A method for manufacturing an article, e.g. a nuclear pressure vessel. The method involves: a) charging at least one hopper with steel powder; b) supplying an oxide stripping medium to the steel powder in the at least one hopper; c) removing the oxide stripping medium and any oxide particles stripped from the steel powder from the at least one hopper; d) discharging the oxide stripped steel powder into a can that provides a mould for the article; and e) converting the steel powder to solid steel by hot isostatic pressing to form the article. Stripping the steel powder of oxides whilst the steel powder is in the at least one hopper optimises desirable material properties of the article and thereby quality and safety of the article.

A method for manufacturing an article, e.g. a nuclear pressure vessel. The method involves: a) charging at least one hopper with steel powder; b) supplying an oxide stripping medium to the steel powder in the at least one hopper; c) removing the oxide stripping medium and any oxide particles stripped from the steel powder from the at least one hopper; d) discharging the oxide stripped steel powder into a can that provides a mould for the article; and e) converting the steel powder to solid steel by hot isostatic pressing to form the article. Stripping the steel powder of oxides whilst the steel powder is in the at least one hopper optimises desirable material properties of the article and thereby quality and safety of the article.

Illustrative methods are provided for annealing nuclear fission reactor materials, such as without limitation, a nuclear fission reactor core or fuel assembly or components thereof within the nuclear core. Annealing a metallic component of a nuclear fission reactor within the reactor core may include determining an annealing temperature for at least a portion of at least one metallic component of a nuclear fission fuel assembly of the reactor. The temperature of the core may be adjusted to affect the determined annealing temperature, which in some cases may be greater than the predetermined operating temperature range of the nuclear fission fuel assembly. The portion of the at least one metallic component of the nuclear fission fuel assembly is annealed within the core at the annealing temperature range.

Illustrative methods are provided for annealing nuclear fission reactor materials, such as without limitation, a nuclear fission reactor core or fuel assembly or components thereof within the nuclear core. Annealing a metallic component of a nuclear fission reactor within the reactor core may include determining an annealing temperature for at least a portion of at least one metallic component of a nuclear fission fuel assembly of the reactor. The temperature of the core may be adjusted to affect the determined annealing temperature, which in some cases may be greater than the predetermined operating temperature range of the nuclear fission fuel assembly. The portion of the at least one metallic component of the nuclear fission fuel assembly is annealed within the core at the annealing temperature range.

One variation of a system includes a pressure vessel: including a wall; defining a primary working fluid circuit extending vertically within the wall; defining a secondary working fluid circuit extending vertically within the wall and fluidly isolated from the primary working fluid circuit; and configured to store a nuclear fuel, a primary working fluid, and a secondary working fluid. The wall of the pressure vessel: defines a heat exchanger configured to transfer thermal energy from the primary working fluid flowing through the primary working fluid circuit into the secondary working fluid flowing through the secondary working fluid circuit; and defines a radiation shield configured to attenuate radiation emitted by the nuclear fuel.

A method for the inner-contour passivation of steel surfaces of a nuclear reactor consists in filling a first contour of a nuclear reactor with a liquid metal coolant, introducing a reagent into the liquid metal coolant, said reagent interacting with the material of elements of the first contour, forming a protective film, and heating the liquid metal coolant, having the reagent introduced therein, to a temperature allowing for conditions for forming the protective film. The liquid metal coolant having the reagent introduced therein is kept at said temperature until a continuous protective film is formed on the surface of the material of the elements of the first contour. The liquid metal coolant having reagent introduced therein is heated by means of the friction thereof against rotating vanes of a vane pump, which is submerged in the liquid metal coolant. The present invention thus provides for a simpler passivation process, a more reliable passivation mode, an increase in the safety thereof and a simpler control over the process of passivation of steel surfaces.

A method for the inner-contour passivation of steel surfaces of a nuclear reactor consists in filling a first contour of a nuclear reactor with a liquid metal coolant, introducing a reagent into the liquid metal coolant, said reagent interacting with the material of elements of the first contour, forming a protective film, and heating the liquid metal coolant, having the reagent introduced therein, to a temperature allowing for conditions for forming the protective film. The liquid metal coolant having the reagent introduced therein is kept at said temperature until a continuous protective film is formed on the surface of the material of the elements of the first contour. The liquid metal coolant having reagent introduced therein is heated by means of the friction thereof against rotating vanes of a vane pump, which is submerged in the liquid metal coolant. The present invention thus provides for a simpler passivation process, a more reliable passivation mode, an increase in the safety thereof and a simpler control over the process of passivation of steel surfaces.

A structure and process for containing a nuclear reaction is disclosed. The structure and process may involve a nuclear containment structure including a plurality of metallic rings stacked axially to form the nuclear containment structure, the nuclear containment structure being configured to: mitigate, by using a physical barrier, the movement of radionuclides from inside a containment structure to a surrounding space; shield, by varying the alloy properties throughout the containment structure, an exterior of the containment structure from radiation produced inside of the containment structure; regulate, by transferring thermal energy, a temperature within the containment structure; regulate, by storing thermal energy, the temperature within the containment structure; shield, components within the nuclear containment structure from kinetic events external to the nuclear containment structure; and shield, the external environment, from kinetic events within the nuclear containment structure.

A system includes a nuclear reactor pressure vessel comprising a heat exchange wall. An interior of the vessel contains nuclear fuel which heats a primary fluid. A primary fluid circuit extends vertically within the wall. The primary fluid circulates in a loop that includes the interior and the primary fluid circuit in the wall. A secondary fluid circuit also extends vertically within the wall, and is fluidly isolated from the primary fluid circuit. A secondary fluid circulates in a loop that includes a power generating system and the secondary fluid circuit in the wall. The wall acts as a heat exchanger in which thermal energy is transferred to the wall from primary fluid flowing through the primary fluid circuit, and then is transferred from the wall to secondary fluid flowing through the secondary fluid circuit.

A nuclear reactor is designed to allow efficient packing of components within the reactor vessel, such as by offsetting the core, and/or vertically stacking components. The in-vessel storage system can be separate from the support cylinder and these components can be fabricated and shipped separately and coupled together at the construction site. Furthermore, the in-vessel storage system can be located adjacent to the core rather than being located circumferentially around it, and may also be located beneath the heat exchanger to further improve packing of components within the vessel. Through these, and other changes, the delicate components can be manufactured in a manufacturing facility, assembled, and shipped by commercial transportation options without exceeding the shipping envelope.