NATURAL CIRCULATION TYPE PASSIVE COOLING SYSTEM FOR CONTAINMENT CONSTRUCTION

PURPOSE: To prevent leakage of radioactivity by arranging a plurality of dry well chambers, suppression pool chambers and cooling pool chambers for circulating leaked water or steam naturally around the pressure vessel for core in a containment structure. CONSTITUTION: A pressure vessel 12 incorporating a core 14 is provided with pipes 16, 18 and heated high pressure steam or high temperature pressurized water is circulated through a turbine (not shown). A plurality of dry welts 24, suppression pool chambers 26 applied with fluid nonpermeable liner 22 and cooling pool chambers 30 are arranged around the pressure vessel 12 while being communicated through pipes 28, 36. Enclosed heat transmission vessels 32A-32A" are disposed at the lower end of pipe 36 while being coupled, at the upper end thereof, with the enclosed condensation vessels 34A-34A" in cooling pool 30. Leaked steam and pressurized water are absorbed by the enclosed heat transmission vessel 32 and temperature raised steam is condensed in the enclosed condensation vessel 34 before the absorbed thermal energy is discharged. According to the structure, thermal energy can be transported to the outside of containment structure while preventing leakage of radioactive substance.