Hitachi, Ltd.

Koichi Kotani

Yasuhiro Masuhara

Motoaki Utamura

Osamu Yokomizo

Masanori Naitoh

Shinichi Kashiwai

Iwao Yokoyama

Atsuo Yamanouchi

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 start-up method of starting up a boiling water reactor which is in the cold shut-down state. The method includes

Nuclear reactor start-up method

Growing community of inventors

Hitachi, Japan

Koichi Kotani