Hitachi, Ltd.

Hitachi Engineering Co., Ltd.

Toichi Shida

Takeshi Yokota

Kanji Kato

Hiroshi Ujita

Kimiko Isono

Toshiya, Kurakake

Naoshi Tanikawa

Hitoshi Sakuma

Nasho Tanikawa

Tetsuya Miyakawa

A reactor core coolant flow rate control system for a BWR type nuclear power plant in which electric power is generated by a turbine-driven generator driven by a steam turbine rotating under the work of a main steam generated from a cooling water recirculated through a boiling water reactor includes an internal pump driving unit comprised of an electric motor driven by an electric power generated by the turbine-driven generator, a fluid coupling for transmitting an output torque of the electric motor and a variable-frequency generator whose rotation number is changed in accordance with the torque transmitted by way of the fluid coupling, a fluid coupling control signal generating unit for generating a fluid coupling control signal for the fluid coupling in response to at least one of deviation in a load and a rotation speed of the turbine-driven generator and deviation in a rotation speed of the internal pumps, and a plurality of internal pumps for recirculating the cooling water. Each of the internal pumps is connected to the variable-frequency generator of the internal pump driving unit and driven by an output power of the variable-frequency generator. Rotation number of the internal pump changes in dependence on the rotation number of the variable-frequency generator. The fluid coupling changes a transmission efficiency for the torque transmitted to the variable-frequency generator from the driving motor in response to the fluid coupling control signal.

Reactor core coolant flow rate control system for a BWR type nuclear

An intelligent education and simulation system which is capable of executing an optimized follow-up reeducation to the learner reflecting his/her idiosyncrasy toward understanding in learning. The intelligent education and simulation system has an execution instruction to execute a curriculum comprising a plurality of instruction courses regarding the subject teaching of an educational object and its simulation-based instruction. According to this execution instruction, intelligent computer assisted instruction of the subject teaching and the simulation-based instruction are implemented. The degree of understanding of these instructions by the learner is evaluated, and according to the degree of understanding thus comprehended, a pertinent follow-up instruction course(s) is chosen for reeducation. In this way, a pertinent reeducation instruction course(s) optimized for each learner is capable of being selected, and the time required for reeducation of the learner is minimized.

Intelligent education and simulation system and method

A method of preventing a recirculation pump cavitation and a forced recirculation type steam-generating apparatus are disclosed in which water is forcibly circulated by a recirculation pump. The pressure of the steam-generating section of the steam-generating apparatus and the temperature of water at the suction side of the recirculation pump are detected. The rotational speed of the recirculation pump is reduced to a predetermined speed level when the difference between the saturation temperature associated with the detected pressure and the water temperature is reduced below a predetermined value, thus preventing the cavitation which otherwise might occur in the recirculation pump.

Method of preventing recirculation pump cavitation and forced

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Hitachi, Japan

Toichi Shida