Hitachi, Ltd.

Tomy Seiko Co., Ltd.

Hitachi Engineering Co., Ltd.

Other

Mitsubishi Denki Kabushiki Kaisha

Hitachi-ge Nuclear Energy, Ltd.

Kenji Tominaga

Tetsuo Horiuchi

Tsuyoshi Niino

Shozo Yamanari

Masanori Naitoh

Toshihiko Sugisaki

Shigeo Hatamiya

Yoshiyuki Kataoka

Kumiaki Moriya

Tooru Takahashi

Isao Sumida

Hiroaki Suzuki

Michio Murase

Masataka Hidaka

Tadashi Fujii

Minoru Miki

Kanehiro Ochiai

Shouichirou Kinoshita

Minoru Akita

Tohru Fukui

Takashi Nakayama

Yuichi Uchiyama

Masayuki Saito

Hiroshi Goto

Tsuneo Sato

Masashi Sugiyama

Toshitsugu Nakao

Hirohisa Satomi

Masaki Matsumoto

Tomoki Yoshimura

Yukihiro Katayama

Hitoshi Tate

Satoshi Miura

Kenji Moriya

Kazuo Kage

Ryuji Kubota

Hideo Morishima

Toyoharu Yasuno

Akihiko Shiozawa

Shouichiro Kinoshita

Ichirou Shimoda

Hideo Ogasawara

Syozo Yamanari

A recirculation pump motor is supplied with a power from a unit auxiliary middle voltage bus through a power supply system including a first circuit breaker, a voltage source inverter, and a second circuit breaker electrically connected in series to provide a no-load operation by use of the voltage source inverter. The second circuit breaker may be multiplexed with more than one breaker electrically connected in series. An existing nuclear plant using a induction motor driving a hydraulic coupling mechanically coupled to a synchronous generator for driving the recirculation pump, such as an MfG set, may be subjected to a method of replacing the induction motor, the hydraulic coupling, and the synchronous generator with the voltage source inverter and a circuit breaker through electrically disconnection and removal.

Nuclear power plant, method of replacement in the same and method of operating the same

A judgement section ( ) and a ratio calculation section ( ) in an image processing apparatus input image signals in digital form of n color components forming colors, transferred externally in time series, and calculate conversion parameters indicating change of ratios of signal strength values between input image signals per color component based on a total sum of the ratios of synthesis signal values, each conversion section ( ) and a signal range calculation section ( ) converts input image signals to output image signal without any change of the ratio of signal strength values between the input image signals based on the conversion parameters, per color component.

Image processing apparatus

Sterilizer

Nuclear reactor and nuclear reactor cooling facilities, and also a nuclear power generation plant and a method of its operation are disclosed. The reliability of cooling function at the time of anticipated accidents is substantially improved through enhancing a cooling efficiency of the gas in the reactor container without resorting to any particular active means. Guide structure is provided for circulating the gas present in the reactor container so as to accelerate heat removal therefrom to the outside through the surface of the reactor container. The arrangement includes an internal structure for retaining a coolant in the reactor container; and upper space portion disposed over the internal structure; a first gas flow passage for directing downward the gas present in the above upper space portion; and a second gas flow passage connecting the first gas flow passage with the upper space portion. Further, circulation structure is provided for circulating the gas in the above reactor container through utilization of the decay heat of the core. By means of the natural circulation through the wet well vapor phase including the upper space portion, with nitrogen gas (N.sub.2) rendered ubiquitous in the wet well vapor phase portion thereby the gas temperature being evenly distributed, it is possible to substantially improve the core decay heat removal efficiency in the reactor container by air cooling.

Nuclear reactor with cooling apparatus and method

A reactor containment facility having a reactor pressure vessel containing a core; a dry well in which the reactor pressure vessel is arranged; a suppression chamber holding suppression-pool water and forming above the suppression-pool water a wet well; and a plurality of vent pipes allowing the dry well to communicate with the suppression-pool water; a steel wall which is in contact with the suppression-pool water of the suppression chamber and which surrounds at least the pool water so as to form a containment vessel which houses the dry well and the suppression chamber; and an outer peripheral pool containing cooling water in contact with the outer peripheral surface of the steel wall. The facility further includes: a dividing structure for dividing the wet well of the suppression chamber into a first space which is in contact with the water surface of the suppression-pool water and a second space which is not in contact therewith; a first passage which allows the first space to communicate with the second space and which has an area smaller than that of the dividing device; and a cooling device for keeping the second space at a temperature lower than that of the first space.

Reactor containment facilities

There is disclosed a nuclear reactor installation. An accumulator-type emergency core cooling system, a gravity-driven core cooling system and an equalizing system for submerging a reactor core are provided within a primary containment vessel containing a reactor pressure vessel in which the reactor core is disposed. These cooling systems are automatically operated sequentially in accordance with the pressure in the reactor pressure vessel without the need for any particular powered source. The primary containment vessel is made of steel, and the interior of this containment vessel is divided into a space containing the reactor pressure vessel and a space containing an operation floor in such a manner that the two spaces are isolated from each other. An opening device is provided between the two spaces so as to communicate the two spaces with each other in the event of an accident, the upper portion of the primary containment vessel being air-cooled while the lower portion of this containment vessel being water-cooled.

Nuclear reactor installation

Centrifuge

A nuclear reactor facility including a primary containment vessel, a reactor pressure vessel installed in the primary containment vessel and accommodating a reactor core in a lower part thereof, and a vertical cylindrical wall disposed in a lower part of the primary containment vessel around and spaced from the reactor pressure vessel so as to delimit an annular space therebetween. The vertical cylindrical wall has an upper end disposed at a position higher than an upper end of the reactor core and a diaphragm extends substantially horizontally between the upper end of the vertical cylindrical wall and an inner wall of the primary containment vessel for cooperating with the vertical cylindrical wall to separate a space in the primary containment vessel around the reactor pressure vessel into a pressure suppression chamber and a drywell which includes annular space. The pressure suppression chamber accommodates therein a pool of liquid coolant wherein a level of the liquid coolant of the pool is higher than the upper end of the reactor core. The vertical cylindrical wall has a plurality of vent passages having an upper part at the upper end of the vertical cylindrical wall and exposed to the drywell and a lower part exposed to the pool of the liquid coolant in the pressure suppression chamber. A submergence line and a channel member are also provided.

Nuclear power facilities

A container-outer-periphery pool in which water is stored is provided between a primary containment vessel and a reactor building, and outside of a pressure suppression pool. Consequently, the natural heat transfer capabilities of reactor facilities is enhanced, and the inherent safety of the reactor facilities is improved.

The present invention is to provide an improved container rotor for use in a centrifugal separator which can serve different types of the centrifugal separating operation by the employment of a specific rotor which allows three types of bucket to be exchanged readily with one out of the swing type, the angled aperture type and the horizontal aperture type accordingly to the kind of specimen to be separated, which comprises, in combination, a rotor body and a plurality of buckets, wherein the rotor body includes receiving recesses and an opposed pair of supports for receiving operatively the plurality of buckets, the buckets being adapted to afford three different types of centrifugal separating operations, i.e., the swing type, the angled aperture type and the horizontal aperture type.

Container rotor for a centrifugal separator

An emergency reactor core cooling structure comprises a flow passage provided on an upper core plate so as to extend downward therefrom into the core. The flow passage has an orifice member at a lower portion thereof. The orifice member has such a portion that the cross-sectional area of the flow passage is made minimal at the orifice member. The flow passage causes the cooling water held on the upper plate by vapor flowing up on an accident to flow down therethrough, whereby the core is cooled rapidly.

Emergency reactor core cooling structure

Two systems of low-pressure core spray appratuses have coolers, and are adapted to supply cooling water to a core spray header provided in a core-surrounding cylindrical shroud in a reactor pressure vessel. Two systems of high-pressure core flooding apparatuses and one system of high-pressure coolant injection apparatus are adapted to supply the cooling water to a region formed between the shroud and reactor pressure vessel. The elevation of the openings, which are in the reactor pressure vessel, of the high-pressure core flooding apparatuses and high-pressure coolant injection apparatus are higher than that of the core spray header. A pipe for returning the cooling water in the reactor pressure vessel to the above-mentioned coolers is connected to either the portion of the interior of the reactor pressure vesssel which is below the core or the portion of the interior of the reactor pressure vessel which is between the walls of the shroud and reactor pressure vessel. The above-mentioned pipe is provided therein with a valve which is adapted to be closed when the nuclear reactor stops being operated in an emergency in which the breakage of a pipe occurs, and to be opened when the nuclear reactor is stopped under normal conditions.

Emergency core cooling apparatus

A containment vessel for a nuclear reactor having a dry well for mounting therein a pressure vessel for containing the nuclear reactor, a pressure suppressing chamber having a pool of coolant therein, and a vent pipe device for releasing therethrough into the pool of coolant within the pressure suppressing chamber steam which will be produced as a result of the occurrence of an accident and escape into the dry well. The vent pipe device includes a plurality of vent pipe members inserted in the pool of coolant within the pressure suppressing chamber and each having at least one exhaust port opening in the coolant. The vent pipe members are divided into a plurality of groups in such a manner that the vent pipe members of different groups differ from one another in the length of submerged portions of the vent pipe members interposed between the liquid of the coolant within the pressure suppressing chamber and the exhaust ports of the vent pipe members.

Containment vessel for a nuclear reactor

A device having a tubular body of an increased diameter closed at its bottom and connected at its top to the lower end of a vent pipe in such a state that the tubular body is immersed in a water pool. The tubular body is formed in its side wall with a multitude of openings for venting steam therethrough to the water pool to condense the same.

Vent exit device for condensing steam

Fuel assemblies forming the core of a nuclear reactor each include an open-ended tubular channel, upper and lower tie plates formed therein with a multitude of through holes and arranged in the vicinity of upper and lower ends of the tubular channel respectively, and elongated fuel elements located parallel to one another and extending between the upper and lower tie plates. The channel of each fuel assembly is formed in its walls with openings which are disposed below the upper tie plate and above the upper end edge of the fuel of each fuel element.

Fuel assembly for a nuclear reactor

Growing community of inventors

Tokyo, Japan

Kenji Tominaga