Abstract: A high reliable water injection device is provided that injects water into a reactor containment vessel and can reliably shut off cooling water at normal times and quickly and reliably inject water into the reactor containment vessel without the need for external power, in a case of emergency. The water injection device injects water into a reactor containment vessel includes a flow path through which cooling water is supplied; a disk that closes the flow path; a swing arm that is connected to the disk and performs closing and opening of the flow path by the disk; and a weight that is connected to the swing arm via a swing lever, in which the weight is supported by a support member made of a low melting point alloy.

Abstract: A butterfly valve includes a valve body-side valve seat section, a valve box-side valve seat section, and a valve movement mechanism. The valve movement mechanism includes a cam groove, a cam projection, and a reverse key. The valve movement mechanism moves the valve body in an extending direction of the flow passage along with rotation of the valve shaft between a blocking position and an open position. One of the valve body-side valve seat section and the valve box-side valve seat section is formed of a laminated material composed of alternatingly stacked plates made of metal and plates made of expanded graphite.

Abstract: A high reliable water injection device is provided that injects water into a reactor containment vessel and can reliably shut off cooling water at normal times and quickly and reliably inject water into the reactor containment vessel without the need for external power, in a case of emergency. The water injection device injects water into a reactor containment vessel includes a flow path through which cooling water is supplied; a disk that closes the flow path; a swing arm that is connected to the disk and performs closing and opening of the flow path by the disk; and a weight that is connected to the swing arm via a swing lever, in which the weight is supported by a support member made of a low melting point alloy.

Abstract: Provided is a butterfly valve configured so that the sealing performance of the butterfly valve is ensured even if the butterfly valve is exposed to high-temperature fluid and is installed in a high radiation environment. A butterfly valve has: a valve body-side valve seat section which is formed on the outer periphery of a valve body; a valve box-side valve seat section which is formed on a valve box; and a valve movement mechanism which, as a valve shaft pivots, moves the valve body in the direction of extension of a flow passage, between a blocking position at which the valve body-side valve seat section and the valve box-side valve seat section are in contact with each other to close a flow passage, and an open position at which the valve body-side valve seat section and the valve box-side valve seat section are separated from each other to open the flow passage.