The present invention relates to a method for preparing a fully ceramic capsulated nuclear fuel material containing three-layer-structured isotropic nuclear fuel particles coated with a ceramic having a composition which has a higher shrinkage than a matrix in order to prevent cracking of ceramic nuclear fuel, wherein the three-layer-structured nuclear fuel particles before coating is included in the range of between 5 and 40 fractions by volume based on after sintering. More specifically, the present invention provides a composition for preparing a fully ceramic capsulated nuclear fuel containing three-layer-structured isotropic particles coated with the substance which includes, as a main ingredient, a silicon carbine derived from a precursor of the silicon carbide wherein a condition of ΔL.sub.c>ΔL.sub.m at normal pressure sintering is created, where the sintering shrinkage of the coating layer of the three-layer-structured isotropic nuclear fuel particles is ΔL.sub.c and the sintering shrinkage of the silicon carbide matrix is ΔL.sub.m; material produced therefrom; and a method for manufacturing the material. The residual porosity of the fully ceramic capsulated nuclear fuel material is 4% or less.

A nuclear fuel element includes a core comprising a fissile element and an additional element. A protective structure surrounds the core and comprises at least a first material surrounding the nuclear fuel. The first material comprises the fissile element and the additional element and comprises a greater than stoichiometric amount of the additional element. An outer portion of the nuclear fuel element comprises a metal. Related nuclear fuel elements, and related methods are also disclosed.

Disclosed herein is a method comprising coating a fissile, uranium-containing ceramic material with a water-resistant layer, the layer being non-reactive with the fissile, uranium-containing ceramic material. The coating is applied to a surface of the fissile, uranium-containing ceramic material. Also disclosed is a fuel for use in a nuclear reactor.

A method for detecting the thicknesses of coating layers of nuclear fuel particles, comprising: collecting a surface image of a sample to be tested under a first amplification factor (S310); determining a testable particle in the surface image (S320); collecting a cross section image of the testable particle under a second amplification factor, wherein the second amplification factor is greater than the first amplification factor (S330); and determining the center of the testable particle in the cross section image and profile lines of all coating layers, and determining the thickness of each coating layer according to the center and the profile lines of each coating layer (S340). Also provided is a device for detecting the thicknesses of coating layers of the nuclear fuel particles.

To reduce size and mass of a nuclear reactor system, an integrated in-vessel shield separates the role of a neutron reflector and a neutron shield. Nuclear reactor system includes a pressure vessel including an interior wall and a nuclear reactor core located within the interior wall of the pressure vessel. Nuclear reactor core includes a plurality of fuel elements and at least one moderator element. Nuclear reactor system includes a reflector located inside the pressure vessel that includes a plurality of reflector blocks laterally surrounding the plurality of fuel elements and the at least one moderator element. Nuclear reactor system includes the in-vessel shield located on the interior wall of the pressure vessel to surround the reflector blocks. In-vessel shield is formed of two or more neutron absorbing materials. The two more neutron absorbing materials include a near black neutron absorbing material and a gray neutron absorbing material.

Device and method for checking fuel rods with IFBA, their zirconium diboride coating. The device includes a variable magnetic field generator and a magnetic field pickup device, arranged in the vicinity of the rod, as well as a control system for comparing both fields in order to measure the electric conductivity of the rod. The method includes the steps of: arranging the rod to be measured between the generator and the pickup device; generation of a variable magnetic field in the generator; picking-up of the magnetic field; comparison between the generated magnetic field and the picked-up one in order to quantify the electric conductivity of the rod; if the electric conductivity differs from a reference value, consider the rod for checking or recycling.

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.

Micro encapsulated fuel particles enhance safety in high-temperature gas cooled reactors by employing multiple barriers to fission product release. Microencapsulated fuel particles also have the potential to do the same in other reactor platforms. The present disclosure provides a method for enhancing the ability of microencapsulated fuel particles to retain radionuclides and thereby further enhance safety in nuclear reactors. Specifically, a nuclear fuel particle including a fuel kernel; a buffer graphitic carbon layer; an inner pyrolytic carbon layer; a multilayer pressure vessel; and an outer pyrolytic carbon layer is disclosed. The multilayer pressure vessel includes alternating layers of silicon carbide and pyrolytic carbon.

A methodology is disclosed for compaction of a ceramic matrix of certain nuclear fuels incorporating neutron poisons, whereby those poisons aid in reactor control while aiding in fuel fabrication. Neutronic poisons are rare-earth oxides that readily form eutectics suppressing fuel fabrication temperature, of particular importance to the fully ceramic microencapsulated fuel form and fuel forms with volatile species.

Fuel pellets can include a fission material powder, a protective layer coated on the fission material powder, and an oxidation diffusion barrier coated on the protective layer, with the protective layer and oxidation diffusion barrier being formed through ALD to achieve infiltration of the coatings within the fuel pellets.