data Exchange (ETDEWEB)

Perylene bisimides (PBIs) represent an important class of organic n-type semiconductors exhibiting a relatively high electron affinity among large-band-gap materials. Herein synthesis and characterization of several unsymmetrical N-substituted PBI dyes is presented and the thermotropic behavior, which is strongly affected by the respective N-substituents was investigated. Two different series of highly soluble and fluorescent derivatives have been synthesized: (1) PBIs bearing swallow-tailed alkyl chains, different in size or (2) one swallow-tailed alkyl chain and one branched oligoethylenglycolether. Synthesis of these PBIs is generally feasible by two distinct divergent synthesis approaches. Thermotropic behavior was studied by DSC, POM and XRD measurements. Inherent {pi}-{pi} interactions between cofacially orientated perylene molecules and the elliptic shape of the molecule favor the ordering in columns and self-organized architectures. Among them hexagonal columnar CoIh ...

Energy Technology Data Exchange (ETDEWEB)

Geothermal energy pile foundations are an alternative energy source for heating and cooling needs. Utilising this source of energy has great potential due to the environmental, economic and social benefits. This paper looks at an extensive amount of literature on the technology behind the system including the overall process, primary considerations for each of the main components including latest developments as well as design implications such as the integration of ground energy systems into structural piles of buildings. Environmental considerations including performance-dependent parameters of the subsurface are described. Main parameters include thermal conductivity, thermal diffusivity, specific heat capacity and moisture content. Temperature and groundwater effects are also discussed and design considerations are provided. Mathematical models are available to aid in the design of these systems but there are various other issues and ...

Energy Technology Data Exchange (ETDEWEB)

In a PWR type reactor, a primary coolant circuit system using a steam generator is adopted in order to accelerate depressurization of a primary coolant circuit upon small rupture LOCA in which the pressure of the primary coolant circuit is moderately depressurized. A secondary coolant circuit depressurization valve is disposed to a main steam pipeline. The valve has a performance of automatically opening to remove heat by evaporation of water stored in SG for a short period of time when the pressure in the primary circuit is decreased to about 50kg/cm[sup 2] upon occurrence of LOCA or the like. Then, the secondary side of the SG is depressurized to about atmospheric pressure and gravitational water injection from a condensate tank is started. Further, a gas vent valve is disposed to a water chamber of the steam generator. The valve has a performance of automatically opening to discharge incondensible gas mixed to the primary coolant circuit to the outside of the circuit when the ...

Science.gov (United States)

Recent proposals have shown that a quantum degenerate gas of alkaline earth atoms can be used for a number of novel quantum computing and quantum simulation experiments. Strontium is a good candidate for such experiments because it can be controlled with high precision, as demonstrated in recent atomic clock experiments. Unfortunately, the small scattering length of strontium is not amenable to evaporative cooling techniques that are used to reach quantum degeneracy. Furthermore, increasing the scattering length of alkaline earths with a magnetic Feshbach resonance is not possible due to their spinless electronic ground state configuration. However, recent theoretical and experimental work suggests the possibility of changing scattering lengths in alkaline earths with laser light. Using this optical Feshbach resonance near strontium's narrow ^1S0->^3P1 intercombination transition might allow its scattering length to be controlled without ...

Science.gov (United States)

The macroscopic rotation of plasma in a toroidal containment device is an important feature of the equilibrium. Toroidal and poloidal rotation in the high beta tokamak Torus II is measured experimentally by examining the Doppler shift of the 4685.75 A He II line emitted from the plasma. The toroidal flow at an average velocity of 1.6 x 10/sup 6/ cm/sec, a small fraction of the ion thermal speed, moves in the same direction as the toroidal plasma current. The poloidal flow follows the ion diamagnetic current direction, also at an average speed of 1.6 x 10/sup 6/ cm/sec. In view of certain ordering parameters, the toroidal flow is compared with predictions from neoclassical theory in the collosional, Pfirsch-Schluter regime. The poloidal motion, however results from an E x B drift in a positive radial electric field, approaching a stable ambipolar state. This radial electric field is determined from theory by using the measured poloidal velocity. Mechanisms for the time evolution of ...

CERN Document Server

We investigate the formation and evolution of dwarf galaxies in a high resolution, hydrodynamical cosmological simulation of a Milky Way sized halo and its environment. Our simulation includes gas cooling, star formation, supernova feedback, metal enrichment and UV heating. In total, 90 satellites and more than 400 isolated dwarf galaxies are formed in the simulation, allowing a systematic study of the internal and environmental processes that determine their evolution. We find that 95% of satellite galaxies are gas-free at z=0, and identify three mechanisms for gas loss: supernova feedback, tidal stripping, and photo-evaporation due to re-ionization. Gas-rich satellite galaxies are only found with total masses above ~ 5x10^9 solar masses. In contrast, for isolated dwarf galaxies, a total mass of ~ 10^9 solar masses constitutes a sharp transition; less massive galaxies are predominantly gas-free at z=0, more massive, isolated dwarf galaxies are ...

Energy Technology Data Exchange (ETDEWEB)

It is reported that due to the large demand for electricity in Japanese homes and given the fact that the energy consumption rate of air conditioners to the total energy consumption rate in an average home exceeds 20%, an energy saving-type room air conditioner is essential, also for environmental reasons. Japanese customers ranked high running costs as a major drawback of conventional equipment. Toshiba started developing the first generation energy saving air conditioners in 1993. Improvements to the concept were made and the 1995 model offers a heating COP of 4.65 and a cooling COP of 4.3 at rated conditions, an improvement of more than 30% compared to the conventional model. Various component improvements have led to this high performance including the indoor fan design, a DC compressor motor and inverter using digital sampling, advanced (PMV) control technology, and compact heat exchangers. The latest feature is genetic algorithm control. ...

International Nuclear Information System (INIS)

The Fast Flux Test Facility (FFTF) is a liquid-metal-cooled test reactor located on the Hanford Site. The FFTF is the only reactor of this type designed and operated with the intent of meeting the licensing requirements of the Nuclear Regulatory Commission (NRC). Unique characteristics of the FFTF that present special challenges related to leak rate testing include thin wall containment vessel construction, cover gas systems that penetrate containment, and a low-pressure design basis accident. The successful completion in 1986 of the third FFTF Integrated Leak Rate Test (ILRT) five days ahead of schedule and 10% under budget was a major achievement for the Westinghouse Hanford Company. The success of this operational safety test was due in large part to a special local area network (LAN) of three IBM PC/XT computers that monitored the sensor data, calculated the containment vessel leak rate, and displayed test results. The multiple computer ...

International Nuclear Information System (INIS)

Acute pneumothorax is a frequent complication after percutaneous pulmonary radiofrequency (RF) ablation. In this study we present three cases showing delayed development of pneumothorax after pulmonary RF ablation in 34 patients. Our purpose is to draw attention to this delayed complication and to propose a possible approach to avoid this major complication. These three cases occurred subsequent to 44 CT-guided pulmonary RF ablation procedures (6.8%) using either internally cooled or multitined expandable RF electrodes. In two patients, the pneumothorax, being initially absent at the end of the intervention, developed without symptoms. One of these patients required chest drain placement 32 h after RF ablation, and in the second patient therapy remained conservative. In the third patient, a slight pneumothorax at the end of the intervention gradually increased and led into tension pneumothorax 5 days after ablation procedure. Underlying bronchopleural fistula along ...

International Nuclear Information System (INIS)

During 17 years since the start of operation of the first commercial LWR in Japan, many LWRs have experienced various corrosion damages, but the causes of them were clarified, and the counter-measures were executed effectively in actual plants, as the results, the cause of corrosion damage decreased remarkably, and now, the high rate of operation has become to be maintained. In this paper, the major cases of corrosion damage experienced in LWRs in Japan and foreign countries, the causes of them and the countermeasures, the problems of hereafter and so on are described. The corrosion damage of metallic materials in the environment of LWRs occurs in the parts in contact with high temperature, high pressure water and steam, such as stainless steel piping in the primary cooling system of BWRs, and nickel alloy heating tubes of steam generators, carbon steel feed water piping and zirconium alloy fuel cladding tubes in PWRs. Recently, accompanying the advance of LWR ...

Energy Technology Data Exchange (ETDEWEB)

In this work theoretical investigations are carried out for cooling systems, which are used in fuel cell vehicles. This work focuses mainly on the capability of increasing the heat rejection rate by using new alternative cooling systems and by improving the conventional cooling system. Fuel cell vehicles have a higher demand of heat rejection to the ambient than comparable vehicles with combustion engine. The performance of conventional liquid cooling systems, especially at high loads and high ambient temperatures, is often not sufficient anymore. Hence, cooling systems with improved performance are necessary for fuel cell vehicles. The investigations in this work are based on DaimlerChrysler's ''A-Class'' having a PEM-Fuel Cell system integrated. Specific computational models are developed for radiators and condensers to evaluate the ...

Science.gov (United States)

A drift dye tracer experiment, using Rhodamine (WT) dye, was conducted on airborne drift from a natural draft cooling tower at PEPCO's Chalk Point, Maryland Power Generating Station. This experiment was designed to separate and identify cooling tower aero...

British Library Electronic Table of Contents (United Kingdom)

Ways of improving the water chemistry used in the turbine generator stator?s cooling systems at Russian nuclear power plants are considered. Data obtained from operational chemical monitoring of indicators characterizing the quality of cooling water in the turbine generator stator cooling systems of operating power units at nuclear power plants are presented.

International Nuclear Information System (INIS)

In order to achieve the safe core cooling during normal operation and upset conditions, HANARO adopted an upward forced convection cooling system with dual containment arrangements instead of the forced downward flow system popularly used in the majority of forced convection cooling research reactors. This kind of upward flow system was selected by comparing the relative merits of upward and downward flow systems from various points of view such as safety, performance, maintenance. However, several operational matters which were not regarded as serious at design come out during operation. In this paper are presented the design and operational experiences on the unique cooling features of HANARO. (author)

Energy Technology Data Exchange (ETDEWEB)

A new type of passive cooling system has been invented (Forsberg 1993): the Temperature-Initiated Passive Cooling System (TIPACS). The characteristics of the TIPACS potentially match requirements for an improved reactor-cavity-cooling system (RCCS) for the modular high-temperature gas-cooled reactor (MHTGR). This report is an initial evaluation of the TIPACS for the MHTGR with a Rankines (steam) power conversion cycle. Limited evaluations were made of applying the TIPACS to MHTGRs with reactor pressure vessel temperatures up to 450 C. These temperatures may occur in designs of Brayton cycle (gas turbine) and process heat MHTGRs. The report is structured as follows. Section 2 describes the containment cooling issues associated with the MHTGR and the requirements for such a cooling system. Section 3 describes TIPACS in nonmathematical terms. Section 4 describes ...

Energy Technology Data Exchange (ETDEWEB)

Apatite fission track analysis, vitrinite reflectance data, and K-Ar dating of Permian-Carboniferous and Mesozoic core samples have been successfully integrated to reconstruct the thermal and tectonic history of the Ordos basin, China. Apatite fission track ages of Carboniferous-Jurassic sedimentary rocks range between 3 and 137 Ma, and are significantly younger than the stratigraphic ages. Confined fission track lengths demonstrate exclusively mixed length distribution, indicating complex thermal history. The data suggest that the samples must have all experienced higher paleotemperatures in the past. Mean virtinite reflectance values (R{sub o}) of the Triassic rocks range from 0.61 to 1.06%, giving a high coalification gradient of 0.36%/km and suggesting a high paleothermal gradient of 57{degrees}C/km. Permian-Carboniferous rocks have R{sub o} values on the order of 1.0-3.0%, and locally up to 4.0-6.0%. Some high R{sub o} values coincide with positive gravity and magnetic anomalies. ...

Energy Technology Data Exchange (ETDEWEB)

This user's guide describes BNW-III, a computer code developed by the Pacific Northwest Laboratory (PNL) as part of the Dry Cooling Enhancement Program sponsored by the US Department of Energy (DOE). The BNW-III code models a modular dry/wet cooling system for a nuclear or fossil fuel power plant. The purpose of this guide is to give the code user a brief description of what the BNW-III code is and how to use it. It describes the cooling system being modeled and the various models used. A detailed description of code input and code output is also included. The BNW-III code was developed to analyze a specific cooling system layout. However, there is a large degree of freedom in the type of cooling modules that can be selected and in the performance of those modules. The costs of the modules are input to the code, giving the user a great deal of flexibility.

Science.gov (United States)

A full-scale model of a rigid sectorial ring and a set of bellows which was covered with a temperature control layer and a coolant supply equipment was constructed to verify the adequacy of the heating and cooling system designed for JT-60. To cool and heat it effectively and to decrease the temperature differences among the various parts in the vacuum vessel, heater units and cooling pipes were located on the surface of the ring. The temperature control layer is to heat the vessel to 500/degree/sub //C within 70 hours and to maintain it at the temperature for 48 hours for simulating the state of bakeout. Subsequently the vessel is cooled down within about the same time as in heating. Prior to the series of tests, numerical analyses were performed to predict the cooling and heating efficiencies on the model and to examine the method of the temperature regulation.

Energy Technology Data Exchange (ETDEWEB)

In an effort to minimize the distortion of bearing steel rings during the production process, 100Cr6 steel billets are spray formed with a unique cooling control system to control the cooling and solidification behavior of the deposits. Effects of heating around the deposits, gas cooling at the substrate bottom and the gas flow over the deposits are investigated both by numerical simulation and experiment. Porosity profiles and microstructures of spray formed bearing steel are examined and evaluated. The investigation results show that the thermal boundary conditions of the deposits play important roles on the cooling and solidification behavior of the deposits, especially at the deposit periphery. Porosity in the 100Cr6 bearing steel deposit can be reduced significantly with the special cooling control system.

CERN Document Server

We present a single solid-state laser system to cool, coherently manipulate and detect $^{25}$Mg$^+$ ions. Coherent manipulation is accomplished by coupling two hyperfine ground state levels using a pair of far-detuned Raman laser beams. Resonant light for Doppler cooling and detection is derived from the same laser source by means of an electro-optic modulator, generating a sideband which is resonant with the atomic transition. We demonstrate ground-state cooling of one of the vibrational modes of the ion in the trap using resolved-sideband cooling. The cooling performance is studied and discussed by observing the temporal evolution of Raman-stimulated sideband transitions. The setup is a major simplification over existing state-of-the-art systems, typically involving up to three separate laser sources.

UK PubMed Central (United Kingdom)

BackgroundRadiofrequency ablation (RFA) of tumors by means of internally cooled electrodes (ICE) combined with interstitial infusion of saline may improve clinical results. To date,...Full Text Available

International Nuclear Information System (INIS)

The guide describes a method acceptable to the NRC staff for complying with the Commission's regulations with regard to quality assurance requirements for installation, inspection, and testing of mechanical equipment and systems for water-cooled and high-temperature gas-cooled nuclear power plants.

Science.gov (United States)

The evolution of the Doublet III neutral beam armor is followed from the initial design of a radiation cooled metallic tile to the present actively cooled graphite design. Results of the thermal and stress analyses that dictated the present design are reviewed.

UK PubMed Central (United Kingdom)

This article describes process evaluation methods for the Pool Cool Diffusion Trial across four years. Pool Cool is a skin cancer prevention program that was...Full Text Available

International Nuclear Information System (INIS)

This study aims to investigate the difference in the interaction of antimicrobial peptides with two classes of zwitterionic peptides, phosphatidylethanolamines (PE) and phosphatidylcholines (PC). Further experiments were performed on model membranes prepared from specific bacterial lipids, lipopolysaccharides (LPS) isolated from Salmonella minnesota. The structure of the lipid-peptide aqueous dispersions was studied by small-and wide-angle X-ray diffraction during heating and cooling from 5 to 85 C. The lipids and peptides were mixed at lipid-to-peptide ratios 10-10000 (POPE and POPC) or 2-50 (LPS). All experiments were performed at synchrotron soft condensed matter beamline A2 in Hasylab at Desy in Hamburg, Germany. The phases were identified and the lattice parameters were calculated. Alamethicin and melittin interact in similar ways with the lipids. Pure POPC forms only lamellar phases. POPE forms lamellar phases at low temperatures that upon heating transform ...

International Nuclear Information System (INIS)

(1974). Netherlands Ferreira, S. Rio de Janeiro Univ. (Brazil) v. 31(3)

International Nuclear Information System (INIS)

(May 1974). United States Klystra, CD Univ. of Florida, Gainesville v.

Science.gov (United States)

disciplinary methods were used to independently determine the aerodynamic loads, the thermal response, and strardural performance of the hydrogen cooled ...

Science.gov (United States)

... They comprise of a power model for the representation of the electric system, a fluid model that represents the cooling fluid flow, three layers of ...

Energy Technology Data Exchange (ETDEWEB)

A radial-flow type internally oil-cooled oil-filled cable has been developed. This system is characterized in that the oil flows radially through the paper insulation. The thermal resistance of the insulation is equivalently decreased by the radial-flow. The decreased thermal resistance as well as the cooling effect of the oil flow in the central oil duct and the outer oil duct under an aluminum sheath increase the current capacity. A calculation method of cooling characteristics is introduced. The stability of the cable and accessories was confirmed through initial electrical tests and a long-term field test.

Science.gov (United States)

... The performance at reduced condenser water temper- atures was assumed to be the same as that of the single-effect unit. ...

International Nuclear Information System (INIS)

An AHR (Advanced HANARO Reactor) based on the HANARO has been conceptually developed for the future needs of research reactors. Generally, a natural convection cooling in nuclear installations is an ultimate heat removal mechanism as an inherent safety feature. This paper presents the preliminary thermal hydraulic characteristics and safety margins for a natural convection cooling in the AHR.

Energy Technology Data Exchange (ETDEWEB)

The Doublet III device is operating with an extensive system of plasma limiters and wall protective armor. Operations with up to 8MW of neutral beam power and 1.5MA plasma current are planned. Design and operational performance of the following systems are discussed: 1. Water-cooled graphite moveable limiter. 2. Water-cooled graphite fixed limiter and neutral beam wall armor. 3. Radiatively cooled Inconel divertor plates.

International Nuclear Information System (INIS)

On nuclear power stations with high temperature reactors and helium turbine cycles (HTR-single circuits) the residual heat from the energy conversion process in the primary and intermediate coolers is removed from cycled gas, helium. Water, which is circulated for safety reasons through a closed circuit, is used for cooling. The primary and intermediate coolers as well as other cooling equipment of the power plant are installed within the reactor building. The heat from the helium turbine cycle is removed to the environment most effectively by natural draught cooling towers. In this way a net plant efficiency of about 40% is attainable. The low quantities of residual heat thereby produced and the high (in comparison with power stations with steam turbine cycles) cooling agent pressure and cooling water reheat pressure in the circulating coolers enable an economically favourable ...

Science.gov (United States)

Results are reported from dye tests of the dispersion of the vapor plume from the natural draft cooling tower of a fossil-fuel power plant located in the coastal region of Maryland.

Energy Technology Data Exchange (ETDEWEB)

Grain refinement behavior of copper alloys cast in permanent molds was investigated. This is one of the least studied subjects in copper alloy castings. Grain refinement is not widely practiced for leaded copper alloys cast in sand molds. Aluminum bronzes and high strength yellow brasses, cast in sand and permanent molds, were usually fine grained due to the presence of more than 2% iron. Grain refinement of the most common permanent mold casting alloys, leaded yellow brass and its lead-free replacement EnviroBrass III, is not universally accepted due to the perceived problem of hard spots in finished castings and for the same reason these alloys contain very low amounts of iron. The yellow brasses and Cu-Si alloys are gaining popularity in North America due to their low lead content and amenability for permanent mold casting. These alloys are prone to hot tearing in permanent mold casting. Grain refinement is one of the ...

British Library Electronic Table of Contents (United Kingdom)

In order to provide pigs a comfortable sleeping area in hot weather, a floor cooling system was designed and applied to production buildings. Experiments were conducted to compare the floor temperatures and to observe the lying behaviour of pigs in the sleeping area of the buildings with and without floor cooling system. The results showed that, without the floor cooling system, the floor temperature was nearly the same as the air temperature in the open pig house. With the floor cooling system, the floor temperature of the sleeping area was controlled at 22-26degreeC, even though the air temperature was as high as 34degreeC, which improved the comfort of the pigs in the sleeping area. The pig lying behaviour was greatly affected by the floor temperature. More than 85% of the pigs were lyi...

Energy Technology Data Exchange (ETDEWEB)

Different cooling speeds after previous solution annealing at 1130deg C for 0.5 hour were simulated in laboratory experiments. The following conditions were examined: (1) Direct water quenching, (2) cooling in air for 0.5 min to 950deg C/water quenching, (3) cooling in air for 1.5 min to 750deg C/water quenching, (4) cooling in furnace for 5 min to 750deg C/water quenching. The results of the investigations have shown that a variation of the cooling conditions causes considerable changes in the creep behaviour. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Both simulations and recent experiments conducted at the Advanced Photon Source showed that the performance of liquid-nitrogen-cooled single-silicon crystal monochromators can degrade in a very rapid nonlinear fashion as the power and for power density is increased. As a further step towards improving the performance of silicon optics, we propose cooling with liquid helium, which dramatically improves the thermal properties of silicon beyond that of liquid nitrogen and brings the performance of single silicon-crystal-based synchrotrons radiation optics up to the ultimate limit. The benefits of liquid helium cooling as well as some of the associated technical challenges will be discussed, and results of thermal and structural finite elements simulations comparing the performance of silicon monochromators cooled with liquid nitrogen and helium will be given.

Energy Technology Data Exchange (ETDEWEB)

The present invention concerns a high thermal load heat receiving plate such as a divertor plate of a thermonuclear device. The high thermal load heat receiving plate of the present invention has a cooling performance capable of suppressing the temperature of an armour tile to less than a threshold value of the material against high thermal loads applied from plasmas. Spiral polygonal pipes are inserted in cooling pipes at a portion receiving high thermal loads in the high temperature load heat receiving plate of the present invention. Both ends of the polygonal pipes are sealed by lids. An area of the flow channel in the cooling pipes is thus reduced. Heat conductivity on the cooling surface of the cooling pipes is increased in the high thermal load heat receiving plate having such a structure. Accordingly, temperature elevation of the armour tile can be suppressed. (I.S.).

CERN Document Server

The Cooling and Ventilation Group has started the LHC construction work in September 1999 and will get into full activity when LEP will be stopped and dismantled: in total 12 major contracts for an amount of about 120 MCHF will be established to build the needed installations for the LHC. The author will report on the current works that are in progress on the different LEP Points distinguishing between the Ventilation and the Water Cooling installations. The Ventilation work, completed in the new surface buildings in Points 18, is currently held in Points 4 and 5. Point 1 will follow in the near future. The work for the Cooling plants comprehend the pumping stations, the cooling towers and the chilled water production stations in Points 1 and 5, the buried pipes in Points 1 and 4. For all of these activities, an updated report of the progress of the work, of the planning and of the expenses is given. ...

Energy Technology Data Exchange (ETDEWEB)

The possibilities for heat recovery in a cast iron melting furnace were studied. A cupola furnace which produces 40 tonnes steel per hour, produces 25,000 Nm/sup 3//h of flue gases which contain 16-22% CO. Taking into account the heat losses at the chimney where fumes are cooled to 200/sup 0/C the recoverable heat is about 12.4-10/sup 6/ kcal/h which mainly consists of combustion heat in CO. This study showed that the heat can be used for the production of electricity, which will be used in the plant. Recovery of 87 kWh of electricity per tonne of steel produced is possible. A steam turbine driven generator of 3.5 MW will be required. The combustion of the low calorific gas (approximately 400 kcal/Nm/sup 3/) has been studied and gave positive results: wet CO gas can be burnt without addition of methane and preheating of air is not required. The pilot plant consisting of a thermic system (combustion chamber and equipment to produce and condense steam without turbine ...

Energy Technology Data Exchange (ETDEWEB)

In cooling systems, an improved control of scale deposit and corrosion processes is a major challenge and an realistic evaluation tool for water treatments is of the utmost economic importance. In this study, a channel flow cell was used to allow in-situ electrochemical measurements in well defined electrolyte tube flowing conditions. An expression of the mass transfer towards the electrode was established where the diffusion-limited current is a function of Re{sup 1/3} in the laminar regime and was verified experimentally using the redox couples Fe[CN]{sub 6}{sup 4-}/ Fe[CN]{sub 6}{sup 3-} and O{sub 2}/OH{sup -}. This hydrodynamically controlled experimental device was developed to investigate scale deposit processes and to evaluate scale inhibitor efficiency using a electrochemical quartz crystal microbalance. Experiments were performed on three different waters, at various flow rates and temperatures. The efficiency of a well known phosphonate (HEDP) was tested ...

International Nuclear Information System (INIS)

The Self Actuated Shutdown System (SASS) is now under development for use in a large scale FBR, in order to establish the passive shutdown capability against the postulated ATWS events, i.e. ULOF, UTOP and ULOHS. The function of SASS makes use of the safety characteristics of a liquid metal cooled FBRs such as a large subcooling and low pressure system. The insertion of the control rods insertion is assured even in the most conservative seismic design condition by employing articulate rods and the SASS will be installed into the detaching mechanism employing a curie point the magnet alloy. ULOF analysis of the present FBR shows that coolant boiling inception is prevented if a control rod of the SASS is detached at the uppermost temperature of 680degC for the Curie point magnet, and after the reactor shutdown the coolant temperature is kept below 600degC by the pony motor flow. Therefore the SASS will establish passive shutdown capability without affecting the core ...

Energy Technology Data Exchange (ETDEWEB)

The Helium and Lead Observatory (HALO) is a supernova neutrino detector under development for construction at SNOLAB. It is intended to fulfill a niche as a long term, low cost, high livetime, and low maintenance, dedicated supernova detector. It will be constructed from 80 tonnes of lead, from the decommissioning of the Deep River Cosmic Ray Station, and instrumented with approximately 384 meters of {sup 3}He neutron detectors from the final phase of the SNO experiment. Charged- and Neutral-Current neutrino interactions in lead expel neutrons from the lead nuclei making a burst of detected neutrons the signature for the detection of a supernova. Existing neutrino detectors are mostly of the water Cerenkov and liquid scintillator types, which are primarily sensitive to electron anti-neutrinos via charged-current interactions on the hydrogen nuclei in these materials. By contrast, the large neutron excess of a heavy nucleus like Pb acts to Pauli-block p)n transitions induced by electron ...

International Nuclear Information System (INIS)

The objective of this study is to evaluate the lifetime of Zr-2.5Nb pressure tube at Wolsung Unit-1. The testing materials (Effective full power year: 9.3 year, Accumulated nuetron fluence: 7.66#approx#8.91 x 1025 n/m"2) were sampled from M-11 tube at various position(inlet, middle and outlet). The cutting was carried out at hot cell to fabricate CT(Compact tension) specimen with 48 ppm hydrogen content. In the result of DHC test, irradiation-damaged specimen showed 4#approx#6 times faster DHC velocity(5.298E-0.8#approx#7.039E-8 m/s: 182 .deg. C) than non-irradiated specimen. These DHCV results also show slight faster than one of specimen from Pickering plant (average DHCV: 4.5E-8 m/s: 182 .Deg C). This faster DHCV can be explained with the fact that Wolsung Unit-1 have been operated in a severe conditions(higher cooling water temperature, high power and efficiency) than Pickering one. The striation spacing which was seen DHC fracture surface at irradiated specimen ...

Energy Technology Data Exchange (ETDEWEB)

When a shortened enzymatic version of the Tetrahymena self-splicing intervening sequence (IVS) RNA is placed under catalytic conditions and irradiated at 254 nm, a covalent cross-link forms with high efficiency. The position of the cross-link was mapped by using three independent methods: RNase H digestion, primer extension with reverse transcriptase, and partial hydrolysis of end-labeled RNA. The cross-link is chemically unusual in that it joins two adenosines, A57 and A95. Formation of this cross-link depends upon the identity and concentration of divalent cations present and upon heat-cool renaturation of the IVS in a manner that parallels conditions required for optimal catalytic activity. Furthermore, cross-linking requires the presence of sequences within the core structure, which is conserved among group I intervening sequences and necessary for catalytic activity. Together these correlations suggest that a common folded structure permits cross-linking and ...

International Nuclear Information System (INIS)

This paper deals with the calculations of 3D nuclear heat generation profile in the charcoal filter and subsequently the commencement time of Primary Containment Cleanup (PCC) system of 540MWe Pressurized Heavy Water Reactor (PHWR). Fuel failure is predicted due to overheating of the fuel under loss of Coolant Accident (LOCA) without Emergency Core Cooling System (LOCA without ECCS). Subsequently fission product gasses along with water vapours are released to Reactor Building (RB) atmosphere. Plate-out and water trapping mechanism stabilizes the concentration of significant fission products i.e. radioiodines in about 4 hours before being circulated through charcoal filters of Containment Cleanup system. After cleaning up the RB atmosphere, it is discharged to outside atmosphere through stack. The isotopes of radioiodine emit beta and gamma radiations. Gamma radiations are partly stopped within the charcoal and heat is generated. The part of ...

Energy Technology Data Exchange (ETDEWEB)

A new industrial process allowing to reach very high cooling rates in the cooling section after soaking of a continuous annealing line for steel sheets is presented. This process constitutes the successful conclusion of a long term research programme, jointly carried out at CRM and Arcelor Cockerill-Sambre for three years, including laboratory experiments, pilot scale trials and several industrial campaigns. It is running on from developments performed in the framework of the HOWAQ (Hot Water Quench) process. The process successively combines a moderate cooling step (600 deg C/s for 0.8 mm thick strips), in boiling water, and a faster cooling step (above 700 deg C/s), by impinging turbulent cold water in a box. Its main features are simplicity, resulting from advanced developments, soundness, flexibility and cooling homogeneity. As treated steel products are characterized by ...

International Nuclear Information System (INIS)

The tremendous heat generated in a computer chip or very large scale integrated circuit raises many challenging issues to be solved. Recently, liquid metal with a low melting point was established as the most conductive coolant for efficiently cooling the computer chip. Here, by making full use of the double merits of the liquid metal, i.e. superior heat transfer performance and electromagnetically drivable ability, we demonstrate for the first time the liquid-cooling concept for the thermal management of a computer chip using waste heat to power the thermoelectric generator (TEG) and thus the flow of the liquid metal. Such a device consumes no external net energy, which warrants it a self-supporting and completely silent liquid-cooling module. Experiments on devices driven by one or two stage TEGs indicate that a dramatic temperature drop on the simulating chip has been realized without the aid of any fans. The higher the ...

CERN Document Server

We show the propagation of regularity, uniformly in time, for the scaled solutions of the inelastic Maxwell model for small inelasticity. This result together with the weak convergence towards the homogenous cooling state present in the literature implies the strong convergence in Sobolev norms and in the $L^1$ norm towards it depending on the regularity of the initial data. The strategy of the proof is based on a precise control of the growth of the Fisher information for the inelastic Boltzmann equation. Moreover, as an application we obtain a bound in the $L^1$ distance between the homogeneous cooling state and the corresponding Maxwellian distribution vanishing as the inelasticity goes to zero.

Energy Technology Data Exchange (ETDEWEB)

This paper describes the design, operation, and performance of an HVAC system installed as part of a project to demonstrate energy efficiency and environmental responsibility in commercial buildings. The systems installed in the 2180 m{sup 2} office building provide superior air quality and thermal comfort while requiring only half the electrical energy of conventional systems primarily because of the hydronic heating and cooling system. Gas use for the building is higher than expected because of longer operating hours and poor performance of the boiler/absorption chiller.

International Nuclear Information System (INIS)

The invention concerns an integrated nuclear reactor comprising natural convection cooling of the supporting skirt on which rests the shield closing the reactor vessel. Cooling is achieved by making the air circulate from the bottom to the top around the skirt and removing this air by a stack. The air can be atmospheric air or air taken from the low parts of the reactor. In the latter case, the stack emerges near a metal roof releasing its heat to the atmosphere by radiation, the air then dropping to the low parts. Application to fast nuclear reactors.

Energy Technology Data Exchange (ETDEWEB)

Mixed microstructures have been studied in low- carbon microalloyed steels suitable for automotive applications, after continuous cooling from the hot-rolled condition. Microstructural features such as polygonal ferrite, bainitic and acicular ferrite and microphase constituent are identified using transmission electron microscopy. The influence of these mixed structures on the tensile strength, impact toughness and fracture behaviour is examined. It is found that improvements in impact toughness as compared with microalloyed medium- carbon ferrite/pearlite steels can be achieved from these predominantly acicular structures developed by controlling alloy composition and continuous cooling of these lower carbon steels. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The aim of this document is to make a state-of-the-art of the techniques of heating-cooling ceilings and cold beams. These systems offer many advantages: they generate a high quality thermal comfort, they are energy efficient, and offer important room saving, particularly interesting in the case of building renovation. The document comprises 5 parts dealing with: 1 - the heating-cooling ceilings; 2 - the cold beams; 3 - the elements necessary for the dimensioning (building-system interactions, ventilation, temperature regulation and safety systems); 4 - dimensioning method; 5 - design, realization and operation: the rules to follow. (J.S.)

Energy Technology Data Exchange (ETDEWEB)

A 20-cell PEFC stack was designed and built. Resin impregnated graphite was used as bipolar plate material. The air cooling of the stack was optimized by introducing high surface structures into the open space of the cooling plates. At {eta} (H{sub 2} LHV) = 0.5 a power of 880 W was obtained under conditions of low gas-pressures of 1.15 bar{sub a}. The auxiliary power for process air supply and cooling at 880 W power is less than 7% of the power output, indicating that the described system may be operated at a high efficiency. (author) 5 figs., 2 refs.

International Nuclear Information System (INIS)

Several design options for improved passive circulation flow have been investigated for use in small, modular liquid metal cooled reactors (LMRs). The purpose is to enhance the transition to natural convection cooling following loss of forced circulation flow, reducing thermal transients experienced by the fuel and possibly eliminating the need for emergency pony-motor flow. Design details to minimize pressure drops may also enhance maximum equilibrium power levels possible under natural circulation only.

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In this study the authors examine the convective cooling provided by fluid trapped in the cavity between two consecutive rollers in a roller bearing. In order to calculate the steady-state temperature of the roller, the designer must know nor only the rolling-contact heat input received by the roller but also the convection cooling effect of the surrounding fluid. Until recently, this lateral convection cooling effect was modeled by assuming a certain (constant) heat transfer coefficient h at the roller surface, and then calculating the steady-state temperature distribution around the roller.

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The US National Energy Policy of 2001 advocated the development of advanced fuel and fuel cycle technologies that are cleaner, more efficient, less waste-intensive, and more proliferation resistant. The need for advanced fuel development is emphasized in on-going DOE-supported programs, e.g., Global Nuclear Energy Initiative (GNEI), Advanced Fuel Cycle Initiative (AFCI), and GEN-IV Technology Development. The Directorates of Energy & Environment (E&E) and Chemistry & Material Sciences (C&MS) at Lawrence Livermore National Laboratory (LLNL) are interested in advanced fuel research and manufacturing using its multi-disciplinary capability and facilities to support a design concept of a small, secure, transportable, and autonomous reactor (SSTAR). The E&E and C&MS Directorates co-sponsored this Laboratory Directed Research & Development (LDRD) Project on Mono-Uranium Nitride Fuel Development for SSTAR and Space Applications. In fact, three out ...

Energy Technology Data Exchange (ETDEWEB)

In many regions of the world, flooded mines are a potentially cost-effective option for heating and cooling using geothermal heat pump systems. For example, a single coal seam in Pennsylvania, West Virginia, and Ohio contains 5.1 x 1012 L of water. The growing volume of water discharging from this one coal seam totals 380,000 L/min, which could theoretically heat and cool 20,000 homes. Using the water stored in the mines would conservatively extend this option to an order of magnitude more sites. Based on current energy prices, geothermal heat pump systems using mine water could reduce annual costs for heating by 67% and cooling by 50% over conventional methods (natural gas or heating oil and standard air conditioning).

British Library Electronic Table of Contents (United Kingdom)

The economic feasibility of the residential solar thermal (ST) cooling system designed in the companion article [1] is ascertained by comparing it with a solar electric (SE) cooling system, and also with the baseline (i.e., control case), a grid dependent, highest efficiency COPC=5.66 heat pump. The economic scenario is analyzed for 24 cities across the southern USA, south of the 37degreeN. The SE cooling system provides lifecycle (20 year) savings to the homeowner only where electric rates are high and it is heavily subsidized. The overall societal effect (sum of taxpayer funded rebate and homeowner savings) is actually an increased cost everywhere except the California Central Valley, where the net savings is $1500. In the same valley, The ST cooling system provides greater lifecycle sav...

Science.gov (United States)

Oct 2, 2007 ... Other payloads included the Orbiter Experiments Autonomous Supporting Instrumentation System-1 (OASIS-1), a cooling system designed for ...

Energy Technology Data Exchange (ETDEWEB)

Short communication. 4 refs.

International Nuclear Information System (INIS)

Jun 1973. 2 p. United States USAEC Directorate of Regulatory Standards,

International Nuclear Information System (INIS)

Object: To minimize the range of the liquid level variation of the cooling system and reduce the time required for the liquid level control by sealing the gas of a cover gas respiration system which acts upon an evaporator and pump overflow column. Structure: In liquid level control by the cover gas pressure of a high-speed reactor secondary cooling system, upon occurrence of a sudden change in the rate of flow of the recirculated liquid, automatic check valves provided in an evaporator and pump overflow column cover gas respiration system are completely or substantially closed, while at the same time the recirculation cooling medium is sucked up and an automatic check valve provided in the overflow system is closed. (Kamimura, M.).

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Contamination and blockages of the cooling tubes in the turbine condenser disturb the heat transfer, thereby causing power losses at the turbine and increasing the fuel demand. Corrosions cause tubing leakages which require operating downtimes and reduce the lifetime of the pipes. Tube cleaning systems and backflushing cooling water filters eliminate these problems. Nevertheless it can come to coatings in the condenser tubes, if the tube cleaning equipment does not operate optimally or if coarse dirt is entered. Under this aspect, the author of the contribution under consideration reports on these problems on the basis of practical examples. The author gives references to the optimized operation of the tube cleaning system and the cooling water filtration.

Science.gov (United States)

was deemed adequate and a cooling system designed utilizing the Melcor CP2-15- 10B thermoelectric module. Wall temperature achieved with this system was - 36 ...

Science.gov (United States)

Investigations have been conducted to determine the feasibility of using collisional cooling for reducing the energy spreads and, consequently, the emittances of negative-ion beams. We have designed a gas-filled RF-quadrupole ion cooler equipped with provisions for retarding energetic negative ion beams to energies below thresholds for electron detachment at injection and for re-acceleration to high energies after the cooling process. The device has been used to cool O{sup -} and F{sup -} ion beams with initial energy spreads, {Delta}E > 10 eV to final energy spreads, {Delta}E {approx} 2 eV FWHM. Overall transmission efficiencies of {approx}14% for F{sup -} beams have been obtained. Experimental results show that electron detachment is the major loss mechanism for negative ions.

Science.gov (United States)

... transformed at 705°C. The cooling rate and temperature dependence of matrix decomposition for Ti6242 was thus similar to that for Ti64 x [9]. ...

Science.gov (United States)

... Lincoln Laboratory Distribution Models for Optical Scintillation Due to Atmospheric Turbulence RR Parenti RJ Susiela Group 107 ...

International Nuclear Information System (INIS)

A survey was conducted of experience with steam generator tubes at nuclear power stations during 1976. Failures were reported at 25 out of 68 water-cooled reactors. The causes of these failures and the repair and inspection procedures designed to cope with them are summarized. Examination of the data indicates that corrosion was the major cause of steam generator tube failures. Improvements are needed in steam generator design, condenser integrity and secondary water chemistry control. (author).

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A project to demonstrate residential heating and cooling with a well-water source heat pump is documented. The system is schematically illustrated and described, and project experience is discussed. The system is capable of using source water as cool as 40/sup 0/F. Project expenses are accounted for. (LEW)

Energy Technology Data Exchange (ETDEWEB)

The aim of this study concerns the use of numerical methods for the resolution of the Reynolds Averaged Navier Stokes equations adapted to the simulation of the cooling of the trailing edge of a stator in a high pressure turbine. These methods, based on the elsA solver developed at ONERA, use a four steps Runge Kutta time discretization scheme and a Jameson centered space discretization scheme. The scheme is applied through a finite volume approach on control volume centered on the cells of a multi-block structured mesh. Turbulence is simulated either through the algebraic Michel model, or through the one-transport-equation Spalart-Allmaras model, or through the two-transport-equations k 1, k {omega} and k {epsilon} models, and through ASM model. A simulation of the flow in a bidimensional stator, without cooling, is carried out. The cooling, which is realized with trailing edge slots, is then simulated on a bidimensional ...

International Nuclear Information System (INIS)

The liquid-metal-cooled fast breeder reactor presented includes a fuel assembly made up of several long sub-assemblies rising side by side. Each of the sub-assemblies of an external area of the fuel assembly comprises an electromagnetic braking system for regulating the flow of coolant in the sub-assembly, the magnetic fields of the braking systems being temperature sensitive.

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This study assesses the feasibility of the so-called heat pipe technique for cooling the piston of a mediumspeed diesel engine and is part of a research project 'EVE HPD, Extreme Value Engine Tests with High Power Density' carried out by HUT Internal Combustion Engine Laboratory. Diesel engines are being developed to give greater power from a given cylinder swept volume, which means higher temperatures in combustion chamber. The traditional oil cooling cannot be used beyond certain temperature level. Heat pipe technology could provide one solution to the cooling problem. The general properties, principles of operation, and structures of different types of heat pipes are described. Working fluids and container materials of heat pipes are discussed. The operation limitations of heat pipes are studied, especially, the limitations of a reciprocating heat pipe, in which the return of the condensate to the ...

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This handbook provides the necessary tools for the engineer to design forced-cooled HPOF pipe-type cable systems. It represents the final objective of a major project which included an extensive research program at the Waltz Mill Forced-Cooling Test Facility. The formulas and procedures presented in this handbook are consistent with the results of this program as well as other full-scale and model investigations. Introductory material, including historical information, general design concepts and basic heat transfer and fluid dynamics theory is given for those who are unfamiliar with the fundamental principles of forced-cooling. The nucleus of the handbook consists of equations and calculating procedures for determining forced-cooled parameters and thermal/hydraulic performance levels. Both simple and sophisticated procedures have been provided, with the more complex procedures treating such areas as ...

Science.gov (United States)

This report contains data collected on a monthly basis over the period April, 1973 - April, 1975 for dustfall particulates, sodium and chloride and SO2 levels obtained from 12 monitoring sites near the Chalk Point Generating Station operated by PEPCO and ...

Energy Technology Data Exchange (ETDEWEB)

The precipitation hardened, ferrite-pearlite medium-carbon steels microalloyed with vanadium (AFP steels) have been developed over the last few years as materials allowing processing by controlled, continuous cooling down from forging temperatures, for achieving benefits such as reducing the number of required heat treatment and working processes and saving expensive alloying materials. Due to their cost-saving advantages, the steels rapidly have been accepted as an alternative material to the quenched and tempered steels and re particularly used for fabrication of automobile parts. Their drawbacks however are the lower yield strength, and low ductility and toughness as compared to the heat-treatable steels. The research project therefore was intended to enhance the properties of the microalloyed, medium-carbon steels and widen their applicability by establishing further and improving existing thermomechanical treatment processes that will ...

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The influences of temperature and duration of tempering on hardness and microstructure were investigated at high-temperature martensitic and low-carbon steels with 9% chrome and the further alloying elements molybdenium, vanadium, niobium and partially tungsten. After austenitizing and subsequent air cooling the steels were tempered at temperatures below, at and above Ac{sub 1b} for different times and finally a hardness test was performed. Making use of the temperature dependence of the hardness tempering diagrams were constructed and the Hollomon-Jaffe-Parameter on the three steels was determined within its application limits. Micrographs of the structure shows the formation of the carbides and the martensite. At tempering temperatures below Ac{sub 1b} a decrease of hardness occurs, above Ac{sub 1b}, a hardness rise due to the partial austenitizing was obtained. While hardening below Ac{sub 1b}, the tempering quality increases from P 91, NF ...

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows: Energy and environment are two major concerns in our modern society due to the coming shortage in fossil energy sources and the growing of greenhouse gas emissions. The challenge for the coming years is to discover new energy resources and to develop devices that are compatible with a sustainable development and generate few (or zero) emission. One of these devices is the fuel cell feed by hydrogen, whose application fields are very large. In particular, the proton exchange membrane fuel cell (PEMFC) is the most realistic device for automotive application. However, hydrogen storage remains one of the most important challenges regarding its development. Although different techniques are available for storing hydrogen, no ideal solution has been found yet. Compression needs elaborated tanks in shape for supporting high pressures, liquefaction requires an expensive hydrogen cooling and adapted tanks. Chemical ...

Science.gov (United States)

Decay heat removal analyses for lead-bismuth cooled natural circulation reactors are described in this paper. A combined multi-dimensional plant dynamics code (MSG-COPD) has been developed to conduct the system analysis for the natural circulation reactors. For the preliminary study, transient analysis has been performed for a 100 MWe lead-bismuth-cooled reactor designed by Argonne National Laboratory (ANL). In addition, decay heat removal characteristics of a 400 MWe lead-bismuth-cooled natural circulation reactor designed by Japan Nuclear Cycle Development Institute (JNC) has been evaluated by using MSG-COPD. PRACS (Primary Reactor Auxiliary Cooling System) is prepared for the JNC's concept to get sufficient heat removal capacity. During 2000 sec after the transient, the outlet temperature shows increasing tendency up to the maximum temperature of 430 Centigrade, because the buoyancy force in ...

International Nuclear Information System (INIS)

Liquid metal cooling for the first wall and blanket of a magnetic confinement fusion reactor has various advantages. However, it has the disadvantages of large magnetohydrodynamic pressure drops and heat transfer deterioration under a strong magnetic field. Thus, the present authors have proposed cooling with a helium-lithium annular mist flow as well as the cooling with a liquid metal boiling flow, and as fundamental studies, investigated the effect of a magnetic field on the flow characteristics and heat transfer of liquid metal two-phase systems since the 1970s. In the present paper we summarize the important findings obtained from our experimental studies for (i) an air-mercury stratified flow in a horizontal rectangular channel, (ii) a helium-lithium annular mist flow in a horizontal rectangular channel, (iii) the mercury pool boiling on a horizontal surface, and (iv) air-mercury upward flows in a vertical circular ...

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A cooling system was developed which could be used even in such areas where the maximum and minimum temperatures of a day might differ widely. The system features in that a latent heat storage unit is connected to the natural circulation cooling unit consisting of 2 heat exchangers where condensed gas (refrigerant) which performs gas-liquid change has been sealed, enabling to cool objects night and day without the requirement for any power source. Electronic equipment was installed in an insulated shelter. Lauric acid and refrigerant R-22 were used as the latent heat storage medium and the heat transport medium respectively. Natural convection heat transfer performance of the outside surfaces of the condenser and the evaporator and the transient behavior of the system during the melting and solidification periods of the latent heat storage medium were tested. As a result of a 48 hour simulation experiment with load ...

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A computer model of cryogenic system for storing solid antimatter is used to explore the radiative cooling-power requirements for long-term antimatter storage. If vacuum-chamber pressures as low as 10 to -18th power torr can be reached, and the rest of the large set of assumptions is valid, milligram quantities of solid antimatter could be stored indefinitely at 1.5 K using cooling powers of less than a microwatt. Many of the assumptions made are problematic and need verification, as they could potentially change the results greatly. The system modeled is a sphere of solid anti-parahydrogen at 1.5 K or below levitated in a spherical cryogenic vacuum chamber. The free matter gas in the chamber is assumed to be molecular hydrogen, and sublimation of both matter and antimatter is assumed to be negligible. The antihydrogen is assumed to be in thermal equilibrium, although annihilation-energy deposition is localized and hydrogen's ...

International Nuclear Information System (INIS)

The device of the present invention improves reactor safety by suppressing lowering of water level in a shroud which surrounds a reactor core, even upon occurrence of rupture of pipelines in an emergency reactor core cooling system in a recycling pump-incorporated type reactor. Namely, an opening of each of cooling systems which forms the emergency reactor core cooling device in a reactor pressure vessel is disposed above the upper end of the reactor core. Further, it also comprises an independent high pressure water injection system, gravitational dropping type water injection system and an automatic depressurization system. With such a constitution, even if rupture of pipelines in the system should be assumed, coolants never flow directly from the shroud which surrounds the reactor core. In addition, there are no pipelines to be ruptured below the upper end of the reactor core with respect to the structure. Accordingly, a ...

Science.gov (United States)

Hydrothermal oxidation (HTO) is a promising technology for the treatment of aqueous-fluid hazardous and mixed waste streams. Waste streams identified as likely candidates for treatment by this technology are primarily aqueous fluids containing hazardous organic compounds, and often containing inorganic compounds including radioisotopes (mixed wastes). These wastes are difficult and expensive to treat by conventional technologies (e.g. incineration) due to their high water content; in addition, incineration can lead to concerns related to stack releases. An especially attractive potential advantage of HTO over conventional treatment methods is the total containment of all reaction products within the overall system. The potential application of hydrothermal oxidation (HTO) technology for the treatment of DOE hazardous or mixed wastes has been uncertain due to concerns about safe and efficient operation of the technology. In principle, aqueous ...

Science.gov (United States)

Understanding climate development in the central Andes is important in determining the relationship between mountain range uplift and climate change. Recent work along the western margin of the central Andes has led to the development of two competing hypotheses: 1) that climate change is directly responsible for uplift or 2) that uplift controls climate change. In the first scenario, uplift results from increased friction at the plate boundary due to sediment-starvation of the trench which is a function of decreased run-off (particularly post 14 Ma) due to global cooling. In the second scenario progressive uplift of the Andean Cordillera during the Miocene resulted in a strong orographic effect with a concomitant rainshadow west of the Andes. To determine the relationship between climate change and uplift it is necessary to ascertain precisely, when the climate changed, the nature of that change and when uplift occurred. ...

International Nuclear Information System (INIS)

Several research programs have been conducted to evaluate the capability of natural circulation cooling of reactors following a loss of cooling accident. Both experimental and RELAP5 simulation results were obtained for these studies in a facility with vertical heated tube(s) and a unheated bypass channel. The analytical results showed that, under a certain power level, a natural circulation pattern can be developed from both initial upflow and downflow conditions, and maintained for a significant cooling period. This power level, for the discussion of this paper, is defined as the natural circulation cooling (NCC) power limit. Two import factors, namely the pump coastdown rate and the initial flow direction, are examined in this paper. In the benchmark case, as compared to the experimental results, the RELAP5 simulation program accurately predicted the transient phenomena from forced convection through ...

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A great deal of current research is directed to finding a way to minimize thermal injury in the esophagus during radiofrequency catheter ablation of the atrium. A recent clinical study employing a cooling intraesophageal balloon reported a reduction of the temperature in the esophageal lumen. However, it could not be determined whether the deeper muscular layer of the esophagus was cooled enough to prevent injury. We built a model based on an agar phantom in order to experimentally study the thermal behavior of this balloon by measuring the temperature not only on the balloon, but also at a hypothetical point between the esophageal lumen and myocardium (2 mm distant). Controlled temperature (55 {sup 0}C) ablations were conducted for 120 s. The results showed that (1) the cooling balloon provides a reduction in the final temperature reached, both on the balloon surface and at a distance of 2 mm; (2) coolant temperature has a ...

International Nuclear Information System (INIS)

One of the characteristic safety features of a pool type research reactor is a safety flapper valve. The valve enables natural convection cooling mechanism in one of the following events. (a) Opening flapper valve promote decay heat removal following reactor's shutdown. (b) Also the valve is gravity driven. There is a possibility that the valve fails to open when it is required to do so. In the present paper the cooling characteristics of the core are analyzed for this event. A steady state study was performed for 5 MW power and 18 FE following a reactor shutdown. It is shown that enough margin exists to assure adequate reactor core cooling should the safety flapper valve fails to open. (authors)

Energy Technology Data Exchange (ETDEWEB)

An analysis is presented of the electron temperature in a linear device which includes the effect of thermal conduction, heat flux limit, radiation, and end plugs. It is found that the thermal conduction and the heat flux limit are dominant in the initial phase of cooling, while the later phase is almost completely controlled by radiation that spatially homogenizes the temperature distribution. In the case of bremsstrahlung, within the frame of the present model, the temperature decays to zero in a finite time. This process takes the form of a cooling wave that moves from the ends of the column to the center. Impurities cause a milder, exponential decay, which is still much faster than the algebraic conduction decay. The thermal effectiveness of the end plugs is described by a convective transfer coefficient h/sub p/. Its scaling law (in terms of the coupled plamsa-plug system) reveals that a very high plug-plasma density ratio provides a ...

British Library Electronic Table of Contents (United Kingdom)

The effect of phosphonate anion (PHOS) on the corrosion of ordinary steel in simulated cooling water has been studied using weight loss, polarization curves and electrochemical impedance spectroscopy measurements. PHOS was studied in the concentration range from 7.5x10^-^5 to 10^-^3M. The results obtained reveal that PHOS perform excellently as corrosion inhibitor for ordinary steel in simulated cooling water. The inhibition efficiency of PHOS was increased with increasing both its concentration and water circulation velocity. These two factors seem to promote the adsorption of phosphorus and oxygen ions on the metal surface, leading to the formation of a protective layer with a greater charge transfer resistance and lower permeability. The inhibition efficiency decreased slightly with tem...

Energy Technology Data Exchange (ETDEWEB)

The effect of sodium gluconate anion (SG) on the corrosion and scale inhibition of ordinary steel in simulated cooling water has been studied using weight loss, polarisation curves, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) techniques. SG was studied in concentration from 10{sup -4} M to 10{sup -1} M. Results obtained reveal that SG perform excellently as corrosion and scaling inhibitor for ordinary steel in simulated cooling water. An increase of SG concentration leads to the increase of the corrosion potential towards the positive direction. The inhibition efficiency was a low temperature dependence. The inhibitor mechanism was treated as an adsorption process according to Langmuir adsorption isotherm. The SEM/EDAX data show that was a corrosion and scale inhibitor.

International Nuclear Information System (INIS)

Active Process Water (APW) System, provided as unitized closed loop system in Tarapur Atomic Power Project Units-3 and 4, serves to remove heat from various heat exchangers. One of the important loads served by APW system is shutdown cooling heat exchangers and if APW shutdown is taken then reactor cannot be maintained in cold shutdown condition. It is estimated that after 7 days of reactor shutdown, if about 20% of the normal cooling flow to shutdown cooling heat exchangers is provided then along with keeping PHT in cold shutdown state, reactor components, moderator, end shield water, calandria vault water and calandria vault concrete temperature can be maintained within technical specification limits for extended duration. (author)

British Library Electronic Table of Contents (United Kingdom)

A novel continuous laminar shear structuring crystallizer with a suitable cooling system was designed and built. This is a new method to continuously crystallize edible fat in the desirable polymorphic form from the melt while being uniformly sheared.The machine consists of four main sections: Feed unit, shearing mechanism, cooling system and power unit. In each of these sections specific design considerations are taken into account which makes the process controllable and continuous. The shearing unit is made of two concentric cylinders. The internal cylinder is stationary and has a cooling system inside for temperature control. The outer cylinder rotates to produce a uniform shear in the sample fluid placed in the 1.5mm gap between the cylinders. The sample's feed rate is controlled whil...

International Nuclear Information System (INIS)

The present work summarizes efforts on the simulation of natural convection cooling within the IFMIF target and test cell. The simulations have been performed with the STAR-CD code using the k-#omega# high-Reynolds number turbulence model. A dedicated thermohydraulic model has been devised including Lithium loop components. Nuclear heat production has been calculated by the Monte-Carlo code McDeLicious for different parts of the target and test cell walls and was used as input for the STAR-CD simulations. Helium atmospheres at several pressures from 0.1 to 10"-"5 MPa have been investigated. In order to limit the maximum temperature of the concrete walls to 80 deg. C it was necessary to add thermal insulation layers to the hot Lithium loop surfaces and a conceptual system of two cooling layers in different depths of the concrete walls.

Energy Technology Data Exchange (ETDEWEB)

The modeling and optimizing processes of a Ground Coupled Heat Pump (GCHP) with closed Horizontal Ground Heat eXchanger (HGHX) are presented in this paper. After thermal modeling of GCHP including HGHX, the optimum design parameters of the system were estimated by minimizing a defined objective function (total of investment and operation costs) subject to a list of constraints. This procedure was performed applying Genetic Algorithm technique. For given heating/cooling loads and various climatic conditions, the optimum values of saturated temperature/pressure of condenser and evaporator as well as inlet and outlet temperatures of the water source in cooling and heating modes were predicted. Then, for our case study, the design parameters as well as the configuration of HGHX were obtained. Furthermore, the sensitivity analysis of change in the total annual cost of the system and optimum design parameters with the climatic conditions, ...

Science.gov (United States)

A model is presented for heat and fluid flow during hammer and anvil splat cooling. Predictions are made for the effects of superheat and hammer speed on splat thickness, cooling rate, and subsequent glass formation. The regime of Newtonian heat flow is extended well beyond the previously accepted limiting value of Nusselt number. Measurements of the structure, stability, and thickness of Fe{sub 80}B{sub 20} and Pd{sub 80}Si{sub 20} hammer and anvil splats qualitatively confirm the model prediction. Variations of superheat in shock tube splats produced similar trends to those observed in the hammer and anvil device. In an attempt to vary the equivalent of hammer speed in a shock tube device, an orifice producing a supersonic shock wave was utilized. Significant splat flake thickness reductions resulted as compared to subsonic orifices.

Energy Technology Data Exchange (ETDEWEB)

With the combination of source ventilation and ceiling cooling for air-conditioning of working and recreation rooms, a ventilation system is available which fulfills the highest demands regarding thermal comfort. In order to utilize the advantages of this ventilation system with regard to air quality and thermal comfort to an optimum, the influence of the radiation exchange between cooling ceiling and walls on the flow in the room is investigated experimentally. Energy transfer from the walls to the cooled ceiling may result in an insufficient temperature of the walls compared to ambient air and in an upward flow on the wall surfaces (downward flow of) driven by gravity, which influences the flow pattern in the case of source ventilation. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The YGN Units 3 and 4 plant conditions during shutdown operation were reviewed to identify the possible event scenarios following the loss of shutdown cooling. The thermal hydraulic analyses were performed for the five cases of RCS configurations under the worst event scenario, unavailable secondary cooling and no RCS inventory makeup, using the RELAP5/MOD3.2 code to investigate the plant behavior. From the analyses results, times to boil, times to core uncovery and times to core heat up were estimated to determine the containment closure time to prevent the uncontrolled release of fission products to atmosphere. These data provide useful information to the abnormal procedure to cope with the event. 6 refs., 7 figs., 2 tabs. (Author)

British Library Electronic Table of Contents (United Kingdom)

Abstract Satellite measurements and numerical forecast model reanalysis data are used to compute an updated estimate of the cloud radiative effect on the global multi-annual mean radiative energy budget of the atmosphere and surface. The cloud radiative cooling effect through reflection of short wave radiation dominates over the long wave heating effect, resulting in a net cooling of the climate system of - 21 Wm-2. The short wave radiative effect of cloud is primarily manifest as a reduction in the solar radiation absorbed at the surface of - 53 Wm-2. Clouds impact long wave radiation by heating the moist tropical atmosphere (up to around 40 Wm-2 for global annual means) while enhancing the radiative cooling of the atmosphere over other regions, in particular higher latitudes and sub-trop...

Energy Technology Data Exchange (ETDEWEB)

Today's building industry is promoting the use of renewable sources of energy to heat, cool, and illuminate commercial buildings. Societies such as the International Solar Energy Society sponsor conferences such as this one to share knowledge and experience in the area of solar energy. However, the technologies presented here assume a need for heating, cooling or illumination. A simple technique is presented for determining the actual heating, cooling, and lighting requirements for commercial buildings, and for reducing those requirements through proper building design before applying solar technologies. The energy nomographs are a graphic energy design tool developed to aid designers in making cost effective decisions about energy alternatives early in the design process. Reducing loads at this point can help reduce the expense of a passive or active solar system which is usually sized to meet a certain percentage ...

Science.gov (United States)

... in the body. PTH is made by the parathyroid glands -- four small glands located in the neck behind ... is due to excess PTH release by the parathyroid glands. This excess occurs due to an enlargement of ...

Energy Technology Data Exchange (ETDEWEB)

Gas turbine component protection remains essential but environmental regulations emphasize the gas-turbine efficiency. Heating and cooling are features often integrated into the GI air intake packages to provide the optimum operating conditions. This paper describes modern inlet air treatment systems and discusses their effectiveness. (author)

International Nuclear Information System (INIS)

Assessment on the back end fuel cycle, in PEACER (Proliferation-resistant Environmental-friendly Accident-tolerant Continuable and Economical Reactor) that was designated as a new transmutation concept, was performed. Recovery system of uranium and TRU for PEACER is based on pyroprocessing. In the assessment of Long-Lived Fission Products (LLFP) wastes, initially "9"0Sr and "1"3"7Cs are dominant contributor nuclides until 30 years and especially "9"0Sr and "1"3"7Cs have the highest activity and decay heat than other LLFP. In this study, recovery of "9"0Sr and "1"3"7Cs is recommended for reducing of wastes loading. The acceptable decontamination factor is investigated by the toxicity of PEACER spent fuel. The acceptable decontamination factor is about 1.02E+05 for the actinides from PEACER spent fuel after 10 years cooling, 4.26E+05 after 100 years cooling, 1.97E+04 after 300 years cooling, 9.52E+03 after 1000 years ...

International Nuclear Information System (INIS)

In this paper, we calculated the radioactive concentration distribution of radioactive waste water, the temperature distribution of drained cooling water and the effect of implement from the Daya Bay Nuclear Power Plant on nearby waters range, discussed and analysed some problems of computational results and computation with Alternating Direction Implicit Method (ADI). The contents of the article included: the establishment of two-dimension tidal current equation, radioactive waste water pollutant dispersion equation and cooling water heat convection diffusion equation, the numerical difference calculation model of tidal current field, concentration field as well as temperature field, effect impingement with ADI method, numerical calculation results. The result of research showed that: when the Daya Bay Nuclear Power Plant is on normal operation and after the low level radioactive waste water and low temperature cooling ...

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Forms used in conducting a national survey about solar energy are presented. Forms for representatives from the domestic, commercial, and industrial sectors, owners and non-owners of solar equipment, are shown. Participants were to be contacted by telephone, mail, and personal visits. (MCW)

Science.gov (United States)

The melting unit, consisting of a water-cooled cupola furnace, afterburner, heat exchanger, air preheater, consumes most of the supplied energy in the rockwool process. The report maps the energy flows and defines factors of merit according to thermodynam...

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A study has been made of the precipitation and growth processes which occur during cooling from solution treatment and under isothermal hold conditions in a magnesia-partially-stabilized zirconia alloy. Three types of precipitate have been identified which develop during cooling or during isothermal hold treatments just above and below the eutectoid temperature. These precipitate forms are termed (i) primary, (ii) large random, and (iii) secondary. Further precipitation, slow growth of existing precipitates, and subeutectoid decomposition result when an additional 1100/sup 0/C aging treatment is given to the previously cooled material. It is shown that type (iii) secondary precipitates from rapidly within the temperature range of 1300/sup 0/ to 1375/sup 0/C. The secondary precipitates are largely responsible for the improved room-temperature strength properties of the heat-treated samples. The formation and effects on ...

Energy Technology Data Exchange (ETDEWEB)

This report has reviewed the construction of a cooling tower for the K reactor at the DOE Savannah River Site in Aiken, South Carolina. It has been found that the cooling tower would prevent further destruction of cypress and tupelo trees, would maintain a more consistent flow from site streams, and would allow earlier recovery of stream corridors inside a portion of the site. About 630 acres of wetlands have already been affected by the hot water discharged by the K reactor during the past 35 years. GAO believes that about 10 to 12 acres of additional damage would be prevented by the tower for every year the reactor is operated, and if current plans for re-start and retirement of the reactor are followed, less than 100 acres would be preserved. As requested, GAO also identified an example of a project that could be funded as compensation to the public for the damage the K reactor would do if Congress exempted it from the Clean Water Act and ...

International Nuclear Information System (INIS)

Certain postulated faults during refuelling of AGRs may give rise to compacted fuel and graphite sleeve debris. This debris must be maintained below some safe limiting temperature. As part of a programme to assess the benefits of natural convection in cooling such debris in a region experiencing no forced cooling, a simple geometry incorporating typical debris has been studied both experimentally and by prediction. The experiment comprised an array of electrically heated fuel rods mounted co-axially in a closed cylindrical vessel and surrounded by fragments of graphite. The vessel was cooled on its cylindrical surface, the ends being insulated. Rods and vessel wall were thermocoupled. Tests covered a range of temperature and pressures in both CO_2 and N_2. Significant natural convection heat removal was demonstrated, particularly at high pressure. Predictions utilising the PHOENICS code agreed well with measured ...

Energy Technology Data Exchange (ETDEWEB)

The design and performance of small incinerators used at the Mound Laboratory for the disposal of explosives are described. These units, which cost less than $1000 each, are about the size of a 55-gal drum, have water jackets for cooling, and have provided a flexible, efficient, and clean burning explosives disposal unit. (LCL)

Science.gov (United States)

The Heavy Water Reactor Facility (HWRF), as part of the defense-in-depth philosophy to mitigate the effect of design-basis and severe accidents, is equipped with a passive containment cooling system (PCCS). The function of the PCCS is to provide a safety-grade path to the ultimate heat sink for the removal of the reactor coolant system sensible heat and core decay heat. Ambient air enters an annular space between the steel containment shell and the surrounding concrete shield building through inlets in the shield building wall, is heated via natural convection, rises, and exits the building through a chimney located above the containment dome. A test program is in place to access parameters important to the effective operation of the PCCS. This paper focuses on the large-scale tests (LSTs). The objectives of these tests are as follows: (1) demonstrate natural circulation cooling with more prototypic cylinder and dome surface area ratios than ...

Energy Technology Data Exchange (ETDEWEB)

Recent developments in heat pump technology have made geothermal-based heat exchange systems particularly well-suited for the heating and cooling needs of buildings even in cold climates. The principles of geothermally-coupled heat pump heating and cooling systems were presented. Results of an in-situ study conducted by Hydro-Quebec on the efficiency of the geothermal heat pump system installed at the Saint-Hyacinthe professional school were summarized. This investigation was meant to be a case study of the applicability of these new technologies to the needs of the Quebec market. After the first year of service, the Saint-Hyacinthe system clearly demonstrated its cost effectiveness over conventional systems. It was predicted that geothermal heat pump systems will gain in popularity in Quebec because they can fully meet the heating and cooling needs of public buildings at considerable cost reductions, besides offering ...

Energy Technology Data Exchange (ETDEWEB)

A multi-faceted research program has been performed to investigate in detail several aspects of free and forced convective cooling of underground electric cable systems. There were two main areas of investigation. The first one reported in this volume dealt with the fluid dynamic and thermal aspects of various components of the cable system. In particular, friction factors for laminar flow in the cable pipes with various configurations were determined using a finite element technique; the temperature distributions and heat transfer in splices were examined using a combined analytical numerical technique; the pressure drop and heat transfer characteristics of cable pipes in the transitional and turbulent flow regime were determined experimentally in a model study; and full-scale model experimental work was carried out to determine the fluid dynamic and thermal characteristics of entrance and exit chambers for the cooling oil. The second major ...

British Library Electronic Table of Contents (United Kingdom)

A solar-driven 10-ton LiBr/H2O single-effect absorption cooling system has been designed and installed at the School of Renewable Energy Technology (SERT), Phitsanulok, Thailand. Construction took place in 2005, after which this system became fully operational and has been supplying cooling for our main testing buildings air-conditioning. Data on the systems operation were collected during 2006 and analyzed to find the extent to which solar energy replaced conventional energy sources. Here, we present these data and show that the 72m2 evacuated tube solar collector delivered a yearly average solar fraction of 81%, while the remaining 19% of thermal energy required by the chiller was supplied by a LPG-fired backup heating unit. We also show that the economics of this cooling system are domi...

Science.gov (United States)

The goal of this study was to evaluate topics used to troubleshoot circuit boards with known or suspected thermally intermittent components. Failure modes for thermally intermittent components are typically mechanical defects, such as cracks in solder paths or joints, or broken b...

Energy Technology Data Exchange (ETDEWEB)

The feasibility study on conceptual design methodology for accelerator-driven sodium-cooled sub-critical transmutation reactors has been conducted to optimize the design parameters from the scale laws and validates the reactor performance with the integrated code system. A 1000 MWth sodium-cooled sub-critical transmutation reactor has been scaled and verified through the methodology in this paper, which is referred to Advanced Liquid Metal Reactor (ALMR). A Pb-Bi target material and a partitioned fuel are the liquid phases, and they are cooled by the circulation of secondary Pb-Bi coolant and by primary sodium coolant, respectively. Overall key design parameters are generated from the scale laws and they are improved and validated by the integrated code system. Integrated Code System (ICS) consists of LAHET, HMCNP, ORIGEN2, and COMMIX codes and some files. Through ICS the target region, the core region, and ...

Science.gov (United States)

Results of feasibility experiments for determining the mineral content of individual stains on special Sensitized Paper are presented. The stains were formed on the paper by the impaction of laboratory generated salt water droplets. Of the techniques exam...

UK PubMed Central (United Kingdom)

Remote sensing data over North America document the ubiquity of secondary aerosols resulting from a combination of primary biogenic and anthropogenic emissions. The spatial and temporal distribution...Full Text Available

CERN Document Server

We investigate the thermodynamic and chemical structure of the intracluster medium (ICM) across a statistical sample of 20 galaxy clusters analysed with the Chandra X-ray satellite. In particular, we focus on the scaling properties of the gas density, metallicity and entropy and the comparison between clusters with and without cool cores (CCs). We find marked differences between the two categories except for the gas metallicity, which declines strongly with radius for all clusters (Z ~ r^{-0.31}), outside ~0.02 r500. The scaling of gas entropy is non-self-similar and we find clear evidence of bimodality in the distribution of logarithmic slopes of the entropy profiles. With only one exception, the steeper sloped entropy profiles are found in CC clusters whereas the flatter slope population are all non-CC clusters. We explore the role of thermal conduction in stabilizing the ICM and conclude that this mechanism alone is sufficient to balance ...

UK PubMed Central (United Kingdom)

Profound myocardial hypothermia (below 17° C, and more often around 12° C) is imperative in myocardial protection while the aorta is cross-clamped. Based on our experience in...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

An analytical study of the ice-formation process associated with heat-conducting plates located perpendicularly to isothermally heated and cooled surfaces with some clearance is presented. It is proposed that the onset conditions, which describe whether the ice-volume fraction in a steady state is greater than or less than that without heat-conducting plates, are defined by the dimensionless distances between the heated/cooled walls and the heat-conducting plates. It is shown that the onset conditions are dependent on the pitch and the thickness of the heat-conducting plates and are less dependent on the thermal conductivity of the plates.

International Nuclear Information System (INIS)

Site studies for CANDU type NPP began in a careful manner since 1982 as a first part of the Nuclear Power Plant Romanian Program adopted by political and governmental authorities at the time. A team was charged to develop all packages of the necessary main studies. The first Romanian NPP CANDU 6 type reactor gone to erection on Cernavoda site, planned to have 5 units and, like Wolsong NPP, applied the same design for the nuclear island. For the BOP parts the ANSALDO-GE project was applied with a thorough concern about requirements raised by connection to NSP. The first mission of design and research multi-branch team was to adapt the NPP Cernavoda project having an open water cooling circuit 'once-through' to the new parameters of a close recirculation water cooling circuit. Also, the structural design was re-evaluated for the case of soft foundation strata instead of hard rock ones. The close recirculation water cooling ...

Energy Technology Data Exchange (ETDEWEB)

Researchers are developing polymer-based coating systems to reduce scaling and corrosion of air-cooled condensers that use a geothermal fluid spray for heat transfer augmentation. These coating systems act as barriers to corrosion to protect aluminum fins and steel tubing; they are formulated to resist the strong attachment of scale. Field tests have been done to determine the corrosion and scaling issues related to brine spraying and a promising organometallic polymer has been evaluated in salt spray tests.

CERN Document Server

Everyone is developing iPhone applications, and it's clear why. The iPhone is the coolest mobile device available, and the App Store makes it simple to get an application out into the unstoppable iPhone app market. With hundreds of thousands of app developers entering the game, it's crucial to learn from those who have actually succeeded. This book shows you how some of the most innovative and creative iPhone application developers have developed cool, best-selling apps. Not only does every successful application have a story, but behind every great app is excellent code. In this book, you'll

International Nuclear Information System (INIS)

This paper discusses the remote plugging of leaks in inaccessible pipework, with main reference to small leaks which frequently appear in ancillary cooling water circuits of nuclear reactors. Initially developed to cure problems of the pre-stressed concrete pressure vessels of UK reactors, the ZORIC sealant has been used to repair leaking biological shield pipework on six CANDU reactors. ZORIC is based on a water-soluble epoxy resin and an aqueous suspension of a refined mineral clay. This paper describes the evolution of the sealant, the qualification and testing program, and their application to CANDU reactor systems. 2 refs., 6 figs.

Energy Technology Data Exchange (ETDEWEB)

An apparatus is provided for rapidly restarting the flow of coolant through the cold electromagnetic shield of a superconducting rotor following a thermal transient episode. A vortex diode inhibits coolant flow in the undesirable reverse direction and encourages the reestablishment of a normal thermosyphon cooling loop flow quickly following the termination of a thermal transient such as that caused by transmission line faults. The present invention requires no moving parts and may therefore be permanently sealed in the superconducting rotor without risk of costly repair efforts caused by components failure.

International Nuclear Information System (INIS)

The feasibility of a high-energy electron cooling device has been studied through tests on a prototype of the electron device. The apparatus consists of a pulsed ((20-60) keV, 2#mu#s) electron gun, a drift region 1 m long and of a depressed collector for recovering the electron energy. Tests on beam optics and energy recovery have been performed, a high-energy recovery efficiency has been attained. Experimental results are discussed in this paper.

International Nuclear Information System (INIS)

Within the framework of the EU power plant conceptual study (PPCS), a modular He-cooled divertor concept with integrated pin array (HEMP) is being developed at the Forschungszentrum Karlsruhe. The design goal is to achieve a high heat flux of at least about 10-15 MW/m"2, which is proposed for a near-term reactor model like DEMO. The development and optimization of the divertor concept require a close link between the main issues: design, analyses, materials and fabrication technology, and experiments with feedbacks between them to be accounted for. Design-specific requirements on materials and fabrication issues will be discussed.

International Nuclear Information System (INIS)

The justification, strategies, and technology options for implementing advanced district heating and cooling systems in the United States are presented. The need for such systems is discussed in terms of global warming, ozone depletion, and the need for a sustainable energy policy. Strategies for implementation are presented in the context of the Public Utilities Regulatory Policies Act and proposed new institutional arrangements. Technology opportunities are highlighted in the areas of advanced block-scale cogeneration, CFC-free chiller technologies, and renewable sources of heating and cooling that are particularly applicable to district systems.

International Nuclear Information System (INIS)

An experimental program has been conducted to determine the feasibility of natural convection cooling of a reactor following a beyond-design-based accident. The particular application under consideration was the heavy-water new production reactor. The questions to be resolved include the verification that a natural convection cooling pattern would be established and the determination of the power limit for which convective cooling will occur for a significant period of time. In the experiment, the reactor configuration was simulated using small-diameter vertical heated tubes in parallel with a large-diameter bypass line. Following a loss-of-flow event, the flow in the bypass line will reverse direction and pass through the heated channel by means of natural convection. If, however, the channel power is too high, void formation will block the channel and prevent the reverse flow pattern from occurring. The test procedure ...

KoreaScience (Korea)

Full Text Available

International Nuclear Information System (INIS)

... excessive. Due to the response being too weak, attempts to use Infrared

DEFF Research Database (Denmark)

Udgivelsesdato: 2006/8

KoreaScience (Korea)

Full Text Available

International Nuclear Information System (INIS)

The operation and safety of both fossil-fuel and nuclear power stations depend on adequate cooling of the thermal source involved. This is usually accomplished using liquid coolants that are forced through the high temperature regions by a pumping system; this fluid then transports the thermal energy to another section of the power station. However, fluids that undergo boiling during this process create vapor that can be detrimental, and influence safe operation of other system components. The behavior of this vapor, or void, as it is generated and transported through the system is critical in predicting the operational and safety performance. This study uses two advanced penetrating radiation techniques, Real Time Neutron Radiography (RTNR), and High Speed X-Ray Tomography (HS-XCT), to examine void generation and transport behavior in a flow boiling system. The geometries studied were tube side flow boiling in a cylindrical configuration, and a similar flow ...

Science.gov (United States)

The brain hypothermia treatment is an attractive therapy for the neurologist because of its neuroprotection in hypoxic-ischemic encephalopathy patients. The present paper deals with the possibility of controlling the brain and other viscera in different temperatures from the viewpoint of system control. It is theoretically attempted to realize the special brain hypothermia treatment to cool only the head but to warm the body by using the simple apparatus such as the cooling cap, muffler and warming blanket. For this purpose, a biothermal system concerning the temperature difference between the brain and the other thoracico-abdominal viscus is synthesized from the biothermal model of hypothermic patient. The output controllability and the asymptotic stability of the system are examined on the basis of its structure. Then, the maximum temperature difference to be realized is shown dependent on the temperature range of the apparatus and also on ...

Energy Technology Data Exchange (ETDEWEB)

A cryocondensation pump was designed for the baffle chamber of General Atomics DIII-D tokamak and will be installed in the fall of 1992. The purpose of the pump is to study plasma density control by pumping the divertor. The pump is toroidally continuous, approximately 10 m long and located in the lower outer corner of the vacuum chamber of the machine. It consists of a 1 m{sup 2} liquid helium-cooled surface surrounded by a liquid nitrogen-cooled shield to limit the heat load on the helium-cooled surface. The liquid nitrogen-cooled surface is surrounded by a radiation/particle shield to prevent energetic particles from impacting and releasing condensed water molecules. A thermal enhancement coating was applied to the nitrogen shell to lower the maximum temperature of the shell. The coating is non-continuous to keep the toroidal electrical resistance high. The whole pump is supported off the ...

Science.gov (United States)

The largest solar heating and cooling system undertaken to date is now operating at the George A. Towns Elementary School in Atlanta, Georgia. It is expected to provide more than 60 percent of the building's heating and cooling requirements, using commercially available components and techniques. The Towns project is a United States Energy Research and Development Administration-sponsored experiment. The principal components of the solar heating and cooling system designed for the school--the solar collector array, the existing gas-fired boiler, the absorption chiller, and hot and cold water underground tanks to provide thermal storage--are described. To derive maximum benefit from the experiment, the system is fully instrumented for accurate measurement of performance. Environmental data, including insolation and ambient temperture, humidity, and wind conditions will be recorded. The inlet temperatures, outlet ...

International Nuclear Information System (INIS)

In order to study the boundary conditions for the occurrence of ratcheting, a testing rig was erected. In this rig, small-scale mock-ups of the first wall were tested under mechanical conditions similar to those expected during disruptions. These mock-ups were made of stainless steel AISI 316. They were heated on the surface and water cooled from inside. Disruption forces were simulated by a high-speed hydraulic bending system by impact loads. The mock-ups were heated by a high-frequency generator and cooled by water through two cooling channels.In addition to the experimental work, simplified analytical analysis and numerical calculations were carried out using the finite element program ABAQUS. In these calculations, the temperature and stress fields in the mock-ups were investigated and the influence of the different constitutive equations was studied.The experimental results confirm the ratcheting behaviour predicted by ...

Energy Technology Data Exchange (ETDEWEB)

One of the most important factors affecting the postharvest life and quality of horticultural crops is temperature. Quality loss after harvest occurs as a result of physiological and biological processes, the rates of which are influenced primarily by product temperature. As the maintenance of market quality is of vital importance to the success of the horticultural industry, it is necessary not only to cool the product but to cool it as quickly as possible after harvest. The process of precooling is the removal of field heat which arrest the deteriorative and senescence processes so as to maintain a high level of quality that ensures customer satisfaction. This paper provides a critical review to portray precooling as an intricate part of temperature management and to highlight the importance of its utilisation for extending the shelf life and maintaining the quality of horticultural products with emphasis on cut flowers. Various different ...

CERN Document Server

We calculate the structure of accretion disks around Kerr black holes for accretion rates 0.001 - 10 M_sun/s. Such disks are plausible candidates for the central engine of gamma-ray bursts. Our disk model is fully relativistic and treats accurately microphysics of the accreting matter: neutrino emissivity, opacity, electron degeneracy, and nuclear composition. The neutrino-cooled disk forms above a critical accretion rate that depends on the black hole spin. The disk has the ``ignition'' radius r_ign where neutrino flux rises dramatically, cooling becomes efficient, and the proton-to-nucleon ratio Y_e drops. Other characteristic radii are r_alpha where most of alpha-particles are disintegrated, r_nu where the disk becomes neutrino-opaque, and r_trap where neutrinos get trapped and advected into the black hole. We find r_alpha, r_ign, r_nu, r_trap and show their dependence on the accretion rate. We discuss the qualitative picture of accretion ...