Hitachi, Ltd.

Hitachi-ge Nuclear Energy, Ltd.

Hisamichi Inoue

Naoyuki Ishida

Yoshiyuki Kataoka

Moriaki Tsukamoto

Masanori Naitoh

Michio Murase

Hiroaki Suzuki

Takashi Ikeda

Toshihiko Sugisaki

Masanori Naioh

A nozzle apparatus of a jet pump includes a nozzle base member, and a plurality of nozzles installed to the nozzle base member and forming a plurality of narrowing portions, in which a fluid passage cross-sectional area of a driving fluid passage formed in the nozzle is reduced.

Jet pump and reactor

A jet pump has a plurality of nozzles installed to a nozzle base, a throat and a diffuser. A first nozzle straight-tube portion, a first nozzle narrowing portion, a second nozzle straight-tube portion, a second nozzle narrowing portion, and a nozzle lower end portion formed in those nozzles are disposed in this order from the nozzle base to a ejection outlet. A narrowing angle of the second nozzle narrowing portion is larger than of the first nozzle narrowing portion. The jet pump forms, in a lower end portion of the throat, a flow passage narrowing portion having a flow passage cross-sectional area that gradually diminishes. This flow passage narrowing portion is inserted into an upper end portion of the diffuser.

Jet pump and nuclear reactor

Disclosed is an alkali metal thermoelectric power generator comprising a plurality of thermoelectric converters, which are connected in electrical series to one another by an external electronic conductor device, each of the converters converting thermal energy into electrical energy by utilizing the phenomenon that an alkali metal, arranged on each side of a solid electrolyte, diffuses across the electrolyte if the density thereof on one side of the electrolyte differs from that on the other side of the same. The generator further comprises a piping consisting of a plurality of connection pipes for returning the alkali metal condensed in a second spatial region of each thermoelectric converter to a first spatial region thereof through a common pump. Further, the respective open ends of the connection pipes, which connect the respective first regions of the converters to one another, are positioned in those portions of the respective first regions where only the vapor phase alkali metal exists.

Alkali metal thermoelectric power generator

An emergency core cooling system for spraying cooling water onto a nuclear reactor core of a nuclear reactor includes at least one header disposed in the nuclear reactor and arranged at an upper and outer circumferential position with respect to the reactor core. A plurality of spray nozzles are mounted on the at least one header for spraying cooling water onto the reactor core. The spray nozzles have a center axis and at least one of the plurality of spray nozzles is mounted on the at least one header so that the center axis thereof extends upwardly with respect to a horizontal axis whereas at least one of the remaining plurality of spray nozzles has the center axis thereof extending downwardly with respect to the horizontal axis. Cooling water is conducted to the at least one header for enabling spraying of the water in the emergency situation.

Emergency core cooling system

The emergency core cooling structure according to the present invention is provided with a water storage container which holds therein emergency cooling water to be supplied to a core region in a nuclear reactor in case of an emergency, for example, when the primary cooling water flows out from a reactor vessel, so as to maintain the temperature of the emergency cooling water in the upper portion of the water storage container in a level higher than the level of that of the emergency cooling water in the lower portion thereof, the lower portion of the water storage container, which is filled with the low-temperature cooling water, being communicated at all times with the core of the nuclear reactor by a means which has substantially no movable member. When the primary cooling water flows out, so that the pressure in a reactor vessel decreases, the emergency cooling water in the high-temperature region is boiled to expand to cause the low-temperature emergency cooling water in the lower portion of the water storage container to be raised, the resultant low-temperature emergency cooling water being supplied to the core region.

Growing community of inventors

Takahagi, Japan

Hisamichi Inoue