Passive cooling and depressurization system and pressurized water nuclear power plant

A passive cooling and depressurization system for a pressurized water nuclear plant having a reactor pressure vessel for containing a reactor core cooled by primary coolant, a steam generator connected to the reactor pressure vessel by a hot leg pipe and a cold leg pipe, and a containment vessel containing the reactor pressure vessel, the steam generator, the hot leg pipe and the cold leg pipe, the passive cooling and depressurization system comprising:

• a pressurizer connected to the hot leg pipe by a riser pipe for pressurizing an inside of a reactor pressure boundary where the primary coolant flows;
• a cooling water pool;
• a heat exchanger installed in the cooling water pool including an upper header, a lower header and a heat exchanger tube;
• a steam supply piping extending from a gas phase of the pressurizer to the upper header of the heat exchanger;
• a steam supply valve equipped on the steam supply piping;
• a coolant return pipe extending from the heat exchanger to a liquid phase of the reactor pressure boundary;
• and
• an outlet valve equipped on the coolant return pipe,
• wherein the heat exchanger exchanges heat between water stored in the cooling water pool and steam supplied through the steam supply piping.