A method for heating primary coolant in a nuclear reactor system during system start-up. A primary coolant loop fluidly couples together a reactor vessel and a steam generating vessel. The primary coolant loop is filled with primary coolant. A portion of the primary coolant is taken from the primary coolant loop and placed into a start-up sub-system. The portion is heated while in the sub-system to form a heated portion of the primary coolant. The heated portion is returned into the primary coolant loop. The method allows for the primary coolant to be heated to a no-load operating temperature.

In view of above problems, an object of the invention is to provide a primary containment vessel venting system having a structure capable of continuously discharging vapor in a primary containment vessel out of the system and continuously reducing pressure of the primary containment vessel without discharging radioactive noble gases to the outside of the containment vessel and without using an enclosing vessel or a power source. In order to achieve the above object, an nuclear power plant of the invention includes a primary containment vessel which includes a reactor pressure vessel, a radioactive substance separation apparatus which is disposed inside the primary containment vessel and through which the radioactive noble gases do not permeate but vapor permeates, a vent pipe which is connected to the radioactive substance separation apparatus, and an exhaust tower which is connected to the vent pipe and discharges a gas, from which a radioactive substance is removed, to the outside.

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.

The invention is related to safety systems for nuclear power plants (NPP) which can be used in various operational modes, including emergency mode, and is aimed at controlling air flows inside NPP containment buildings.

NPP containment building separation system dividing the NPP containment building into isolated rooms. It includes the containment building separation shutters located in the circular gap which divides the containment building rooms and the containment building walls; an air supply unit connected to a manifold ring which, in turn, is connected to the air-inflated shutters designed to ensure insulation of the airspace inside the containment building rooms when inflated and at connecting the airspace when deflated. In emergency mode the air supply to the air-inflated shutters is terminated, the shutters get deflated and fully open the circular gap which ensures convection process throughout the whole area of containment building.

The invention is related to safety systems for nuclear power plants (NPP) which can be used in various operational modes, including emergency mode, and is aimed at controlling air flows inside NPP containment buildings.

NPP containment building separation system dividing the NPP containment building into isolated rooms. It includes the containment building separation shutters located in the circular gap which divides the containment building rooms and the containment building walls; an air supply unit connected to a manifold ring which, in turn, is connected to the air-inflated shutters designed to ensure insulation of the airspace inside the containment building rooms when inflated and at connecting the airspace when deflated. In emergency mode the air supply to the air-inflated shutters is terminated, the shutters get deflated and fully open the circular gap which ensures convection process throughout the whole area of containment building.

A pressure-relief system for a containment of a nuclear plant has a pressure-relief line which is led through the containment and is closed by a shutoff device, and a wet scrubber being switched into the pressure-relief line lying outside the containment, for the pressure-relief gas flow developing in the pressure-relief operating mode with the shutoff device being open. An effective, reliable operation of the wet scrubber with a compact structural configuration is made possible. This is achieved by a reservoir, arranged in the containment or fluidically connected therewith such that an overpressure, as compared with the outer environment, present in the containment, is transferred to the reservoir, and a feeding line which is led from the reservoir to the wet scrubber and can be closed by a shutoff device, for feeding a liquid active as a scrubbing liquid from the reservoir to the wet scrubber.

A pressure-relief system for a containment of a nuclear plant has a pressure-relief line which is led through the containment and is closed by a shutoff device, and a wet scrubber being switched into the pressure-relief line lying outside the containment, for the pressure-relief gas flow developing in the pressure-relief operating mode with the shutoff device being open. An effective, reliable operation of the wet scrubber with a compact structural configuration is made possible. This is achieved by a reservoir, arranged in the containment or fluidically connected therewith such that an overpressure, as compared with the outer environment, present in the containment, is transferred to the reservoir, and a feeding line which is led from the reservoir to the wet scrubber and can be closed by a shutoff device, for feeding a liquid active as a scrubbing liquid from the reservoir to the wet scrubber.

A breaker valve assembly for a nuclear reactor containment includes a valve body, a valve body insert, and a lid. The valve body includes a first side wall defining a chamber, a first opening in a top portion of the first side wall, and a second opening in a bottom portion of the first side wall. The second opening communicates with the first opening of the valve body. The valve insert body includes a second side wall defining a second chamber, and a third opening in a bottom portion of the second side wall. The valve insert body is nested in the valve body. The lid is arranged on an upper edge of the side wall of the valve insert body. The valve insert body is configured to move substantially vertically with respect to the valve body.

A breaker valve assembly for a nuclear reactor containment includes a valve body, a valve body insert, and a lid. The valve body includes a first side wall defining a chamber, a first opening in a top portion of the first side wall, and a second opening in a bottom portion of the first side wall. The second opening communicates with the first opening of the valve body. The valve insert body includes a second side wall defining a second chamber, and a third opening in a bottom portion of the second side wall. The valve insert body is nested in the valve body. The lid is arranged on an upper edge of the side wall of the valve insert body. The valve insert body is configured to move substantially vertically with respect to the valve body.