Cooling system in a nuclear plant

A cooling system in a nuclear power plant, the system comprising:

• a boundary section disposed inside a containment configured to be divided into a first area and a second area disposed inside the containment, the boundary section disposed between the first area (Lower Containment Area (LCA)) and the second area (Upper Containment Area (UCA)) of a radioactive material suppression facility, wherein the boundary section is formed to surround the first area (LCA), wherein the first area (LCA) is a first space of an inner area of the boundary section, and the second area (UCA) is a second space that is an upper area inside the containment at the outside of the boundary section, wherein the boundary section is configured to prevent steam and radioactive materials from leaking into the second space (UCA) when an accident occurs in the nuclear power plant, and then the first space (LCA) contains steam or radioactive materials;
• an In-Containment Refueling Water Storage Tank disposed outside the boundary section and configured to store refueling water therein;
• an emergency cooling tank disposed outside the containment and provided with a condensation heat exchanger;
• a gas-liquid separator disposed outside the containment and connected to the emergency cooling tank;
• and
• a return line configured to connect the gas-liquid separator and the boundary section such that condensate is discharged toward the boundary section upon an occurrence of the nuclear power plant accident, the condensate being generated by condensing the steam of the boundary section through the emergency cooling tank and the gas-liquid separator,
• wherein the return line extends from a condensate discharge line of the gas-liquid separator and is disposed such that the condensate separated through the gas-liquid separator passes through the in-containment refueling water storage tank,
• wherein if the nuclear power plant accident occurs, steam and air discharged to the containment are introduced into the condensation heat exchanger through a steam line, and at least part of the introduced steam is condensed and introduced into the gas-liquid separator disposed at a rear end of the condensation heat exchanger, to be separated into non-condensable gas and the condensate,
• wherein the non-condensable gas separated through the gas-liquid separator flows into the containment along a non-condensable gas line, and the condensate separated through the gas-liquid separator flows into the boundary section along the return line.