A nuclear power plant comprises a nuclear reactor, the nuclear reactor comprising reactor fuel elements, a reactor vessel surrounding the nuclear reactor and a primary shield surrounding the reactor vessel. The reactor fuel elements are arranged between a first height and a second height above the first height. The primary shield comprises a base portion, an intermediate portion and a top portion. The base portion has an upper height below the first height and the base portion comprises concrete. The top portion has a lower height above the second height and the top portion comprises concrete. The intermediate portion is arranged vertically between the base portion and the top portion of the primary shield. The intermediate portion comprises at least one support structure and a matrix material containing tungsten or boron, and the least one support structure extends between the top portion and the bottom portion of the primary shield.

A method and system for generating and maintaining a solid structure is provided. The system includes a frame composed of an interconnected network of pipes configured for transporting liquid, the frame having a substantially spherical shape, a plurality of nozzles uniformly distributed along the pipes, wherein the plurality of nozzles are configured for dispensing liquid, a repository that holds a liquid composed of water and at least one additive, a refrigeration unit configured for refrigerating the liquid from the repository to at least a freezing temperature, and a pump for pumping the liquid from the refrigeration unit through the pipes and out of the nozzles, wherein the system is configured to dispense the liquid at said freezing temperature so as to freeze upon egress and create a solid structure surrounding the pipes. The system may also return melted liquid from the solid structure to the repository.

A method and system for generating and maintaining a solid structure is provided. The system includes a frame composed of an interconnected network of pipes configured for transporting liquid, the frame having a substantially spherical shape, a plurality of nozzles uniformly distributed along the pipes, wherein the plurality of nozzles are configured for dispensing liquid, a repository that holds a liquid composed of water and at least one additive, a refrigeration unit configured for refrigerating the liquid from the repository to at least a freezing temperature, and a pump for pumping the liquid from the refrigeration unit through the pipes and out of the nozzles, wherein the system is configured to dispense the liquid at said freezing temperature so as to freeze upon egress and create a solid structure surrounding the pipes. The system may also return melted liquid from the solid structure to the repository.

A migration prevention system for radioactive wastewater from an underground nuclear power plant. The underground nuclear power plant includes a nuclear island including an underground cavern group including a reactor cavity and auxiliary cavities. The migration prevention system includes a protective layer coating the reactor cavity and an impermeable layer surrounding the nuclear island. The protective layer includes an inner liner, a drainage layer, and a filling layer of rock fractures in that order. The inner liner is configured to prevent exosmosis of the radioactive wastewater of the reactor cavity. The drainage layer is configured to gather and drain seepage water. The impermeable layer is disposed in the periphery of the underground cavern group including the reactor cavity and the auxiliary cavities, and is configured to isolate the underground cavern group from natural underground water.

A migration prevention system for radioactive wastewater from an underground nuclear power plant. The underground nuclear power plant includes a nuclear island including an underground cavern group including a reactor cavity and auxiliary cavities. The migration prevention system includes a protective layer coating the reactor cavity and an impermeable layer surrounding the nuclear island. The protective layer includes an inner liner, a drainage layer, and a filling layer of rock fractures in that order. The inner liner is configured to prevent exosmosis of the radioactive wastewater of the reactor cavity. The drainage layer is configured to gather and drain seepage water. The impermeable layer is disposed in the periphery of the underground cavern group including the reactor cavity and the auxiliary cavities, and is configured to isolate the underground cavern group from natural underground water.

A method for manufacturing a core barrel according to the embodiment includes: welding one end part of a short ring to a lower core support plate; and machining the lower core support plate to which the short ring is welded. The machining of the lower core support plate includes forming a placement surface on which the fuel assembly is to be placed; and forming a fuel alignment pin hole, in which a fuel alignment pin for positioning the fuel assembly is to be inserted. After the machining of the lower core support plate, a main body barrel is welded to the other end part of the short ring, where the main body barrel covers the reactor core including the fuel assembly to be placed on the placement surface.

A method for manufacturing a core barrel according to the embodiment includes: welding one end part of a short ring to a lower core support plate; and machining the lower core support plate to which the short ring is welded. The machining of the lower core support plate includes forming a placement surface on which the fuel assembly is to be placed; and forming a fuel alignment pin hole, in which a fuel alignment pin for positioning the fuel assembly is to be inserted. After the machining of the lower core support plate, a main body barrel is welded to the other end part of the short ring, where the main body barrel covers the reactor core including the fuel assembly to be placed on the placement surface.

The invention relates to the field of nuclear technology, and specifically to a method for the in situ passivation of steel surfaces. The method consists in installing, in a position intended for a regular core, a core simulator in the form of a model of the core, which models the shape thereof, the relative position of the core components, and also the mass characteristics thereof; next, the reactor is filled with a heavy liquid metal heat transfer medium, the heat transfer medium is heated to a temperature which provides for the conditions of passivation, and in situ passivation is carried out in two stages, the first of which includes an isothermal passivation mode in conformity with the conditions determined for this stage, and the second mode includes non-isothermal passivation, which is carried out under different conditions, after which the core simulator is removed and the regular core is installed in the place thereof. The method provides for the corrosion-resistance of steel elements in a heavy liquid metal heat transfer medium environment and permits a decrease in the maximum rate of oxygen consumption during the initial period of operation of a nuclear actor.

The invention relates to the field of nuclear technology, and specifically to a method for the in situ passivation of steel surfaces. The method consists in installing, in a position intended for a regular core, a core simulator in the form of a model of the core, which models the shape thereof, the relative position of the core components, and also the mass characteristics thereof; next, the reactor is filled with a heavy liquid metal heat transfer medium, the heat transfer medium is heated to a temperature which provides for the conditions of passivation, and in situ passivation is carried out in two stages, the first of which includes an isothermal passivation mode in conformity with the conditions determined for this stage, and the second mode includes non-isothermal passivation, which is carried out under different conditions, after which the core simulator is removed and the regular core is installed in the place thereof. The method provides for the corrosion-resistance of steel elements in a heavy liquid metal heat transfer medium environment and permits a decrease in the maximum rate of oxygen consumption during the initial period of operation of a nuclear actor.

The invention relates to a method for reducing the radioactive contamination of the surface of a component used in a nuclear reactor, which component is in contact with radioactively contaminated water, in which method a hydrophobic film is produced on the surface of a component by virtue of the surface being wetted with an aqueous solution which contains a film-forming amphiphilic substance.