VENT PIPE WITH INSULATING DEVICE OF HUMIDITY INSIDE REACTOR CONTAINER

PURPOSE:To suppress a rise in humidity in a normal operation and to improve a corrosive environment condition of an apparatus piping in a dry well by the effect of this reduction of humidity, by a construction wherein an insulating device which can be opened and closed is equipped between a dry well part and a pressure suppression chamber. CONSTITUTION:An insulating device 1 needs only to be capable of preventing humidity which is propagated from a pressure suppression chamber 8 to a dry well 4, and it is provided integrally in a sate of being mounted on a vent pipe 5. A partition plate 1a is divided into two sections and has a structure of being opened and closed in the central part. The divided part are so designed as to overlap each other partially inside and, besides, a sealing material 3 is provided at the part of overlapping. When an accident occurs, in this constitution, steam of high temperature and high pressure is released into the dry well 4 and a pressure inside the dry well turns high. By a force applied to the partition plate 1a, a counterweight 2 is pushed upward while the partition plate 1a is pushed downward, and thereby a flow passage can be ensured.