Patent Number: 
Section: claims

1. An underwater electricity production module comprising:an elongated cylindrical box comprising:a receiving compartment anda reactor compartment,wherein the reactor compartment further comprises:a reservoir chamber anda dry chamber,an electricity production unit integrated in the elongated cylindrical box, said electricity production unit comprisinga nuclear boiler which comprises:a reactor container located in the dry chamber andan electricity generator located in the receiving compartment,wherein the electricity generator is configured to be connected to an external electricity distribution station by electrical cables,at least one connecting element adapted to connect the dry chamber to the reservoir chamber, the reservoir chamber forming a safety water storage reservoir, at least a radial wall of which is in a direct heat exchange relationship with a marine environment surrounding the cylindrical box,wherein the receiving compartment includes one connecting device adapted to connect the receiving compartment to the dry chamber,wherein the connecting device includes a water introducing arrangement adapted to introduce quenching water into the dry chamber,wherein the water introducing arrangement is located in a lower portion of the receiving compartment,the water introducing arrangement includinga seawater inlet formed in a radial wall of the receiving compartment,a duct between the seawater inlet and the dry chamber, anda quenching valve in the duct. 2. The underwater electricity production module according to claim 1, wherein the nuclear boiler includes a primary circuit comprising at least one reactor container, a pressurizer, a steam generator and a primary pump and a primary backup circuit in parallel on that primary circuit and at least one primary passive heat exchanger located in the reservoir chamber. 3. The underwater electricity production module according to claim 2, wherein each primary passive heat exchanger located in the reservoir chamber is located at a higher level than that of each reactor container. 4. The underwater electricity production module according to claim 2, wherein each branch of the primary backup circuit includes a valve. 5. The underwater electricity production module according to claim 2, wherein the nuclear boiler includes a secondary circuit associated with the electricity generator and a secondary backup circuit in parallel on that secondary circuit and being connected to at least one secondary passive heat exchanger located outside the elongated cylindrical box in the marine environment. 6. The underwater electricity production module according to claim 5, wherein the secondary passive heat exchanger located outside the elongated cylindrical box in the marine environment is located at a higher level than that of the steam generator. 7. The underwater electricity production module according to claim 5, wherein each branch of the secondary backup circuit includes a valve. 8. The underwater electricity production module according to claim 5, wherein the secondary circuit includes at least two isolating valves and wherein the secondary backup circuit is connected between isolating valves. 9. The underwater electricity production module according to claim 5, wherein the secondary circuit extends partially in the receiving compartment and wherein the secondary backup circuit passes through the radial wall of the receiving compartment, each secondary passive heat exchanger is located outside the receiving compartment. 10. The underwater electricity production module according to claim 1, wherein the dry chamber is directly connected to the reservoir chamber of the reactor by first depressurizing means including a first depressurizing valve located in an upper portion of the dry chamber and connected to a bubbler located in a lower portion of the reservoir chamber and wherein excess flow check means are provided between an upper portion of the reservoir chamber and the upper portion of the dry chamber. 11. The underwater electricity production module according to claim 1, wherein the nuclear boiler includes a reactor container, located in a reactor pit whereof a lower portion is connected to a lower portion of the reservoir chamber through a water intake duct located along a radial wall of the elongated cylindrical box and whereof an upper portion is connected to a corresponding portion of the reservoir chamber through a water return duct. 12. The underwater electricity production module according to claim 11, wherein valves are located in the intake and return ducts. 13. The underwater electricity production module according to claim 11, wherein an enclosure made from a thermally insulating material is located around a portion of the reactor container housed in the reactor pit, at a distance from a wall of the reactor container, so as to define an interstice forming a thermal barrier between enclosure and the reactor container. 14. The underwater electricity production module according to claim 11, wherein during normal operation of the underwater electricity production module, when no accident occurs in the reactor container, the reactor pit comprises borated water. 15. The underwater electricity production module according to claim 1, wherein the nuclear boiler includes a pressurizer connected by second depressurizing means to the reservoir chamber. 16. The underwater electricity production module according to claim 15, wherein the second depressurizing means includes a depressurizing circuit provided with a second depressurizing valve connected to a bubbler placed located in a lower portion of the reservoir chamber. 17. The underwater electricity production module according to claim 1, wherein a device for deviating jets of water is located in front of the water introducing arrangement. 18. The underwater electricity production module according to claim 1, wherein vent-forming means are located in an upper portion of the dry chamber between the dry chamber and the receiving compartment. 19. The underwater electricity production module according to claim 1, wherein the module includes a valve for connecting the reservoir chamber to the reactor container.