Sandia Labs FY21 LDRD Annual Report

FY21 ANNUAL REPORT

Predicting behavior of molten salt reactor facilities before final design. One challenge of using land-based, thermal reactors with uranium fuel is the complex coupling between the neutronics and thermal hydraulics due to chemical changes caused by fission products in the molten salt, which is both the fuel and the coolant. Although many promising capabilities for liquid-fueled molten salt reactors (MSR) exist, researchers face limited experience operating these designs for generating electricity, a lack of high-quality validation experiments, and a lack of knowledge of the long-term behavior of new fuels. This LDRD project produced a simulation software tool to predict the behavior of these MSRs before designs are finalized that will enable NNSA to define new monitoring processes and measurement equipment before this new class of nuclear reactors is deployed internationally. (PI: Vincent Mousseau)

This diagram represents the complexity of molten salt reactors, showing traditional physics codes by color and nonlinear coupling between physics as arrows.

Extremely lightweight structures made from folded and 3D-printed metal. Sandia opto-mechanical engineers used origami-style folding of photo-etched and micro-welded sheet metal along with 3D-printed metal parts to create ultralightweight structures for spaceborne optical systems. Traditional light-weighting usually starts with a heavy block of material that is then cut away. Sandia uses material thinner than traditionally machined ribs and walls and folds it to create the stiff structures the design requires. Photo-etching creates the shapes and fold lines for easy assembly. Two optical systems were created with

designs guided by topological optimization techniques. Both

approaches realized structure weight savings of >90% and 20% diameter reduction compared to traditional space system optical design and fabrication methods. Because the price and speed of photo-etching is fairly independent of a part’s complexity , these designs are both less expensive and more quickly realized than standard machined assemblies. The possibility of extreme weight savings also makes using heavier materials like steel, invar, or copper more feasible for space applications. (PI: Edward Winrow)

(Left) Folded and hybrid 3D-printed ultralight optical structures. (Right) Folded and unfolded lens subcell components.

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LABORATORY DIRECTED RESEARCH & DEVELOPMENT

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