Disclosed herein is a nuclear power plant main steam system, which reduces the atmospheric discharge of radioactive materials generated in an accident, the system including: a decontamination water tank containing decontamination water; and a connection pipe for connecting the decontamination water tank from a main steam pipe which connects a steam generator and a turbine, wherein the connection pipe is connected to the decontamination water tank through a main steam safety valve or a connection valve, wherein the main steam safety valve or the connection valve is configured by a three-way valve and is configured to discharge the generated steam to the air when an accident occurs within a design basis and to transfer the generated steam to the decontamination water tank when a severe accident occurs. A main steam system according to the present invention has an effect of reducing discharge of radioactive materials to the air when a containment bypass accident including a steam generator tube rupture caused by high-temperature steam occurs.

A passive containment cooling and filtered venting system includes: an outer well; a scrubbing pool arranged in the outer well; a cooling water pool installed above the dry well and the outer well; a heat exchanger partly submerged in the cooling water; a gas supply pipe that is connected to the inlet plenum of the ruin of the heat exchanger at one end and connected to a gas phase region of the containment vessel at the other end; a condensate return pipe that is connected to the outlet plenum of the heat exchanger at one end, and connected to inside the containment vessel at other end; and a gas vent pipe that is connected to the outlet plenum of the heat exchanger at one end and is submerged in the scrubbing pool at other end.

A passive containment cooling and filtered venting system includes: an outer well; a scrubbing pool arranged in the outer well; a cooling water pool installed above the dry well and the outer well; a heat exchanger partly submerged in the cooling water; a gas supply pipe that is connected to the inlet plenum of the ruin of the heat exchanger at one end and connected to a gas phase region of the containment vessel at the other end; a condensate return pipe that is connected to the outlet plenum of the heat exchanger at one end, and connected to inside the containment vessel at other end; and a gas vent pipe that is connected to the outlet plenum of the heat exchanger at one end and is submerged in the scrubbing pool at other end.

A power module assembly includes a reactor core immersed in a coolant and a reactor vessel housing the coolant and the reactor core. An internal dry containment vessel submerged in liquid substantially surrounds the reactor vessel in a gaseous environment. During an over-pressurization event the reactor vessel is configured to release the coolant into the containment vessel and remove a decay heat of the reactor core through condensation of the coolant on an inner surface of the containment vessel.

A power module assembly includes a reactor core immersed in a coolant and a reactor vessel housing the coolant and the reactor core. An internal dry containment vessel submerged in liquid substantially surrounds the reactor vessel in a gaseous environment. During an over-pressurization event the reactor vessel is configured to release the coolant into the containment vessel and remove a decay heat of the reactor core through condensation of the coolant on an inner surface of the containment vessel.

A containment cooling system capable of improving coolant utilization rate comprises a cooling water tank disposed above the containment, a spray header connected to the cooling water tank by a first communicating pipe, a bell-shaped shield, and a clearance, wherein the cooling water tank is disposed on top of the shield, and the spray header is located in the clearance; cooling fins are disposed in the clearance, wherein a flow passage is disposed between the cooling fins and the outer wall of the containment. The containment cooling system has a higher coolant utilization rate.

A nuclear reactor cooling system includes a cooling water tank disposed above a containment; a spray header connected to the cooling water tank through a first communicating pipe; and an air tank disposed inside the containment; wherein the spray header is disposed outside the containment and used for spraying cooling water to the outer wall of the containment; the cooling water tank is a closed container, and the air tank is connected to the top portion of the cooling water tank through a second communicating pipe. The nuclear reactor cooling system has higher reliability in cooling containment.

A containment cooling apparatus includes a cooling water tank disposed above a containment; a spray header connected to the cooling water tank via a first communicating pipe, wherein the spray header is disposed on an outside of the containment for spraying cooling water to an outer wall of the containment; a bell shaped shield covering the containment, wherein the cooling water tank is disposed on a top portion of the shield; a space formed between an inner wall of the shield and the outer wall of the containment, wherein the spray header is disposed in the space; an exhaust hole disposed on the top portion of the shield; and a water separator disposed in the exhaust hole and/or the space. The containment cooling apparatus has higher utilization of coolant.

A passive safe cooling system includes a water replenishing tank, an advanced safe injection tank, a built-in material replacing water tank, a pressure relief system, a passive emergency water supply system and a passive containment cooling system, the passive emergency water supply system is adapted for hermetically running through the containment and is configured correspondingly to a steam generator in the containment, and the passive containment cooling system is adapted for hermetically running through the containment to remove the heat from the containment. This system can effectively implement safety functions such as nuclear core reactivity control, residual heat removal and containment of radioactive material under a nuclear accident, ensure the reactor core to be effectively cooled down and maintain in a safe shutdown state, improve the safety of the nuclear power plant and greatly reduce the construction costs and operation and maintenance costs.

A passive safe cooling system includes a water replenishing tank, an advanced safe injection tank, a built-in material replacing water tank, a pressure relief system, a passive emergency water supply system and a passive containment cooling system, the passive emergency water supply system is adapted for hermetically running through the containment and is configured correspondingly to a steam generator in the containment, and the passive containment cooling system is adapted for hermetically running through the containment to remove the heat from the containment. This system can effectively implement safety functions such as nuclear core reactivity control, residual heat removal and containment of radioactive material under a nuclear accident, ensure the reactor core to be effectively cooled down and maintain in a safe shutdown state, improve the safety of the nuclear power plant and greatly reduce the construction costs and operation and maintenance costs.