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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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Measurement of radiolytic hydrogen generation and impact of drying treatments on reactor exposed and surrogate aluminum materials
Technical challenges associated with dry storage of Aluminum-clad Spent Nuclear Fuel (ASNF) include a need to better understand the potential extent of gaseous molecular hydrogen (H 2 ) production through radiolytic degradation of the aluminum (oxy)hydroxide films present on ASNF. The characterization of radiolytic gas generation from ASNF (oxy)hydroxide layers has been identified as a key knowledge gap which poses a technical challenge to the long-term storage of ASNF. Task 2 of the action plan for the extended (>50 years) dry storage of ASNF addresses this gap. Previous radiolysis studies performed under Task 2 established baseline estimates of H 2 generation rates from the attendant hydrated oxides. The results confirmed that net radiolytic H 2 production has a dependency on absorbed gamma dose, as well as relative humidity and cover gas composition (air, nitrogen, and argon). Further experiments revealed that the physisorbed water on the samples may significantly impact the radiolytic H 2 yield. This phenomenon complicates the determination of H 2 generation rates for hydrated oxides, which may lead to inaccurate modeling predictions of the long-term H 2 yields in sealed storage systems containing ASNF, particularly when compared to spent fuel casks which have undergone some drying process intended to remove physically- and chemically-bound water. This report describes the testing methods utilized and the hydrogen generation results obtained in an investigation of the effects of gamma irradiation on aluminum materials for a variety of (oxy)hydroxide surface compositions and drying conditions. The testing methods included small-area aluminum material testing in ampules, and large-area aluminum material testing in steel vessels. Test material preparation, irradiation, and radiolytic H 2 measurement methods are summarized. The measured H 2 concentrations, which reflect the variable initial hydrated inventory and drying treatments, are compared to one another as well as to previously published data, to identify the primary factors affecting radiolytic H 2 generation rates and potential equilibrium H 2 concentrations.
Accelerating phase-field based predictions via surrogate models trained by machine learning methods.
Abstract not provided.
Recent Advances in Adaptive Refinement of (Regression-Based) Multifidelity Surrogates for UQ.
Abstract not provided.
Hyper-Differential Sensitivity Analysis for Robust Machine Learned Surrogate Models.
Abstract not provided.
Surrogate Modeling of Spent Fuel Degradation for Repository Performance Assessment.
Abstract not provided.
30 cm Horizontal Drop of a Surrogate 17x17 PWR Fuel Assembly.
Abstract not provided.
Summary: 30 cm Horizontal Drop of a Surrogate 17x17 PWR Fuel Assembly.
Abstract not provided.
Soot Temperature Distributions in Turbulent Non-Premixed Ethylene and JP-8 Surrogate Jet Flames.
Abstract not provided.
Adaptive resource allocation for surrogate modeling of systems comprised of multiple disciplines with varying fidelity.
Abstract not provided.
Machine learned surrogate models for threaded fastener geometries in finite element analysis.
Abstract not provided.
Surrogate Modeling For Efficiently, Accurately and Conservatively Estimating Measures of Risk.
Abstract not provided.
Impact of Sampling Strategies in the Polynomial Chaos Surrogate Construction for Monte Carlo Transport Applications.
Abstract not provided.
Physics-Informed Machine Learning Surrogates with Optimization-Based Guarantees: Applications to AC Power Flow.
Abstract not provided.
E3SM Atmosphere surrogate construction using machine learning and reduced order modeling methods.
Abstract not provided.