Additive manufacturing methods use a surrogate slurry to iteratively develop an additive manufacturing protocol and then substitutes a final slurry composition to then additively manufacture a final component using the developed additive manufacturing protocol. In the nuclear reactor component context, the final slurry composition is a nuclear fuel slurry having a composition: 30-45 vol. % monomer resin, 30-70 vol. % plurality of particles of uranium-containing material, >0-7 vol. % dispersant, photoactivated dye, photoabsorber, photoinitiator, and 0-18 vol. % (as a balance) diluent. The surrogate slurry has a similar composition, but a plurality of surrogate particles selected to represent a uranium-containing material are substituted for the particles of uranium-containing material. The method provides a means for in-situ monitoring of characteristics of the final component during manufacture as well as in-situ volumetric inspection. Compositions of surrogate slurries and nuclear fuel slurries are also disclosed.

Additive manufacturing methods use a surrogate slurry to iteratively develop an additive manufacturing protocol and then substitutes a final slurry composition to then additively manufacture a final component using the developed additive manufacturing protocol. In the nuclear reactor component context, the final slurry composition is a nuclear fuel slurry having a composition: 30-45 vol. % monomer resin, 30-70 vol. % plurality of particles of uranium-containing material, >0-7 vol. % dispersant, photoactivated dye, photoabsorber, photoinitiator, and 0-18 vol. % (as a balance) diluent. The surrogate slurry has a similar composition, but a plurality of surrogate particles selected to represent a uranium-containing material are substituted for the particles of uranium-containing material. The method provides a means for in-situ monitoring of characteristics of the final component during manufacture as well as in-situ volumetric inspection. Compositions of surrogate slurries and nuclear fuel slurries are also disclosed.

A water jet peening device includes a sealed vessel provided to cover a surface of a welded portion, and adapted to be in a sealed state where an internal pressure is higher than an outside, a jet nozzle adapted to jet high-pressure water to create a cavitation bubble toward the surface of the welded portion, inside the sealed vessel, and a pressure control hole adapted to be able to adjust the internal pressure of the sealed vessel. The water jet peening device can efficiently reform a tensile residual stress on the surface of the welded portion to a compressive residual stress.

A water jet peening device includes a sealed vessel provided to cover a surface of a welded portion, and adapted to be in a sealed state where an internal pressure is higher than an outside, a jet nozzle adapted to jet high-pressure water to create a cavitation bubble toward the surface of the welded portion, inside the sealed vessel, and a pressure control hole adapted to be able to adjust the internal pressure of the sealed vessel. The water jet peening device can efficiently reform a tensile residual stress on the surface of the welded portion to a compressive residual stress.

A system for removing particulates of a fissile material includes first and second filtration paths. A first filter and a first valve are disposed in the first filtration path. A second filter and a second valve are disposed in the second filtration path. The first valve and the second valve are configured to switch between a dual open state and a mixed open/closed state. During the dual open state, the first valve and the second valve axe open to permit concurrent flows of the effluent gas through the first and second filtration paths. During the mixed open/closed state, one of the first valve and the second valve is open while the other of the first valve and the second valve is closed to permit the particulates on a corresponding one of the first filter and the second filter to be dislodged by a countercurrent flow of a purging gas.

The invention is a process of repairing cracked or microstructurally damaged portions of irradiated materials, such as nuclear reactor pressure vessels and shrouds. A damaged portion of the irradiated substrate is first removed, such as by electrical discharge machining (EDM). After removing the damaged portion, the recast layer inherent in the EDM process is then removed. Once the repair area substrate material has been removed to a calculated depth, the created cavity is then filled without releasing transmutated elements within the irradiated material. A chamber may be placed on the irradiated material surrounding the repair area to create an isolated work space.

The invention is a process of repairing cracked or microstructurally damaged portions of irradiated materials, such as nuclear reactor pressure vessels and shrouds. A damaged portion of the irradiated substrate is first removed, such as by electrical discharge machining (EDM). After removing the damaged portion, the recast layer inherent in the EDM process is then removed. Once the repair area substrate material has been removed to a calculated depth, the created cavity is then filled without releasing transmutated elements within the irradiated material. A chamber may be placed on the irradiated material surrounding the repair area to create an isolated work space.

A method for peening an obstructed region of a metal assembly that is obstructed by an obstructing part of the metal assembly is provided. The method includes determining an optimal peening path for treating the obstructed region irrespective of the obstructing part; identifying a portion of the obstructing part within the optimal peening path; determining a section of the portion of the obstructing part that is removable without affecting a mechanical integrity and functionality of the obstructing part; removing, by machining, the section so as to create additional space along the optimal peening path; and peening the obstructed region, a path of the peening at least partially crossing through the additional space. A method for peening a nuclear reactor pressure vessel is also provided.

Provided is a laser welding apparatus for spacer grid of nuclear fuel assembly comprising a base frame in which a chamber installment hole is formed horizontally to the center in a way that the hole penetrates the chamber and a guide rail is installed along the chamber installment hole; a welding chamber unit assembled with the base frame in guidance by the guide rail and equipped with an operable door in front and a glass window at the top to be airtight; a laser welding unit mounted on the base frame for radiating laser through the glass window to weld spacer grid in the welding chamber; and a locking member for fixing the welding chamber on the base frame.

Provided is a laser welding apparatus for spacer grid of nuclear fuel assembly comprising a base frame in which a chamber installment hole is formed horizontally to the center in a way that the hole penetrates the chamber and a guide rail is installed along the chamber installment hole; a welding chamber unit assembled with the base frame in guidance by the guide rail and equipped with an operable door in front and a glass window at the top to be airtight; a laser welding unit mounted on the base frame for radiating laser through the glass window to weld spacer grid in the welding chamber; and a locking member for fixing the welding chamber on the base frame.