Abstract: Provided is a structure for operating a watertight door by use of buoyancy. The structure includes: a detention tank for storing rainwater flowing from a street inlet; a buoyant member which is installed in the detention tank; and a sensor installed in the detention tank, in which if the buoyant member raised by the buoyant of the rainwater collected in the detention tank comes into contact with the sensor, the watertight door is automatically operated. The watertight door structure manually operated at localized heavy rain is improved, and the watertight door is automatically operated if the water level reaches the predetermined level.

Abstract: Provided is a structure for operating a watertight door by use of buoyancy. The structure includes: a detention tank for storing rainwater flowing from a street inlet; a buoyant member which is installed in the detention tank; and a sensor installed in the detention tank, in which if the buoyant member raised by the buoyant of the rainwater collected in the detention tank comes into contact with the sensor, the watertight door is automatically operated. The watertight door structure manually operated at localized heavy rain is improved, and the watertight door is automatically operated if the water level reaches the predetermined level.

Abstract: The present invention provides a porous cooling block for cooling corium, comprising: a base part that includes a plurality of pores; a plurality of porous cooling blocks that include a channel part that communicates with some of the plurality of pores of the base part; a sacrificial part that covers the exposed upper surfaces of the porous cooling blocks; and a cooling-water supply unit that supplies cooling water to the porous cooling blocks. Corium is cooled by using steam or cooling water discharged from the porous cooling blocks. Therefore, the corium can be cooled and solidified in the shape of a porous form. Further, the cooling water is uniformly supplied to one surface formed by the cooling block on the whole, thereby easily cooling the corium.

Abstract: The present invention provides a porous cooling block for cooling corium, comprising: a base part that includes a plurality of pores; a plurality of porous cooling blocks that include a channel part that communicates with some of the plurality of pores of the base part; a sacrificial part that covers the exposed upper surfaces of the porous cooling blocks; and a cooling-water supply unit that supplies cooling water to the porous cooling blocks. Corium is cooled by using steam or cooling water discharged from the porous cooling blocks. Therefore, the corium can be cooled and solidified in the shape of a porous form. Further, the cooling water is uniformly supplied to one surface formed by the cooling block on the whole, thereby easily cooling the corium.