Methods for fabricating articles having different materials through hot isostatic pressing and additive manufacturing, methods for fabricating nuclear fuel assemblies through hot isostatic pressing and additive manufacturing, and related nuclear fuel assemblies

A method of fabricating a nuclear fuel assembly, the method comprising:

• forming a cladding via additive manufacturing, the cladding exhibiting a first density that is less than a theoretical maximum density of a material of the cladding, the cladding defining an interior volume;
• introducing a nuclear fuel into the interior volume of the cladding;
• and
• densifying the cladding and the nuclear fuel in the interior volume via hot isostatic pressing, the cladding exhibiting a second density that is greater than the first density.

A nuclear fuel assembly comprising:

• a lattice cladding formed of a cladding material, the lattice cladding defining a nuclear fuel-receiving interior volume and coolant passageways separated from the nuclear fuel-receiving interior volume by walls of the lattice cladding;
• nuclear fuel disposed within the nuclear fuel-receiving interior volume;
• and
• a transition manifold coupled to an end region of the lattice cladding, the transition manifold comprising a port and branching passageways between the port and openings at a boundary of the lattice cladding,
• wherein the lattice cladding comprises a complex geometry defining one or more of tortuous passageways or intertwined internal passageways, and
• wherein the lattice cladding exhibits a density of at least about 95% of a theoretical maximum density of the cladding material, and wherein the nuclear fuel exhibits a density of at least about 70% of a theoretical maximum density of the nuclear fuel.