Patent Number: 
Section: claims

1. A nuclear reactor cooling system, comprising:a cooling water tank disposed above a containment and containing cooling water therein;a spray header connected to the cooling water tank through a first communicating pipe; andan air tank disposed inside the containment; wherein the spray header is disposed outside the containment and used for spraying the cooling water to an outer wall of the containment; the cooling water tank is a closed container, and the air tank is connected to a top portion of the cooling water tank through a second communicating pipe, and the nuclear reactor cooling system further comprises a bell-shaped shield around an exterior of the containment. 2. The nuclear reactor cooling system according to claim 1, wherein the shield is used for covering the containment and setting the containment in its interior, the spray header is disposed in a space between an inner wall of the shield and the outer wall the containment, and the cooling water tank is disposed on a top portion of the shield. 3. The nuclear reactor cooling system according to claim 2, further comprising an exhaust hole disposed on the top portion of the shield. 4. The nuclear reactor cooling system according to claim 3, wherein the cooling water tank has a shape of annulus, the axis of the cooling water tank is collinear with the axis of the shield. 5. The nuclear reactor cooling system according to claim 3, further comprising a rupture disk disposed in the air tank and/or in the second communicating pipe, wherein the rupture disk is ruptured during an increase of pressure in the air tank, and the rupture disk in an intact state is capable of isolating a space on both sides thereof. 6. The nuclear reactor cooling system according to claim 4, further comprising a rupture disk disposed in the air tank and/or in the second communicating pipe, wherein the rupture disk is ruptured during an increase of pressure in the air tank, and the rupture disk in an intact state is capable of isolating a space on both sides thereof. 7. The nuclear reactor cooling system according to claim 2, further comprising a cooling water outlet disposed on a bottom portion of the shield. 8. The nuclear reactor cooling system according to claim 7, further comprising a rupture disk disposed in the air tank and/or in the second communicating pipe, wherein the rupture disk is ruptured during an increase of pressure in the air tank, and the rupture disk in an intact state is capable of isolating a space on both sides thereof. 9. The nuclear reactor cooling system according to claim 2, wherein the spray header is axisymmetrically disposed above the containment. 10. The nuclear reactor cooling system according to claim 9, further comprising a rupture disk disposed in the air tank and/or in the second communicating pipe, wherein the rupture disk is ruptured during an increase of pressure in the air tank, and the rupture disk in an intact state is capable of isolating a space on both sides thereof. 11. The nuclear reactor cooling system according to claim 2, further comprising a rupture disk disposed in the air tank and/or in the second communicating pipe, wherein the rupture disk is ruptured during an increase of pressure in the air tank, and the rupture disk in an intact state is capable of isolating a space on both sides thereof. 12. The nuclear reactor cooling system according to claim 1, further comprising a rupture disk disposed in the air tank and/or in the second communicating pipe, wherein the rupture disk is ruptured during an increase of pressure in the air tank, and the rupture disk in an intact state is capable of isolating a space on both sides thereof.