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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 163 records · Page 9

MC-Lite: Development of a new lightweight multiplicity counter

This report details the development of a neutron multiplicity counter based on lithium doped plastic scintillators. This system has the capability to measure and discriminate fast neutrons, thermal neutrons, and gamma-rays allowing for multi-particle correlations in one device. The system was built and tested at Lawrence Livermore National Laboratory with Cf-252 in both bare configurations and surrounded by polyethylene and compared against the MC-15 multiplicity counter. Additionally, the detector was also placed outside of a subcritical assembly and demonstrated the ability to use correlated gamma-rays as a probe on the multiplication of the item.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Analysis of the Aeroelastic Dynamics of Lightweight Flexible Variations of the SNL-NRT Turbine

Current trends show that wind turbines are growing in size to meet a rising demand for renewable energy generation, and their upscaled rotors have inherently become more flexible to maintain a proportionally lighter design. This is because larger rotors must be less massive relative to their diameter to minimize the levelized cost of energy (LCOE), which means that blades that are notably less stiff are produced as a result. These structural changes to blades are often reflected in their compromised aeroelastic stability and amplified deformation during operation, which has the potential to decrease the blade’s expected lifetime and the performance of the machine overall. Variations in blade flexibility are also known to influence vortex-wake structures downstream of the turbine, causing patterns of velocity deficit to evolve in ways that affect the performance of other turbines in the farm. This research explores how the increased flexibility of modern utility-scale wind turbine blades influences rotor aeroelastic behavior and interactions with farm flow. High-fidelity simulations of Sandia National Laboratories’ (SNL) National Rotor Testbed (NRT) wind turbine are presented. Flexible variations of the NRT baseline blade are simulated in a variety of realistic operational conditions typically expected at the SNL’s SWiFT facility in Lubbock, Texas. Solutions are then compared to investigate how specific changes to the structural properties of the NRT baseline blade’s design and construction can influence its aeroelastic response at the rotor and the evolution of the turbine’s wake.

Farrell, Alayna (ORCID:000000023555720X)↗

A Boundary Topology Optimization Approach for Lightweighting Electric Machines Inspired by Additive Manufacturing

Minimizing the mass in electric machines while maintaining superior performance has become a new requirement for the advancement of drivetrains used in wind energy and electric mobility. Topology optimization for light-weighting electric machines using traditional approaches typically explore a restricted design space allowed by standard parametrizable geometry and manufacturing, while advanced methods like cell-based density approaches suffer from a lack of robust manufacturability constraints during the optimization process. To overcome these drawbacks, we explore a grid-independent, boundary TO where the outer shape of the magnet is parameterized using Bezier curves. We conduct a design of experiments (DOE) to study the effect of different magnet shapes on machine performance by varying the control points on the Bezier curves. A machine-learning based surrogate model is constructed using the data from the DOE to quantify the relationship between the control points, air-gap torque and mass. The control points are then optimized to maximize the torque density. The approach is used for minimizing electrical steel mass in the IEA-15MW radial flux direct-drive wind turbine generator. The free-from boundary TO resulted in smooth and concise shapes that can be easily additively manufactured with upto 20-ton reduction in electrical steel mass.

additive manufacturing↗

Short-Lived Modules Need to be Efficient, Lightweight, and Circular for the Energy Transition

Deployment projections for decarbonizing the grid predict 1.75 TW of PV is needed in the United States by 2050. This entails a cumulative demand of 97 million metric tonnes of virgin materials for c-Si modules. These material needs are extraction and energy intensive, making them a key target for improving PV sustainability. Emerging PV technologies, such as perovskites, are targeting 15-year modules, high efficiencies, and circular designs. Previous analysis found that by just modifying the life expectancy to 15 years (keeping target c-Si efficiencies and BOM), an additional 1.4 TW of replacement modules are required to maintain capacity, increasing virgin material demand by 1.75x unless >95% closed-loop recycling is maintained. This study examines the effect of achieving higher efficiencies with thin-film designs and a 15-year expectancy. Higher efficiencies and thin film designs can decrease deployment and material demands, making the level of circularity more attainable. If BOM mass is reduced by 50%, closed-loop recycling rates need to be >80% to reduce virgin material demands compared to a 35-yr c-Si module. If module efficiencies are 30%, closed-loop recycling rates can be reduced to 65%. This efficiency increase also reflects that 1500 million fewer modules can be deployed, however, this is still 2000 million more modules than a 35-year module needs to deploy to achieve energy transition targets, and no PV technology is closed-loop recycled for all component materials.

circular economy↗