Patent Number: 
Section: claims

1. A passive containment air cooling device with an isolated pressure boundary, comprising:a plurality of heat exchangers positioned inside and outside a containment, penetrating through an outer wall of the containment to be connected to the containment through a pipe and thus form a closed loop, and including a coolant;a plurality of air induction ducts circulating air outside the plurality of heat exchangers; and a cooled air exhaust unit formed in at least one of the plurality of air induction ducts to increase cooling efficiency of the plurality of heat exchangers,wherein each quadrant of an outer part of the containment is provided with one of the plurality of heat exchangers and one of the plurality of air induction ducts and the plurality of air induction ducts are converged into one in an upper part of the containment and have a single air outlet. 2. The device as set forth in claim 1, wherein the heat exchanger comprises: a containment internal heat exchanger exposed to an inside of the containment; a containment external heat exchanger exposed to an outside of the containment; a gas phase connection pipe penetrating through the outer wall of the containment and connecting a side of an upper part of the containment internal heat exchanger and a side of an upper part of the containment external heat exchanger; and a liquid phase connection pipe penetrating through the outer wall of the containment and connecting a side of a lower part of the containment internal heat exchanger and a side of a lower part of the containment external heat exchanger. 3. The device as set forth in claim 2, wherein the containment internal heat exchanger, the containment external heat exchanger, the gas phase connection pipe, and the liquid phase connection pipe constitute a closed loop. 4. The device as set forth in claim 2, wherein the containment internal heat exchanger and the containment external heat exchanger have a heat exchanger tube assembly structure enduring internal and external pressures of the containment. 5. The device as set forth in claim 2, wherein the gas phase connection pipe is inclined at a slope of 5° or more to a ground surface from the inside of the containment to the outside, and the liquid phase connection pipe is inclined at a slope of −5° or less to the ground surface from the outside of the containment to the inside. 6. The device as set forth in claim 2, wherein the containment internal heat exchanger vaporizes a coolant in the containment internal heat exchanger due to internal heat of the containment. 7. The device as set forth in claim 2, wherein the containment external heat exchanger emits heat to external air to condense a coolant in the containment external heat exchanger. 8. The device as set forth in claim 1, wherein the cooled air exhaust unit is selectively provided on any one of upper, lower, and middle portions inside the air induction duct.