A nuclear fuel assembly is constructed with fuel assembly components that are wire wrapped and positioned in hexagonal rings within a fuel assembly duct. The fuel assembly components positioned in an outermost ring of the fuel assembly are wire wrapped with a pitch that is shorter than fuel assembly components positioned at an interior ring of the fuel assembly. The shorter pitch at the outer ring of the fuel assembly increases pressure drop of a coolant fluid at the edge and corner subchannels and thereby reduces the temperature gradient across the fuel assembly, which provides a higher output temperature of the nuclear reactor without substantially increasing peak temperature of the fuel cladding.

A method for manufacturing a nuclear fuel compact is provided. The method includes forming an additive structure, consolidating a fuel matrix around the additive structure, and thermally processing the fuel matrix to form a fuel compact in which the additive structure is encapsulated therein. The additive structure optionally includes a vertical segment and a plurality of arm segments that extend generally radially from the vertical segment for conducting heat outwardly toward an exterior of the fuel compact. In addition to improving heat transfer, the additive structure may function as burnable absorbers, and may provide fission product trapping.

Method of fuel elements installation into fuel assemblies including fuel elements fabrication and control operations, application of a protective coating on each fuel element, installation of prepared fuel elements into a fuel assembly, attachment of top and bottom nozzles, washing off of the protective coating and drying. The protective coating application and fuel elements installation are combined using a water soluble lubricant containing nonylphenol ethoxylate and monobasic unsaturated fatty acids as protective coating, which is applied on the surface of the fuel element being moved during fuel elements installation in the fuel assembly on an assembly stand in horizontal direction along its own axis to the cells of grids through a protective coating application device installed on the assembly stand. The protective coating is washed off using water jets under pressure at room temperature.

Method of fuel elements installation into fuel assemblies including fuel elements fabrication and control operations, application of a protective coating on each fuel element, installation of prepared fuel elements into a fuel assembly, attachment of top and bottom nozzles, washing off of the protective coating and drying. The protective coating application and fuel elements installation are combined using a water soluble lubricant containing nonylphenol ethoxylate and monobasic unsaturated fatty acids as protective coating, which is applied on the surface of the fuel element being moved during fuel elements installation in the fuel assembly on an assembly stand in horizontal direction along its own axis to the cells of grids through a protective coating application device installed on the assembly stand. The protective coating is washed off using water jets under pressure at room temperature.

Fuel rod designs and techniques are provided to encapsulate nuclear fuel pellets in nuclear fuel rods. The tubular cladding in the disclosed fuel rods includes silicon carbide and a metal filler structure formed of a metal that becomes molten during a nuclear reaction of the nuclear fuel pellets and located inside the tubular cladding to include a metal tube that fills in a gap between the nuclear fuel pellets and an interior side wall of the tubular cladding and structured to include a closed metal end cap at one end of the nuclear fuel pellets to leave a space between one end of the interior of the tubular cladding and the closed metal end cap of the metal filler structure as a reservoir.

Process for manufacturing a composite nuclear component comprising i) a support containing a substrate comprising a metallic material and a ceramic material (1), the substrate (1) being coated or not coated with an interposed layer (3) positioned between the substrate (1) and at least one protective layer (2) and ii) the protective layer (2) composed of a protective material comprising chromium; the process comprising a step a) of vaporizing a mother solution followed by a step b) of depositing the protective layer (2) onto the support via a DLI-MOCVD deposition process. Composite nuclear component comprising i) a support containing a substrate comprising a metallic material and a ceramic material (1), the substrate (1) being coated or not coated with an interposed layer (3) positioned between the substrate (1) and at least one protective layer (2) and ii) the protective layer (2) composed of a protective material comprising chromium; the process comprising a step a) of vaporizing a mother solution followed by a step b) of depositing the protective layer (2) onto the support via a DLI-MOCVD deposition process. The composite nuclear component has improved resistance to oxidation and/or migration of undesired material. The invention also relates to the use of the composite nuclear component for combating oxidation and/or degradation of the ceramic material contained in the substrate.

Process for manufacturing a composite nuclear component comprising i) a support containing a substrate comprising a metallic material and a ceramic material (1), the substrate (1) being coated or not coated with an interposed layer (3) positioned between the substrate (1) and at least one protective layer (2) and ii) the protective layer (2) composed of a protective material comprising chromium; the process comprising a step a) of vaporizing a mother solution followed by a step b) of depositing the protective layer (2) onto the support via a DLI-MOCVD deposition process. Composite nuclear component comprising i) a support containing a substrate comprising a metallic material and a ceramic material (1), the substrate (1) being coated or not coated with an interposed layer (3) positioned between the substrate (1) and at least one protective layer (2) and ii) the protective layer (2) composed of a protective material comprising chromium; the process comprising a step a) of vaporizing a mother solution followed by a step b) of depositing the protective layer (2) onto the support via a DLI-MOCVD deposition process. The composite nuclear component has improved resistance to oxidation and/or migration of undesired material. The invention also relates to the use of the composite nuclear component for combating oxidation and/or degradation of the ceramic material contained in the substrate.

Composite nuclear component comprising i) a support containing a substrate comprising a metallic material and a ceramic material (1), the substrate (1) being coated or not coated with an interposed layer (3) positioned between the substrate (1) and at least one protective layer (2) and ii) the protective layer (2) composed of a protective material comprising chromium; the process comprising a step a) of vaporizing a mother solution followed by a step b) of depositing the protective layer (2) onto the support via a DLI-MOCVD deposition process. The composite nuclear component has improved resistance to oxidation and/or migration of undesired material. The invention also relates to the use of the composite nuclear component for combating oxidation and/or degradation of the ceramic material contained in the substrate.

Composite nuclear component comprising i) a support containing a substrate comprising a metallic material and a ceramic material (1), the substrate (1) being coated or not coated with an interposed layer (3) positioned between the substrate (1) and at least one protective layer (2) and ii) the protective layer (2) composed of a protective material comprising chromium; the process comprising a step a) of vaporizing a mother solution followed by a step b) of depositing the protective layer (2) onto the support via a DLI-MOCVD deposition process. The composite nuclear component has improved resistance to oxidation and/or migration of undesired material. The invention also relates to the use of the composite nuclear component for combating oxidation and/or degradation of the ceramic material contained in the substrate.

The known fully ceramic microencapsulated fuel (FCM) entrains fission products within a primary encapsulation that is the consolidated within a secondary ultra-high-temperature-ceramic of Silicon Carbide (SiC). In this way the potential for fission product release to the environment is significantly limited. In order to extend the performance of this fuel to higher temperature and more aggressive coolant environments, such as the hot-hydrogen of proposed nuclear rockets, a zirconium carbide matrix version of the FCM fuel has been invented. In addition to the novel nature to this very high temperature fuel, the ability to form these fragile TRISO microencapsulations within fully dense ZrC represent a significant achievement.