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Fuel cell system. Nenryo denchi system
1994-02-10
The cooling water temperature or the pressure of the conventional fuel cell system, in which the absorption refrigerator is run by waste heat, are maintained constant even when the cooling water temperature of the absorption refrigerator increases, and the coefficient of performance of the absorption refrigerator decreases in summertime when larger cooling capacity is required. This invention is concerned with a fuel cell system, wherein the cooling water temperature of the refrigerator operated by utilizing the thermal energy of the cooling water of the fuel cell is measured, the measured value of the temperature or the pressure of the cell cooling water is calculated in accordance with the refrigerator cooling water temperature, and the cell cooling water temperature control means or the pressure control means is controlled to become the measured value of the calculated temperature or the pressure. As a result, the temperature or the pressure of the fuel cell cooling water is varied according to the cooling water temperature of the absorption refrigerator to improve the coefficient of performance throughout the year. 9 figs.
Cooling system of an internal combustion engine having a turbo-charger
1986-09-02
A cooling system of an internal combustion engine is described having a turbo-charger, comprising a cooling water circulation passageway filled with cooling water for cooling the engine including at least a cylinder head cooling portion, a cooling water circulation passageway for cooling the turbo-charger including a turbo-charger cooling portion, and means for supplying a part of the engine cooling water to the turbo-charger cooling water ciruclation passageway and returning it from there to the engine cooling water cirulation passageway, characterized in that the turbo-charger cooling portion is positioned at the same level or higher than the cylinder head cooling portion of the engine, the turbo-charger cooling water circulation passageway includes a water volume positioned at a level higher than the turbo-charger cooling portion. The volume is connected to a cooling water reservoir tank via a pressure relief valve which is opened when pressure in the volume exceeds a predetermined value to supply cooling water to the volume.
Nuclear power plant cooling facility
1993-02-09
When a pipeline rupture accident should occur, steams generated by after-heat are condensed in a heat transfer pipes of a heat exchanger in a cooling water pool at the outside of a reactor container, and they are refluxed to a reactor pressure vessel again. A cooling water chamber is disposed between the reactor pressure vessel and the heat exchanger in the cooling water pool for cooling a dry well on the side of the reactor container. The cooling water chamber and the heat exchanger are connected by a condensate return pipe. The cooling water chamber and the reactor pressure vessel are connected by water injection pipelines of an emergency cooling water system. Further, the height of the junction point of a condensate return pipe to the cooling water chamber is made higher than the height of the junction point of the emergency cooling water injection pipelines and the cooling water chamber. With such a constitution, even when there is no difference between the pressure in the dry well in the reactor container and the pressure in a suppression chamber, incondensible gases in the heat transfer pipe of the heat exchanger can be exhausted. Accordingly, since there is no accumulation of the incondensible gases, after-heat can be removed efficiently. (I.S.).
Fuel cell power generating plant. Nenryo denchi hatsuden plant
1993-03-26
The relationship among the cooling water system, reforming gas system/air system, and the fuel cell system of the conventional fuel cell power generating plant is cooling water system pressure > reforming gas system/air system pressure > fuel cell system pressure, and the fuel cell system pressure must be lower always than the cooling water system pressure. The pressure of the cooling water system determined as above becomes the maximum operating pressure in the plant, which becomes the bottleneck for increasing the working pressure which impedes the improvement in the power generating efficiency. This invention is concerned with provision of a pressurization means for the steam extracted by the separator, in the passage between the reformer and the separator which separates steam from the cooling water in the fuel cell, to increase the operating pressure of the fuel cell higher than the pressure of the cooling water system. This extracted steam is pressurized to a predetermine pressure by the pressurization means before being mixed with the raw fuel. The pressure of the hydrogen rich gas obtained in the reforming gas system is increased by this method, and the working pressure of the fuel cell can be increased. 2 figs.
Fuel cell cooling water system
1987-11-17
Since clogging of a cooling water loop of a fuel cell cooling water system progresses slowly, there is danger of failing to grasp such clogging until the decrease of the amount of the cooling water and a rise of the cell temperature, etc. become conspicuous. In this invention, a differential pressure detector detecting the differential pressure of the cooling water between the cooling water intake line and the cooling water outlet line of the main body of the fuel cell was installed between the above two lines, a signal from the differential pressure detector was sent to the control device of the fuel cell plant and prevention of a damage to the cell was made possible by sounding an alarm from the alarm device when the differential pressure exceeded the permissible value. (6 figs)
1981-02-05
A post-shutdown cooling circuit is set to work when shutting down the PWR. The post-shutdown cooling circuit is arranged physically above the primary cooling circuit, so that an emergency cooling circuit with natural circulation can operate.
1990-01-01
The represent invention concerns a reactor system with improved water injection means to a pressure vessel of a BWR type reactor. A steam pump is connected to a heat removing system pipeline, a high pressure water injection system pipeline and a low pressure water injection system pipeline for injecting water into the pressure vessel. A pump actuation pipeline is disposed being branched from a main steam pump or a steam relieaf pipeline system, through which steams are supplied to actuate the steam pump and supply cooling water into the pressure vessel thereby cooling the reactor core. The steam pump converts the heat energy into the kinetic energy and elevates the pressure of water to a level higher than the pressure of the steams supplied by way of a pressure-elevating diffuser. Cooling water can be supplied to the pressure vessel by the pressure elevation. This can surely inject ...
2009-01-01
Computational results obtained for fuel assemblies and a core with uni- and bidirectional coolant flow are presented for a water-cooled reactor with a thermal neutron spectrum. It is shown that a bidirectional scheme for cooling fuel assemblies has advantages over a unidirectional scheme and holds promise for Gen IV water-cooled reactors with supercritical coolant pressure, which make it possible to perfect the technology for closing and drawing thorium into the fuel cycle.
1996-12-17
The conventional fuel cell has long cooling water piping ranging from the fuel cell exit to the steam separator; in addition, the supply water is cooler than the cooling water. When the amount of supply water increases, the temperature of the cooling water is lowered, and the pressure fluctuation in the steam separator becomes larger. This invention relates to the water supply method of opening the supply water valve and supplying water from the supply water system to the cooling water system in accordance with the signal of the level sensor of the steam separator, wherein opening and closing of the supply valve are repeated during water supply. According to the method the pressure drop in every water supply becomes negligibly small; therefore, the pressure fluctuation of the cooling water system can be made small. The interval of the supply water valve from opening to closing is preferably from 3 seconds to 2 minutes. The method is effective when equipment for recovering heat from the cooling water is installed in the downstream pipeline of the fuel cell. 2 figs.
Nuclear reactor containing facility
1994-01-01
In a reactor containing facility, a condensation means is disposed above the water level of a cooling water pool to condensate steams of the cooling water pool, and return the condensated water to the cooling water pool. Upon occurrence of a pipeline rupture accident, steams generated by after-heat of a reactor core are caused to flow into a bent tube, blown from the exit of the bent tube into a suppression pool and condensated in a suppression pool water, thereby suppressing the pressure in the reactor container. Cooling water in the cooling water pool is boiled by heat conduction due to the condensation of steams, then the steams are exhausted to the outside of the reactor container to remove the heat of the reactor container to the outside of the reactor. In addition, since cooling water is supplied to the cooling water pool quasi-permanently by gravity as a natural force, the reactor ...
1976-05-13
The invention relates to a reactor for coal gasification under pressure with a cooling-water shell enclosing the reaction space. Next to this, there is a collector, mounted on the reaction vessel, from which the evaporated cooling water flows into the reaction space across a steam line in the form of saturated steam. A surge tank connected to this steam line is provided; it has a downpipe leading to the bottom of the cooling water room and a probe for measuring the cooling water level.
Automobile driven by fuel cell; Nenryo denchi jidosha
1994-08-12
In the PEM type fuel cell in which a proton exchange membrane is employed, the cooling water is included in the reactive hydrogen gas and the oxygen gas for humidifying purpose. In this system, however, the use of impure cooling water causes the attaching of metal ions contained in the cooling water on the proton exchange membrane to decrease the proton conductivity of the membrane. Accordingly, an anti-freeze coolant used in automobiles cannot be used for preventing the freezing of the cooling water. This invention solves the problem. In the automobile driven by the electric power generated by the fuel cell, the cooling water circulation system is equipped with a pressurized gas supply device for draining the cooling water. When the fuel cell operation is stopped, the device is operated to supply the pressurized gas to the cooling water circulation system to drain out the cooling water. With this device, it becomes unnecessary to use anti-freeze coolant for preventing the freezing of the cooling water of the fuel cell cooling water circulation system. 10 figs.
Transient moderating system of nuclear power plant
1995-01-01
In a BWR-type reactor, if a feedwater loss transient event should occur, and a reactor water level is lowered to a predetermined level, a reactor isolation cooling system is started, and cooling water is supplied to the reactor to cool the reactor core, and at the same time, a timer for starting a high pressure water injection system is started. If a predetermined period of time is measured, a start-up logic starts the high pressure water injection system. The start-up logic outputs an AND logic signal when a water level non-recovery signal, a reactor isolation cooling system failure signal and a timer's time up signal are inputted simultaneously to the AND logic. At least one of the AND signal and a water level signal are applied to an OR logic, a high pressure water injection system is started. A failure detection device detects a flow rate of pumps of a reactor isolation cooling system ...
Demineralised water cooling in the LHC accelerator
In spite of the LHC accelerator being a cryogenic machine, it remains nevertheless a not negligible heat load to be removed by conventional water-cooling. About 24MW will be taken away by demineralised water cooled directly by primary water from the LHC cooling towers placed at the even points. This paper describes the demineralised water network in the LHC tunnel including pipe diameters, lengths, water speed, estimated friction factor, head losses and available supply and return pressures for each point. It lists all water cooled equipment, highlights the water cooled cables as the most demanding equipment followed by the radio frequency racks and cavities, and by the power converters. Their main cooling requirements and their positions in the tunnel are also presented.
1990-10-11
The represent invention concerns a reactor system with improved water injection means to a pressure vessel of a BWR type reactor. A steam pump is connected to a heat removing system pipeline, a high pressure water injection system pipeline and a low pressure water injection system pipeline for injecting water into the pressure vessel. A pump actuation pipeline is disposed being branched from a main steam pump or a steam relieaf pipeline system, through which steams are supplied to actuate the steam pump and supply cooling water into the pressure vessel thereby cooling the reactor core. The steam pump converts the heat energy into the kinetic energy and elevates the pressure of water to a level higher than the pressure of the steams supplied by way of a pressure-elevating diffuser. Cooling water can be supplied to the pressure vessel by the pressure elevation. This can surely inject cooling water into the pressure vessel upon loss of coolant accident or in a case if reactor scram is necessary, without using an additional power source. (I.N.).
Pulsed cooling-water systems for actively cooled beam dumps
A pulsed water system offers an economically attractive way of supply cooling water for beam dumps, as the water flow and pressure requirements increase. A pilot system was built and used in testing prototype beam dumps. Operating experience gained with the pulsed water system has proved the feasibility of this design.
Pulsed cooling-water systems for actively cooled beam dumps
1981-10-01
A pulsed water system offers an economically attractive way of supply cooling water for beam dumps, as the water flow and pressure requirements increase. A pilot system was built and used in testing prototype beam dumps. Operating experience gained with the pulsed water system has proved the feasibility of this design.
1991-11-25
With the water cooling system for the conventional fuel cell power generation plant, the temperature of the cooling water increases transiently and the pressure inside the vapor separator decreases suddenly because the thermal energy generated in the cooler of the fuel cell at the time of load cut-off has nowhere to go. Therefore, the cooling water pump must be kept operating even when the pressure is less than the value of the preset available NPSH (net positive suction head). According to this invention, two cooling water pumps are connected to the steam evaporator in parallel which perform parallel operation when the pressure inside the steam separator becomes lower than the predetermined pressure, and either one of the cooling water pump is operated when the pressure inside the steam separator is restored to the predetermined pressure. As a result, the available NNPSH value per one cooling water pump is increased, and the necessary NPSH value is decreased to increase the difference between the two for the system operation with a large margin. 7 figs.
Study of impulsive pressure response in a tank
1994-01-01
The Advanced Thermal Reactor (ATR) is a boiling-light-water-cooled heavy-water-moderated pressure-tube-type reactor. If simultaneous break of the pressure tube and of calandria tube were to occur resulting from a severe accident, high-pressure and high-temperature coolant would be discharged into the cool moderator. Although the moderator is cool enough to condense the evaporated vapor from the view point of a long term behavior, an impulsive pressure may occur due to the high-energy liquid ejection into the low-energy liquid in the case of no existence of water surface in the calandria vessel. The integrity of the calandria vessel was confirmed using a full-scale facility that had a water surface in the vessel. In the experiment, pressure in the vessel surface was about 0.3 MPa due to the pressure absorption by gas layer above the heavy water surface. A rupture disk is ...
1977-01-01
This guide describes a preoperational test program acceptable to the staff specifically for emergency core cooling systems (ECCS) in pressurized water reactor power plants. Although this guide is applicable to all pressurized water reactors, certain aspects may not be completely applicable to specific nuclear steam supply designs.
1993-01-01
A gravitationally dropping type reactor core cooling pool is disposed and a pressure suppression pool is disposed below the pool. A steam injector, a steam supply line, a feedwater line, a cooling water discharge line, a drain line, depressurization valves for the steam supply line, control valves for the feedwater line and a control device are disposed. Upon emergency, water is supplied from the reactor core cooling pool to the steam injector, then, steams released from the depressurization valve are intaken to start the steam injector and water in the reactor core cooling pool is injected to cool the reactor core. During normal operation, only such an amount of water as flowing from the reactor core pool to the pressure suppression pool passing through the drain line of the steam injector is pumped up to the reactor core cooling pool. Then, dynamic equipments such as a feedwater ...
1993-04-09
A gravitationally dropping type reactor core cooling pool is disposed and a pressure suppression pool is disposed below the pool. A steam injector, a steam supply line, a feedwater line, a cooling water discharge line, a drain line, depressurization valves for the steam supply line, control valves for the feedwater line and a control device are disposed. Upon emergency, water is supplied from the reactor core cooling pool to the steam injector, then, steams released from the depressurization valve are intaken to start the steam injector and water in the reactor core cooling pool is injected to cool the reactor core. During normal operation, only such an amount of water as flowing from the reactor core pool to the pressure suppression pool passing through the drain line of the steam injector is pumped up to the reactor core cooling pool. Then, dynamic equipments such as a feedwater pump for starting the steam injector and a control valve operated upon emergency can be saved, and cooling water can be injected in a wide pressure range from high pressure to low pressure, thereby enabling to reduce the number of depressurization valves. (N.H.).
1991-01-25
The after-removal system for BWR type reactor according to the present invention is automatically operated in a reactor water injection mode depending on container pressure high or reactor level low signal. Further, it is also operated automatically in a pressure suppression chamber cooling mode depending on the pressure suppression chamber pressure high or pressure suppression chamber temperature high signal. However, when both of mode demand signals are issued simultaneously, priority is given to the reactor core cooling and the system is operated in the water injection mode. Further, if the pressure or the temperature is increased in the pressure suppression chamber by some or other reason, it is automatically operated in the pressure suppression chamber cooling mode to conduct cooling for the pressure suppression chamber. This can automatically start the pressure suppression chamber cooling with the priority being given to the reactor core cooling, to moderate operators burden and maintain the integrity of the pressure suppression chamber and the container. (I.S.).
Mass concrete pre-cooling system with vacuume aggregate cooling; Masukonkurito no purekuringu
1997-06-10
Mass concrete such as dams or long span bridges requires pre-cooling to lower concrete placing temperature in a hot season to prevent crack formation in the concrete structure. The vacuum aggregate cooling method is used when the cooling of mixing water cannot cope with a situation. In this method, aggregate is cooled by vaporization of the surface water under reduced pressure. This paper outlines this cooling system and introduces actual results on two dams of different application methods. In the case of the Kodama dam, Fukushima-ken, the vacuum aggregate cooling facility was attached to the butcher plant and the crude aggregate 2005 is cooled up to 13degC so that the placing temperature was maintained roughly below 25degC. In the Shima river dam, Gunma-ken, cooling of the mixing water, the vacuum cooling of the crude aggregate 2005 and water sprinkling cooling of the crude aggregate 4020 were adopted in combination. The aggregate storage bin on the aggregate supply line was used as a vacuum cooling vessel in consideration of the condition of the forbidden nighttime placing, which enables miniaturization of the mechanical facility and mass production of cooled concrete. 8 figs., 6 tabs.
1976-01-01
Purpose: To provide a cooling water freezer wherein, in order to carry out in-service inspection of a pressure tube in a pressure tube reactor, cooling water at the inlet and outlet of the pressure tube is effectively cooled and an ice plug is formed in a short period of time. Constitution: An ice plug device is provided on the outer wall of a pipe of a pressure assembly, and a coolant path through which the coolant passes is formed in the jackets of the device in a spiral configuration. The through-flow speed of the coolant of liquid nitrogen is increased, and the coolant flows through the spiral coolant path and uniformly cools the outer wall of the pipe. This accomplishes the improvement in heat transmission ratio and the effective utilization of latent heat of liquid nitrogen. (Kamimura, M.)
1967-08-01
A pilot water injection project involving 8 wells was conducted to determine water injection rates and pressures, parting pressure of the formation, and degree of formation cooling by the injected water. Satisfactory water injection rates resulted only at pressures high enough to fracture the formation. However, a uniform water front resulted even in presence of fractures. The injected water cooled the formation around the well from 65/sup 0/C to 20/sup 0/C. When water injection ceased, well-bottom temperature rose slowly. At present, not enough supply water is available for the pressure maintenance program. Steps are being taken to solve this problem.
1967-08-01
A pilot water injection project involving 8 wells was conducted to determine water injection rates and pressures, parting pressure of the formation, and degree of formation cooling by the injected water. Satisfactory water injection rates resulted only at pressures high enough to fracture the formation. However, a uniform water front resulted even in presence of fractures. The injected water cooled the formation around the well from 65/sup 0/C to 20/sup 0/C. When water injection ceased, well-bottom temperature rose slowly. At present, not enough supply water is available for the pressure maintenance program. Steps are being taken to solve this problem.
Development of the ECRH water-cooling system in HL-2A tokamak
2008-01-01
The ECRH water cooling system of HL-2A tokamak has been successfully developed, the maximum flux and pressure of this system reach 94m3centre doth-1 and 0.6MPa, respectively. The system design, the pressure control, and the parameter measurement are briefly introduced. The water-resistance calculation under high voltage condition has been done, and the leak electric current in the cooling water loop of the gyrotron-anode has been measured to be less than 1mA. (authors)
2009-01-01
Cooling towers are equipment devices commonly used to dissipate heat from power generation units, water-cooled refrigeration, air conditioning and industrial processes. Water drift emitted from cooling towers is objectionable for several reasons, mainly due to human health hazards. It is common practice to fit drift eliminators to cooling towers in order to minimize water loss from the system. It is foreseeable that the characteristics of the installed drift eliminators, like their pressure drop, affect the thermal performance of the cooling tower. However, no references regarding this fact have been found in the reviewed bibliography. This paper studies the thermal performance of a forced draft counter-flow wet cooling tower fitted with different drift eliminators for a wide range of air and water mass flow rates. The data registered in the experimental set-up were ...
Fuel cell power generating system. Nenryo denchi hatsuden system
1991-09-26
There is the problem that, when the inside of the water vapor separator becomes negative pressure in the state below 100{degree}C, in the shutdown time of a tuel cell power generating system, the separator inhales surrounding air, oxygen in air dissolves into cell cooling water and the cooler of the fuel cell main body and cell cooling water pipes are corroded, because of cooling water of high oxygen content. The fuel cell power generating system of the invention is added with the pressurization means to, that the vapor phase pressure of a water vapor separator is maintained higher than atmospheric pressure, by means of inert gas pressurization. Therefore, the vapor phase zone of the watew vapor separator is pressurized, the inner pressure is maintained above atmospheric pressure and inert gas intrusion can be prevented. Further, by making the gas exhaust means that the vapor phase of the cooling system is opened to atmosphere and noncondensable gas is exhausted in the time of starting and raising the temperature, proper pressure in the vapor phase zone of the vapor separator can be maintained and exact temperature control can be performed. 3 figs.
Dry cooling tower operating experience in the LOFT reactor
1980-01-01
A dry cooling tower has been uniquely utilized to dissipate heat generated in a small experimental pressurized water nuclear reactor. Operational experience revealed that dry cooling towers can be intermittently operated with minimal wind susceptibility and water hammer occurrences by cooling potential steam sources after a reactor scram, by isolating idle tubes from the external atmosphere, and by operating at relatively high pressures. Operating experience has also revealed that tube freezing can be minimized by incorporating the proper heating and heat loss prevention features.
Propellant actuated nuclear reactor steam depressurization valve
A nuclear fission reactor combined with a propellant actuated depressurization and/or water injection valve is disclosed. The depressurization valve releases pressure from a water cooled, steam producing nuclear reactor when required to insure the safety of the reactor. Depressurization of the reactor pressure vessel enables gravity feeding of supplementary coolant water through the water injection valve to the reactor pressure vessel to prevent damage to the fuel core.
Propellant actuated nuclear reactor steam depressurization valve
A nuclear fission reactor combined with a propellant actuated depressurization and/or water injection valve is disclosed. The depressurization valve releases pressure from a water cooled, steam producing nuclear reactor when required to insure the safety of the reactor. Depressurization of the reactor pressure vessel enables gravity feeding of supplementary coolant water through the water injection valve to the reactor pressure vessel to prevent damage to the fuel core.
Propellant actuated nuclear reactor steam depressurization valve
A nuclear fission reactor combined with a propellant actuated depressurization and/or water injection valve is disclosed. The depressurization valve releases pressure from a water cooled, steam producing nuclear reactor when required to insure the safety of the reactor. Depressurization of the reactor pressure vessel enables gravity feeding of supplementary coolant water through the water injection valve to the reactor pressure vessel to prevent damage to the fuel core.
Water treatment system in fuel cell; Nenryo denchino mizu shori sochi
1996-01-12
Fuel cells require the cooling water with a low electric conductivity for insulation and corrosion protection. As for the water treatment system, ion exchange resin is used to keep the quality of the cell cooling water stable. However, the filter in the water treatment system has to be cleaned or replaced periodically. Otherwise the pump is too much loaded because of the blockage of the filter. This invention solves the problem. The pipeline of the water treatment system in the fuel cell and its accessories are installed in some place at the boundary of the water treatment system and the cell cooling water system consisting of rust-forming material and the rust-collecting filter is installed at the water treatment side rather than the heat exchanger which is installed at the boundary between the cell cooling water system and the water treatment system. This construction makes it possible to collect the rust floating in the lowdown water by the rust collecting filter. In addition, the high pressure of the cell cooling water system is applied to the low pressure of the water treatment system so as to collect the rust particles by the filter without pumping. 2 figs.
Fuel cell power generation system; Nenryo denchi hatsuden setsubi
1996-02-06
The conventional fuel cell power generation system employs pumps driven by motors for operating the water recovery system of fuel cell cooling system. Since a part of power generated by the plant is consumed by these pumps, the power generation efficiency is reduced correspondingly. This invention solves the problem. In place of power-driven motors, steam injectors are employed for operating the water recovery system and water supply system of fuel cell cooling water system. The steam is supplied to these steam injectors from the cell cooling water system to generate a high pressure water jet stream. The steam supplied to the steam injector is generated by reduced flush by means of steam supply method which uses a high temperature cooling water of the cell cooling system. This method does not need the power for driving the pumps. So that the power consumption can be reduced to a great extent. 9 figs.
1995-09-12
The invented water treatment system for fuel cell power generation system is constructed so as to supply cooling water from which impurities are removed by means of reverse osmosis type impurity removal technique to the supplementary water supply line. In addition, a heat exchange system is installed to heat up the cooling water to be supplied to the circulation line through the supplementary water supply line. The system is also equipped with an impurity removal device which removes impurities from the cooling water to be supplied to the heat exchanger by means of ion exchange method. The principle of impurity removal by the reverse osmosis method is to remove impurities from the cooling water in the course of passing through the semipermeable membrane by the aid of water pressure in the cooling water circulation system. This method makes it possible to remove sufficiently all types of impurities including silica type scale. The removed impurities remain at the upstream of the semipermeable membrane in the cooling water flow. The remaining impurities are discarded from the discard outlet as a highly concentrated cooling water. 5 figs.
Water feed and effluent treatment for hydrogen sulfide - water system
1977-01-01
There is provided a process for treatment of the liquid water feed and effluent of a gas and liquid contact system in which flows of hydrogen sulfide gas saturated with water vapor and liquid water saturated with hydrogen sulfide are contacted at elevated temperature and pressure. The process comprises recovering heat and hydrogen sulfide from the effluent for return to the gas and liquid contact system by passing the effluent through at least one zone maintained at a pressure lower than the system pressure but higher than atmospheric pressure in order to release hydrogen sulfide gas containing water vapor. The released gas is cooled by direct contact with a flow of water, thereby raising the temperature of the water, which is then passed to the gas and liquid contact system. The cooled released gas is compressed for return to the gas and liquid contact system. (LL)
1994-01-01
A cooling pipe disposed to a high temperature heat receiving plate has a double wall structure, and the pressure is increased in the inner pipe than the outer pipe, as well as holes are perforated to a portion of the inner pipe so that cooling water is jetted out from the holes to a portion where a thermal load is exerted. This can remove heat of the inner pipe of the cooling pipe more effectively than a swirling flow, as well as film boiling on the wall surface can be suppressed. In addition, since low temperature cooling water is brought into contact with the portion where the thermal load is exerted, thermal load resistance is improved. (T.M.)
1981-01-01
Purpose: To prevent boiling of saturated water in the drain tank of a humidity separator by charging cooling water in the drain tank upon power decrease of a turbine. Constitution: Saturated water is separated from high pressure turbine exhausts in a humidity separator and stored in a drain tank. The saturated water in the drain tank is controlled to a constant level and the excess water is sent to a condensator and a feedwater heater. A cooling water feed pipe is branched as a cooling water feed pipe from the exhaust side of a reactor feedwater pump and connected by way of a closing valve to a spray nozzle provided in the drain tank. While the closing valve is usually closed to keep the water level constant in the drain tank, the closing valve is opened upon sudden decrease in the turbine power to charge the condensates by way of the cooling water feed pipe to the drain tank. Thus, the saturated ...
Analysis of a solar space cooling system using liquid desiccants
1990-12-01
For tropical countries, solar space cooling is an attractive proposition. Dehumidification of air in hot, humid climates is almost as important as cooling. Removal of moisture from the air is much easier to achieve than cooling the air. The proposed cooling system operates on the ventilation mode. The ambient air is dehumidified using liquid desiccants followed by adiabatic evaporative cooling. The desiccant soon becomes saturated with the water extracted from the air and can be regenerated by using solar energy. For this system, a simple expression is derived in this paper to predict the amount of heat removed from the space to be conditioned in terms of known initial parameters through a simplified vapor pressure correlation and effectiveness of the dehumidifier and the heat exchanger. The effect of ambient air conditions, solution concentration, the cooling water temperature and the effectiveness of the dehumidifier and the heat exchanger on the performance of the cooling system are also discussed in this paper.
2009-01-01
Cooling towers are equipment devices commonly used to dissipate heat from power generation units, water-cooled refrigeration, air conditioning and industrial processes. Water drift emitted from cooling towers is objectionable for several reasons, mainly due to human health hazards. It is common practice to fit drift eliminators to cooling towers in order to minimize water loss from the system. It is foreseeable that the characteristics of the installed drift eliminators, like their pressure drop, affect the thermal performance of the cooling tower. However, no references regarding this fact have been found in the reviewed bibliography. This paper studies the thermal performance of a forced draft counter-flow wet cooling tower fitted with different drift eliminators for a wide range of air ...
1996-10-01
The invented preheating system of cooling water of fuel cell power generation plant consists of a cooling water return system and a cooling water preheater. In the cooling water return system, the cooling water in the water/vapor separator is returned to the water/vapor separator by means of cooling water pump, bypassing the fuel cell. In the cooling water preheater, the cooling water flowing in the cooling water return system is heated by heat exchange with the fuel air which comes out of the fuel air preheater and flows in the fuel air supply system. With this structure, the following are performed: The flow rate of the cooling water flowing in the cooling water return system is controlled; the waste heat of the fuel exhaust gas is recovered by the heat exchange with the combustion air heated by the fuel exhaust gas of the fuel reformer by means of cooling water preheater; and the fuel cell is heated up at the time of start-up. So that the installation of electric heater or start-up boiler is not necessary. In addition, in case of low load power generation operation, the pressure control is done by using the combustion heat which is obtained by the direct combustion of town gas as the heat resource. So that the heat efficiency is increased as compared with the electric heating using the power generated by the fuel cell. 2 figs.
Fuel cell power generating system. Nenryo denchi hatsuden system
1993-02-19
The invention relates to a fuel cell power generating system using steam from the cell cooling water for reforming the fuel and aims to enable stable waste heat recovery by stable and continuous feeding of the cooling water of the fuel while the temperature and the pressure of the cooling water is kept to be constant. The invention concerns a fuel cell power generating system in which the generating electric current from the fuel cell is measured with a detector of the generating electric current, the obtained data is fed to a controller to calculate the amount of the steam necessary for the gas reforming and the rotational speed of the feeding pump of the cell cooling water is controlled to the feeding of the cell cooling water corresponding to the generating electric current with a controlling tool of the rotational speed. The invention provides also another construction installed with a pressure detection tool of the steam-water separator in which the signal from the pressure detection tool is fed the control tool of the rotational speed of the feeding pump of the cell cooling water to achieve the object of the invention. 6 figs.
After-heat removal system in BWR type reactor
1991-09-20
An after-heat removal system having a duel low pressure coolant injection mode (LPCI) selects an integral recycling loop based on a pressure difference between reactor recycling loops to inject emergency cooling water to the reactor. In this case, if the pressure difference between the recycling loops is less than such a pressure difference as capable of injecting a sufficient amount of cooling water to the reactor core, injection lines to both of the recycling loops are lined up. With such a constitution, the injection lines of LPCI can be retarded in most of the cases of requiring LPCI, to remarkably improve the reliability and sufficiently utilize the retardation of the four pumps. (I.S.).
Theoretical study of flashing and water hammer in a supercritical water cycle during pressure drop
2010-01-01
During a loss of coolant accident (LOCA) the pressure of the coolant can drop significantly in the vicinity of the leak. It will be shown that unlike in pressurized water reactors (PWRs) where this pressure drop can cause only sudden vaporization - also called flashing - in supercritical water cooled reactors (SCWRs) it can cause sudden condensation (condensation-induced water hammer), too. The reason is that from supercritical state the system can go to metastable liquid as well as to metastable vapour state after LOCA. Relaxation from metastable fluid states is a fast process, followed by a local positive or negative pressure-jump, which might increase the damage around the leak. Conservative estimation will be given for the magnitude of these pressure jumps caused by the flashing or water hammer by assuming various initial pressure losses. In our calculations, three ...
Effective stress and water pressure in saturated clays during heating-cooling cycles
1992-01-01
Experiments with heating and cooling cycles in undrained constant total stress conditions in triaxial apparatus are presented. Heating induces a large pore-water pressure increase, which eventually leads to a large irreversible strain and possible mechanical failure. Subsequent cooling produces a drop in water pressure. In one test the drop during cooling was more than two times higher than the previous increase during heating, reaching values of up to 2.30 MPa. An analysis of these findings in terms of a thermoplastic model is presented. The interpretation of these tests relies heavily on the kind of stress-partitioning hypothesis that is used. It was found that the phenomena described can be quantitatively dealt with using the classical effective stress principle, if the shear stress and consolidation are described in terms of temperature-dependent plastic yield ...
Operation of stationary cooling plants during winter. [USSR]
1985-08-01
The system used in Artemugol' mines to supply cool air to underground mine roadways is described. Brine (an aqueous CaCl/sub 2/ solution) is pumped from a stationary KhTMF-248-4000 cooling plant at the surface to high pressure heat exchangers underground. These deliver cooled water to ARVEh air coolers in the roadways. In winter the cooling plant is bypassed and the used cooling water is circulated from the heat exchangers via surface cooling towers to take advantage of atmospheric cold. For 3-4 months of the year water at 2-6 C is provided by the cooling tower; with a water flow rate of 800-1000 m/sup 3//h the tower has a cooling output of 3.5-4.5 MW. Power savings can amount to 1.6 MWh. The winter months can be used to carry out essential maintenance on the cooling plants.
This paper identifies the topics needed to understand pressurized water reactor response to an extended loss of residual heat removal event during refueling and maintenance outages. By identifying the possible plant conditions and cooling methods that would be used for each cooling mode, the controlling thermal-hydraulic processes and phenomena were identified. Controlling processes and phenomena include: gravity drain, core water boil-off, and reflux cooling processes. Important subcategories of the reflux cooling processes include: the initiation of reflux cooling from various plant conditions, the effects of air on reflux cooling, core level depression effects, issues regarding the steam generator secondaries, and the special case of boiler-condenser cooling with once-through steam generators. 25 refs., 6 figs., 1 tab.
This paper identifies the topics needed to understand pressurized water reactor response to an extended loss of residual heat removal event during refueling and maintenance outages. By identifying the possible plant conditions and cooling methods that would be used for each cooling mode, the controlling thermal-hydraulic processes and phenomena were identified. Controlling processes and phenomena include: gravity drain, core water boil-off, and reflux cooling processes. Important subcategories of the reflux cooling processes include: the initiation of reflux cooling from various plant conditions, the effects of air on reflux cooling, core level depression effects, issues regarding the steam generator secondaries, and the special case of boiler-condenser cooling with once-through steam generators. 25 refs., 6 figs., 1 tab.
1991-02-01
This paper identifies the topics needed to understand pressurized water reactor response to an extended loss of residual heat removal event during refueling and maintenance outages. By identifying the possible plant conditions and cooling methods that would be used for each cooling mode, the controlling thermal-hydraulic processes and phenomena were identified. Controlling processes and phenomena include: gravity drain, core water boil-off, and reflux cooling processes. Important subcategories of the reflux cooling processes include: the initiation of reflux cooling from various plant conditions, the effects of air on reflux cooling, core level depression effects, issues regarding the steam generator secondaries, and the special case of boiler-condenser cooling with once-through steam generators. 25 refs., 6 figs., 1 tab.
1991-02-01
This paper identifies the topics needed to understand pressurized water reactor response to an extended loss of residual heat removal event during refueling and maintenance outages. By identifying the possible plant conditions and cooling methods that would be used for each cooling mode, the controlling thermal-hydraulic processes and phenomena were identified. Controlling processes and phenomena include: gravity drain, core water boil-off, and reflux cooling processes. Important subcategories of the reflux cooling processes include: the initiation of reflux cooling from various plant conditions, the effects of air on reflux cooling, core level depression effects, issues regarding the steam generator secondaries, and the special case of boiler-condenser cooling with once-through steam generators. 25 refs., 6 figs., 1 tab.
Making geothermal more productive
2009-09-08
University of Utah researchers will inject cool water and pressurized water into a "dry" geothermal well during a five-year, $10.2 million study aimed at boosting the productivity of geothermal power plants and making ...
Experience with steam generator tubes in water-cooled nuclear power reactors
1978-04-01
Steam generator tube failures have been a persistent problem at many watercooled nuclear power stations. These include pressurized water reactors, pressurized heavy water reactors and boiling water reactors with secondary steam generators. Although the number of leaking tubes may be small, even a single leak can force a shutdown. And for a 1000 MWe reactor, the cost of replacement power could amount to $250,000 per day.
Cooling system for cooling the bits of a cutting machine
1984-06-26
The invention refers to a system for cooling the bits of a cutting machine and comprising a nozzle for the cooling water to be ejected under pressure, said nozzle being arranged at the area of the bit, the water supply to said nozzle being closable by means of a shutoff valve and the bit being supported on the bit holder for limited axial shifting movement under the action of the cutting pressure against the force of a spring and against the hydraulic pressure of the cooling water and the shutoff valve being coupled with the bit by means of a coupling member such that the shutoff valve is opened on shifting movement of the bit in direction of the cutting pressure. In this system the arrangement is such that the bit (6) has in a manner known per se the shape of a cap and is enclosing a bit shaft (3) adapted to be inserted into the bit holder (1), in that the cap-shaped bit (6) is supported on the shaft (3) for shifting movement in axial direction and in that the shutoff valve (11) and the coupling member (10) are arranged within the bit shaft (3). The coupling member is formed of a push rod (10) acting on the closure member (11) of the valve, said push rod being guided within a central bore (9) of the bit shaft and the closure member (11) closing the valve in opposite direction to the action of the cutting pressure and being moved in open position by the push rod (10) in direction of the acting cutting pressure.
Analysis of BDBA in RBMK-1500 reactor with long-term loss of heat removal from the core
2008-01-01
The Ignalina nuclear power plant (NPP) is a twin-unit with two RBMK-1500, graphite moderated, boiling water, multichannel reactors. The accident management guidelines for beyond design basis accidents (BDBAs) are in a stage of preparation at Ignalina NPP. The most challenging event from BDBAs is the unavailability of water sources for heat removal from fuel channels (FCs). Due to specific design of RBMK, there are a few possibilities for heat removal from reactor core by non-regular means: depressurisation of reactor cooling system (RCS) (if pressure in cooling circuit is high) and supply of water into cooling system from low pressure water sources, removal of heat from graphite stack by reactor gas circuit, removal of heat from reactor core using cooling circuit of control and protection ...
Cooling towers with counter flow principle
1982-10-01
The concept of counterflow means that the water which is to be cooled is sprayed and flows downwards. Air flow in the other direction from bottom to top. Such a counterflow cooling tower need a smaller quantity of air at a given cooling capacity due to the more favourable temperature difference. A further plus: if there is danger of frost the counterflow cooling tower is less susceptible for freezing that the cross-flow type. Further advantages: long service life, no corrosion, high stability at low maintenance expenditure, low ground pressure, short erection times. A further positive feature, which should not be underestimated is the extension capacity of existing plants. Some additional keyword information is provided.
Many of the in-core components in pressurized water reactors are constructed of austenitic stainless steels. The potential behavior of these components can be predicted using data on similar steels irradiated at much higher displacement rates in liquid-metal reactors or water-cooled mixed-spectrum reactors. Consideration of the differences between the pressurized water environment and that of the other reactors leads to the conclusion that significant amounts of void swelling, irradiation creep, and embrittlement will occur in some components, and that the level of damage per atomic displacement may be larger in the pressurized water environment.
1984-09-01
Experimental studies using a prototypical experimental flow model of a pressurized water reactor (PWR) demonstrate water hammer in the cold legs due to the admission of emergency core cooling (ECT). Such water hammer can occur in an actual PWR during reflood provided there exists a stratified flow of steam and water in the cold legs. The hydraulic conditions in an actual PWR making it susceptible to such water hammer are postulated in this report. Calculations, based on a published criterion for water hammer initiation, show that the amount of ECC administered by the high pressure safety injection system, is not great enough to produce liquid depths in the cold leg which can lead to slug formation and subsequent steam bubble collapse water hammer. However, a few water hammers can occur during ECC as the cold leg is being refilled. A simple analysis developed in this report calculates the water hammer pressures possible under these postulated flow conditions. Potentially dangerous water hammer pressures are predicted during reflood at high system operating pressures characteristic of a small-break loss-of-coolant accident. Similar calculations done for the geometry of the experimental apparatus were compared to measurements taken during water hammer. 28 figures.
An evaluation of the reactor concepts under consideration for remote military power plants is presented. The concepts include water-cooled and - moderated reactors, both direct and indirect cycle. organic-cooled and -moderated reactors, heavy-water-cooled and -moderated reactors. gas-cooled reactors, sodium- cooled graphite-moderated reactors, fast reactors, and fluid-fuel reactors. The limitations and advantages, technological status, economics, and future potential of each reactor are reviewed. From the reviews it is concluded that direct-cycle boiling-water and pressurized-water reactors are most suitable for applications requiring power before 1965. (C.J.G.)
The spent fuel pit of a pressured water reactor (PWR) nuclear power plant has sufficient coolant capacity that a safety rated cooling system is not required. A non-safety rated combined cooling and purification system with redundant branches selectively provides simultaneously cooling and purification for the spent fuel pit, the refueling cavity, and the refueling water storage tank, and transfers coolant from the refueling water storage tank to the refueling cavity without it passing through the reactor core. Skimmers on the suction piping of the combined cooling and purification system eliminate the need for separate skimmer circuits with dedicated pumps. 1 figures.
The spent fuel pit of a pressured water reactor (PWR) nuclear power plant has sufficient coolant capacity that a safety rated cooling system is not required. A non-safety rated combined cooling and purification system with redundant branches selectively provides simultaneously cooling and purification for the spent fuel pit, the refueling cavity, and the refueling water storage tank, and transfers coolant from the refueling water storage tank to the refueling cavity without it passing through the reactor core. Skimmers on the suction piping of the combined cooling and purification system eliminate the need for separate skimmer circuits with dedicated pumps.
The spent fuel pit of a pressured water reactor (PWR) nuclear power plant has sufficient coolant capacity that a safety rated cooling system is not required. A non-safety rated combined cooling and purification system with redundant branches selectively provides simultaneously cooling and purification for the spent fuel pit, the refueling cavity, and the refueling water storage tank, and transfers coolant from the refueling water storage tank to the refueling cavity without it passing through the reactor core. Skimmers on the suction piping of the combined cooling and purification system eliminate the need for separate skimmer circuits with dedicated pumps.
The spent fuel pit of a pressured water reactor (PWR) nuclear power plant has sufficient coolant capacity that a safety rated cooling system is not required. A non-safety rated combined cooling and purification system with redundant branches selectively provides simultaneously cooling and purification for the spent fuel pit, the refueling cavity, and the refueling water storage tank, and transfers coolant from the refueling water storage tank to the refueling cavity without it passing through the reactor core. Skimmers on the suction piping of the combined cooling and purification system eliminate the need for separate skimmer circuits with dedicated pumps.
Army Gas-Cooled Reactor Systems program: portable gas cooled reactor space heat feasibility study
1959-02-16
The study was made to determine the feasibility of utilizing waste heat from the Portable Gas-Cooled Reactor power plant for space heating. The report recommends a pressurized hot water recovery system, and outlines alternate methods that are considered less desirable.
An experimental study on feasibility of ex-vessel cooling through the external guide vessel
2000-11-01
This paper presents the results of a series of experiments for assessing the efficacy of ex-vessel cooling through the external guide vessel during a severe accident. Four tests were performed in the LAVA test facility at KAERI, varying the boundary conditions at the outer surface of the vessel. The first test was a dry condition test conducted without cooling the outside of the vessel. On the other hand, in the second test, the cooling of the vessel surface was produced by gravity-driven forced injection of water along the annular gap of 25 mm between the vessel and the external guide vessel. Water flow rate was about 0.85 kg/s and total mass of available water was 300 kg. For the evaluation of the water flow rate effect, the third test was performed with a pool type cooling in the annulus without any circulation of water. These two external cooling tests were performed under elevated pressure of about 1.6 MPa. Finally, the fourth test was conducted under atmospheric pressure to evaluate the effect of system pressure on boiling heat transfer characteristics. In the dry test and the pool type ex-vessel cooling test performed under atmospheric pressure, the vessel was failed by a melt penetration at about 40 degree upper position from the vessel bottom, which is coincident with the boundary of the Al{sub 2}O{sub 3}/Fe melt separated layers. On the other hand, in both of the ex-vessel cooling tests conducted under elevated pressure of about 1.6 MPa, the vessel didn't fail. Compared with the pool boiling test, the vessel experienced effective cooling due to the inlet flow in the forced flow test. Synthesized the results of the tests, it was shown that the heat removal with ex-vessel cooling through the guide vessel is feasible, but the additional evaluations should be performed to guarantee enough thermal margin. (author)
2009-03-15
Cooling towers are equipment devices commonly used to dissipate heat from power generation units, water-cooled refrigeration, air conditioning and industrial processes. Water drift emitted from cooling towers is objectionable for several reasons, mainly due to human health hazards. It is common practice to fit drift eliminators to cooling towers in order to minimize water loss from the system. It is foreseeable that the characteristics of the installed drift eliminators, like their pressure drop, affect the thermal performance of the cooling tower. However, no references regarding this fact have been found in the reviewed bibliography. This paper studies the thermal performance of a forced draft counter-flow wet cooling tower fitted with different drift eliminators for a wide range of air and water mass flow rates. The data registered in the experimental set-up were employed to obtain correlations of the tower characteristic, which defines the cooling tower's thermal performance. The outlet water temperature predicted by these correlations was compared with the experimentally registered values obtaining a maximum difference of {+-}3%. (author)
Safety analysis of a supercritical-pressure water-cooled fast reactor under supercritical pressure
2010-01-01
The supercritical-pressure water-cooled fast reactor (SWFR) is a fast spectrum supercritical water-cooled reactor (SCWR) studied by the University of Tokyo. The SWFR is designed as a two-pass core with an outlet temperature 500 deg. C. The SWFR has fuel channels cooled by downward flow, higher power density, and smaller coolant density reactivity feedback compared with Super LWR. This paper describes the safety analyses of abnormal events for the SWFR. SPRAT-F code is used for the safety analysis at supercritical pressure considering the downward flow cooled seed fuel channel. This code is based on a 1-D node junction model with point kinetics and decay heat calculations. Flow redistribution among parallel paths is calculated by pressure-loss balance and momentum conservation. The initiating events are selected from those of LWRs. For the safety analysis, nine abnormal ...
CFD MODELING AND ANALYSIS FOR A-AREA AND H-AREA COOLING TOWERS
2009-09-02
Mechanical draft cooling towers are designed to cool process water via sensible and latent heat transfer to air. Heat and mass transfer take place simultaneously. Heat is transferred as sensible heat due to the temperature difference between liquid and gas phases, and as the latent heat of the water as it evaporates. Mass of water vapor is transferred due to the difference between the vapor pressure at the air-liquid interface and the partial pressure of water vapor in the bulk of the air. Equations to govern these phenomena are discussed here. The governing equations are solved by taking a computational fluid dynamics (CFD) approach. The purpose of the work is to develop a three-dimensional CFD model to evaluate the flow patterns inside the cooling tower cell driven by cooling fan and wind, considering the cooling fans to be on or off. Two types of the cooling towers are considered here. One is cross-flow type cooling tower located in A-Area, and the other is counterflow type cooling tower located in H-Area. The cooling tower located in A-Area is mechanical draft cooling tower (MDCT) consisting of four compartment cells as shown in Fig. 1. It is 13.7m wide, 36.8m long, and 9.4m high. Each cell has its own cooling fan and shroud without any flow communications between two adjacent cells. There are water distribution decks on both sides of the fan shroud. The deck floor has an array of about 25mm size holes through which water droplet falls into the cell region cooled by the ambient air driven by fan and wind, and it is eventually collected in basin area. As shown in Fig. 1, about 0.15-m thick drift eliminator allows ambient air to be humidified through the evaporative cooling process without entrainment of water droplets into the shroud exit. The H-Area cooling tower is about 7.3 m wide, 29.3 m long, and 9.0 m high. Each cell has its own cooling fan and shroud, but each of two corner cells has two panels to shield wind at the bottom of the cells. There is some degree of flow communications between adjacent cells through the 9-in gap at the bottom of the tower cells as shown in Fig. 2. Detailed geometrical dimensions for the H-Area tower configurations are presented in the figure. The model was benchmarked and verified against off-site and on-site test results. The verified model was applied to the investigation of cooling fan and wind effects on water cooling in cells when fans are off and on. This report will discuss the modeling and test results.
CFD MODELING AND ANALYSIS FOR A-AREA AND H-AREA COOLING TOWERS
Mechanical draft cooling towers are designed to cool process water via sensible and latent heat transfer to air. Heat and mass transfer take place simultaneously. Heat is transferred as sensible heat due to the temperature difference between liquid and gas phases, and as the latent heat of the water as it evaporates. Mass of water vapor is transferred due to the difference between the vapor pressure at the air-liquid interface and the partial pressure of water vapor in the bulk of the air. Equations to govern these phenomena are discussed here. The governing equations are solved by taking a computational fluid dynamics (CFD) approach. The purpose of the work is to develop a three-dimensional CFD model to evaluate the flow patterns inside the cooling tower cell driven by cooling fan and wind, considering the cooling fans to be on or off. Two types of the cooling towers are considered here. One is cross-flow type cooling tower located in A-Area, and the other is counterflow type cooling tower located in H-Area. The cooling tower located in A-Area is mechanical draft cooling tower (MDCT) consisting of four compartment cells as shown in Fig. 1. It is 13.7m wide, 36.8m long, and 9.4m high. Each cell has its own cooling fan and shroud without any flow communications between two adjacent cells. There are water distribution decks on both sides of the fan shroud. The deck floor has an array of about 25mm size holes through which water droplet falls into the cell region cooled by the ambient air driven by fan and wind, and it is eventually collected in basin area. As shown in Fig. 1, about 0.15-m thick drift eliminator allows ambient air to be humidified through the evaporative cooling process without entrainment of water droplets into the shroud exit. The H-Area cooling tower is about 7.3 m wide, 29.3 m long, and 9.0 m high. Each cell has its own cooling fan and shroud, but each of two corner cells has two panels to shield wind at the bottom of the cells. There is some degree of flow communications between adjacent cells through the 9-in gap at the bottom of the tower cells as shown in Fig. 2. Detailed geometrical dimensions for the H-Area tower configurations are presented in the figure. The model was benchmarked and verified against off-site and on-site test results. The verified model was applied to the investigation of cooling fan and wind effects on water cooling in cells when fans are off and on. This report will discuss the modeling and test results.
1998-12-31
In medium-speed diesel engines higher and higher effective mean pressures and maximum firing pressures are used to obtain low specific engine price and high efficiency. This requires a high charge air pressure and cooling down of the charge air to a low temperature. Both of these factors will increase the formation of condensate in the charge air system. Condensed water is formed on the surface of the cooling plates in the charge air cooler. If the condensed water is not removed from the charge air, free water will sooner or later enter the cylinders. Condensed water can be removed from the charge air between the cooler and the receiver. This paper describes experience, observations of charge air and movements of water droplets, measurements on engines and how these factors are combined to form the basis for the design of an effective water mist catcher. (au)
2002-01-01
A safety analysis code for a high temperature supercritical pressure light water cooled reactor (SCLWR-H) with water rods cooled by descending flow, SPRAT-DOWN, is developed. The hottest channel, a water rod, down comer, upper and lower plenums, feed pumps, etc. are modeled as junction of nodes. Partial of the feed water flows downward from the upper dome of the reactor pressure vessel to the water rods. The accidents analyzed here are total loss of feed water flow, feed water pump seizure, and control rods ejection. All the accidents satisfy the criteria. The accident event at which the maximum cladding temperature is the highest is total loss of feedwater flow. The transients analyzed here are loss of feed water heating, inadvertent start-up of an auxiliary water supply system, partial loss of feed water flow, loss of offsite power, loss of load, and abnormal withdrawal of ...
Fuel cell power generating system. Nenryo denchi hatsuden system
1992-03-03
In a fuel cell power generating system, a cell stack composed of multiply layered unit fuel cells is accomodated in a cloesed pressure vessel, cooling water is introduced to a cooler through a cooling water loop and the water which absorbs the heat generated in the cell is separated into water and steam in a water-steam separator equipped in the outlet side of the cell stack. Moreover, the pressure vessel is purged periodically with inert gas such as nitrogen to prevent explosion or other dangers caused by inevitable gas leakage. The inert gas purge requires substantial costs of installation and operation. The invention aims to provide a cheaper tool of the gas purge of the pressure vessel and concerns a fuel cell power generating system in which a part of the steam released from the water-gas separator installed with the cooling water loop is introduced into the pressure vessel and purges the pressure vessel. The construction of the invention does not require the storage and the feeding apparatus of inert gas and enables cost reduction. 2 figs.
Theoretical study of flashing and water hammer in a supercritical water cycle during pressure drop
2010-01-01
During a loss of coolant accident (LOCA) the pressure of the coolant can drop significantly in the vicinity of the leak. It will be shown that unlike in pressurized water reactors (PWRs) where this pressure drop can cause only sudden vaporization - also called flashing - in supercritical water cooled reactors (SCWRs) it can cause sudden condensation (condensation-induced water hammer), too. The reason is that from supercritical state the system can go to metastable liquid as well as to metastable vapour state after LOCA. Relaxation from metastable fluid states is a fast process, followed by a local positive or negative pressure-jump, which might increase the damage around the leak. Conservative estimation will be given for the magnitude of these pressure jumps caused by the flashing or wat...
Closed loop system lowers service water temperature
1993-10-01
This article describes, Gulf States Utilities completed conversion of the service water system at River Bend station to a treated demineralized water closed loop system. The modification to this 63,000-gpm system required separating service water from the larger circulating water cooling system that cools the main condenser. New service water pumps were installed along with eight parallel plate and frame heat exchangers. The heat exchangers transfer heat from the service water system to a new service water cooling system. The cooling system is composed of a 63,000-gpm five-cell mechanical draft cooling tower, three cooling tower pumps, and eight automatic pressure flush strainers. Motor-operated valves, piping, and controls are also provided that allow automatic operation. This includes heat exchanger backflushing, strainer flushing, and tower fan operation to control temperature.
Study of fuel cladding materials for supercritical-pressure, light-water-cooled reactor
2000-07-01
As for preliminary screening test of fuel cladding materials for supercritical-pressure, light-water-cooled reactors (SCRs), mechanical and corrosion tests were conducted about several kinds of commercial materials, i.e. high Cr ferritic steels, austenitic stainless steels, high Ni alloys and Ti alloys. Corrosion and stress corrosion cracking (SCC) tests were done under supercritical water (SCW) and superheated steam conditions at 566C. Based on the results of these tests, cladding material candidates for SCRs were preliminarily evaluated. (author)
Equipment of after-heat removal system
1997-04-04
In a BWR type reactor, a connection line is disposed between an exit of a heat exchanger of an after-heat removal facility and an inlet of a filtration desalting device of a spent fuel pool cleaning and cooling facility to provide a cleaning function to a pressure suppression chamber, a spent fuel pool and a reactor. Spent fuel pool water is passed through a skimmer surge tank of the spent fuel pool cleaning and cooling facility, pressurized by a pump of the after-heat removal facility, cooled by the heat exchanger, passed through the connection line, cleaned by the filtration desalting device and returned to the spent fuel pool. The pool water in the pressure suppression chamber is pressurized by a pump of the after-heat removal facility and cleaned by the filtration desalting device of the spent fuel pool cleaning and cooling facility and returned to the pressure suppression chamber. Finally, reactor water is pressurized by the pump of the after-heat removal facility, passed through the heat exchanger and the connection line and then cleaned by the filtration desalting device of the spent fuel pool cleaning device and returned to the reactor. (N.H.)
Review of supercritical pressure reactor and steam cooled fast breeder reactor in the past
1998-01-01
The studies of supercritical water cooled reactor were developed for increasing thermal efficiency and improving steam condition of the nuclear power plant in 1950-1960: SCR-WH (by Westinghouse co.). SCP-GE (by General Electric co.). The conceptional designs of steam cooled fast breeder reactor (SCFBR or SCFR) were presented by Babcock and Wilcox co., and by Germany (Kernforschungszentrum Karlsruhe) in 1960. The study of steam-water power reactor (SWPR) was published by Russia in 1988, also. These reactors were a heavy water or graphite moderated-light water cooled reactor, and needed many suppression tubes and plenty of heavy water or graphite. Each core structure of the reactors was complex, large scale and very expensive. The supercritical pressure light water reactor, which is presented in the paper, is a once-through, direct-cycle, light water cooled reactor. The ...
Frazil ice concerns for channels, pump-lines, penstocks, siphons, and tunnels in mountainous regions
2009-01-01
This paper discusses frazil ice concerns associated with water-conveyance systems located in mountainous regions. Such systems commonly comprise open-water channels (or reservoirs) linked to pressurized conduits (pump-lines, penstocks, siphons, and tunnels) that pass water down, up, over, or through steep terrain. The discussion addresses fundamental aspects of frazil formation and behavior in flows undergoing substantial pressure changes. An important consideration for such flows is that increased pressure depresses the freezing temperature of water. As flow pressure subsequently decreases (e.g., on passing through a turbine, or rising up a pump-line), water may become supercooled and prone to form frazil. The melting of ice entering a pressurized conduit (e.g., a penstock) can cool water...
Preliminary study on water analyzer with optical measurement under neutron irradiation environment
2009-01-01
It is important to clarify the mechanism and to prevent the stress corrosion cracking (SCC) in order to control the water quality of primary cooling water in LWRs. It is also necessary to measure the concentration of some corrosive chemical species of the structural materials such as oxygen and hydrogen peroxide in the cooling water. Generally, the concentration of oxygen and hydrogen peroxide in the cooling water has been measured with sampled water outside the reactor, and the corrosive environment has been estimated. However, it is difficult to evaluate the accurate concentration of the corrosive chemical species by this method, because the species are varied due to the high temperature and pressure under neutron irradiation condition. Therefore, the in-situ water analyzer has been developed for the concentration measurement of corrosive chemical species. The analyzer ...
1999-01-01
The regulatory guide of the KTA defines the requirements of in-service inspections and monitoring activities to be performed in the pressurized components of the primary loop of water cooled reactors (LWR type reactors) following first criticality. (orig./CB)
Hydraulically controlled valve for a cool tower and the like
1992-06-16
This patent describes a cooling tower. It comprises a tower having a hollow core and at least one opening at a top portion thereof and at least one opening at a bottom portion; evaporative pads located over the at least one opening at a top portion of the tower; a pressurized water line; and a hydraulically timed water valve system; a float valve having a float sensor and a valve responsive thereto; and means for filling the primary tank when the float valve is open.
Application of radiation chemistry research to the operation of nuclear reactors
1982-01-01
The applications of radiation chemistry research in improving the operating efficiency of nuclear reactors are reviewed. Examples discussed are the inhibition of graphite moderator corrosion and prevention of carbon deposition in gas-cooled reactors, suppression of radiolysis of the cooling water in concrete pressure vessels, hydrogen formation following a loss of coolant accident in a PWR and improving the stability of decontamination reagents for water reactors.
Method and apparatus for secondary and tertiary recovery of hydrocarbons
1987-07-07
This patent describes an apparatus for secondary and tertiary recovery of hydrocarbons from oil fields comprising: a. a bipropellant generator capable of producing exhaust gases at supercritical pressures and temperatures; b. transport means for carrying the exhaust gases into a well bore, at least a portion of the well bore extending into a hydrocarbon bearing formation from which hydrocarbons are to be recovered; c. means for introducing water into the transport means; and d. a water cooling jacket extending into at least the upper portion of the well bore, the center of the cooling jacket receiving the exhaust gases from the transport means, means being provided for the introduction of chemical additives through a portion of the cooling jacket. A process is described for secondary and tertiary recovery of hydrocarbons from geological formations comprising: a. providing a well bore extending at least into the strata of the geologic formation containing the hydrocarbons to be recovered; b. providing at least the upper portion of the well bore with a cooling jacket, the cooling jacket being provided with a central, open portion; c. generating gases at supercritical temperatures and pressures; d. introducing water into the supercritical gases to form steam; e. forcing the mixture of supercritical combustion gases and steam through the central open portion of the cooling jacket and the well bore into the hydrocarbon strata; and f. adding chemical additives to the mixture of combustion gases and steam below the cooling jacket.
1997-12-01
Hydrogen peroxide has been evaluated in a pilot cooling tower system as an alternative to continuous chlorination and intermittent dosing with non-oxidizing biocides. Hydrogen peroxide demand in the cooling system was considerably higher than predicted based on its vapor pressure and spontaneous decomposition in alkaline waters. This might be explained by the selection of peroxidase and catalase positive organisms in the cooling water which decompose hydrogen peroxide to water and oxygen. Although continuous feed of 2 to 3 ppm of hydrogen peroxide failed to control the bulk water bacterial population, it did suppress the growth of sessile organisms. Hydrogen peroxide was found to be corrosive toward mild steel and copper. However this effect could be adequately controlled through the use of proprietary corrosion inhibitors. Deposit control agents selected for their ability to withstand oxidation by hydrogen peroxide were highly successful in maintaining a low rate of scale formation. Based on these observations and the environmentally friendly nature of hydrogen peroxide, its use as an alternative cooling water biocide should be further explored.
2007-08-15
This paper presents an open air-vapor compression refrigeration system for air conditioning and hot water cooled by cool water and proves its feasibility through performance simulation. Pinch technology is used in analysis of heat exchange in the surface heat exchanger, and the temperature difference at the pinch point is selected as 6 {sup o}C. Its refrigeration depends mainly on both air and vapor, more efficient than a conventional air cycle, and the use of turbo-machinery makes this possible. This system could use the cool in the cool water, which could not be used to cool air directly. Also, the heat rejected from this system could be used to heat cool water to 33-40 {sup o}C. The sensitivity analysis of COP to {eta} {sub c} and {eta} {sub t} and the simulated results T {sub 4}, T {sub 7}, T {sub 8}, q {sub 1}, q {sub 2} and W {sub m} of the cycle are given. The simulations show that the COP of this system depends mainly on T {sub 7}, {eta} {sub c} and {eta} {sub t} and varies with T {sub 3} or T {sub wet} and that this cycle is feasible in some regions, although the COP is sensitive to the efficiencies of the axial compressor and turbine. The optimum pressure ratio in this system could be lower, and this results in a fewer number of stages of the axial compressor. Adjusting the rotation speed of the axial compressor can easily control the pressure ratio, mass flow rate and the refrigerating capacity. The adoption of this cycle will make the air conditioned room more comfortable and reduce the initial investment cost because of the obtained very low temperature air. Humid air is a perfect working fluid for central air conditioning and no cost to the user. The system is more efficient because of using cool water to cool the air before the turbine. In addition, pinch technology is a good method to analyze the wet air heat exchange with water.
2007-08-15
This paper presents an open air-vapor compression refrigeration system for air conditioning and hot water cooled by cool water and proves its feasibility through performance simulation. Pinch technology is used in analysis of heat exchange in the surface heat exchanger, and the temperature difference at the pinch point is selected as 6 C. Its refrigeration depends mainly on both air and vapor, more efficient than a conventional air cycle, and the use of turbo-machinery makes this possible. This system could use the cool in the cool water, which could not be used to cool air directly. Also, the heat rejected from this system could be used to heat cool water to 33-40 C. The sensitivity analysis of COP to {eta}{sub c} and {eta}{sub t} and the simulated results T{sub 4}, T{sub 7}, T{sub 8}, q{sub 1}, q{sub 2} and W{sub m} of the cycle are given. The simulations show that the COP of this system depends mainly on T{sub 7}, {eta}{sub c} and {eta}{sub t} and varies with T{sub 3} or T{sub wet} and that this cycle is feasible in some regions, although the COP is sensitive to the efficiencies of the axial compressor and turbine. The optimum pressure ratio in this system could be lower, and this results in a fewer number of stages of the axial compressor. Adjusting the rotation speed of the axial compressor can easily control the pressure ratio, mass flow rate and the refrigerating capacity. The adoption of this cycle will make the air conditioned room more comfortable and reduce the initial investment cost because of the obtained very low temperature air. Humid air is a perfect working fluid for central air conditioning and no cost to the user. The system is more efficient because of using cool water to cool the air before the turbine. In addition, pinch technology is a good method to analyze the wet air heat exchange with water. (author)
Steam bubble condensation in sub-cooled water in case of co-current vertical pipe flow
2007-01-01
The structure of a steam-water flow in a vertical pipe of 195.3 mm inner diameter was studied using novel wire-mesh sensors for high-pressure/high-temperature operation (max 7 MPa/286 deg. C). Tests were carried out at pressures of 1 and 2 MPa under nearly adiabatic conditions as well as with slightly sub-cooled water (6 K at max). Steam was injected into sub-cooled water and condensed during the upwards flow. The evolution of radial gas fraction profiles and bubble size distributions along the pipe in a high-pressure steam-water flow was measured for the first time. The experimental data allow correlating the intensity of steam condensation in contact with sub-cooled water with the structure of the interfacial area and the bubble size distribution, which is very important for the model development. The data were used to test the complex interaction of local bubble ...
Emergency reactor core cooling device
1994-09-22
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 great amount of water can be stored in the reactor core upon occurrence of accidents. Further, since the number of high pressure type emergency reactor core cooling systems is increased from existent one to three systems, durability against rupture of medium diameter pipes can be increased. (I.S.).
2008-01-01
The paper presents the development, experimental analysis and simulation of a solar heat driven ammonia/water (NH3/H2O) diffusion-absorption cooling machine (DACM). The designed cooling capacity of the machine is 2.5kW for air-conditioning applications. The indirectly heated generator with its bubble pump is the main new feature of this cooling machine and it showed good performance for all prototypes constructed. A major challenge of the technology is the constant total pressure level in all components, which makes condensate distribution into the evaporator vertical tubes with no distribution pressure extremely difficult. As a consequence, the first prototype had problems in the auxiliary gas circuit, which only works with very low driving pressures and stops to work, when evaporation ra...
Method and apparatus for increasing air conditioner efficiency
1980-07-22
A description is given of an apparatus for increasing air conditioner efficiency by cooling the air conditioner compressor pump high temperature high pressure refrigerant gas outlet pipeline by water spray at the air conditioner condenser comprising means to treat water, said means including a fluid stabilizer rod in communication with the water to retain in the water particulate matter dissolved and suspended in the water; and means to bathe a portion of the compressor gas output pipeline with a spray of water so treated, said means including a nozzle and a shield to selectively direct the water to a portion of the pipeline, said nozzle located interiorly to said shield, and said shield attached to the air conditioner condenser adjacent said compressor gas output pipeline whereby the refrigerant gas is cooled by the spray of water and the particulate matter in the water does not precipitate out to form scale upon the compressor gas output pipeline or cooling fins of the air conditioner condenser. A method for increasing air conditioner efficiency by cooling the air conditioner compressor pump high temperature high pressure refrigerant gas output pipeline with water at the air conditioner condenser comprising the steps of: (A) treating water to retain in the water particulate matter dissolved and suspended therein, (B) sensing the air conditioner compressor pump input refrigerant gas pressure, and (C) sensing the compressor pump refrigerant gas output temperature, and (D) controllably bathing the compressor pump refrigerant gas output pipeline with the treated water in accordance with compressor input gas pressure and output temperature so sensed whereby the water carries off the heat from the high temperature high pressure refrigerant gas output pipeline and the pipeline is not scaled by the particulate matter in the treated water.
Wet quenching of incandescent coke
Method for the reduction of emissions from the wet quenching of incandescent coke in a quenching tower adapted to receive in its base a quench car containing the coke which comprises positioning the car with the coke in the quenching chamber of the tower, effecting a gas seal to substantially prevent air from infiltrating the quenching chamber and ascending the tower, quenching the coke with the resultant generation of steam and other quenching emissions, cooling and cleaning the emissions with water sprays, demisting the cooled emissions, sensing the external and internal pressures of the tower during the quenching process, maintaining a substantially zero gauge internal pressure by controlling the emissions flow exiting the tower and collecting, cooling and recycling the quenching and cooling waters. Apparatus for practicing the method is also disclosed.
Wet quenching of incandescent coke
1981-04-21
Method for the reduction of emissions from the wet quenching of incandescent coke in a quenching tower adapted to receive in its base a quench car containing the coke which comprises positioning the car with the coke in the quenching chamber of the tower, effecting a gas seal to substantially prevent air from infiltrating the quenching chamber and ascending the tower, quenching the coke with the resultant generation of steam and other quenching emissions, cooling and cleaning the emissions with water sprays, demisting the cooled emissions, sensing the external and internal pressures of the tower during the quenching process, maintaining a substantially zero gauge internal pressure by controlling the emissions flow exiting the tower and collecting, cooling and recycling the quenching and cooling waters. Apparatus for practicing the method is also disclosed.
Safety of a light water cooled reactor operating at supercritical pressure
1997-12-01
The concept of supercritical water cooled reactors is developed for the innovation toward cost reduction. Design and safety features of the reactor and the plant system are described. The reactor coolant system is the once-through direct-cycle. It is different from those of BWR and PWR. It is the simplest, but no natural circulation is established when main feedwater pumps are stopped. Safety system was designed based on the transient and accident analyses. Turbine driven auxiliary feedwater systems are provided for fast core cooling at LOSP. This reduces the capacity of emergency diesel generators in spite of the high system pressure. Accumulators are required for cooling the tight lattice core at LOCA. Safety of the reactor is evaluated by simplified PSA. The core damage frequency is maintained as the same level of Japanese conventional BWR due to the diversity of feedwater systems in the direct-cycle reactors. 13 refs., 8 figs., 6 tabs.
2006-01-01
For development of high heat flux components for fusion machines, JAERI has developed high performance cooling tubes using pressurized water flow. A cooling tube with triangular fins on its inner surface has been tested. Because the fins can be machined by a simple mechanical threading, this tube is called a screw tube. The present study is intended to investigate heat transfer characteristics of the screw tube with M10 thread of 1.5-mm-pitch, which has the highest critical heat flux (CHF) in the previous experimental campaign compared with the tubes with various threads of different pitches. In addition, another CHF tests have been performed to examine the reduction of the heat removal performance of the screw tube caused with the increase of cooling water temperature up to 100degreeC at ...
RELAP5-3D Code for Supercritical-Pressure Light-Water-Cooled Reactors
2003-04-01
The RELAP5-3D computer program has been improved for analysis of supercritical-pressure, light-water-cooled reactors. Several code modifications were implemented to correct code execution failures. Changes were made to the steam table generation, steam table interpolation, metastable states, interfacial heat transfer coefficients, and transport properties (viscosity and thermal conductivity). The code modifications now allow the code to run slow transients above the critical pressure as well as blowdown transients (modified Edwards pipe and modified existing pressurized water reactor model) that pass near the critical point.
Water Hammer Analysis of an Emergency Cooling System With the Presence of Air
2006-01-01
In this paper the effect of air presence in an emergency cooling system of a nuclear power plant during the pipelines pressurization stage is analyzed. The pressure waves propagation along the system pipelines after a fast pressurization of the water tanks is considered. The presence of different amounts of air in one pipe is analyzed. A code was developed to simulate the pressure waves propagation in the system. This code uses the classical Method of Characteristics (MOC) solving the mass and momentum equations. The two phase homogeneous model was used to represent the two-phase mixture in the pipe with presence of air. The maximal pressure in each pipe is calculated for the presence of different amounts of air in one pipe and a time ramp of 0.50 seconds for the operations of valves. The influence of the presence of air in the system is shown. (authors)
Passive containment cooling system with drywell pressure regulation for boiling water reactor
A boiling water reactor is described having a regulating valve for placing the wetwell in flow communication with an intake duct of the passive containment cooling system. This subsystem can be adjusted to maintain the drywell pressure at (or slightly below or above) wetwell pressure after the initial reactor blowdown transient is over. This addition to the PCCS design has the benefit of eliminating or minimizing steam leakage from the drywell to the wetwell in the longer-term post-LOCA time period and also minimizes the temperature difference between drywell and wetwell. This in turn reduces the rate of long-term pressure buildup of the containment, thereby extending the time to reach the design pressure limit. 4 figures.
Passive containment cooling system with drywell pressure regulation for boiling water reactor
A boiling water reactor having a regulating valve for placing the wetwell in flow communication with an intake duct of the passive containment cooling system. This subsystem can be adjusted to maintain the drywell pressure at (or slightly below or above) wetwell pressure after the initial reactor blowdown transient is over. This addition to the PCCS design has the benefit of eliminating or minimizing steam leakage from the drywell to the wetwell in the longer-term post-LOCA time period and also minimizes the temperature difference between drywell and wetwell. This in turn reduces the rate of long-term pressure buildup of the containment, thereby extending the time to reach the design pressure limit.
Passive containment cooling system with drywell pressure regulation for boiling water reactor
A boiling water reactor having a regulating valve for placing the wetwell in flow communication with an intake duct of the passive containment cooling system. This subsystem can be adjusted to maintain the drywell pressure at (or slightly below or above) wetwell pressure after the initial reactor blowdown transient is over. This addition to the PCCS design has the benefit of eliminating or minimizing steam leakage from the drywell to the wetwell in the longer-term post-LOCA time period and also minimizes the temperature difference between drywell and wetwell. This in turn reduces the rate of long-term pressure buildup of the containment, thereby extending the time to reach the design pressure limit.
Technological innovations of the EL-600 project. Recent results
From international nuclear industries fair; Basel, Switzerland (16 Oct 1972). Studies made on the EL-600 project, a pressurized heavy water cooled and moderated reactor, are presented. These emphasize study of the assembly technology and control techniques. (JSR)
Rating water cooled cathodes of xenon bulbs
1982-01-01
Based on the thermal balance, the basic design dimensions are identified of the cathodes of ultrahigh pressure xenon bulbs made of thoriated tungsten, which support the production on the operational face of a temperature of 2,600 to 2,900K, which corresponds to the maximal service life of the cathode.
1990-05-30
The steam generator of a sodium-cooled fast reactor is operated at sub-atmospheric pressure on the sodium side, in order to reduce the boiling point of the sodium. This will inhibit excessive temperature rise in the event of leakage which results in a sodium/water reaction. (author).
Code Case acceptability: ASME Section III materials. [BWR; PWR]
1976-11-01
The regulatory guide lists those Section III ASME Code Cases oriented to reactor coolant pressure boundary component materials and testing that are generally acceptable to the NRC staff for implementation in the licensing of light-water-cooled nuclear power plants.
Code Case acceptability: ASME Section III design and fabrication. [BWR; PWR]
1976-11-01
The regulatory guide lists those Section III ASME Code Cases oriented to reactor coolant pressure boundary component design and fabrication that are generally acceptable to the NRC staff for implementation in the licensing of light-water-cooled nuclear power plants.
AGU Journal highlights -- February 23, 2007
2007-02-23
In this issue: Ground rises at Naples volcano; Unclouded water-vapor measurements; Irrigation cools atmosphere; Undersea landslide sans methane; When sea heights reveal deep pressures; Ocean mixing near Japan; Shear ...
40 CFR 63.654 - Heat exchange systems.
...tube within the heat exchanger; (3) Changing...pressure so that water flows into the process...Replacing the heat exchanger or heat exchanger...ppmw, by the flow rate of the cooling...leaking tower or heat exchanger and by the...
Water-droplet cooling process in a steam-turbine bypass flow
1996-12-31
In industrial power plant operations the performance of a co-generator is equally important to that of a main gas turbine system. Controlling steam temperature in a bypass pipe system needs to be carefully performed by a cooling system in a steam turbine co-generator in order to enhance the system efficiency and life. This paper presents a study of the numerical simulations of a steam flow and heat transfer behavior when subjected to a cooling water spray in the pipe downstream from a high-pressure turbine bypass valve. The structure of a cooling water spray injected into a steam flow was studied for the purpose of developing a physical model to investigate the dissipation and evaporation processes of the cooling water droplets in a high temperature, high turbulent steam flow passage. Heat transfer rates were calculated for a better understanding of the temperature variations in the entire system. A dispersed two-phase model was incorporated for the particle tracking of the droplets injected into the steam flow and the water evaporation process was observed. Further, this study was continued by installing a perforated plate in the pipe section downstream from the water cooling injections. The results of the calculations are quite reasonable, and show a physically sound state.
Water requirements of nuclear power stations
2006-01-01
Currently the Government is undertaking a feasibility study into the possibility of establishing a nuclear power industry in Australia. Among the concerns raised about the development of a nuclear power industry in Australia is the amount of water consumed by nuclear power plants compared with other power stations. Nuclear power plants need more cooling water than fossil-fired power stations. This is because the steam in nuclear power stations is designed to operate at lower temperatures and pressures, which means they are less efficient at using the heat from the reactor and thus require more water for cooling. Publisher: Information and Research Service, Parliamentary Library Coverage: Australia
Segregation in aqueous methanol enhanced by cooling and compression
2004-12-16
Molecular segregation in methanol-water mixtures is studied across a wide concentration range as a function of temperature and pressure. Cluster distributions obtained from both neutron diffraction and molecular dynamics simulations point to significantly enhanced segregation as the mixtures are cooled or compressed. This evolution toward greater molecular heterogenity in the mixture accounts for the observed changes in the water-water radial distribution function and there are indications also of a change in the topology of the water clusters. The observed behavior is consistent with an approach to an upper critical solution point. Such a point would appear to be ``hidden'' below the freezing line, thereby precluding observation of the two-fluid region.
Water: Thermodynamic and Dynamic Anomalies
2009-01-01
While the majority of fluids contract upon cooling, water expands when cooled below T = 4 deg. C at atmospheric pressure. This effect is called density anomaly. Besides the density anomaly, there are more than 60 other anomalies known for water. Diffusivity is one of them. For normal liquids the diffusion coefficient decreases under compression. However, experimental results have shown that for water at temperatures below approximately 10 deg. C, the diffusion coefficient increases under compression and has a maximum. The temperature of maximum density line, inside which the density anomaly occurs, and the line of maximum in diffusivity are located in the same region of the pressure-temperature phase diagram of water. We show how simulations for water also show thermodynamic and dynamic anomalies. These anomalies are then demonstrated to be related to two length scales ...
CTR Fuel recovery system using regeneration of a molecular sieve drying bed
A primary molecular sieve drying bed is regenerated by circulating a hot inert gas through the heated primary bed to desorb water held on the bed. The inert gas plus water vapor is then cooled and passed through an auxiliary molecular sieve bed which adsorbs the water originally desorbed from the primary bed. The main advantage of the regeneration technique is that the partial pressure of water can be reduced to the 10.sup.-9 atm. range. This is significant in certain CTR applications where tritiated water (T.sub.2 O, HTO) must be collected and kept at very low partial pressure.
Performance improvement of the combined power plant for cooling and heating production
2006-07-01
Many industrial processes cause thermal pollution by ejecting heat into the environment at high temperatures. This paper presented optimization criteria for a refrigeration plant. The plant was first evaluated without the modification of functional parameters. A waste recovery system was then modelled to theoretically improve the plant's exergetic efficiency. The influence of intermediary pressure on the compression rate and refrigerating mass flow from the cooling plant was examined. Temperatures produced by the heat pump were analyzed for their exergetic efficiency. Results indicated that the water inlet temperature from the heat pump is an important parameter. Hot water mass flow was increased by decreasing the intermediary pressure. It was concluded that optimization measures should consider cooling loads and intermediary pressures during the design process. 5 refs., 7 figs.
2007-01-01
In China, the application of small size gas-fired air-cooled absorption refrigeration systems as an alternative for electric compression air conditioning systems has shown broad prospects due to occurrence of electricity peak demand in Chinese big cities and lack of water resources. However, for conventional air-cooled absorption refrigeration systems, it is difficult to enhance the heat and mass transfer process in the falling film absorber, and may cause problems, for example, remarkable increase of pressure, temperature and concentration in the generators, risk of crystallization, acceleration of corrosion, degradation of performance, and so on. This paper presents a gas-fired air-cooled adiabatic absorption refrigeration system using lithium bromide-water solutions as its working fluid, which is designed with a cooling capacity of 16 kW under standard ...
Design and develop speed/pressure regulator
1993-09-01
The Physics Division at Oak Ridge National Laboratory has several recirculating water cooling systems. One of them supplies deionized water at 150 psi, which is mainly used for cooling magnet windings at the Oak Ridge Isochronous Cyclotron (ORIC). The system has three 125-hp water pumps, each of which is capable of supplying water at the rate of 1000 gpm. One of the major requirements of this water supply system is that the supply pressure must be kept constant. An adjustable-frequency speed controller was recently installed to control the speed of one of the pump motors. A servo-system was provided with the adjustable-frequency controller for regulating motor speed and, subsequently, the water pressure. After unsuccessful attempts to operate the servo, it was concluded that the regulator may not work for the existing system. Prior to installation of the variable-frequency controller, pressure regulation was accomplished with a pneumatically controlled load by-pass valve. To maintain constant pressure in the system, it is necessary to run always at full load, even if full load is not on the system. Hence, there is a waste of energy when full load is not connected to the system. So, designing and implementing one regulator that works at any load condition has become necessary. This report discusses the design of such a pressure regulator.
Thermal-fluid assessment of the design options for reactor vessel cooling in a prismatic core VHTR
2010-01-01
The design of the reactor pressure vessel is an important issue in the VHTR design due to its high operating temperature. The extensive experience base in Light Water Reactor makes SA508/533 steel emerge as a strong candidate for the VHTR reactor vessel but requires maintaining the vessel temperature below the ASME code limit. To meet the temperature requirement, three types of vessel cooling options for a prismatic core VHTR are considered: an internal vessel cooling, an external vessel cooling, and an internal insulation. The performances of the vessel cooling options are evaluated by using a system thermo-fluid analysis code and a commercial computational fluid dynamics code during normal operation and accidents. The results suggested that the internal vessel cooling with the modified i...
Concept of a pressurized water reactor cooled with supercritical water in the primary loop
2010-01-01
A novel concept of a pressurized water reactor with a primary loop cooled with supercritical water is introduced and analyzed in this work. A steam cycle analysis has been performed to illustrate the advantages of such a nuclear power plant with respect to specific power and thermal efficiency. Moreover, a reactor pressure vessel concept including its internals and a suitable core and fuel assembly design are presented overcoming the problems, which arise due to the high heat up of the coolant and the density change involved with it. The core power and coolant density distributions are predicted with coupled neutronic and thermal-hydraulic analyses. The method features the definition of inlet orifices for coolant mass flow adjustment within the core as well as an additional tool for the in...
Deaerator for a fuel cell. Nenryo denchi ni okeru dakki sochi
1991-09-13
A large amount of oxygen is dissolved in the water recovered from an exhaust gas evolved from the fuel cell system or in a make-up water from such extrior system as city water. In order to remove this oxygen content, such water for treatment as recovered water or make-up water is heated up to the boiling state to remove most of the dissolved oxygen, thus attaining the level of approximately 10 ppb of dissolved oxygen which is required for a cooling water for a fuel cell. In this invention, a blow-down water extracted from the cell cooling system is used for heating this water to be treated to a boiling state. As the water in the cell cooling systom is usually in the pressurized state of 10 Kg/cm{sup 3}, and temperature of 160 to 180{degree}C, the water to be treated can be easily made boiling by the injection/mixing of the blow down water. In this case, an injection of the blow down water counterwise against the water to be treated which flows in the deaerator tank effectively enhances the effect of deaeration. 5 figs.
...systems for light-water nuclear power reactors. 50.46 Section 50.46...systems for light-water nuclear power reactors. (a)(1)(i) Each boiling...pressurized light-water nuclear power reactor fueled with uranium...
1975-12-01
This report considers the cooling-water requirement for 3 types of cooling systems generally used in Florida: cooling ponds, evaporative cooling towers, and once-through cooling. A distinction is made between the quantity of water withdrawn from a water supply for cooling purposes and the quantity of water that is consumed as a result of the cooling process. (GRA)
Proposal for Dual Pressurized Light Water Reactor Unit Producing 2000 MWe
2009-01-01
The Dual Unit Optimizer 2000 MWe (DUO2000) is put forward as a new design concept for large power nuclear plants to cope with economic and safety challenges facing the 21st century green and sustainable energy industry. DUO2000 is home to two nuclear steam supply systems (NSSSs) of the Optimized Power Reactor 1000 MWe (OPR1000)-like pressurized water reactor (PWR) in single containment so as to double the capacity of the plant. The idea behind DUO may as well be extended to combining any number of NSSSs of PWRs or pressurized heavy water reactors (PHWRs), or even boiling water reactors (BWRs). Once proven in water reactors, the technology may even be expanded to gas cooled, liquid metal cooled, and molten salt cooled reactors. With its in-vessel retention external reactor vessel cooling (IVR-ERVC) as severe accident management strategy, DUO can not only put the single ...
Active cooling-based surface confinement system for thermal soil treatment
A thermal barrier is disclosed for surface confinement with active cooling to control subsurface pressures during thermal remediation of shallow (5-20 feet) underground contaminants. If steam injection is used for underground heating, the actively cooled thermal barrier allows the steam to be injected into soil at pressures much higher (20-60 psi) than the confining strength of the soil, while preventing steam breakthrough. The rising steam is condensed to liquid water at the thermal barrier-ground surface interface. The rapid temperature drop forced by the thermal barrier drops the subsurface pressure to below atmospheric pressure. The steam and contaminant vapors are contained by the thermal blanket, which can be made of a variety of materials such as steel plates, concrete slabs, membranes, fabric bags, or rubber bladders. 1 fig.
Minimum pressure requirements at top of riser -- RDA DC-6, cooling water studies
1952-02-11
This report consists of a graph which plots the minimum requirements for the pressure at the top of riser after an electrical power failure verses time after the electrical power failure. Pressure is expressed in pounds per square inch. Points for shutdown of maximum operation and normal operation are given.
1982-01-01
The purpose of the PHEBUS installation is to study the behaviour of fuel for pressurized water reactors in simulated cooling conditions in accidental circumstances. The thermohydraulic and thermochemical behaviours of a pressurized water reactor core during a primary coolant loss accident (PCLA) of the ''large hole'' type, are described. The source reactor, as well as the test loop are also described. The adjustable and fixed test parameters are given. The programmes of tests in hand are then presented
2003-07-01
Several pressure tube reactor designs utilizing light water coolant in combination with heavy water moderator have/are being considered; for example, Gentilly 1, SGHWR, and more recently CANDU X and the ACR. PTR-1000 takes the next step, and eliminates the heavy water moderator; the result is a pressure tube PWR. The light water cooled and moderated Pressure Tube Reactor (PTR) design provides a water cooled reactor with substantially reduced capital cost relative to current reactors that are light water and/or heavy water cooled and moderated. To achieve these objectives, PTR avoids both the capital and operating costs associated with the heavy water utilized by CANDU Pressurized Heavy Water Reactors, and the expensive pressure vessel assembly required by Pressurized water reactors (PWRs). The reference 3000 MWth PTR-1000 reactor, with a net electrical output of about 1100 MW, consists of 438 vertical pressure tube assemblies arranged within an annular Reflector/Shield Tank (RST). The volume within the RST surrounding the fuel channels is filled with CO{sub 2}; no heavy water is utilized by PTR. PTR takes advantage of established CANDU technologies including the use of pressure tubes and on-power refueling. PTR can be designed and constructed based on existing technology; no research is required and development is limited to fuel CHF tests, fuel endurance tests, and fuel channel flow endurance testing. The latest in modularized construction technologies and advanced control system technologies are incorporated. (author)
Validation of accident analysis capability of MARS code during shutdown operation
2003-03-01
Various accidents are simulated to demonstrate the capability of MARS code for low power/shutdown accident. These are stuck open of PSV in POS2, loss of shutdown cooling accident in POS3, loss of shutdown cooling accident and loss of coolant accident in POS4, and loss of shutdown cooling accident with gravity feed from RWST in POS5. For these accidents, major thermal hydraulic variables, such as the RCS pressure, water level in the reactor vessel, the pressure and the water level in the steam generator, heat transferred through steam generators, total release of water outside of RCS, boiling time in the reactor core, the uncovery time in the core, and core damage time, are compared. The results of MARS code is very close to the results of RELAP5 code for these accidents. This means that the capability of MARS code is equivalent to the RELAP5 code in simulating accidents in shutdown condition.
1983-01-01
Light water reactor degraded core accident sequences have been postulated which lead to deposition of superheated debris beds in the reactor cavity. The debris beds are assumed to be cooled by an overlying pool of cooling water. The quenching of the debris is predicted to pressurize the containment building as a result of the steam generated during the quench process. Mechanistic models of debris bed quenching are required to predict the containment pressurization response to the steam and to the gases released from the concrete. The objective of this paper is to present recent experimental data for the rate of steam generation resulting from cooling of superheated packed beds of spheres by a saturated overlying pool of water. The effects of bed temperature and of sphere diameter are discussed.
1994-02-25
In a sealed pipe generated with a cooling cavity as a result of contraction of hot liquid due to cooling, opening a valve on one end of the pipe causes the cooling cavity depressurized close to the saturated vapor pressure to get collapsed with atmospheric pressure, where a water hammer or a transient phenomenon occurs. This paper describes a water hammer modeling experiment in which one cooling cavity generated at a closed end of a short pipe is collapsed. A calculation formula to derive the water hammering pressure has been sought, waveforms in the pressure variation in the water hammer to collapse the cooling cavity have been measured, and the liquid column impinging velocities have been estimated from the experiment. The collapsing water hammer for the cooling cavity has been modeled by means of combining the rigid body theory with a piston cylinder system, handling the air in the cavity as moist air, and connecting the water hammer system to thermodynamics of the cavity. Then, a numerical calculation incorporating an energy equation and heat transfer terms has been performed upon correcting the cavity shape in the heat transfer area and identifying the heat transfer coefficient. As a result, a simulated calculation has become possible on measured wave forms with large decay, which cannot be reproduced with pipe fraction or valve loss alone. 11 refs., 12 figs.
Critical heat flux in a heater rod bundle cooled by R-134a fluid near the critical pressure
2007-01-01
In the development of supercritical pressure water cooled reactors, it is important to understand the characteristics of a heat transfer near the thermodynamic critical point. An experimental study on the critical heat flux neat the critical pressure has been performed with a 5x5 square array heater rod bundle cooled by R-134a fluid (Pc=4.059 MPa, Tc=101degC). The critical power has been accurately measured up to the reduced pressure of 0.99 (4.03 MPa). The critical power decreases sharply at a pressure of about 3.8-3.9 MPa as the pressure approaches the critical pressure. For the low mass fluxes of 50 to 250 kg/m2, a sharp decrease in the critical power is not observed near the critical pressure. The CHF phenomenon near the critical pressure no longer leads to an inordinate increase in the heated wall temperature such as the case of DNB at ...
Low pressure corium dispersion experiments in the DISCO test facility with cold simulant fluids
2006-01-01
In a severe accident special pressure relief valves in the primary circuit of German Pressurized Water Reactors (PWR) will transfer a high pressure accident into a low pressure scenario. However, there may be a time window during late in-vessel reflooding scenarios where the pressure is in the order of 1 or 2 MPa at the moment of the reactor vessel rupture. A failure in the bottom head of the reactor pressure vessel, followed by melt expulsion and blowdown of the reactor cooling system, might disperse molten core debris out of the reactor pit, even at such low pressures. The mechanisms of efficient debris-to-gas heat transfer, exothermic metal/oxygen reactions, and hydrogen combustion may cause a rapid increase in pressure and temperature in the reactor containment. Integral experiments are necessary to furnish data for modeling these processes in computer codes, that will be ...
Keeping cool on the job. [Heat-resistant protective clothing]
1982-09-01
Maintenance workers at nuclear power plants need special protective clothing that slows overheating from the 55/sup 0/C temperature caused by waste heat from pipes and pressure vehicles. Cooling garments increase efficiency by extending the time workers can function, as well as safeguarding their health and morale. The Electric Power Research Institute evaluated two cooling concepts: circulating liquid suits already available on the market and a prototype frozen-water garment. Performance tests of the frozen-water suit found that it can more than double the 65-minute stay-time of liquid-cooled systems. The frozen-water garment permits mobility, is compatible with radiation protection and other garments and equipment, is easty to clean or decontaminate, has no moving parts, and is attractively priced. 4 figures. (DCK)
Cooling facility for reactor container
1994-11-15
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 cooling water. Since the liquid membrane is formed on the entire surface of the container with no drying of the outer surface, the area of cooling surface of the container can be increased, thereby enabling effective cooling. (T.M.).
Operational Experience of Cooling Water Systems for Accelerator Components at PLS
The cooling water system has been utilized for absorbing heat generated by a multitude of electromagnetic power delivering networks at PLS. The separate cooling water distribution systems for the storage ring, beam transport line and linear accelerator have been operated with a different operating temperature of supplying water. All water used for heat removal from the accelerator components are deionised and filtered to provide with over 2 MO-cm specific resistance. The operating pressures and flows of input water are also controlled with flow balancing scheme at a specified range. The operating temperature of components in the accelerator is sustained as tight as below ±0.1 deg C to minimize the influence of temperature fluctuation on the beam energy and stability. Although the PLS cooling systems were initially installed with a high degree of flexibility to allow for easy maintenance, a number of system improvements have been employed to enhance operational reliability and to incorporate the newly developed operating interfaces such as EPICS accelerator control systems. The important design and operational features of PLS cooling water systems are presented as well as lessons learned from around 10-years normal operation.
Pressure suppressing enclosure for nuclear reactor
1973-01-01
Purpose: To restrict considerably increase of pressure in dry well, and to reduce considerably depth of reactor enclosing space in order to be favorable to earth quake proof effect, by using toroidal air room surrounding dry well, said toroidal air room is connected to pressure suppressing room. Constitution: On accident of breaking in primary cooling system of reactor, steam vapor is burst into space of dry well and is introduced into water in pressure suppressing room through vent tube. Gas which is not condensed at pressure suppressing room is introduced into toroidal air room. (M. K.)
Fuel cell system; Nenryo denchi system
1994-08-12
The conventional cooling water system in the fuel cell system needs the water quality adjustment to the cell cooling water coming from the water source. It is, therefore, indispensable to have a water treatment equipment including an ion exchange resin for water quality adjustment and a supply water cooler for cooling down the temperature of supply water below the tolerable temperature of the ion exchange resin. According to this invention, the water supply is done in the following way: A water quality monitor is installed to monitor always the quality of cooling water which is circulating in the cooling water circulation system including the fuel cell cooling pipe, the cooling water circulation pump, and the steam separator. When the monitor detects the degradation of water quality of the cooling water, a part of the circulating water is discharged and the equivalent volume of cooling water is supplied from the cooling water supply system to the cooling water circulation system. In this way, the degradated cooling water is replaced by the fresh cooling water to prevent the degradation of water quality of cooling water which is circulating in the cooling water supply system. 5 figs.
1979-01-01
An emergency core coolant system is described that will, upon the improbable loss of coolant and resulting decrease in pressure in the reactor vessel, cause borated water to flow directly onto the reactor fuel assemblies. Borated water automatically flows from pressurized storage tanks, through backflow preventer valves, into a plenum below the reactor core lower support plate. Each fuel assembly in the reactor core is constructed with four perforated manifolds. The manifolds, one in each quadrant of each fuel assembly, extend the entire axial dimensial of the fuel assembly. These perforated manifolds are connected to a chamber integral with each fuel assembly.This chamber is located directly above openings in the core lower support plate. The borated water flows from the lower plenum into the perforated manifolds which eject coolant at various points along the entire length of the fuel assembly. High capacity injection pumps will continue to supply cooling water to the perforated manifold after the pressurized storage tanks are depleted.
1989-12-12
The present invention concerns a reactor container for advanced boiling water reactors (ABWR). A floor plate vertically partitioning the lower dry well is disposed in the reactor pedestal. Then, a water storing layer in communication with pool water in a suppression chamber is disposed to a plenum portion below the floor plate. During reactor operation, the floor plate is heated by the temperature elevation in the lower dry well and the radiation heat from the bottom of the reactor pressure vessel. However, if the water storing layer in the plenum portion is filled, the heat of the floor plate is directly cooled by the water storing layer in contact therewith, to suppress the temperature elevation of the floor plate in this way. Since the cooling function is provided to the floor portion below the reactor pressure vessel, it is possible to prevent the occurrence of thermal stresses and improve the adaptability to ABWR. (I.S.).
Electrochemistry of Water-Cooled Nuclear Reactors
2006-01-01
This project developed a comprehensive mathematical and simulation model for calculating thermal hydraulic, electrochemical, and corrosion parameters, viz. temperature, fluid flow velocity, pH, corrosion potential, hydrogen injection, oxygen contamination, stress corrosion cracking, crack growth rate, and other important quantities in the coolant circuits of water-cooled nuclear power plants, including both Boiling Water Reactors (BWRs) and Pressurized Water Reactors (PWRs). The model is being used to assess the three major operational problems in Pressurized Water Reactors (PWR), which include mass transport, activity transport, and the axial offset anomaly, and provide a powerful tool for predicting the accumulation of SCC damage in BWR primary coolant circuits as a function of operating history. Another achievement of the project is the development of a ...
Coupled neutronics and thermohydraulics calculations with burn-up for HPLWRs
2008-01-01
The HPLWR (High-Performance Light Water Reactor) is the European version of the SCWR (Supercritical-pressure Water Cooled Reactor) concept, which is one of the Generation IV reactors. In this reactor the primary water enters the core of the HPLWR under supercritical-pressure condition (25MPa) at a temperature of 280degreeC and leaves it at a temperature of up to 510degreeC. Due to the significant changes in the physical properties of water at supercritical-pressure the system is susceptible to local temperature, density and power oscillations. This inclination is increased by the pseudocritical transformation of the supercritical-pressure water used as primary coolant.At the Budapest University of Technology a coupled neutronics-thermohydraulics program system has been developed which is c...
Water chemistry in pressurized water reactors - A Goesgen-Daeniken-specific overview
2005-01-01
The three main water circuits of the Goesgen pressurized water reactor and their chemistries are described. In the primary water circuit the cooling water and its contents undergo chemical as well as radiochemical reactions. Chemical agents - such as boric acid - are used for long-term reactivity control. The boron concentration therefore is dictated by reactor physics and may not be optimal from a chemical viewpoint. Under the given circumstances the chemistry of the primary water circuit cannot be adjusted to a sole optimum covering all the tasks. Nevertheless it is possible to operate the power plant using a chemical regime that avoids excessive corrosion within the expected plant life time of 60 years. The water-steam cycle with its two phases must be conditioned chemically in a way to protect the water and steam side components from corrosion. This is done by adding hydrazine ...
2010-01-01
In sea water based once through cooling water system for power plants, sea water is pumped through the condenser and the return hot water is let back to sea. The cooling water pumps (CWP) in power plants generally operate at constant speed, pumping variable quantities of water depending on the tide level in the sea. The variable flow causes variation in condenser back pressure resulting in changes in the turbine cycle heat rate. If the pump speed is controlled using a variable frequency drive (VFD) to maintain design flow irrespective of the tide level, the CWP power consumption can be reduced compared to the case with constant speed CWP. However, the turbine cycle heat rate benefit that could have accrued at tide levels above the pre defined level (for fixing the CWP head) with constant s...
Analysis of BDBA in RBMK-1500 reactor with long-term loss of heat removal from the core
2008-01-01
The Ignalina nuclear power plant (NPP) is a twin-unit with two RBMK-1500, graphite moderated, boiling water, multichannel reactors. The accident management guidelines for beyond design basis accidents (BDBAs) are in a stage of preparation at Ignalina NPP. The most challenging event from BDBAs is the unavailability of water sources for heat removal from fuel channels (FCs). Due to specific design of RBMK, there are a few possibilities for heat removal from reactor core by non-regular means: depressurisation of reactor cooling system (RCS) (if pressure in cooling circuit is high) and supply of water into cooling system from low pressure water sources, removal of heat from graphite stack by reactor gas circuit, removal of heat from reactor core using cooling circuit of control and protection system channels, etc. The possibility to remove the heat using cooling circuit of ...
2009-01-01
Pressure tube reactors, especially of the CANDU-type, have a low-pressure vessel calandria - under an internal pressure near atmospheric. The calandria vessel is immersed into the water contained inside a concrete structure - the calandria vault. In the case of accidents with the loss of normal core heat sinks, the moderator inside the calandria (heavy water) could become the ultimate heat sink. Accident analysis using a newly developed model (ASQR) strengthens the importance of the inside cooling of the fuel channels in order to prevent severe accidents. Even if implementing those methods related to moderator for eliminating the impairment of the outside cooling of fuel channels, these are not sufficient. The new model has been compared against the well-known in-reactor LOCA experiment - PBF - NRU. Thus, the paper makes a review of author's article [Mehedinteanu, S., 2001. ...
Modeling and optimization of a novel pressurized CHP system with water extraction and refrigeration
2008-01-01
A novel cooling, heat, and power (CHP) system has been proposed that features a semi-closed Brayton cycle with pressurized recuperation, integrated with a vapor absorption refrigeration system (VARS). The semi-closed Brayton cycle is called the high-pressure regenerative turbine engine (HPRTE). The VARS interacts with the HPRTE power cycle through heat exchange in the generator and the evaporator. Waste heat from the recirculated combustion gas of the HPRTE is used to power the absorption refrigeration unit, which cools the high-pressure compressor inlet of the HPRTE to below ambient conditions and also produces excess refrigeration in an amount that depends on ambient conditions. Water produced as a product of combustion is intentionally condensed in the evaporator of the VARS, which is d...
A novel pressurized CHP system with water extraction and refrigeration
2010-01-01
A novel Cooling, Heat, and Power (CHP) system has been proposed that features a semi-closed Brayton cycle with pressurized recuperation, integrated with a Vapor Absorption Refrigeration System (VARS). The semi-closed Brayton cycle is called the High Pressure Regenerative Turbine Engine (HPRTE). The VARS interacts with the HPRTE power cycle through heat exchange in the generator and the evaporator. Waste heat from the recirculated combustion gas of the HPRTE is used to power the absorption refrigeration unit, which cools the high-pressure compressor inlet of the HPRTE to below ambient conditions and also produces excess refrigeration in an amount which depends on ambient conditions. Water produced as a product of combustion is intentionally condensed in the evaporator of the VARS, which is ...
Primary coolant feed and bleed operating regions for the Midland Plant
1985-03-01
Operating regions for primary coolant feed and bleed cooling are developed for the Midland Plant using core decay heat, the high-pressure injection (HPI) system capacity, and flow rate relief through the power-operated relief valve (PORV). This mode of cooling is used for accident scenarios in which the normal core cooling means of a nuclear power plant is lost because of loss of water inventory in the steam generators. The HPI flow is based on the capacities of one and two pumps. Saturated steam, saturated water, and subcooled water are considered to be possible states of the fluid being relieved through the PORV. In estimating the PORV relief rate, flow equations are derived from the Electric Power Research Institute test data obtained from the same model and size valve that is used in the Midland Plant. For easy reference by operators, the operating region is displayed on a plane of reactor coolant system pressure and temperature. The technique developed for the Midland Plant provides a convenient method for examining the feed and bleed cooling capability for a nuclear power plant that employs a pressurized water reactor system.
Modeling and experimentation of a novel pressurized CHP system with water extraction
2008-01-01
A novel cooling and power cycle is proposed, which combines a semi-closed cycle gas turbine called the high-pressure regenerative turbine engine (HPRTE) with a vapor absorption refrigeration system (VARS). This combined HPRTE/VARS cycle is capable of producing power, water and refrigeration effect for external loads. In a previous study, the combined cycle was modeled using zero-dimensional steady-state thermodynamics, with specified values of polytrophic efficiencies and pressure drops for the turbo-machinery and heat exchangers. In this study, a modified version of the combined HPRTE/VARS cycle is experimentally investigated for the demonstration of the combined cycle concept and for the model validation. This modified HPRTE has two water-cooled heat exchangers instead of the absorption ...
2002-01-01
The paper describes elements of design consideration of supercritical-pressure, light water cooled reactors as well as the status and prospects of the research and development. It summarizes the results of the conceptual design study at the University of Tokyo from 1989. The research and development started in Japan, Europe and USA. The major advantages of the reactors are 1. Compact reactor and turbines due to high specific enthalpy of supercritical water 2.Simple plant system because of the once-through coolant cycle 3.Use of the experience of LWR and fossil-fired power plants. The temperatures of the major components such as reactor pressure vessel, coolant pipes, pumps and turbines are within the experience, in spite of the high outlet coolant temperature. 4.Similarity to LWR safety design and criteria, but no burnout phenomenon 5.Potential cost reduction due to ...
2007-01-01
The preparation and size control for mono-dispersed fullerene C60 fine particles was successfully achieved during the high temperature and high pressure fluid (HTPL) crystallization process, in which acetone was used as the HTPL solvent and pure water or the mixture of acetone and water as the cooling solvent. The prepared fullerene C60 particles had spherical shape and narrow size distribution with the average size ranging from 44nm to 110nm depending on the various experimental conditions, such as fluid temperature, solvent flow rate, system pressure and the ratio of acetone and water in cooling solvent. The products were characterized by using X-ray powder diffraction (XRD), scan electron microscopy (SEM), dynamic light scattering technique (DLS) and UVVIS spectrum, respectively....
Cooling arrangement for water-cooled internal combustion engine
1986-10-14
A cooling arrangement is described for a water-cooled internal combustion engine. The cooling arrangement comprises a radiator, a water jacket of the internal combustion engine, a cooling water passage for circulating the cooling between the radiator and the water jacket, and a cooling water temperature detecting means for outputting signal related to the cooling water temperature detecting means for outputting signal related to the cooling water temperature. The cooling arrangement also includes a device for adjusting a circulating amount of the cooling water between the radiator and the water jacket, a cooling water temperature control means for periodically increasing and decreasing the cooling water circulating to the radiator. The control means operates the adjusting device in the direction to increase the circulating amount when the cooling water temperature is above a set value, and in a direction to decrease the circulating amount when the cooling water temperature is below a set value. An operating condition detecting means detects the operating condition of the internal combustion engine, and modifying means modifies the cooling water circulating amount in the increasing direction of the adjusting device and the circulating amount in the decreasing direction of the adjusting device by the cooling water temperature control means according to the signal received from the operating condition detecting means.
1996-07-01
Water in an overhead pool can serve as a general-purpose passive emergency heat sink for water-cooled reactors. It can be used for containment cooling, for emergency depressurization of the heat transport-system, or to receive any other emergency heat, such as that from the CANDU{reg_sign} moderator. The passive emergency water system provides in-containment depressurization of steam generators and no other provision is needed for supply of low-pressure emergency water to the steam generators. For containment cooling, the pool supplies water to the tube side of elevated tube banks inside containment. The elevation with respect to the reactor heat source maximizes heat transport, by natural convection, of hot containment gases. This effective heat transport combines with the large heat-transfer coefficients of tube banks, to reduce containment overpressure during accidents. Cooled air from the tube banks is directed past the break in the heat-transport system, to facilitate removal of hydrogen using passive catalytic recombiners.
The Spallation Neutron Source (SNS) is a facility being designed for scientific and industrial research and development. The SNS will generate and employ neutrons as a research tool in a variety of disciplines including biology, material science, superconductivity, chemistry, etc. The neutrons will be produced by bombarding a heavy metal target with a high-energy beam of protons, generated and accelerated with a linear particle accelerator, or linac. The low energy end of the linac consists of, in part, a multi-cell copper structure termed a coupled cavity linac (CCL). The CCL is responsible for accelerating the protons from an energy of 87 MeV, to 185 MeV. Acceleration of the charged protons is achieved by the use of large electrical field gradients established within specially designed contoured cavities of the CCL. While a large amount of the electrical energy is used to accelerate the protons, approximately 60-80% of this electrical energy is dissipated in the CCL's copper structure. To maintain an acceptable operating temperature, as well as minimize thermal stresses and maintain desired contours of the accelerator cavities, the electrical waste heat must be removed from the CCL structure. This is done using specially designed water cooling passages within the linac's copper structure. Cooling water is supplied to these cooling passages by a complex water cooling and temperature control system. This paper discusses the design, analysis, and testing of a water cooling system for a prototype CCL. First, the design concept and method of water temperature control is discussed. Second, the layout of the prototype water cooling system, including the selection of plumbing components, instrumentation, as well as controller hardware and software is presented. Next, the development of a numerical network model used to size the pump, heat exchanger, and plumbing equipment, is discussed. Finally, empirical pressure, flow rate, and temperature data from the prototype CCL water cooling tests are used to assess water cooling system performance and numerical modeling accuracy.
2002-01-01
The Spallation Neutron Source (SNS) is a facility being designed for scientific and industrial research and development. The SNS will generate and employ neutrons as a research tool in a variety of disciplines including biology, material science, superconductivity, chemistry, etc. The neutrons will be produced by bombarding a heavy metal target with a high-energy beam of protons, generated and accelerated with a linear particle accelerator, or linac. The low energy end of the linac consists of, in part, a multi-cell copper structure termed a coupled cavity linac (CCL). The CCL is responsible for accelerating the protons from an energy of 87 MeV, to 185 MeV. Acceleration of the charged protons is achieved by the use of large electrical field gradients established within specially designed contoured cavities of the CCL. While a large amount of the electrical energy is used to accelerate the protons, approximately 60-80% of this electrical energy is dissipated in the CCL's copper structure. To maintain an acceptable operating temperature, as well as minimize thermal stresses and maintain desired contours of the accelerator cavities, the electrical waste heat must be removed from the CCL structure. This is done using specially designed water cooling passages within the linac's copper structure. Cooling water is supplied to these cooling passages by a complex water cooling and temperature control system. This paper discusses the design, analysis, and testing of a water cooling system for a prototype CCL. First, the design concept and method of water temperature control is discussed. Second, the layout of the prototype water cooling system, including the selection of plumbing components, instrumentation, as well as controller hardware and software is presented. Next, the development of a numerical network model used to size the pump, heat exchanger, and plumbing equipment, is discussed. Finally, empirical pressure, flow rate, and temperature data from the prototype CCL water cooling tests are used to assess water cooling system performance and numerical modeling accuracy.
Evaluation of materials for EPR power generation
1979-01-01
The blanket materials employed for heat generation in the Argonne Expermental Power Reactor (EPR) are evaluated. The EPR blanket consists of annealed Type 316 stainless steel sections cooled by pressurized water and Inconel 718 sections cooled by steam. The predicted lifetimes of the two different blanket sections are approximately 2 years of normal operation. The lifetime of annealed Type 316 stainless steel is limited by swelling considerations, while the lifetime of Inconel 718 is limited by ductility considerations.
Performance enhancement of gas turbines by inlet air-cooling in hot and humid climates
2006-01-01
In this paper, a model to study the effect of inlet air-cooling on gas turbines power and efficiency is developed for two different cooling techniques, direct mechanical refrigeration and an evaporative water spray cooler. Energy analysis is used to present the performance improvement in terms of power gain ratio and thermal efficiency change factors. Relationships are derived for an open gas turbine cycle with irreversible compression and expansion processes coupled to air-cooling systems. The obtained results show that the power and efficiency improvements are functions of the ambient conditions and the gas turbine pressure ratio. The performance improvement is calculated for, ambient temperatures from 30 to 50degreeC, the whole range of humidity ratio (10-100%) and pressure ratio from 8...
1977-01-01
This is the final report of a six-month preliminary investigation into the applicability of the Chemical Heat Pump (CHP) for day-and-night, heating-and-cooling of residences with solar energy. The CHP consists of two containers and a joining conduit. Its working mechanism is the reversible absorption of water vapor onto a dessicant such as powdered magnesium chloride dihydrate in one container, the reversible evaporation of water in the other container, and the reversible passage of water vapor through the conduit. These vapor processes occur as consequences of differing temperatures imposed on the two containers. Thus, heating the absorber container with solar energy increases vapor pressure of the enclosed material and results in its dehydration, while simultaneously cooling the water container with ambient air, lowers vapor pressure and results in vapor condensation to liquid. When the absorber is no longer heated by the sun, the water will evaporate from the water container at ambient temperature and its vapors will condense onto the dessicant at a higher temperature with release of the heat of hydration. This energy, is used for heating the house. Additionally, evaporation of water from within the water container provides means for residential cooling in warm weather. Analytical and experimental procedures and results are detailed. (WHK)
1985-01-01
Flow oscillation phenomena have been studied as the problem when emergency core cooling water is injected at the time of LOCA in PWRs. As the result, it was clarified that water plugs are formed in pipes under a certain condition, and those oscillate in the vicinity of water injection nozzles. In this study, experiment was carried out with a small scale setup simulating the injection of emergency core cooling water in PWRs, and the effects of the throttles installed upstream and downstream of a water injection nozzle, the volume of steam part, the length of a water plug and the diameter of a pipe exerted on the change of pressure and temperature during oscillation were examined. Moreover, by applying the linear stability theory to the analysis model made on the basis of the observation of the phenomena, the threshold of oscillation occurrence was determined, and compared with the ...
2005-07-01
Full text of publication follows: A fundamental safety issue of liquid-metal-cooled fast breeder reactor (LMFBR) is to maintain the integrity of the secondary cooling system components against violent chemical sodium-water reaction caused by the water leak from the heat transfer tube of steam generators (SG). The produced sodium-water reaction jet would attack more severely surrounding tubes and would cause other tube failures (tube failure propagation), if it was assumed that the water leak was not detected by function-less detectors and proper operating actions to mitigate the tube failure propagation, such as isolations of the SG from the secondary cooling system and turbine water/steam system, and blowing water and steam inside tubes in the SG, were not taken. This study has been made focusing on the affection of large-scale water leak enlarged due to SG tube failure propagation to the structural integrity of the secondary cooling system because the generated pressure pulse caused by a large-scale sodium-water reaction might break heat transfer tubes of the intermediate heat exchanger (IHX). The present work has been made as one part of the study of probabilistic safety assessment (PSA) of LMFBR, because if the heat-transfer tubes of IHX were failed, the reactor core may be affected by the pressure pulse and/or by the sodium-water reaction products transported through the primary cooling system. As tools for PSA of the water leak incident of SG, we have developed QUARK-LP Version 4 code that mainly analyzes the high temperature rupture phenomena and estimates the number of failed tubes during the middle-scale water leak. The pressure pulse behavior generated by sodium-water reaction in the failure SG and the pressure propagation in the secondary cooling system are calculated by using the SWAAM-2 code developed by ANL. Furthermore, the quasi-steady state high pressure and temperature of the secondary cooling system in a long term is estimated by using the SWAAM-LT code also developed in ANL. In this preliminary work event trees have been prepared to make clear the scenario from the initial small-scale leak to the severest large-scale leak due to the tube failure propagation in SG. The probability of failures of leak detectors, nickel membrane-type hydrogen detectors in sodium and pressure gauges that observe the cover gas pressure of SG (EV: evaporator and SH: superheater), is considered in the event trees. On the other hand, rupture disks in SH and EV were assumed to have the normal function in leak detection and reaction products release. In some cases, water/steam blow valves to mitigate leak propagation were assumed hypothetically to fail after the plant trip, and the water and steam remained in SG are not released. A relation between the maximum leak rate resulting from the tube failure propagation and the probability of its occurrence was obtained tentatively from these considerations. Then, the effect of pressure generated by the sodium-water reaction was evaluated to the structural integrity of the secondary cooling system components. (authors)
Nuclear reactor with makeup water assist from residual heat removal system
A pressurized water nuclear reactor uses its residual heat removal system to make up water in the reactor coolant circuit from an in-containment refueling water supply during staged depressurization leading up to passive emergency cooling by gravity feed from the refueling water storage tank, and flooding of the containment building. When depressurization commences due to inadvertence or a manageable leak, the residual heat removal system is activated manually and prevents flooding of the containment when such action is not necessary. Operation of the passive cooling system is not impaired. A high pressure makeup water storage tank is coupled to the reactor coolant circuit, holding makeup coolant at the operational pressure of the reactor. The staged depressurization system vents the coolant circuit to the containment, thus reducing the supply of makeup coolant. The level of makeup coolant can be sensed to trigger opening of successive depressurization conduits. The residual heat removal pumps move water from the refueling water storage tank into the coolant circuit as the coolant circuit is depressurized, preventing reaching the final depressurization stage unless the makeup coolant level continues to drop. The residual heat removal system can also be coupled in a loop with the refueling water supply tank, for an auxiliary heat removal path. 2 figures.
1996-01-01
The features of the direct-cycle, supercritical-pressure, light-water-cooled fast breeder reactor (SCFBR) are high thermal efficiency and simple reactor system. The safety principle is basically the same as that of an LWR since it is a water-cooled reactor. Maintaining the core flow is the basic safety requirement of the reactor, since its coolant system is the one through type. The transient behaviors at control rod, pressure and flow-induced abnormalities are analyzed and presented in this paper. The results of flow-induced transients of SCFBR were reported at ICONE-3, though pressure change was neglected. The change of fuel temperature distribution is also considered for the analysis of the rapid reactivity-induced transients such as control rod withdrawal. Total loss of flow and pump seizure are analyzed as the accidents. Loss of load, control rod withdrawal from ...
Process for pressure stripping of sulfur dioxide from buffered solutions
A process for steam stripping sulfur dioxide from a buffered aqueous solution in which it is abosrbed in a flue gas desulfurization process is carried out at pressure greater than atmospheric. The process of pressure stripping of sulfur dioxide surprisingly results in increased steam economy as compared to stripping at atmospheric pressure and yields sulfur dioxide vapor which can be directly condensed to a liquid product with ordinary cooling water, eliminating the need for drying, refrigeration or compression operations. The high temperatures corresponding to high steam pressures enable economical use of stripping vessel overheads for preheating operations also. Stripping at pressures of 50 to 65 psig results in steam requirements which are only one-third to one-half of that at atmospheric pressure stripping. At the high pressures lower gas flow rates permit the use of more compact stripping equipment.
Process for pressure stripping of sulfur dioxide from buffered solutions
1979-02-20
A process for steam stripping sulfur dioxide from a buffered aqueous solution in which it is abosrbed in a flue gas desulfurization process is carried out at pressure greater than atmospheric. The process of pressure stripping of sulfur dioxide surprisingly results in increased steam economy as compared to stripping at atmospheric pressure and yields sulfur dioxide vapor which can be directly condensed to a liquid product with ordinary cooling water, eliminating the need for drying, refrigeration or compression operations. The high temperatures corresponding to high steam pressures enable economical use of stripping vessel overheads for preheating operations also. Stripping at pressures of 50 to 65 psig results in steam requirements which are only one-third to one-half of that at atmospheric pressure stripping. At the high pressures lower gas flow rates permit the use of more compact stripping equipment.
Recent progress in safety assessments of Japanese water-cooled solid breeder test blanket module
2008-12-15
This paper presents summary of preliminary safety assessment of the water-cooled solid breeder (WCSB) test blanket module (TBM) proposed by Japan for the ITER TBM test program. For the purpose of basic evaluation of source terms on nuclear heating and radioactivity generation, distribution of neutron flux, tritium breeding ratio, nuclear heating, decay heat and induced activity of radioactive waste are calculated. For the purpose of occupational radiological exposure evaluation, radiological isotope (RI) inventories, i.e., tritium in the breeder pebble bed, tritium in purge gas, permeated tritium in cooling system and active corrosion product (ACP) in the cooling system, are estimated. Failure mode effect analysis (FMEA) has been carried out for identification of the postulated initiating events (PIEs) that need safety evaluation. The PIEs are summarized into three groups, i.e., release of RI, pressurization and heatup. With respect to PIEs about release of RI, the maximum released RI is evaluated for three RI inventories, i.e., RI in vacuum vessel (VV) (tritium and radioactive dust), RI in purge gas (tritium) and RI in coolant (tritium and ACP). With respect to the PIEs about pressurization, the maximum pressures of the compartments nearby the pipes of cooling system are evaluated.
Modeling of natural circulation and steam condensation following a LOCA
1990-01-01
In the long-term cooling of a pressurized water reactor following a large cold-leg loss-of-coolant accident, there is an appreciable period during which there is an excess of cooling water, and the quantity of steam generated depends on the fraction of the emergency core cooling system (ECCS) water flowing through the core. Further, in plants designed by Babcock ampersand Wilcox (B ampersand W), the core-barrel vent valves allow some of the steam from the core to condense on the cold water in the downcomer and broken cold leg. The analysis described in this paper and incorporated in the STEAMCON program was devised to determine the rate of core flow and steam condensation at considerable periods after the break (e.g., t
MINLP optimization of mechanical draft counter flow wet-cooling towers
2010-01-01
In this paper, the problem of the optimal design of mechanical draft counter flow cooling towers that meets a set of specified constraints is formulated as a mixed-integer nonlinear programming (MINLP) problem. The Merkel's method is used to specify the characteristic dimensions of cooling towers, together with empirical correlations for the loss and overall mass transfer coefficients in the packing region of the tower. Water-to-air mass ratio, water mass flow rate, water inlet and outlet temperatures, operational temperature approach, type of packing, type of draft, height and area of the tower packing, total pressure drop of air flow, power consumption of the fan, and water consumption provide the set of optimization variables. The MINLP problem is formulated so as to minimize the total ...
Impact of advanced fluids on costs of district cooling systems
1992-01-01
Three alternate fluids, ice-water slurry, friction reduction additive and the combination of them, have been compared for use in District Cooling Systems (DCS). The effect of the fluids on cost and cooling capacities were considered for the two cases of new and existing DCS separately. Two criteria were used in comparisons among fluids in each case: constant pumping power which allows for the most benefit, and constant velocity which is more practical consideration. An economic assessment for a 500 ton system shows a potential cost difference in the total pipe cost for a new system of 70% when a 30% ice slurry is used in place of chilled water. The pipe diameter is reduced to 40% using the slurry. These results apply to the constant comparison and are independent of the use of additive. Friction reduction additives serve to reduce pumping power and pressure drop. The ice-water slurry also has a significant impact on existing district cooling systems. It can potentially expand the cooling capacity by 500% without new piping being installed while maintaining the same pumping power, velocity and pressure-drop as the chilled water system. Again, friction reduction additives serve to reduce pumping power and pressure-drop. They do not influence cooling capacity. The cost for expanding the piping to increase the cooling capacity by the same amount by the use of conventional district cooling technology has been shown to be extremely high compared to the ice-water slurry system.
Impact of advanced fluids on costs of district cooling systems
1992-07-01
Three alternate fluids, ice-water slurry, friction reduction additive and the combination of them, have been compared for use in District Cooling Systems (DCS). The effect of the fluids on cost and cooling capacities were considered for the two cases of new and existing DCS separately. Two criteria were used in comparisons among fluids in each case: constant pumping power which allows for the most benefit, and constant velocity which is more practical consideration. An economic assessment for a 500 ton system shows a potential cost difference in the total pipe cost for a new system of 70% when a 30% ice slurry is used in place of chilled water. The pipe diameter is reduced to 40% using the slurry. These results apply to the constant comparison and are independent of the use of additive. Friction reduction additives serve to reduce pumping power and pressure drop. The ice-water slurry also has a significant impact on existing district cooling systems. It can potentially expand the cooling capacity by 500% without new piping being installed while maintaining the same pumping power, velocity and pressure-drop as the chilled water system. Again, friction reduction additives serve to reduce pumping power and pressure-drop. They do not influence cooling capacity. The cost for expanding the piping to increase the cooling capacity by the same amount by the use of conventional district cooling technology has been shown to be extremely high compared to the ice-water slurry system.
Study of incident water hammer in an engineering loop under two-phase flow experiment
2010-01-01
Water hammer can occur in case of an inflow of sub-cooled water into pipes or other parts of the equipment filled with steam or steam-water mixture. The shock loading due to dynamic pressure during water hammer induces high stresses in the walls of piping especially in the bends. A study was carried out to analyze real life incident of water hammer wherein an attempt was made to recreate water hammer involving steam-water interaction in an instrumented engineering loop to capture pressure, temperature, flow rate and fluid levels in the loop. The arrival time of multiple shocks and the time lag between them is examined in the paper with the support of energy balance equation for variable flow processes.
2006-07-17
The objective of this study was to ascertain the condition of braze joints and cooling water hardware from an accelerator section after prolonged use. Metallographic analysis was used to examine critical sites on an accelerator section that had been in use for more than 30 years. The end flange assembly showed no internal operational damage or external environmental effects. The cavity cylinder stack showed no internal operational damage however the internal surface was highly oxidized. The internal surface of the cooling water tubing was uniformly corroding at a rate of about 1 mil per year and showed no evidence of pitting. Tee fitting internal surfaces are corroding at non-uniform rates due to general corrosion and pitting. Remaining service life of the cooling water jacket is estimated to be about 20 years or year 2027. At this time, water supply pressure will exceed allowable fitting pressure due to corrosion of tubing walls.
1978-10-01
Two processes that have the potential to produce degradation in the properties of pressure boundary materials are neutron irradiation and long-time thermal aging. This paper uses linear-elastic fracture mechanics techniques to assess the effect of these two processes upon the fatigue-crack growth behavior of a number of alloys commonly employed in reactor pressure boundaries. The materials evaluated include ferritic steels, austenitic stainless steels, and nickel-base alloys typical of those employed in a number of reactor types including water-cooled, gas-cooled, and liquid-metal-cooled designs.
Check valve test method using truncated accumulator blowdown
1987-01-01
A method is described for testing a normally closed check valve connected in series with an isolation valve at an outlet of an accumulator tank in a passive injection system for supplying liquid to a reactor cooling system in a pressurized light water nuclear power system. The passive injection system is connected to a low pressure system and supplies liquid to the reactor cooling system only during abnormally low pressure in the reactor cooling system. The accumulator tank has at least two upper taps and at least two lower taps with at least two standpipes each connected to a corresponding pair of upper and lower taps via valves and each of the standpipes having lower ends with drain valves connected. The method comprises of: (a) establishing a range for acceptance criteria applicable to test data provided by a test procedure (b) performing a preoperational test including the test ...
Study of spray cooling of a pressure vessel head of a boiling water reactor
2010-01-01
The present paper deals with a theoretical analysis of the spray cooling of a Reactor Pressure Vessel (RPV) head in a Boiling Water Reactor (BWR). To this end a detailed computational model has been developed. The model predicts the trajectories, diameters and temperatures of subcooled droplets moving in saturated vapor. The model has been validated through comparison with experimental data, in which droplet temperatures were measured as functions of the distance that they cover in saturated vapor from the moment they leave the sprinkler outlet to the moment they impact on the RPV head inner wall. The calculations are in very good agreement with measurements, confirming the model adequacy for the present study. The model has been used for a parametric study to investigate the influence of several parameters on the cooling efficiency of the spray system. Based on the study it has ...
2010-01-01
In the present study, mathematical modeling is performed to simulate the forced convection flow of Al2O3-water nanofluid in the radial flow cooling system using a single-phase approach. Computations are validated with experimental data available in the literature. Results show the same trend as revealed in most of the published works that the heat transfer coefficient increases with the increase of the Reynolds number and the nanoparticle volume fraction, though the increase in pressure drop is more significantly associated with the increase of particle concentration. When taking both the cooling performance and the adverse effect of pressure drop into consideration, no better heat transfer enhancement is found with the use of nanofluid compared to that of pure water under the laminar, med...
Isolation valve disposed to cooling system for FBR type reactor
1988-10-21
Purpose: To obtain an isolation valve with simple structure thus less possibility of failures, requiring short period of time from the occurrence of troubles to the valve actuation and having high reliability. Constitution: If sodium-water reaction should be caused by pipeway destruction accidents in a steam generator, high pressure generated due to the reaction propagates through sodium pipeways, which breaks the breaking plates and the high pressure is introduced by way of a releasing pipe to a pressure receiving chamber of a pressure accumulation cylinder. Then, the high pressure urges the piston to compress the compressible fluid in the pressure accumulation chamber. The pressure in the pressure accumulation chamber causes the release valve to open by way of the pressure pipe, to escape the pressure in a second cylinder chamber into atmosphere, etc., as well as introduce the pressure into a first cylinder to urge the piston and the valve rod to cause the valve closing operation. In this way, the isolation valve is actuated by utilizing the high pressure resulted upon sodium-water reaction to shorten the time required up to the closure of the valve. (Kawakami, Y.).
Joule-Thomson cooling due to CO2 injection into natural gas reservoirs
2007-01-01
Depleted natural gas reservoirs are a promising target for Carbon Sequestration with Enhanced Gas Recovery (CSEGR). The focus of this study is on evaluating the importance of Joule-Thomson cooling during CO2 injection into depleted natural gas reservoirs. Joule-Thomson cooling is the adiabatic cooling or heating that accompanies the expansion of a real gas. During CO2 injection into a natural gas reservoir, the pressure near the injection well declines rapidly as gas expands into the reservoir. If Joule-Thomson cooling during this expansion were large, injectivity and formation permeability could be altered by formation of hydrates, freezing of residual water, and fracturing due to thermal stresses. The TOUGH2/EOS7C module for CO2-CH4-H2O mixtures is used as the simulation analysis tool. For ...
Joule-Thomson cooling due to CO2 injection into natural gas reservoirs
2007-01-01
Depleted natural gas reservoirs are a promising target for Carbon Sequestration with Enhanced Gas Recovery (CSEGR). The focus of this study is on evaluating the importance of Joule-Thomson cooling during CO2 injection into depleted natural gas reservoirs. Joule-Thomson cooling is the adiabatic cooling or heating that accompanies the expansion of a real gas. During CO2 injection into a natural gas reservoir, the pressure near the injection well declines rapidly as gas expands into the reservoir. If Joule-Thomson cooling during this expansion were large, injectivity and formation permeability could be altered by formation of hydrates, freezing of residual water, and fracturing due to thermal stresses. The TOUGH2/EOS7C module for CO2-CH4-H2O mixtures is used as the simulation analysis tool. F...
Methods for evaluating the efficacy of biocides against sessile bacteria
1987-01-01
Dual pilot plant cooling towers were designed and constructed to conduct comparative evaluations of biocides in water systems. The towers were built with instrumentation used to control and monitor environmental parameters. The control of parameters such as pH and conductivity can be used to determine the impact of environmental conditions on biocidal activities. In this paper, the authors describe the cooling towers and give examples of methods that they have developed and incorporated into their cooling systems to detect biological fouling. These methods include a sessile (attached) bacteria monitor, and annual differential pressure device for calculating biological and/or inorganic fouling thicknesses, and an algae collection surface used for gravimetric analysis. The authors concentrated on detecting biological fouling because it is the sessile microorganisms that present the majority of the problems in cooling towers. These problems include pitting corrosion, reduced heat transfer efficiency, restricted flow, and reduced cooling tower performance.
Development of methods in the design of a test section for IRIS pressurizer simulation
2007-07-01
In Pressurized Water Reactors, the pressurizer is responsible for regulating the pressure control in the cooling system. This component consists of a two-phase chamber. By a conveniently controlled action of spray and heaters, pressure is maintained within acceptable bounds. The pressurizer conception in the innovative IRIS reactor is different when compared to a conventional PWR, giving rise to the need of additional analysis and experiments that may guarantee its performance. Nowadays, one of the important themes subjected to investigation is the homogenization of boron concentration in the circulating water between the primary and the pressurizer as a consequence of the new arrangement of the latter. The initial purpose of this work is to develop a set of conjugated methods that preserve the physical meanings of all mechanisms involved in the process, applying them in the design of a test section for carrying out experiments that simulate the conditions of the mixing of water from the primary circuit entering the IRIS pressurizer. Simplified equations based upon Plume Model will be used for dispersion analysis, taking into account temperature and boron concentration differences between the primary circuit water and that of the pressurizer. Fractional Scaling Analysis will be utilized to provide the conditions of similarity for the most relevant processes, which will help develop a reduced scale test section. (author)
1964-01-01
The core of this reactor consists of a vessel containing heavy water, through which pass a series of pressure tubes for circulation of the cooling gas under boat pressure. The basic specifications which greatly influenced the design of this construction relate to aspects of safety in operation (fuel loading from both faces of the reactor, replacement of the components on both faces), neutronic demands (minimum absorption of the components lattice parameter, diameter of the pressure tubes) and thermal considerations (output temperature 500 C). These specifications have led to a' horizontal arrangement of the pressure tubes and raised very difficult problems of clearance, which make it impossible (for the dimensions of EL 4) to resort to expansion bellows on the pressure tubes. The result is a semi-rigid vessel in which the pressure tubes contribute to a large extent the ...
Thermal Hydraulic Design of PWT Accelerating Structures
Microwave power losses on the surfaces of accelerating structures will transform to heat which will deform the structures if it is not removed in time. Thermal hydraulic design of the disk and cooling rods of a Plane Wave Transformer (PWT) structure is presented. Experiments to measure the hydraulic (pressure vs flow rate) and cooling (heat removed vs flow rate) properties of the PWT disk are performed, and results compared with simulations using Mathcad models and the COSMOSM code. Both experimental and simulation results showed that the heat deposited on the structure could be removed effectively using specially designed water-cooling circuits and the temperature of the structure could be controlled within the range required.
1979-01-01
These are the results of our investigations carried out on a packing inside a wet cooling tower for the purpose of studying the mass and heat transfer at the counterflow of water and humid air. The measurements on the experimental tower of the corresponding mathematical model reflect the average coefficient of mass and heat transfer for the unity of the active volume. Further the measurements of pressure drop at the air flow were carried out and thus the coefficient of aerodynamic losses were obtained. The results of measurements are given in the corresponding equations with the dimensionless numbers and diagrams. They will be of great use for the planning of new cooling towers. (author)
1989-11-01
The life of heating and cooling systems is influenced decisively by the heat carrier fluid. Another important factor influencing the choice of a heat carrier fluid is its envisaged application (cooling systems, solar systems, heat pump systems, heat recovery systems, water heating systems, central heating systems, energy roof systems). The heat carrier fluid 'Antifrogen' is presented along with the effects to be considered during planning. Heat transfer, pressure losses, materials selection, corrosion, and the protection time of the antifreeze are gone into. (BWI).
Safety concept and evaluation for the pressurized heavy water reactor Atucha II
1985-01-01
The safety concept for the KWU pressurized heavy-water reactor (PHWR) is based on the same features as that for the pressurized light-water reactor, e.g., reactor building consisting of a spherical steel containment and an outer concrete building with vented annulus in between. However, there are some specialities adherent to the PHWR. Safety related systems are designed to be both diverse and redundant. The moderator cooling system can be used as a high-pressure heat removal system, adding its effectiveness to the heat removal via the steam generators. For reactor shut-down a control rod system and a boron injection system exist independently. A safety evaluation has been performed via a probabilistic risk analysis. The assessed core damage frequency shows the same safety levels as with light-water reactors. The contribution of the different accident types proves the ...
A study on the effects of system pressure on heat and mass transfer rates of an air cooler
2002-01-01
In the present paper, the effects of inlet pressure on the heat and mass transfer rates of an air cooler are numerically predicted by a local analysis method. The pressures of the moist air vary from 2 to 4 bars. The psychometric properties such as dew point temperature, relative humidity and humidity ratio are employed to treat the condensing water vapor in the moist air when the surface temperatures are dropped below the dew point. The effects of the inlet pressures on the heat transfer rate, the dew point temperature, the rate of condensed water, the outlet temperature of air and cooling water are calculated. The condensation process of water vapor is discussed in detail. The results of present calculations are compared with the test data and shows good agreements
2007-01-01
In China, the application of small size gas-fired air-cooled absorption refrigeration systems as an alternative for electric compression air conditioning systems has shown broad prospects due to occurrence of electricity peak demand in Chinese big cities and lack of water resources. However, for conventional air-cooled absorption refrigeration systems, it is difficult to enhance the heat and mass transfer process in the falling film absorber, and may cause problems, for example, remarkable increase of pressure, temperature and concentration in the generators, risk of crystallization, acceleration of corrosion, degradation of performance, and so on. This paper presents a gas-fired air-cooled adiabatic absorption refrigeration system using lithium bromide-water solutions as its working fluid...
1989-10-01
Mastering the safety of chemical processes requires a quick-reading heating/cooling system, and it is also essential that no products should enter the cooling systems and travel from there into the discharged waste water. Both demands are largely met by a pressurized water cycle, which, as a closed heating and cooling system, avoids corrosion and also serves as intermediate cycle and hence as capture zone for possible contaminants. The integration of cryogenic and heat pump systems also permits flexible adaptation to the temperature control of a process, with attendant optimal energy saving and control possibilities thanks to two-component operation. (orig.).
1964-01-01
Bursting of a pressure tube in the tank of a heavy water moderated-gas cooled reactor is an accident which has been studied experimentally about EL-4. A first test (scale 1) having shown that the burst of a tube does not cause the rupture of adjacent tubes, tests on the tank resistance have been undertaken with a very reduced scale model (1 to 10). It has been found that the tank can endure many bursts of tube without any important deformation. Transient pressure in the tank is an oscillatory weakened wave, the maximum of which (pressure peak) has been the object of a particular experimental study. It appears that the most important parameters which affect the pressure peak are. The pressure of the gas included in the bursting pressure tube, the volume of this gas, the mass of air included in the tank and the nature of the gas. A general method to calculate the pressure peak value in reactor ...
MARS vessel safety analysis. LATA report No. 115
A previous study was performed to assess the hazards associated with an accidental leakage of cooling water into the crucible of molten /sup 238/U for the MARS laser isotope separation experiment. Since that study found that the probability of such an explosion is extremely low during an accidental cooling system failure, a study was conducted to define a more realistic design basis accident (DBA) for the final MARS configuration. If the vapor-phase explosion is considered to be a significant threat, the design criteria for the vacuum vessel should be a working pressure of 67 psig or 101 psig momentary single pulse equivalent static pressure.
MARS vessel safety analysis. LATA report No. 115
1979-08-01
A previous study was performed to assess the hazards associated with an accidental leakage of cooling water into the crucible of molten /sup 238/U for the MARS laser isotope separation experiment. Since that study found that the probability of such an explosion is extremely low during an accidental cooling system failure, a study was conducted to define a more realistic design basis accident (DBA) for the final MARS configuration. If the vapor-phase explosion is considered to be a significant threat, the design criteria for the vacuum vessel should be a working pressure of 67 psig or 101 psig momentary single pulse equivalent static pressure.
Influence of generic chemical additives on cooling-system performance: Final report
1988-07-01
Chemical additives are frequently used in recirculated cooling water systems to maintain heat transfer performance by preventing condenser tube scaling and corrosion. However, some of these same additives have also been suspected of potentially degrading cooling system performance either by decreasing the heat transfer film coefficient at the inner surface of the condenser tube or by reducing evaporation in the cooling tower. This report presents the results of a comprehensive literature search and subsequent theoretical evaluation of the influence of generic chemical additives on cooling system performance. Results indicate that, at the concentrations used in power plant cooling systems, additives have no significant detrimental effect on heat transfer in condenser tubes. In cooling towers, certain additives may act as a surfactant and suppress the hydrodynamic waves at the gas-liquid interface for a falling film of water. However, the additives do not change the film thermophysical properties, and, therefore, do not reduce the vapor pressure of the liquid at the surface, which is the driving force for evaporation.
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