A heat exchanger includes a body having an inlet header through which a fluid is introduced, and an outlet header through which the fluid is discharged; and one or more plates accommodated in the body and provided with flow path modules providing flow paths for the fluid introduced through the inlet header to flow to the outlet header. The heat exchanger further includes at least one flow path adjuster each having at least a portion thereof accommodated in the body and being movable or rotatable to open or close a part or all of the flow paths or to change directions of the flow paths so that a flow of the fluid is adjusted.

An ERVC for floating nuclear power plants includes a containment, a reactor vessel, a liquid gallium collection tank, a heat pipe, a cooling cabin and a gallium storage tank. The containment is arranged in a sea environment, and the containment is provided with a containing cavity; the reactor vessel and the liquid gallium collection tank are arranged up and down and located in the containing cavity. An end of the heat pipe is inserted into the liquid gallium collection tank, and another end thereof is arranged outside the liquid gallium collection tank; the gallium storage tank is located in the containing cavity; the gallium storage tank is connected to the liquid gallium collection tank through a liquid gallium release valve; and the cooling cabin is located under the containment and under a sea level of the sea environment.

A depressurisation valve for a cooling system comprising: a main chamber having a main valve, a pilot line having a secondary valve and a blowdown line; the main valve being located to seal a path of the coolant system of the nuclear reactor. The main chamber is connected to the cooling circuit via the pilot line allowing coolant to enter the main chamber, and the blowdown line allows coolant to escape from the main chamber, the pilot line having a lower fluid resistance than the blowdown line. The pressure of coolant in the main chamber maintains the main valve in a closed position, and under elevated temperature and/or pressure conditions fluid is prevented from entering the main chamber via a closure of the secondary valve on the pilot line and reduce the pressure from the valve, moving it to its open position.

This invention involves systems which provide for the safety of nuclear power plants that can be used in the event of serious accidents leading to the destruction of the housing and sealed containment structure of a reactor. In one aspect, the system can increase nuclear power plant safety by preventing the escape of liquid and solid radioactive materials (corium) from a melt confinement device in the event of a serious accident involving the escape of core melt from a nuclear reactor. The invention addresses the problem of increasing the efficiency and reliability of a melt confinement device by improving the conditions for cooling corium. The problem is solved by the use of a filler formed in upper cassettes and in a lower cassette. Said cassettes are configured with vertical and horizontal channels which provide for the uniform distribution of melt in the housing undergoing cooling.

This invention involves systems which provide for the safety of nuclear power plants that can be used in the event of serious accidents leading to the destruction of the housing and sealed containment structure of a reactor. In one aspect, the system can increase nuclear power plant safety by preventing the escape of liquid and solid radioactive materials (corium) from a melt confinement device in the event of a serious accident involving the escape of core melt from a nuclear reactor. The invention addresses the problem of increasing the efficiency and reliability of a melt confinement device by improving the conditions for cooling corium. The problem is solved by the use of a filler formed in upper cassettes and in a lower cassette. Said cassettes are configured with vertical and horizontal channels which provide for the uniform distribution of melt in the housing undergoing cooling.

An inadvertent actuation block valve includes inlet and outlet orifices being in selective fluid communication via a chamber. A disc is disposed within the chamber and a bellows is configured to contract at a predetermined pressure differential between reactor fluid entering a reference pressure orifice and control fluid entering the inlet orifice. When the bellows contracts, the disc engages the outlet orifice and isolates fluid communication between the inlet and outlet orifices. The inadvertent actuation block valve prevents inadvertent opening of an emergency core cooling valve when a reactor is at operating pressure that is above the predetermined set pressure range. The inadvertent actuation block valve permits the emergency cooling valves to open and to remain open when reactor pressure is below the predetermined set pressure range. The inadvertent actuation block valve does not impede long term emergency cooling that occurs when the reactor is at low pressure.

An inadvertent actuation block valve includes inlet and outlet orifices being in selective fluid communication via a chamber. A disc is disposed within the chamber and a bellows is configured to contract at a predetermined pressure differential between reactor fluid entering a reference pressure orifice and control fluid entering the inlet orifice. When the bellows contracts, the disc engages the outlet orifice and isolates fluid communication between the inlet and outlet orifices. The inadvertent actuation block valve prevents inadvertent opening of an emergency core cooling valve when a reactor is at operating pressure that is above the predetermined set pressure range. The inadvertent actuation block valve permits the emergency cooling valves to open and to remain open when reactor pressure is below the predetermined set pressure range. The inadvertent actuation block valve does not impede long term emergency cooling that occurs when the reactor is at low pressure.

A closed loop heat convection cooling system for nuclear reactors. The cooling system is formed outside the containment structure of the nuclear reactor and the structure of the cooling system prevents gas that is not in the closed circuit to approach the reactor within neutron radiation distance. The cooling systems has cooling assemblies that are housed in protective structures, which shield the cooling assemblies for projectile impact. Air inlet and outlet apertures are formed in the protective structures to cause outside air to be drawn into the protective structures to cool the cooling assemblies.

A closed loop heat convection cooling system for nuclear reactors. The cooling system is formed outside the containment structure of the nuclear reactor and the structure of the cooling system prevents gas that is not in the closed circuit to approach the reactor within neutron radiation distance. The cooling systems has cooling assemblies that are housed in protective structures, which shield the cooling assemblies for projectile impact. Air inlet and outlet apertures are formed in the protective structures to cause outside air to be drawn into the protective structures to cool the cooling assemblies.

A main heat and waste heat integrated thermal exchanger for a small nuclear reactor has a first coolant zone for a first main heat loop, a second coolant zone for a second main heat loop and a third coolant zone for a waste heat removal loop. The first coolant for the first main heat loop passes through the first coolant inlet, and then reaches the orifice plate, and finally flows out from the first coolant outlet. The second coolant for the second main heat loop passes through the second coolant inlet, and then reaches the lower tube sheet, and finally flows out from the second coolant outlet. The third coolant for the waste heat removal loop enters the entrance sleeve through the third coolant inlet, and then enters multiple tubes of the tube bundle, and then enters the exit sleeve, and finally flows out from the third coolant outlet.