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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Subcritical Neutron and Gamma Noise Measurements at the Seven Percent Critical Experiment (7uPCX) [Slides]

Post measurement synchronization of noise signals allowed for the investigation of previously unseen correlations. Noise of gamma, thermal and fast neutron signals performed similarly in estimating the prompt neutron decay constant at various subcritical states. The CPSD amplitude terms displayed different magnitudes. The neutron-based amplitudes suffered more from changes in detector efficiency as the number of fuel rods in the system increased. The time lag between 3 He tubes is observable using the CPSD phase angle and agreed with a simplified diffusion estimation.

3He detectors↗
DOE OSTI2021

National Criticality Experiments Research Center, NCERC NEWS (Apr. - Jun. 2021) [Slides]

National Center for Nuclear Security (NCNS) samples were irradiated on Godiva. Fission chamber testing for NCNS was conducted on Flat-Top. This operation involved multiple core configuration changes, which doubled as important training opportunities for NEN-2 Crew Member Trainees. These experiments support nuclear forensics research.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS1969

Cavity reactor critical experiments.

Cavity reactor consisting of dilute fuel core surrounded by moderating reflector to attain very high temperatures in gaseous cores

Hyland, R. E.↗
NASA NTRS1972

Outer planet Grand Tour missions photometry/polarimetry experiment critical components study

Work performed during this effort was limited to two primary areas of technical concern: optical design optimization, and sensor selection. An optical system concept was established, and various system components were evaluated through experimental test sequences. Photodetectors were investigated for the applicability in meeting OPGT requirements as constrained by the photometry/polarimetry team directives. The most promising (gallium arsenide PMT) was further experimentally tested to ascertain its behavior with respect to anticipated environmental conditions. Results of testing and summary of the preceding tradeoff study effort are presented.

Pellicori, S. F.↗
NASA NTRS1991

Critical experiments of the self-consistent model for polycrystalline Hastelloy-X

A viscoplastic constitutive model is presented for the estimation of the overall mechanical response of Hastelloy-X polycrystalline metals from a knowledge of single crystal behavior. The behavior of polycrystal is derived from that of single crystals using a self-consistent formulation. The single crystal behavior which has been used was developed by summing postulated slip on crystallographic slip systems. The plasticity and creep are treated coupledly using unified viscoplastic model which includes the interaction effects between rapid and slow deformation at elevated temperature. The validity of the model is directly tested by experiments on Hastelloy-X in both single crystal and polycrystalline versions.

Shi, Shixiang↗