Patent Number: 
Section: claims

1. A nuclear reactor comprising a depressurization system for a pressurized container, comprising a main valve which comprises:a pneumatic actuator, andan opening spring,wherein:the main valve is configured to be fluidly connected at one side to a pressurized container in which contains a gas and at the other side to the atmosphere, andthe opening spring is adjusted to set a predetermined mechanical pressure such that when a pressure inside the pressurized container is bigger than the predetermined mechanical pressure, the main valve remains closed, and that when the pressure inside the pressurized container is lower than the predetermined mechanical pressure, the main valve opens to establish a fluid communication so as to allow the pressurized gas from the pressurized container be discharged into the atmosphere. 2. The nuclear reactor according to claim 1, wherein the depressurization system further comprises at least one solenoid valve configured to be connected between the pressurized container and the main valve. 3. The nuclear reactor according to claim 1, wherein the depressurization system further comprises at least one manual valve configured to be connected between the pressurized container and the main valve. 4. The nuclear reactor according to claim 1, wherein the depressurization system further comprises a pneumatic line which can connect an output of the main valve with a pneumatic motor of an isolation valve configured to be connected to an output of the pressurized container. 5. The nuclear reactor according to claim 1, wherein the main valve is disposed inside a housing, the housing comprises:a connection to the pressurized container;a pressurized chamber where the gas from the pressurized container is accumulated;a shut-off element which receives the gas pressure from the pressurized chamber and that is associated with the opening spring; andat least one gas outlet,wherein:when the pressure inside the pressurized chamber is bigger than the predetermined mechanical pressure from the opening spring, the shut-off element closes the fluid communication between the pressurized chamber and the gas outlet, against the action of the opening spring, andwhen the pressure inside the pressurized chamber is lower than the predetermined mechanical pressure from the opening spring, the pressurized chamber is in fluid communication with the gas outlet or outlets and the gas from the pressurized container will be discharged to the atmosphere. 6. The nuclear reactor according to claim 5, wherein the pressurized chamber comprises a floater that closes the communication from the connection of the pressurized container with the outlet gas when a certain amount of liquid comes inside the pressurized chamber. 7. The nuclear reactor according to claim 5, wherein the depressurization system further comprises a closing piston associated with a second spring closing the communication connection of the pressurized container with the gas outlet or outlets by injecting air through a first air inlet. 8. The nuclear reactor according to claim 5, wherein the depressurization system further comprises an opening piston associated with a third spring which opens the communication from the connection of the pressurized container with the gas outlet or outlets by injecting air through a second air inlet. 9. The nuclear reactor according to claim 5, wherein the depressurization system further comprises an adjusting disk associated with the shut-off element and with the opening spring so that a relative position to the shut-off element of the adjusting disk defines the default mechanical pressure for the opening spring. 10. The nuclear reactor according to claim 5, wherein the depressurization system further comprises at least three threaded parts placed inside the housing and a plurality of screws housed in threaded holes made in the at least three threaded parts, such that the plurality of screws are configured to adjust the relative position of the at least three threaded parts.