Abstract: An electromagnet for a nuclear reactor shutdown system, which comprises upper and lower cores disposed in an axially symmetrical arrangement and capable of latching with and delatching from each other. When an ambient temperature increases, the upper and lower iron cores are delatched from each other and a control rod connected to the lower iron core falls down into a reactor core. The lower iron core is provided with a plurality of slits to form a plurality of fins therebetween. A temperature sensitive magnetic material (TSMM) is disposed in the outer circumferential lower corner portion of the lower iron core. An interface between the TSMM and an iron core material takes the form of a side surface of a cone whose central axis is coincident with the symmetry axis and whose apex angle lies in the range of 60.degree. to 120.degree..

Abstract: A self-actuated nuclear reactor shutdown system includes a control rod, a temperature sensitive electromagnet disposed above the control rod for causing the control rod to latch thereto and unlatch therefrom, and a control rod insertion portion around which a plurality of wrapper tubes each accommodating a fuel assembly are arranged. The present invention is characterized in that the upper part of the wrapper tube or an extension tube connected to the upper end of the wrapper tube is made of a temperature-sensitive magnetic material having a characteristic by which the saturation flux density thereof will be reduced at the time of an extraordinary rise in the temperature of a coolant flowing through the fuel assembly. The temperature sensitive magnetic material constitutes a part of a magnetic circuit of the electromagnet.

Abstract: An autonomous, decentralized fast breeder reactor includes a single reactor main vessel which houses a plurality of small-size reactor subsystems each having a small-scale fast breeder reactor core, and a plurality steam generator subsystems. These subsystems function in an autonomous manner and are caused to undergo a heat transfer with one another by a coolant circulating naturally through the interior of the main vessel, thereby constructing a cooperatively operating system. Steam generated by the steam generators is introduced to a turbine system and utilized in generating electricity. The condensate from the turbines is cooled by a heat accumulating pool, and the heat is utilized in a separate system. The entire system is installed underground and use is made of the difference in elevation. Use also is made of solid bedrock to construct a housing facility for the reactor.

Abstract: Disclosed are a method of making a connection in a liquid and an apparatus therefor wherein a first connector having a protrusion at its front end is housed in a protecting tube which is open at its lower end and into which a gas is introduced, the protecting tube is filled with the gas so as to form a gaseous space therein within the liquid, a second container which is normally held within the liquid and which has a destructible plate at its upper end is exposed to the gaseous space, and the destructible plate is destroyed by the front end of said one connector so as to connector both connectors, whereby the connection in the liquid can be made without being affected by an ambient liquid.

Abstract: Disclosed are a method of making a connection in a liquid and an apparatus therefor wherein a first connector having a protrusion at its front end is housed in a protecting tube which is open at its lower end and into which a gas is introduced, the protecting tube is filled with the gas so as to form a gaseous space therein within the liquid, a second connector which is normally held within the liquid and which has a destructible plate at its upper end is exposed to the gaseous space, and the destructible plate is destroyed by the front end of said one connector so as to connect both connectors, whereby the connection in the liquid can be made without being affected by an ambient liquid.

Abstract: Disclosed are a method of making a connection in a liquid and an apparatus therefor wherein a first connector having a protrusion at its front end is housed in a protecting tube which is open at its lower end and into which a gas is introduced, the protecting tube is filled with the gas so as to form a gaseous space therein within the liquid, a second connector which is normally held within the liquid and which has a destructible plate at its upper end is exposed to the gaseous space, and the destructible plate is destroyed by the front end of said one connector so as to connect both connectors, whereby the connection in the liquid can be made without being affected by an ambient liquid.