Patent Number: 
Section: claims

1. A device adapted for producing energy by nuclear fission, the device comprising a core container of a core container material, which core container encloses an inner tubing of an inner tubing material, the inner tubing and/or the core container having an inlet and an outlet, the device further comprising a molten halide salt located in the core container or in the inner tubing, which inner tubing comprises at least one section consisting of single crystal corundum, wherein the device further comprises a moderator comprising at least one metal hydroxide, at least one metal deuteroxide or a combination thereof and water at a concentration to provide a pH2O in the range of 2.2 to 3.0, which moderator is located in the core container and which molten halide salt is located in the inner tubing, or which moderator is located in the inner tubing and which molten halide salt is located in the core container. 2. The device according to claim 1, wherein the molten halide salt is a fuel salt, and the halide is fluoride. 3. The device according to claim 1, wherein the inner tubing does not have an inlet and an outlet. 4. The device according to claim 1, wherein the material thickness of the inner tubing material is in the range of 1 mm to 10 mm. 5. The device according to claim 1, wherein the at least one section of the inner tubing consisting of single crystal corundum constitutes 70% to 100% of a total length of the inner tubing. 6. The device according to claim 1, wherein a volume of the inner tubing is in the range of 10% to 90% of a total volume of the core container. 7. The device according to claim 1, wherein the inner tubing comprises a plurality of sections, which sections are spaced at a distance in the range of 0.5 cm to 10 cm. 8. The device according to claim 1, wherein the single crystal corundum is doped with a transition metal. 9. The device according to claim 1, wherein the inner tubing further comprises at least one metallic section consisting of a metal selected from the list consisting of nickel based superalloys, and nickel. 10. The device according to claim 9, wherein a section consisting of single crystal corundum and a metallic section are connected together by a butt joint or a lap joint mechanism. 11. The device according to claim 1, wherein two or more sections consisting of single crystal corundum are connected together by a butt joint or a lap joint mechanism. 12. The device according to claim 1, wherein the inner tubing is coated with nickel or with a nickel based superalloy. 13. The device according to claim 12, wherein the coating has a thickness in the range of 1 μm to 100 μm. 14. A method of controlling a nuclear fission process, the method comprising the steps of:providing a device according to claim 1, the core container of the device having the inlet and the outlet,introducing a molten fuel salt into the inner tubing, which molten fuel salt comprises halides of an alkali metal and a fissile element,introducing into the core container a molten coolant salt,providing a heat exchanger in fluid communication with the inlet and the outlet of the core container so as to define a heat exchange loop for removing heat from the coolant salt circulating in the heat exchange loop,circulating the coolant salt in the heat exchange loop so as to control the temperature of the fuel salt in the inner tubing. 15. The method of controlling a nuclear fission process according to claim 14, wherein the core container contains a blanket of a breeder material. 16. The method of controlling a nuclear fission process according to claim 14, wherein the halide is fluoride. 17. A method of controlling a nuclear fission process, the method comprising the steps of:providing a device according to claim 1, the inner tubing of the device having the inlet and the outlet,introducing a molten fuel salt into the inner tubing, which molten fuel salt comprises halides of an alkali metal and a fissile element,providing a heat exchanger in fluid communication with the inlet and the outlet of the inner tubing so as to define a heat exchange loop for removing heat from the molten fuel salt circulating in the heat exchange loop,circulating the molten fuel salt in the heat exchange loop so as to control the temperature of the fuel salt. 18. The method of controlling a nuclear fission process according to claim 17, wherein the halide is fluoride. 19. A device adapted for producing energy by nuclear fission, the device comprising a core container of a core container material, which core container encloses an inner tubing of an inner tubing material, the inner tubing and/or the core container having an inlet and an outlet, the device further comprising a molten halide salt located in the core container or in the inner tubing, which inner tubing comprises at least one section consisting of single crystal corundum and at least one metallic section consisting of a metal selected from the list consisting of nickel based superalloys and nickel. 20. The device according to claim 19, wherein the molten halide salt is a fuel salt, and the halide is fluoride. 21. The device according to claim 19, wherein the material thickness of the inner tubing material is in the range of 1 mm to 10 mm. 22. The device according to claim 19, wherein the at least one section of the inner tubing consisting of single crystal corundum constitutes 70% to 100% of a total length of the inner tubing. 23. The device according to claim 19, wherein a volume of the inner tubing is in the range of 10% to 90% of a total volume of the core container. 24. The device according to claim 19, wherein the inner tubing comprises a plurality of sections, which sections are spaced at a distance in the range of 0.5 cm to 10 cm. 25. The device according to claim 19, wherein the single crystal corundum is doped with a transition metal. 26. The device according to claim 19, wherein two or more sections consisting of single crystal corundum are connected together by a butt joint or a lap joint mechanism. 27. The device according to claim 19, wherein a section consisting of single crystal corundum and a metallic section are connected together by a butt joint or a lap joint mechanism. 28. The device according to claim 19, wherein the inner tubing is coated with nickel or with a nickel based superalloy. 29. The device according to claim 28, wherein the coating has a thickness in the range of 1 μm to 100 μm. 30. The device according to claim 19, wherein the device further comprises a molten moderator salt comprising at least one metal hydroxide, at least one metal deuteroxide or a combination thereof and water at a concentration to provide a pH2O in the range of 2.2 to 3.0. 31. The device according to claim 19, wherein the inner tubing does not have an inlet and an outlet.