Hitachi, Ltd.

Hitachi Chemical Company, Ltd.

Ibiden Company Limited

Tadashi Fujii

Kenji Tominaga

Yoshiyuki Kataoka

Masataka Hidaka

Nobuyuki Hayashi

Shigeo Hatamiya

Junichi Yamashita

Naoyuki Yamada

Katsushige Tsukada

Isao Sumida

Hiroaki Suzuki

Masanori Naitoh

Kazuyuki Tanaka

Masaya Ohtsuka

Tsuyoshi Niino

Toshitsugu Nakao

Katsunori Tsuchiya

Tohru Fukui

Hitoshi Tate

Shoichiro Kinoshita

Hirobumi Izumi

Tsutomu Toyoda

In an indirect cycle nuclear reactor, a size of the reactor containment vessel is decreased by removing decay heat inside the reactor pressure vessel without using any active component to improve the economic feasibility. A main steam pipe communicating with a heat exchanger of the indirect cycle nuclear reactor is branched in a position upstream of a main steam isolation valve to connect the branched pipe to a heat exchanger in a pressure suppression pool through an isolation valve. A feed water pipe is also branched in a position upstream of an isolation valve to connect the branched pipe to the heat exchanger through the isolation valve. Decay heat is dissipated from the heat exchanger into the pressure suppression pool, and condensed water condensed by heat dissipation is returned to the heat exchanger to cool the inside of the pressure vessel. Heat in the pressure suppression pool is transferred from a condensing type heat exchanger to a heat dissipater outside a containment vessel to be dissipated to the outside of the containment vessel.

Nuclear reactor

In a plant equipment comprising apparatus of a plurality of systems and control means for switching the systems and changing capacities of the apparatus, an apparatus of each system bas a rated capacity which is 1/N of a capacity of the whole equipment, and the plant equipment is constituted of (N+1) systems. In conditions of normal operation, all the (N+1) systems are operated at capacities less than the rated capacity through the control means. During normal operation, when one system is inspected, or when an abnormality occurs in one system, this system is stopped by the control means. Capacities of apparatus in N of the systems which are operated are increased to the rated 1/N capacity through the control means, and operation is continued with a structure of 1/N capacity.times.N systems. When the maintenance of apparatus in the stopped system is finished, the stopped system is restarted, so as to operate all of the (N+1) systems at capacities less than the rated capacity again.

Fluid plant and its operating method

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

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

There is disclosed a photosensitive resin composition solution for formation of a printed wiring board permanent mask to be coated on a substrate to be coated according to the curtain flow coating method or the roll coating method, which comprises (A) an oligomer having at least one epoxy group and at least one polymerizable vinyl group in the side chain, (B) a photopolymerization initiator, (C) an epoxy resin curing agent, (D) a filler and (E) a solvent, characterized in that (1) the solvent (E) contains 10 to 20% by weight of at least one low boiling point solvent selected from the group consisting of methanol, ethanol, methyl ethyl ketone, acetone and ethyl acetate based on the total amount of the solvent, and (2) the composition solution has a viscosity at 25.degree. C. of 100 mPas or more and 200 mPas or less.

Photosensitive resin composition solution

An unsaturated polyester resin composition for coating metal substrates, comprising an unsaturated alkyd component and a polymerizable vinyl monomer, said unsaturated alkyd component selected from the group consisting of:

Unsaturated polyester resin composition for coating metal substrates

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Hitachi, Japan

Tadashi Fujii