Hitachi, Ltd.

Iwao Yokoyama

Yasuhiro Masuhara

Shinichi Kashiwai

Motoaki Utamura

Osamu Yokomizo

Toshitsugu Nakao

Shigeto Murata

Koichi Kotani

Yuichiro Maeda

A piping branch structure includes a branch pipe distributing an inflowing fluid to pipes in at least three directions, and one of the pipes face a direction of flow of the fluid, wherein a fluid inlet of one of the pipes protrudes into the branch pipe. By protruding a fluid inlet of a pipe which faces a direction of flow of the fluid into the branch pipe, the protruding pipe act as obstacles, thus no vortex is generated and the non-vortex flow state can be maintain. In case of piping of recirculating system of a reactor, an inner pipe, whose structure is integral with that of a riser pipe, is provided so that the inner pipe extends toward a master tube side in a cross branch pipe. The inner pipe is provided holes and a flow-regulating plate. The quantity of cooling water circulating through the core of the reactor and the flow state of the cooling water in the pressure vessel are stabilized and balanced.

Piping branch structure

A nuclear reactor is equipped with a cooling water circulation system which includes a water-feed conduit and a drain conduit to circulate the cooling water to and from a pressure vessel which surrounds a reactor core, the cooling water having a free liquid level maintained above the reactor core. The drain conduit is inserted in the pressure vessel from the upper side toward the lower side relative to the free liquid level. A double tube consisting of an inner tube and an outer tube maintaining a gap therebetween is formed in the end portion of the drain conduit. The inner tube and outer tube being continuous with the drain conduit, the opening at the lower end of the inner tube is located below said free liquid level but above the reactor core. The opening at the upper end of the outer tube is located above the free liquid level. The opening at the lower end of said outer tube is located below the reactor core.

Nuclear reactor

Growing community of inventors

Kitaibaraki, Japan

Iwao Yokoyama