Abstract: The mixing nozzle has a throat section, a diffuser section, a gas nozzle section, a first liquid suction port, a liquid nozzle section, a second liquid suction port, a baffle plate, and a jetting port. The first liquid suction port liquidly absorbs the solution in the water storage pool from a side of the gas nozzle section toward the gas nozzle tip. The liquid nozzle section extends to the downstream side of the gas nozzle section with intervening the first liquid suction port. The second liquid suction port liquidly absorbs the solution in the water storage pool from a side of the liquid nozzle section toward the liquid nozzle tip. The baffle plate is provided such that the mixed flow mixed in the diffuser section collides in front of a downstream end of the diffuser section, and divides and reverses the mixed flow.

Abstract: Disclosed is an ultrasonic Doppler flow measurment system that achieves flow measurement regardless of the temperature of a fluid. A temperature sensor 7 is combined with a pipe 1 to measure the temperature of a fluid 2. A controller 9 calculates a frequency that will cause cavitation when an ultrasonic transducer 4 exerts an ultrasonic vibration on the fluid 2 on the basis of a temperature measured by the temperature sensor 7 and controls a sinusoidal oscillator 6.

Abstract: A nuclear reactor containment vessel cooling equipment has: a dry well cooler casing in a containment vessel, having an opening at its top and a shutter at its lower part; a heat transfer tube arranged at an upper part in the dry well cooler casing; a forced cooling water circulation system for feeding cooling water from outside of the containment vessel into the heat transfer tube by a pump; a blower for mobilizing gas around the heat transfer tube; an external pool container arranged outside the containment vessel and above the heat transfer tube and containing cooling water; and a gravity-driven cooling system to supply cooling water in the external pool container into the heat transfer tube, utilizing gravity.

Abstract: Disclosed is an ultrasonic Doppler flow measurment system that achieves flow measurement regardless of the temperature of a fluid. A temperature sensor 7 is combined with a pipe 1 to measure the temperature of a fluid 2. A controller 9 calculates a frequency that will cause cavitation when an ultrasonic transducer 4 exerts an ultrasonic vibration on the fluid 2 on the basis of a temperature measured by the temperature sensor 7 and controls a sinusoidal oscillator 6.

Abstract: The present invention is to provide a reactor core that allows a nuclear plant to continuously operate for a long term period, for example 15 years or longer, without requiring any fuel exchange, reduces the duration and number of maintenance steps involved in regular plant inspections, markedly improves plant availability and economic efficiency, and is effective in terms of nuclear nonproliferation. A plurality of fuel assemblies 103, themselves obtained by arranging fuel rods 100 and water rods 107 in square lattices, are arranged in a square lattice at a certain pitch. The blades 102a of a cross-shaped (cruciform) control rod 102 in a cross section are inserted into four adjacent spaces formed by four fuel assemblies 100 facing each other. A value of 0.

Abstract: The present invention provides a boiling water reactor nuclear power plant in which a reactor core support plate, upper grid plate, and a reactor core consisting of fuel assemblies supported by these plates are provided in the inner base portion of a nuclear reactor pressure vessel. Control rod guide tubes and a reactor core shroud are positioned over the upper grid plate, and a control rod drive mechanism is provided further above same, whereby the control rods can be inserted from above the reactor core, and natural circulation of cooling water inside the reactor can be achieved by means of a chimney effect of the control rod guide tubes. According to the above structure, there can be provided a compact and economical nuclear power plant.

Abstract: A core inlet structure for coolant disposed in a reactor pressure vessel of a boiling water reactor includes a core support plate provided with a plurality of fuel support holes, a reinforcing beam supporting the core support plate, a plurality of control rod guide pipes standing perpendicularly and having upper end portions fitted to the fuel support holes, and a fuel support member inserted into upper end portions of the control rod guide pipes and supported by the core support plate so as to support lower end portions of fuel assemblies. An inlet orifice is formed to the fuel support member so as to adjust flow rate of a coolant flowing in the fuel assemblies, and a vortex control structure is provided for the inlet orifice or provided at a portion on a coolant upstream side of the inlet orifice.

Abstract: The present invention provides a boiling water-type nuclear power plant comprising: a passive safety system having depressurization valves and a gravity driven core cooling system as an emergency core cooling system; a passive containment vessel cooling system in which reactor steam released in the containment vessel is cooled by a heat exchanger in a cooling water pool installed in the upper portion of the containment vessel; and a containment vessel flooding system which injects cooling water into a dry well of the containment vessel on an accident; wherein a containment vessel spray cooling system for injecting cooling water into the containment vessel via a pump is further added as a safety system.

Abstract: The present invention provides a boiling water reactor nuclear power plant in which a reactor core support plate, upper grid plate, and a reactor core consisting of fuel assemblies supported by these plates are provided in the inner base portion of a nuclear reactor pressure vessel. Control rod guide tubes and a reactor core shroud are positioned over the upper grid plate, and a control rod drive mechanism is provided further above same, whereby the control rods can be inserted from above the reactor core, and natural circulation of cooling water inside the reactor can be achieved by means of a chimney effect of the control rod guide tubes. According to the above structure, there can be provided a compact and economical nuclear power plant.

Abstract: The present invention is to provide a reactor core that allows a nuclear plant to continuously operate for a long term period, for example 15 years or longer, without requiring any fuel exchange, reduces the duration and number of maintenance steps involved in regular plant inspections, markedly improves plant availability and economic efficiency, and is effective in terms of nuclear nonproliferation.

Abstract: A jet finishing machine comprises: a water nozzle (1) for spouting a water jet flow of water in a liquid phase; a steam nozzle (3) for increasing the speed of a steam flow (4) in a gas phase to an ultrasonic speed to produce a steam jet flow (11) and for spouting the steam jet flow in excess of a thermal equilibrium with the water jet flow; and a mixing nozzle (2) for mixing the steam jet flow with the water jet flow so as to allow the steam jet flow to accelerate the water jet flow to form a two-phase jet flow (12) of the water jet flow and the steam jet flow and for directly spouting the two-phase jet flow onto a work piece (5).

Abstract: A feed water heating system for heating a feed water for a power-generating plant having a steam turbine, a condenser and a steam generator, comprises: a steam injector unit for receiving a plurality of bled steams having different pressures extracted from the steam turbine and an effluent water discharged from the condenser to mix the effluent water with the plurality of bled steams to raise the temperature and pressure of a mixture of the effluent water with the plurality of bled steams to deaerate and discharge the temperature and pressure raised mixture.

Abstract: A separator/injector having an outlet pressure higher than an inlet pressure thereof is introduced instead of the dynamic equipment for a reactor recirculation system that is necessary in the prior art, to achieve both liquid-vapor separation and forced circulation. A jet pump and a recirculation flow-rate control valve are provided in a lower portion of a downcomer portion of a reactor pressure vessel. A shroud head has a double-walled structure, a two-phase liquid-vapor flow that is flowing from a lower portion of the lower shroud head is accelerated by an accelerator nozzle of the separator/injector, and a liquid component of the thus-separated flow is increased in pressure and guided into a jet pump through a space formed between the double shroud heads.

Abstract: A steam injector includes a casing having a water supply port and a steam intake port, the casing being generally composed of two halves fastened integrally, a water nozzle and a steam nozzle both disposed in the casing and communicated with the water supply port and the steam intake port, respectively, a steam-water mixing nozzle disposed on the downstream side in the casing and a diffuser disposed further downstream side in the casing. The steam injector further includes a guide member such as guide vane or spacer ring for guiding the steam to the steam-water mixing nozzle. The steam injector may includes a needle valve disposed in a steam jetting nozzle, disposed axially in the central portion of the casing, which is provided with a heat transfer preventing structure such as hollow wall structure provided on the outer peripheral surface of the steam jetting nozzle.

Abstract: A boiling water reactor comprises a reactor pressure vessel accommodated in a vertical fashion, a core disposed at a low portion in the reactor pressure vessel, a plurality of control rods to be inserted from an upper side of the core into the spaces between adjacent fuel assemblies and withdrawn therefrom upwardly, a shroud surrounding the fuel assemblies so as to define the core and having an upper end opening, a shroud head which closes the upper end opening of the shroud and through which the control rods are inserted or withdrawn, a separator standing upward from the shroud head to carry out gas-water separation of steam generated from the core, a fixing pedestal disposed above the separator, a control rod driving mechanism mounted on the fixing pedestal and adapted to drive the control rods, a drier unit including a plurality of drier elements annularly arranged along an upper inner wall surface of the reactor pressure vessel and adapted to dry the steam passing through the steam flow hole of the fixing

Abstract: A steam injector includes a casing having water supply port and a steam intake port, the casing being generally composed of two halves fastened integrally, a water nozzle and a steam nozzle both disposed in the casing and communicated with the water supply port and the steam intake port, respectively, a steam-water mixing nozzle disposed on the downstream side in the casing and a diffuser disposed further downstream side in the casing. The steam injector further includes a guide member such as guide vane or spacer ring for guiding the steam to the steam-water mixing nozzle. The steam injector may includes a needle valve disposed in a steam jetting nozzle, disposed axially in the central portion of the casing, which is provided with a heat transfer preventing structure such as hollow wall structure provided on the outer peripheral surface of the steam jetting nozzle.

Abstract: A steam injector system comprises a plurality of steam injectors each being provided with with a check valve adapted for water supply, a check valve adapted for steam supply, a check valve adapted for overflow and a check valve adapted for discharge and the respective water check valves, steam check valves, overflow check valves and discharge check valves are connected. In another aspect, a steam injector system comprises a plurality of first to last stage steam injectors arranged in series with each other, the last stage steam injector being provided with a relief valve disposed at a last stage overflow drain port, and a pressure pulsation absorbing device is disposed at least between the last stage overflow drain valve and the relief valve.

Abstract: In apparatus for measuring a void ratio by using radiation of the type comprising a hollow measuring unit through which fluid containing voids flows, a source of radiation and a radiation detector which are disposed on the opposite sides of the measuring unit, there is provided a rotary disc disposed between the measuring unit and the radiation detector and provided with a plurality of measuring openings which are equally spaced around a periphery of the rotary disc for transmitting the radiation.