A system includes a load-following nuclear power generator including a nuclear reactor configured to generate variable amounts of electricity. The system also includes an electric drive and a propeller controlled by the electric drive.

A temperature-controlled irradiation system may include an outer containment and a sealed capsule disposed within the outer containment. The sealed capsule may be configured to contain a testing material within the sealed capsule. The system may further include a temperature sensor disposed within the sealed capsule. The temperature sensor may be configured to measure a temperature of the testing material. A pressure sensor may be disposed within the sealed capsule. The pressure sensor may be configured to measure an internal pressure of the sealed capsule. The system may include a heater disposed within the sealed capsule. The heater may be configured to control the temperature of the testing material. The heater may be immersed within the testing material. A gas gap is provided between the sealed capsule and the outer containment. The gas gap may be configured to control thermal conductivity between the sealed capsule and the outer containment.

A temperature-controlled irradiation system may include an outer containment and a sealed capsule disposed within the outer containment. The sealed capsule may be configured to contain a testing material within the sealed capsule. The system may further include a temperature sensor disposed within the sealed capsule. The temperature sensor may be configured to measure a temperature of the testing material. A pressure sensor may be disposed within the sealed capsule. The pressure sensor may be configured to measure an internal pressure of the sealed capsule. The system may include a heater disposed within the sealed capsule. The heater may be configured to control the temperature of the testing material. The heater may be immersed within the testing material. A gas gap is provided between the sealed capsule and the outer containment. The gas gap may be configured to control thermal conductivity between the sealed capsule and the outer containment.

A system includes a load-following nuclear power generator including a nuclear reactor configured to generate variable amounts of electricity. The system also includes an electric drive and a propeller controlled by the electric drive.

A system includes a load-following nuclear power generator including a nuclear reactor configured to generate variable amounts of electricity. The system also includes an electric drive and a propeller controlled by the electric drive.

Systems and methods for insulating vessels are disclosed. In one or more embodiments, the disclosure provides a vessel insulation system (e.g., for use with a reactor or pressure vessel), which includes a floating ring sized to circumscribe a top nozzle of a vessel; a plurality of straps connected to the floating ring, the plurality of straps extending downward from the floating ring and being positioned to run along a length of the outer shell of the vessel; and a plurality of segmented rings positioned to circumscribe the outer shell of the vessel and connected to the plurality of straps. The plurality of segmented rings is configured to support an insulation material circumscribing the outer shell of the vessel, which can provide effective securement of the insulation material around the outer shell without welding components on the vessel to secure the insulation material.

Systems and methods for insulating vessels are disclosed. In one or more embodiments, the disclosure provides a vessel insulation system (e.g., for use with a reactor or pressure vessel), which includes a floating ring sized to circumscribe a top nozzle of a vessel; a plurality of straps connected to the floating ring, the plurality of straps extending downward from the floating ring and being positioned to run along a length of the outer shell of the vessel; and a plurality of segmented rings positioned to circumscribe the outer shell of the vessel and connected to the plurality of straps. The plurality of segmented rings is configured to support an insulation material circumscribing the outer shell of the vessel, which can provide effective securement of the insulation material around the outer shell without welding components on the vessel to secure the insulation material.

A high temperature control rod for a nuclear fuel assembly is described herein that includes a neutron absorbing material having a melting point greater than 1500? C. that does not form a eutectic with a melting point less than 1500? C., and may further include a cladding material having a melting point greater than 1500? C. The cladding material is selected from the group consisting of silicon carbide, zirconium, a zirconium alloy, tungsten, and molybdenum. The absorbing material is selected from the group consisting of Gd.sub.2O.sub.3, Ir, B.sub.4C, Re, and Hf. The metal cladding or the absorbing material may be coated with an anti-oxidation coating of Cr with or without a Nb intermediate layer.

A maintenance method for a nuclear reactor replaces flexible arms of thermal shield flexures with contact bodies. The nuclear reactor has reactor core having a center axis, a core barrel concentric to the center axis a thermal shield arranged around the core barrel and secured to the core barrel and a plurality of thermal shield flexures. Each thermal shield flexure includes a main plate secured to the core barrel and a flexible arm extending from the main plate and welded to a lower edge of the thermal shield. The maintenance method includes installing, at a axial height above the lower edge, a contact body in the thermal shield passing radially, with respect to the center axis, through the thermal shield past an inner circumferential surface of the thermal shield such that a tip of the contact body bears against an outer circumferential surface of the core barrel with a predetermined load allowing the contact body to be slidable against the core barrel axially with respect to the center axis.

A maintenance method for a nuclear reactor replaces flexible arms of thermal shield flexures with contact bodies. The nuclear reactor has reactor core having a center axis, a core barrel concentric to the center axis a thermal shield arranged around the core barrel and secured to the core barrel and a plurality of thermal shield flexures. Each thermal shield flexure includes a main plate secured to the core barrel and a flexible arm extending from the main plate and welded to a lower edge of the thermal shield. The maintenance method includes installing, at a axial height above the lower edge, a contact body in the thermal shield passing radially, with respect to the center axis, through the thermal shield past an inner circumferential surface of the thermal shield such that a tip of the contact body bears against an outer circumferential surface of the core barrel with a predetermined load allowing the contact body to be slidable against the core barrel axially with respect to the center axis.