Patent ID: 7920666

Claim:
A safety injection tank with a gravity-driven fluidic device, comprising: a cylindrical pressure vessel configured to contain emergency core cooling water therein; a tubular vertical pipe uprightly placed inside the pressure vessel and provided with at least one first flow inlet port formed in a side surface of a lower portion of the vertical pipe communicating with a lower surface of the pressure vessel and a second flow inlet port defined in an upper end of the vertical pipe which is open to an inner space of the pressure vessel; a gravity-driven fluidic device comprising: a spring placed in the upper end of the vertical pipe; and a vertically movable water tub movably placed on the spring so as to be movable in a vertical direction, and configured to contain the emergency core cooling water therein; and a guide cylinder mounted to the upper end of the vertical pipe and arranged to entirely surround a side surface of the vertically movable water tub and a portion of an upper surface of the vertically movable water tub, and wherein a plurality of through holes are formed in a surface of the guide cylinder; wherein, when the emergency core cooling water contained in the pressure vessel is externally discharged through the vertical pipe and an emergency core cooling water level is reduced lower than a vertical position of the vertically movable water tub, the vertically movable water tub elastically biased by the spring is moved in a downward direction such that a lower surface of the vertically movable water tub comes into contact with the vertical pipe to close the second flow inlet port.