Conceptual design and analysis of a megawatt power level heat pipe cooled space reactor power system

Low-Loss Plasmonics with Nanostructured Potassium and Sodium-Potassium Liquid Alloys

Alkali metals have low optical losses in the visible to near-infrared (NIR) compared with noble metals. However, their high reactivity prohibits the exploration of their optical properties. Recently sodium (Na) has been experimentally demonstrated as a low-loss plasmonic material. Here we report on a thermo-assisted nanoscale embossing (TANE) technique for fabricating plasmonic nanostructures from pure potassium (K) and NaK liquid alloys. We show high-quality-factor resonances from K as narrow as 15 nm in the NIR, which we attribute to the high material quality and low optical loss. We further demonstrate liquid Na-K plasmonics by exploiting the Na-K eutectic phase diagram. Our study expands the material library for alkali metal plasmonics and liquid plasmonics, potentially enabling a range of new material platforms for active metamaterials and photonic devices.

The role of advanced nuclear reactors in non-electrical and strategic applications, producing sustainable energy supplies and reducing the greenhouse gasses

Nowadays, nuclear reactors became extremely fascinating not only for most of the nuclear communities but also for the prominent energy suppliers to fix the global warming effects worldwide. This paper presents a review of the last advances, applications, and challenges of nuclear reactors. Different types and classifications are introduced. Advantages and disadvantages are discussed for best decision-making. Next, nuclear safety is also discussed as the most important challenging subject to develop nuclear reactors worldwide. They are specially mentioned to find the key solution for the future of nuclear energy. A brief review of nuclear roadmaps is compared with other clean green technologies as well. Estimated prospects for projects timelines and progressions of new nuclear reactors are also presented and discussed briefly. Studies confirmed that nuclear reactors are not only required for developing non-electrical applications or even high-tech systems but also they are extremely profitable to restrict global warming effects. Finally, the solution is to enhance the markets of the nuclear reactors, especially the matured Gen III+ Pressurized Water Reactors (PWRs) to resolve short-term problems as well as advanced futuristic developing Small Modular Reactors (SMRs) for the mid-term and long-term strategies. Moreover, research reactors especially advanced Multi-Purpose Research Reactors (MPRR) are necessary tools to develop both nuclear power plants and other advanced technologies as well as the modern Micro Modular Reactors.

Thermodynamic modeling of in-situ rocket propellant fabrication on Mars

In-situ resource utilization (ISRU) to refuel rockets on Mars will become critical in the future. The current effort presents a thorough feasibility analysis of a scalable, Matlab-based, integrated ISRU framework from the standpoint of the second law of thermodynamics. The ISRU model is based on existing technology that can utilize Martian resources (regolith and atmosphere) to produce rocket propellants. Model simulations show that the system analysis is theoretically consistent with a positive entropy generation, and the achievable mass flow rates of liquid methane and liquid oxygen can potentially meet the 16-month rocket refueling deadline (on Mars) as desired by the National Aeronautics and Space Administration. However, the model is sensitive to liquid oxygen storage temperatures, and lower temperatures are necessary to minimize compressor work. This proof-of-concept model can open avenues for further experimental evaluation of the system to achieve a higher technology readiness level.