PURPOSE: Not to produce the thermal shock on the trap itself, by connecting the trap with each inlet and outlet side of vessel and providing the pipe flowing passage having no packing and then, passing gas through by-pass flowing passage switching the flowing passage only when passing the gas from the outlet to the inlet reversely and moreover, intercepting the supply of cooling medium.
CONSTITUTION: When the temperature of liquid metal (Na etc.) in furnace vessel is lowered by the scrum of nuclear reactor etc., cover gas pressure is lowered and pressure difference is produced between each side of inlet and outlet of the cover gas circulating route 3 and then, the difference is detected by the differential pressure gauge 21. Hereby, the air operation valve 18 of the outlet nozzle 12 and the air operation valve 19 of the cooling medium supply route 17, are shut and at the same time, the air operation valve 20 of the bypass tube 16 is opened. The cover gas is flowed in the inlet nozzle 11 passing through the tube 16. Accordingly, mist liquid in the packing material 13 is not solidified by cooling and blockade of flowing passage of the material is not occurred, becuase low temperature cover gas is flowed reversely not passing through the material 13 and also, supply of cooling medium to the cooler 14 is intercepted.
ITAMI KUNIHIKO
SHIBATA YOUJI
