Hitachi, Ltd.

Hitachi Engineering Co., Ltd.

Other

Tsuyoshi Niino

Kenji Tominaga

Yoshiyuki Kataoka

Isao Sumida

Tetsuo Horiuchi

Masanori Naitoh

Masataka Hidaka

Minoru Miki

Kanehiro Ochiai

Tohru Fukui

Shigeo Hatamiya

Kazuhito Koyama

Kumiaki Moriya

Tooru Takahashi

Hiroaki Suzuki

Toshitsugu Nakao

Shouichirou Kinoshita

Minoru Akita

Takashi Nakayama

Yuichi Uchiyama

Michio Murase

Ryuhei Kawabe

Tadashi Fujii

Shozo Yamanari

Masaki Matsumoto

Tadakazu Nakayama

Ryozo Tsuruoka

Matsuo Morikawa

Ryuji Kubota

Hideo Morishima

Toyoharu Yasuno

Kenji Moriya

Akihiko Shiozawa

Kazuo Kage

Shouichiro Kinoshita

Nobukatsu Iwata

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

A pressure control chamber of a reactor containment vessel for receiving the atmosphere of the reactor containment vessel containing leakage steam developing in the event of an accident includes a pressure control pool, and a wet well disposed above the pressure control pool. The wet well is divided into an inner peripheral portion and an outer peripheral portion. The inner and outer peripheral portions are communicated with each other via the pressure control pool. An outlet port for flowing the atmosphere of the reactor containment vessel containing the leakage steam is provided at the inner peripheral side of the pressure control pool. When the atmosphere of the reactor containment vessel containing the leakage steam is introduced into the pressure control pool in the event of the accident, this atmosphere is condensed by the water in the pressure control pool, and the gas of this atmosphere not condensed is accumulated in the inner peripheral portion of the wet well. As a result, the pressure within the inner peripheral portion is increased to increase the water level of the pressure control pool at the outer peripheral portion, so that the area of contact of a reactor containment vessel wall with the pressure control pool water is increased, thereby enhancing a heat radiation performance of the reactor containment vessel.

Reactor containment vessel

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 reactor system of a boiling water type atomic power plant including a reactor pressure vessel, a primary containment vessel containing the reactor pressure vessel, a main turbine, a main steam piping extending through the primary containment vessel between the reactor pressure vessel and the main turbine, and inside and outside main steam isolation valves provided on the main steam piping inside and outside the primary containment vessel, respectively. A closure valve is provided on the main steam piping at a position near the primary containment vessel and is adapted to quickly close in less than 3 seconds upon a break accident of the main steam piping. A volume of the reactor pressure vessel allotted for accommodating steam is correspondingly enlarged to allow the closure valve to quickly close upon a break accident of the main steam piping.

Reactor system

A natural circulation type boiling light-water reactor comprises a pressure vessel, a reactor core disposed within said pressure vessel to heat light water so as to generate main steam, a steam outlet provided in a wall of said pressure vessel for drawing out the main steam therethrough to supply the same to a turbine system, and a steam path along which the main steam flows from the reactor core to the steam outlet. The reactor further comprises a steam guide for prolonging the steam path and/or a radially increased chimney for reducing the velocity of the main steam flowing through the steam path. These causes radioactive isotope .sup.16 N contained in the main steam to flow within the pressure vessel for a time period exceeding its own half-life, so that the inventory of .sup.16 N in the main steam directed towards the turbine system is reduced remarkably. In consequence, shield structures for piping and turbine systems can be reduced in size and weight.

Natural circulation type boiling light-water reactor

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.

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Hitachi, Japan

Tsuyoshi Niino