Patent Number: 
Section: claims

1. A nuclear power plant, comprising:a nuclear island, including one or more nuclear reactors located in one or more underground caverns;side by side with the one or more nuclear reactors, a centre for treating and conditioning radioactive wastes; andtwo repositories, located in the one or more underground caverns, the two repositories including a final repository being adapted to store low-intermediate level nuclear wastes, and a temporary repository being adapted to store spent fuel, high-level long-life radioactive materials, and spare nuclear rods for reactor refueling. 2. The underground nuclear power plant according to claim 1, further comprising:metallic doors for closing an entrance to the one or more underground caverns, and an interposition of walls made of injected concrete between said metallic doors. 3. The underground nuclear power plant according to claim 1, wherein the one or more underground caverns comprise an entrance provided with anti-intrusion devices to secure the nuclear island from attack from outside the one or more underground caverns. 4. The underground nuclear power plant according to claim 1, wherein the one or more underground caverns comprise an entrance provided with anti-flooding devices. 5. The underground nuclear power plant according to claim 1, wherein the one or more underground caverns is formed of rocks appositely formed to host the nuclear island, the centre for treating and conditioning radioactive wastes, and the two repositories. 6. The underground nuclear power plant according to claim 1, further comprising:storage facilities for radioactive wastes of low-intermediate level produced during a service life of the nuclear power plant for final underground storage in safe conditions to avoid transport of the radioactive wastes of low-intermediate level outside. 7. The underground nuclear power plant according to claim 1, wherein the temporary repository is adapted to operate as a final repository for all high-level long-life radioactive materials produced by the underground nuclear power plant. 8. The underground nuclear power plant according to claim 1, wherein substantially all components of the one or more nuclear reactors are underground. 9. The underground nuclear power plant according to claim 1, wherein the one or more nuclear reactors is constructed and arranged to use masses of natural water for cooling. 10. The underground nuclear power plant according to claim 1, wherein an access to an interior of the one or more underground caverns is horizontal. 11. The underground nuclear power plant according to claim 1, further comprising:a system for conditioning and disposing radioactive wastes provided inside the one or more underground caverns. 12. The underground nuclear power plant according to claim 1, wherein the one or more nuclear reactors is one or more commercial, high power PWR reactors. 13. The underground nuclear power plant according to claim 1, wherein the one or more underground caverns housing the nuclear isle and the the two repositories have a roof formed of an inverted arch and side-walls made substantially impermeable and provided with systems for collecting natural or accidentally released fluids. 14. The underground nuclear power plant according to claim 1, wherein the underground nuclear power plant is constructed and arranged to receive the radioactive wastes of the two repositories, thereby avoiding any danger of nuclear pollution to the surrounding environment.