Patent Number: 
Section: claims

1. A containment vessel for containing a reactor pressure vessel, a reactor core, and a steam generator of a pressurized water reactor, the containment vessel comprising:a main body equipped with a polar crane;a diaphragm set above the polar crane,wherein the diaphragm partitions the main body into an upper vessel and a lower vessel,wherein the diaphragm is configured to provide the partition before and after a loss-of-coolant accident (LOCA),the upper vessel being located higher than the lower vessel,the upper vessel including a dome part thereof, wherein an open space is in the dome part,the lower vessel being configured to contain all of an equipment and piping constituting a reactor pressure boundary,the equipment and piping including the reactor pressure vessel and the steam generator of the pressurized water reactor,wherein the diaphragm isolates the upper vessel from the lower vessel;a pressure suppression chamber having a suppression pool and a gas phase,the suppression pool being configured to store water,the gas phase of the pressure suppression chamber is in fluid communication with the open space in the dome part;a LOCA vent pipe fluidly connecting the suppression pool to the lower vessel; anda vacuum breaker configured to equalize a pressure of the upper vessel and a pressure of the lower vessel,the vacuum breaker is configured to open and allow gas flow from the upper vessel to the lower vessel when a pressure difference between the upper vessel and the lower vessel exceeds a preset value. 2. The containment vessel of claim 1, wherein the pressure suppression chamber is provided in the upper vessel. 3. The containment vessel of claim 1, wherein the pressure suppression chamber is provided in the lower vessel, and further comprising a gas phase vent pipe connecting the gas phase to the upper vessel. 4. The containment vessel of claim 1, wherein the pressure suppression chamber is provided outside the main body, and further comprising a gas phase vent pipe connecting the gas phase to the upper vessel. 5. The containment vessel of claim 1, wherein atmosphere in the pressure suppression chamber is inerted with nitrogen to make an oxygen concentration low. 6. The containment vessel of claim 1, wherein atmosphere in the upper vessel is inerted with nitrogen to make an oxygen concentration low. 7. The containment vessel of claim 1, wherein the suppression pool stores borated water. 8. The containment vessel of claim 1, further comprising:a passive containment cooling system (PCCS) pool configured to store water;a PCCS heat exchanger located in the PCCS pool;a suction pipe extending from the lower vessel to the PCCS heat exchanger;a PCCS vent pipe extending from the PCCS heat exchanger to the suppression pool, the PCCS vent pipe being configured to discharge noncondensable gas therethrough, the noncondensable gas comprising a part of gas being introduced through the suction pipe; anda return pipe being configured to supply water condensed by the PCCS heat exchanger back to the lower vessel. 9. The containment vessel of claim 8, wherein the PCCS pool is located outside the main body. 10. The containment vessel of claim 8, wherein the PCCS pool is located in the main body. 11. The containment vessel of claim 1, wherein the main body is made of one of prestressed concrete and reinforced concrete. 12. The containment vessel of claim 1, wherein the main body is made of steel. 13. A nuclear power plant having a pressurized water reactor, the nuclear power plant comprising: a containment vessel including:a main body equipped with a polar crane;a diaphragm set above the polar crane,wherein the diaphragm partitions the main body into an upper vessel and a lower vessel,wherein the diaphragm is configured to provide the partition before and after a loss-of-coolant accident (LOCA),the upper vessel being located higher than the lower vessel,the upper vessel including a dome part thereof, wherein an open space is in the dome part,the lower vessel being configured to contain all of an equipment and piping constituting a reactor pressure boundary,the equipment and piping including the reactor pressure vessel and the steam generator of the pressurized water reactor,wherein the diaphragm isolates the upper vessel from the lower vessel;a pressure suppression chamber having a suppression pool and a gas phase,the suppression pool being configured to store water,the gas phase of the pressure suppression chamber is in fluid communication with the open space in the dome part;a LOCA vent pipe fluidly connecting the suppression pool to the lower vessel; anda vacuum breaker configured to equalize a pressure of the upper vessel and a pressure of the lower vessel,the vacuum breaker is configured to open and allow gas flow from the upper vessel to the lower vessel when a pressure difference between the upper vessel and the lower vessel exceeds a preset value. 14. The nuclear power plant of claim 13, wherein atmosphere in the upper vessel is inerted with nitrogen to make an oxygen concentration low.