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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 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS2018

NH4-Smectite, a Potential Source of N Compounds (NO) in SAM Analyses

Recent detection of nitrate by Curiosity's Sample Analysis at Mars (SAM) instrument suite in Gale Crater sediments on Mars at abundances up to ~600 mg/kg indicates that nitrogen fixation processes occurred in early Martian history. But little is known about other possible N reservoirs on Mars, including those that may contain reduced forms of fixed N (i.e., NH3, NH4+) in the mantle, crust and sediments. Specifically, fixed nitrogen (i.e. NH3, NH4+, NOx or N that is chemically bound to either inorganic or organic molecules and can be released by hydrolysis to form NH3 or NH4+) is useful to terrestrial living organisms Therefore, understanding whether reduced N compounds such as NH4+ are present in surface materials is important to assess habitability in the Martian environment. While these species generally have short photochemical lifetimes, nitrogen in this form may be sequestered and stabilized in the soil by inclusion of NH4+ in certain phyllosilicates.

Andrejkovičová, S.↗
DOE OSTI2023

System Advisor Model (SAM) and PVWatts

The System Advisor Model (SAM) is a free techno-economic software model that facilitates decision-making for people in the renewable energy industry. PVWatts estimates the energy production of grid-connected photovoltaic energy systems throughout the world. It allows homeowners, small building owners, installers, and manufacturers to easily develop estimates of the performance of potential photovoltaic installations.

energy planning↗
DOE OSTI2023

Multiphysics Analysis of the MSRE Experiment Using Griffin-SAM Coupled Code System

Molten salt reactors (MSRs) with flowing fuel have the unique feature of utilizing the fuel salt for heat generation and extraction at the same time since the fuel salt is circulating through the whole primary loop of the reactor. This movement of the fuel salt results in a partial decay of the delayed neutron precursors (DNPs) outside the core and corresponding redistribution in the active core region. To capture this phenomenon accurately, neutronics and thermal hydraulics computational tools need to be modified to handle the movement of the DNPs and their decay. Idaho and Argonne National Laboratories are actively working on developing neutronics and thermal hydraulics tools to model MSRs with flowing fuel. The neutronics code Griffin and the thermal hydraulics code SAM were extended to handle flowing fuel with the drift of the DNPs under the MOOSE framework. In this work, a simplified Multiphysics model of the Molten Salt Reactor Experiment (MSRE) is developed and utilized to perform steady-state and transient analyses. The MSRE experiments were designed to show the impact of the DNPs losses on core reactivity. The following section provides a description of the MSRE experiment with the core main parameters used to develop the model. Then, the developed Multiphysics model of the MSRE is presented. Finally, steady-state verification tests and unprotected loss of flow transient tests are discussed followed by a summary and conclusions.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

Prioritizing Nuclear Materials for SAM-3 Neutron Irradiation Campaign: Structural and Cladding Materials Candidates

This report outlines a framework for selecting structural and cladding materials for the Nuclear Science User Facilities (NSUF) SAM-3 neutron irradiation campaign to support the advancement of nuclear energy technologies. The document begins with an introduction that provides background context, highlights the motivations for launching a new irradiation campaign, and defines the overall objectives. The core of the report describes the design considerations for the irradiation campaign, including capsule configurations, irradiation temperature ranges, and target dose levels (defined by displacements per atom, or dpa). The material recommendation was guided by the Specimen Identification and Prioritization (SIP) Working Group, a multidisciplinary team of experts representing national laboratories, academia, industry, federal government and agency. This group played a central role in identifying candidate materials, evaluating technical justifications, and ensuring alignment with boarder programmatic goals. A detailed set of criteria for material prioritization is then presented, taking into account reactor relevance, performance gaps, advanced manufacturing methods, and emerging material classes. Based on the input of SIP working group, specific materials were selected and justified for inclusion in the irradiation campaign by the NSUF leadership and its U.S. Department of Energy (DOE)-Office of Nuclear Energy (NE) management. The final section provides recommended capsule designs, summarizing critical parameters such as material type, fabrication method, sample geometry, irradiation conditions, and specimen quantities. This report serves as a foundation for executing a focused and high-impact neutron irradiation campaign aimed at addressing key materials challenges for both existing and advanced nuclear reactors.

36 - MATERIALS SCIENCE↗
DOE OSTI2024

Thermal Fluid Modeling Approaches in SAM for High Temperature Gas-Cooled Reactor Applications

This paper provides an overview of the unique modeling and simulation challenges and needs in the system and safety analysis of two common types of High Temperature Gas-cooled Reactor (HTGR) designs. The challenges are associated with the complex core geometry configurations and the change of the dominant heat removal mechanisms between normal operating conditions and decay heat removal transients. This requires that simulation tools utilize models with reasonable length scales and capture both the localized heat transfer and the core-scale heat transfer at the same time. To meet such analysis needs, different methodologies were developed. In conclusion, this includes adopting existing methods and further developing/improving them, as well as proposing innovative methods that leverage advanced computational frameworks such as the Multiphysics Object Oriented Simulation Environment (MOOSE).

HTGR↗
DOE OSTI2022

The Function of Two Radical‐SAM Enzymes, HcgA and HcgG, in the Biosynthesis of the [Fe]‐Hydrogenase Cofactor

Abstract In the biosynthesis of the iron‐guanylylpyridinol (FeGP) cofactor, 6‐carboxymethyl‐5‐methyl‐4‐hydroxy‐2‐pyridinol ( 1 ) is 3‐methylated to form 2 , then 4‐guanylylated to form 3 , and converted into the full cofactor. HcgA‐G proteins catalyze the biosynthetic reactions. Herein, we report the function of two radical S ‐adenosyl methionine enzymes, HcgA and HcgG, as uncovered by in vitro complementation experiments and the use of purified enzymes. In vitro biosynthesis using the cell extract from the Methanococcus maripaludis Δ hcgA strain was complemented with HcgA or precursors 1 , 2 or 3 . The results suggested that HcgA catalyzes the biosynthetic reaction that forms 1 . We demonstrated the formation of 1 by HcgA using the 3 kDa cell extract filtrate as the substrate. Biosynthesis in the Δ hcgG system was recovered by HcgG but not by 3 , which indicated that HcgG catalyzes the reactions after the biosynthesis of 3 . The data indicated that HcgG contributes to the formation of CO and completes biosynthesis of the FeGP cofactor.

Arriaza‐Gallardo, Francisco J.↗
DOE OSTI2022

The Function of Two Radical‐SAM Enzymes, HcgA and HcgG, in the Biosynthesis of the [Fe]‐Hydrogenase Cofactor

Abstract In the biosynthesis of the iron‐guanylylpyridinol (FeGP) cofactor, 6‐carboxymethyl‐5‐methyl‐4‐hydroxy‐2‐pyridinol ( 1 ) is 3‐methylated to form 2 , then 4‐guanylylated to form 3 , and converted into the full cofactor. HcgA‐G proteins catalyze the biosynthetic reactions. Herein, we report the function of two radical S ‐adenosyl methionine enzymes, HcgA and HcgG, as uncovered by in vitro complementation experiments and the use of purified enzymes. In vitro biosynthesis using the cell extract from the Methanococcus maripaludis Δ hcgA strain was complemented with HcgA or precursors 1 , 2 or 3 . The results suggested that HcgA catalyzes the biosynthetic reaction that forms 1 . We demonstrated the formation of 1 by HcgA using the 3 kDa cell extract filtrate as the substrate. Biosynthesis in the Δ hcgG system was recovered by HcgG but not by 3 , which indicated that HcgG catalyzes the reactions after the biosynthesis of 3 . The data indicated that HcgG contributes to the formation of CO and completes biosynthesis of the FeGP cofactor.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗