A debris filter configured for a nuclear fuel assembly bottom end part includes a lower nozzle (8) and the debris filter (18) is supported by the lower nozzle (8). The debris filter (18) has an inlet face (18A) and an outlet face (18B) opposed to the inlet face (18A), and comprises at least one filtering section (18D) that has a retention capacity that increases gradually or stepwise towards from the inlet face (18A) to the outlet face (18B).

Embodiments of the disclosure relate to a ferritic alloy having excellent ability to withstand nuclear power plant accidents and a method of manufacturing a nuclear fuel cladding tube using the same. The alloy includes iron (Fe), aluminum (Al), chromium (Cr), and nickel (Ni). The nickel (Ni) may be included 0.5 to 10 wt % based on a total amount of the alloy. The chromium may be included 13 to 18 wt % based on the total amount of the alloy. The aluminum may be included 5 to 7 wt % based on the total amount of the alloy.

Fission reactor has a shell encompassing a reactor space within which are a central longitudinal channel, a plurality of axially extending rings with adjacent rings defining an annular cylindrical space in which a first plurality of primary axial tubes are circumferential located. Circumferentially adjacent primary axial tubes are separated by one of the plurality of secondary channels and a plurality of webbings connects at least a portion of the plurality of primary axial tubes to adjacent structure. A fissionable nuclear fuel composition is located in at least some of the plurality of secondary channels and a primary coolant passes thorough at least some of the primary axial tubes. Additive and/or subtractive manufacturing techniques produce an integral and unitary structure for the fuel loaded reactor space. During manufacturing and as-built, the reactor design can be analyzed using a computational platform that integrates and analyzes data from in-situ monitoring during manufacturing.

Methods of fabricating structures, such as parts for use in nuclear power generation systems, are described herein. A representative method of fabricating a part for a nuclear reactor system includes coating a plurality of particles of a powder of a first material with a second material, and then pressing and/or heating the coated powder into a monolithic structure. The second material can be substantially solidly insoluble with the first material such that, after pressing and/or heating, the particles of the first material define grains of the monolithic structure and the second material substantially encapsulates the grains in the monolithic structure. The first material can be susceptible to corrosion by a select process, and the second material can be resistant to corrosion by the select process such that the bulk first material of the monolithic structure is resistant to corrosion by the select process.

Methods of fabricating structures, such as parts for use in nuclear power generation systems, are described herein. A representative method of fabricating a part for a nuclear reactor system includes coating a plurality of particles of a powder of a first material with a second material, and then pressing and/or heating the coated powder into a monolithic structure. The second material can be substantially solidly insoluble with the first material such that, after pressing and/or heating, the particles of the first material define grains of the monolithic structure and the second material substantially encapsulates the grains in the monolithic structure. The first material can be susceptible to corrosion by a select process, and the second material can be resistant to corrosion by the select process such that the bulk first material of the monolithic structure is resistant to corrosion by the select process.

A closed-vessel molten salt reactor (cvMSR) is described herein. A cvMSR may comprise a suspended container, such as a metallic container, within a trench surrounded by a concrete enclosure and a concrete cover having a number of channels. The suspended container may be hollow and a solution of fissile materials and salt materials may be provided within the suspended container. The solution may be capable of undergoing a chain reaction nuclear fission process once a threshold temperature is reached. Heat generated by the solution may heat a fluid surrounding the suspended container. The heated fluid may be transported, through the number of channels of the concrete cover, to an external location where the heated fluid may be used in distributing heat and/or electricity generation.

A thermal shield flexure member. The thermal shield flexure member includes a first face portion, a second face portion and a third portion. The first face portion defines openings configured to align with receptacles of a thermal shield. The second face portion defines openings configured to align with openings of a core barrel and openings of an arm portion of a modified thermal shield flexure connected to the core barrel. The third portion is connected to the first face portion and the second face portion, and comprises a radiused portion. The thermal shield flexure member is configured to provide flexibility in an axial direction to accommodate differential axial expansions of the core barrel and the thermal shield, and rigidity in a radial direction to inhibit undesirable shell mode vibrations of the core barrel and/or the thermal shield.

A thermal shield flexure member. The thermal shield flexure member includes a first face portion, a second face portion and a third portion. The first face portion defines openings configured to align with receptacles of a thermal shield. The second face portion defines openings configured to align with openings of a core barrel and openings of an arm portion of a modified thermal shield flexure connected to the core barrel. The third portion is connected to the first face portion and the second face portion, and comprises a radiused portion. The thermal shield flexure member is configured to provide flexibility in an axial direction to accommodate differential axial expansions of the core barrel and the thermal shield, and rigidity in a radial direction to inhibit undesirable shell mode vibrations of the core barrel and/or the thermal shield.

A nuclear reactor structure configuring a pebble accommodating space of a pebble bed type nuclear reactor includes a core material including graphite and a ceramic/ceramic composition material covering a surface of the core material. According to a core material processing step (A) of processing the core material including graphite into a quadrangular prism, a bottom surface of which is an approximately isosceles trapezoid, a step (B) of obtaining a base material by covering the core material with an aggregate including a ceramic fiber, and a CVD step (C) of putting the base material into a CVD reactor and forming a SiC matrix in gaps of the aggregate, thereby forming a ceramic/ceramic composite material on a surface of the core material, the nuclear reactor structure capable of enhancing durability, preventing cracking, etc. from occurring, and preventing exposure of graphite as the core material from occurring, can be provided.

A composite moderator medium for nuclear reactor systems and a method of fabricating a composite moderator block formed of the composite moderator medium. The composite moderator medium includes two or more moderators, such as a low moderating material and a high moderating material. The high moderating material has a higher neutron slowing down power compared to the low moderating material. The low moderating material includes a moderating matrix of silicon carbide or magnesium oxide. The high moderating material is dispersed within the moderating matrix and includes beryllium, boron, or a compound thereof. The high moderating material is encapsulated within the low moderating material such that the high moderating material is not exposed outside of the low moderating material. The method can include selecting a sintering aid and a weight percent of the sintering aid in a composite moderator mixture based on the low moderating material and spark plasma sintering.