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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 937 records · Page 52
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Cluster radioactivity of {sup 128-134}Gd isotopes

The cluster radioactivity exhibited by {sup 128-134}Gd isotopes with the exotic emission of certain clusters like {sup 4}He, {sup 8}Be, {sup 12}C, {sup 16}O, {sup 20}Ne, {sup 24}Mg, and {sup 28}Si have been studied. The half-life values for different cluster emissions were calculated by considering the interacting potential barrier as a sum of Coulomb potential and proximity potential. The emission of {sup 28}Si cluster from {sup 128}Gd isotope leads to the formation of {sup 100}Sn daughter nucleus which is a doubly-magic nucleus. Hence, the {sup 28}Si cluster emission is expected to have the lowest half-life and therefore highly favorable for measurements. Our calculations also corroborate this point and thus emphasize the role of {sup 100}Sn in the exotic decay process. The Geiger-Nuttall plots for different cluster emissions were found to be linear, but with different slopes and intercepts. We have studied the variation of these slopes and intercepts as a function of the proton number of clusters. Based on this, we have arrived at a handy and convenient expression for half-life values for emissions of various clusters from {sup 128-134}Gd isotopes.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2012

Modification of the Monte Carlo method for calculation of the influence of unknown placement of solid radioactive waste on the uncertainty of dose fields at different overall container dimensions

An approach to estimating the uncertainty of initial data in calculations by the Monte Carlo method is considered. The relative geometrical position of parts of the analyzed system is assumed to be unknown. The influence of different approximations in the description of the geometrical shape of system objects is studied. The effect of unknown location and approximate shape description of solid radioactive waste in the container on the magnitude of dose fields is considered for photon transport problems.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2015

Hybrid fusion reactor for production of nuclear fuel with minimum radioactive contamination of the fuel cycle

The paper presents the results of the system research on the coordinated development of nuclear and fusion power engineering in the current century. Considering the increasing problems of resource procurement, including limited natural uranium resources, it seems reasonable to use fusion reactors as high-power neutron sources for production of nuclear fuel in a blanket. It is shown that the share of fusion sources in this structural configuration of the energy system can be relatively small. A fundamentally important aspect of this solution to the problem of closure of the fuel cycle is that recycling of highly active spent fuel can be abandoned. Radioactivity released during the recycling of the spent fuel from the hybrid reactor blanket is at least two orders of magnitude lower than during the production of the same number of fissile isotopes after the recycling of the spent fuel from a fast reactor.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2011

Assessment of the Losses Due to Self Absorption by Mass Loading on Radioactive Particulate Air Stack Sample Filters

This report discusses the effect of mass loading of a membrane filter on the self absorption of radioactive particles. A relationship between mass loading and percent loss of activity is presented. Sample filters were collected from Pacific Northwest National Laboratory (PNNL) facilities in order to analyze the current self absorption correction factor of 0.85 that is being used for both alpha and beta particles. Over an eighteen month period from February 2009 to July 2010, 116 samples were collected and analyzed from eight different building stacks in an effort coordinated by the Effluent Management group. Eleven unused filters were also randomly chosen to be analyzed in order to determine background radiation. All of these samples were collected and analyzed in order to evaluate the current correction factor being used.

air sampling↗
DOE OSTI2016

HMPT: Basic Radioactive Material Transportation

Hazardous Materials and Packaging and Transportation (HMPT): Basic Radioactive Material Transportation Live (#30462, suggested one time) and Test (#30463, required initially and every 36 months) address the Department of Transportation’s (DOT’s) function-specific [required for hazardous material (HAZMAT) handlers, packagers, and shippers] training requirements of the HMPT Los Alamos National Laboratory (LANL) Labwide training. This course meets the requirements of 49 CFR 172, Subpart H, Section 172.704(a)(ii), Function-Specific Training.

42 ENGINEERING↗
DOE OSTI2016

Nuclear Structure Studies of Exotic Nuclei with Radioactive Ion Beams A Final Report

Beta-decay spectroscopy provides important information on nuclear structure and properties needed to understand topics as widely varied as fundamental nuclear astrophysics to applied nuclear reactor design. However, there are significant limitations of our knowledge due to an inability to experimentally measure everything. Therefore, it is often necessary to rely on theoretical calculations which need to be vetted with experimental results. The focus of this report will be results from experimental research performed by the Principal Investigator (PI) and his research group at Mississippi State University in which the group played the lead role in proposing, implementing, performing and analyzing the experiment. This research was carried out at both the National Superconduction Cyclotron Laboratory (NSCL) at Michigan State University and the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. The primary emphasis of the research was the use of \bdec spectroscopy as a tool to understand the evolution of nuclear structure in neutron-rich nuclei which could then be applied to improve theory and to increase the overall knowledge of nuclear structure.

Nuclear Astrophysics↗
DOE OSTI2017

Maxine: A spreadsheet for estimating dose from chronic atmospheric radioactive releases

MAXINE is an EXCEL© spreadsheet, which is used to estimate dose to individuals for routine and accidental atmospheric releases of radioactive materials. MAXINE does not contain an atmospheric dispersion model, but rather doses are estimated using air and ground concentrations as input. Minimal input is required to run the program and site specific parameters are used when possible. Complete code description, verification of models, and user’s manual have been included.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2021

Radioactive Thoron 220 Rn Exhalation From Unfired Mud Building Material Into Room Air of Earthen Dwellings

Thoron ( 220 Rn), an isotope of radon with a strong α-decay energy, and its short-lived metallic progeny can pose an elevated lung cancer hazard in room air when unfired-soil derived building materials are used in earthen dwellings. Changes in moisture content and density influencing the thoron exhalation rate from earthen materials into room air were studied in the laboratory with terra rossa from a village on the Ðòng Van Karst Plateau Geopark, Viêt Nam, where ethnic minorities construct traditional dwellings with unfired terra rossa walls and floors. Our results show that the thoron exhalation rate from mud surfaces depends on (i) the content of radioactive parental nuclides in mineral components; (ii) the moisture content of mud where ~5–10 weight % water maximizes the 220 Rn exhalation rate; and (iii) the density of dry mud as primarily controlled by internal macroscopic voids, fractures, and porosity. Additional time-series of 220 Rn exhalation data from an interior mud wall of a terra rossa-built house under different seasonal and weather conditions show that the temperature is influencing thoron exhalation via the water vapor pressure deficit (VPD) in air and the associated amount of atmospheric moisture adsorbed onto indoor mud surfaces. Our data suggest that occupants of “mud house” earthen dwellings in northern Viêt Nam are exposed to an increased thoron geohazard during cooler weather, low VPD, and high relative humidity in air. Detailed studies are needed to evaluate the thoron geohazard for inhabitants of mud-built dwellings in other climates and geological terrains.

58 GEOSCIENCES↗
DOE OSTI2025

A Fast Framework for Generating Radioactive Mixture Spectra and Its Application to Remote High-Performance Mixture Identification

Remote detection of radioactive materials in mixtures using handheld or portal detectors remains a challenge because of factors such as low concentration, environmental interference, sensor noise, and other complications. This work introduces a fast framework for generating realistic mixture spectra. Moreover, we present mixture isotope identification using data generated by the fast framework. Researchers have examined a range of conventional and recent algorithms within the fields of machine learning and deep learning. An application to uranium enrichment-level prediction has been included. Extensive simulation experiments validated the efficacy of the proposed framework.

GADRAS↗