Patent Number: 
Section: claims

1. A nuclear power plant comprising a nuclear reactor in which a hydrogen concentration of water is controlled, wherein the nuclear reactor comprises:a metal component of a reactor structure having a surface that is exposed to a high-temperature water;an oxide film having a corrosion-resistant property formed on the surface of the metal component; anda catalytic substance excited by heat and deposited on the oxide film,wherein the oxide film has a thickness of from 0.01 μm to 5 μm and comprises at least one of Fe3O4, NiO, and ZnCr2O4, which is composed of particles having an average particle diameter of 1 μm or less, andwherein the catalytic substance is TiO2, which is deposited on the oxide film in an amount of from 10 μg/cm2 to 50 μg/cm2. 2. The nuclear power plant according to claim 1, wherein the high-temperature  water has a temperature of 150° C. or higher. 3. The nuclear power plant according to claim 1, wherein the metal component is made of a stainless steel, a non-steel material, or a non-ferrous metal. 4. The nuclear power plant according to claim 1, wherein the metal component comprises a stainless steel. 5. The nuclear power plant according to claim 1, wherein the metal component comprises a non-steel material. 6. The nuclear power plant according to claim 1, wherein the metal component comprises a non-ferrous metal. 7. The nuclear power plant according to claim 1, wherein the oxide film comprises Fe3O4. 8. The nuclear power plant according to claim 1, wherein the oxide film comprises NiO. 9. The nuclear power plant according to claim 1, wherein the oxide film comprises ZnCr2O4. 10. The nuclear power plant according to claim 1, wherein the oxide film comprises particles of at least one of Fe3O4, NiO and ZnCr2O4, wherein the particles have an average particle diameter of less than 1 μm. 11. The nuclear power plant according to claim 1, wherein the oxide film comprises particles of at least one of Fe3O4, NiO and ZnCr2O4, wherein the particles have an average particle diameter of 0.01-0.1 μm. 12. The nuclear power plant according to claim 1, wherein the oxide film comprises particles of at least one of Fe3O4, NiO and ZnCr2O4, wherein the particles have an average particle diameter of 0.001-0.1 μm. 13. The nuclear power plant according to claim 1, wherein the oxide film comprises particles of at least one of Fe3O4, NiO and ZnCr2O4, wherein the particles have an average particle diameter of from 0.001 μm to 0.01 μm. 14. The nuclear power plant according to claim 1, wherein the metal component comprises an austenitic stainless steel. 15. The nuclear power plant according to claim 14, wherein the austenitic stainless steel comprises molybdenum.