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.

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 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.

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.

Methods for forming particulates that are highly consistent with regard to shape, size, and content are described. Particulates are suitable for use as reference materials. Methods can incorporate actinides and/or lanthanides, e.g., uranium, and can be used for forming certified reference materials for use in the nuclear industry. Methods include formation of an aerosol from an oxalate salt solution, in-line diagnostics, and collection of particles of the aerosol either in a liquid impinger or on a solid surface.

A method is described herein that produces UN from UF.sub.6 in at most two steps comprising UF.sub.6.fwdarw.intermediate.fwdarw.UN. The principle of the reaction is that in a first step, UF.sub.6 would be reduced to U.sub.xN.sub.y, where x may be an integer selected from 1 and 3, and y is an integer selected from 1 and 2. Reduction occurs at or near the surface of a gaseous membrane electrode where it is also in contact with a nitrogen bearing salt. In a second step, U.sub.xN.sub.y decomposes to UN and N.sub.2 gas, either in the same reactor as the first step or after removal to a separate unit for further processing.

A method is described herein that produces UN from UF.sub.6 in at most two steps comprising UF.sub.6.fwdarw.intermediate.fwdarw.UN. The principle of the reaction is that in a first step, UF.sub.6 would be reduced to U.sub.xN.sub.y, where x may be an integer selected from 1 and 3, and y is an integer selected from 1 and 2. Reduction occurs at or near the surface of a gaseous membrane electrode where it is also in contact with a nitrogen bearing salt. In a second step, U.sub.xN.sub.y decomposes to UN and N.sub.2 gas, either in the same reactor as the first step or after removal to a separate unit for further processing.

Disclosed herein is a method for manufacturing oxide fuel pellets. The method for manufacturing the oxide fuel pellets includes (step 1) preparing nuclear fuel powder containing uranium dioxide (UO2+x, x=0 to 0.20), (step 2) compacting the nuclear fuel powder prepared in step 1 to manufacture green pellets, sintering the green pellets manufactured in step 2 at a temperature of about 1,200° C. to about 1,400° C. by using an atmosphere gas, and reducing the green pellets sintered in step 3 at a temperature of about 800° C. to about 1,000° C. by using a reducing atmosphere gas. The method for manufacturing the oxide fuel pellets according to the present invention performs the sintering at a low temperature of about 1,200° C. to 1,400° C. to manufacture economical and safe oxide fuel pellets that are adequate for the nuclear fuel specification.

Passive reactivity control technologies that enable reactivity control of a nuclear thermal propulsion (NTP) system with little to no active mechanical movement of circumferential control drums. By minimizing or eliminating the need for mechanical movement of the circumferential control drums during an NTP burn, the reactivity control technologies simplify controlling an NTP reactor and increase the overall performance of the NTP system. The reactivity control technologies mitigate and counteract the effects of xenon, the dominant fission product contributing to reactivity transients. Examples of reactivity control technologies include, employing burnable neutron poisons, tuning hydrogen pressure, adjusting wait time between burn cycles or merging burn cycles, and enhancement of temperature feedback mechanisms. The reactivity control technologies are applicable to low-enriched uranium NTP systems, including graphite composite fueled and tungsten ceramic and metal matrix (CERMET), or any moderated NTP system, such as highly-enriched uranium graphite composite NTP systems.

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.