Altona, NY EGS Field Site Radon Study
Data include 222Rn activities and complimentary geochemical data for multiple field experiments as part of an EGS project
15 GEOTHERMAL ENERGY↗
SEARCH · Engineering Papers
Results for “THORIUM”
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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Summary Report: Glass-Ceramic Waste Forms for Combined Fission Products
Glass-ceramic waste form development began in FY 2010 examining two combined waste stream options: (1) alkaline earth (CS) + lanthanide (Ln), and (2) + transition metal (TM) fission-product waste streams generated by the uranium extraction (UREX+) separations process. Glass-ceramics were successfully developed for both options however; Option 2 was selected over Option 1, at the conclusion of 2010, because Option 2 immobilized all three waste streams with only a minimal decrease in waste loading. During the first year, a series of three glass (Option 2) were fabricated that varied waste loading-WL (42, 45, and 50 mass%) at fixed molar ratios of CaO/MoO{sub 3} and B{sub 2}O{sub 3}/alkali both at 1.75. These glass-ceramics were slow cooled and characterized in terms of phase assemblage and preliminary irradiation stability. This fiscal year, further characterization was performed on the FY 2010 Option 2 glass-ceramics in terms of: static leach testing, phase analysis by transmission electron microscopy (TEM), and irradiation stability (electron and ion). Also, a new series of glass-ceramics were developed for Option 2 that varied the additives: Al{sub 2}O{sub 3} (0-6 mass%), molar ratio of CaO/MoO{sub 3} and B{sub 2}O{sub 3}/alkali (1.75 to 2.25) and waste loading (50, 55, and 60 mass%). Lastly, phase pure powellite and oxyapatite were synthesized for irradiation studies. Results of this fiscal year studies showed compositional flexibility, chemical stability, and radiation stability in the current glass-ceramic system. First, the phase assemblages and microstructure of all of the FY 2010 and 2011 glass-ceramics are very similar once subjected to the slow cool heat treatment. The phases identified in these glass-ceramics were oxyapatite, powellite, cerianite, and ln-borosilicate. This shows that variations in waste loading or additives can be accommodated without drastically changing the phase assemblage of the waste form, thus making the processing and performance characteristics of the waste form more predictable/flexible. However, in the future, the glass phase still needs to be accurately characterized to determine the effects of waste loading and additives on the glass structure. Initial investigations show a borosilicate glass phase rich in silica. Second, the normalized concentrations of elements leached from the waste form during static leach testing were all below 0.6 g/L after 28d at 90 C, by the Product Consistency Test (PCT), method B. These normalized concentrations are on par with durable waste glasses such as the Low-Activity Reference Material (LRM) glass. The release rates for the crystalline phases (oxyapatite and powellite) appear to be lower (more durable) than the glass phase based on the relatively low release rates of Mo, Ca, and Ln found in the crystalline phases compared to Na and B that are mainly observed in the glass phase. However, further static leach testing on individual crystalline phases is needed to confirm this statement. Third, Ion irradiation and In situ TEM observations suggest that these crystalline phases (such as oxyapatite, ln-borosilicate, and powellite) in silicate based glass ceramic waste forms exhibit stability to 1000 years at anticipated doses (2 x 10{sup 10}-2 x 10{sup 11} Gy). This is adequate for the short lived isotopes in the waste, which lead to a maximum cumulative dose of {approx}7 x 10{sup 9} Gy, reached after {approx}100 yrs, beyond which the dose contributions are negligible. The cumulate dose calculations are based on a glass-ceramic at WL = 50 mass%, where the fuel has a burn-up of 51GWd/MTIHM, immobilized after 5 yr decay from reactor discharge.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Spectroscopy, Thermochemistry, and Reactivity of Lanthanide and Actinide Molecules (Final Report)
The research undertaken under this grant is described in this document. The document describes progress in the construction of an instrument for recording photodissociation action spectra of mass-selected cryo-cooled cations. The instrument is not yet functional, but we anticipate trapping ions and conducting photodissociation experiments before the end of the year. It also describes resonant two-photon ionization spectra that have been recorded for uranium mononitride (UN) in the visible portion of the spectrum. These experiments are still underway at the present time. Although the spectra are a bit difficult to properly fit, due to upper state perturbations, it appears that the molecule has a ground state with Ω = 3.5 and a bond length of approximately 1.76 Å. Finally, results on the thermochemistry and reactivity of Th + are presented. In these studies the bond energies of the following bonds have been determined: D 0 (Th + -2O) = 10.2 ± 0.2 eV; D0(Th + -N) = 6.69 ± 0.35 eV; D0(Th + -O) = 8.40 ± 0.28 eV; D 0 (OTh + -O) = 1.8 ± 0.4 eV.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Understanding the Subsurface Reactive Transport of Transuranic Contaminants at DOE Sites
Our primary hypothesis is that actinides can interact with surfaces in fundamentally different ways than other metals, metalloids, and oxyanions and that this fundamental difference requires new approaches to studying and modeling transuranic sorption to minerals and geomedia. This project supports a key mission of the SBR program to develop sufficient scientific understanding such that DOE sites will be able to incorporate coupled physical, chemical, and biological processes into decision making for environmental management and long-term stewardship, while also supporting DOE’s commitment to education, training, and collaboration with DOE user facilities.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Milestone report: The simulation of radiation driven gas diffusion in UO 2 at low temperature
Below 1000 K it is thought that fission gas diffusion in nuclear fuel during irradiation occurs through atomic mixing due to radiation damage. This is an important process for nuclear reactor performance as it affects fission gas release, particularly from the periphery of the pellet where such temperatures are normal. Here we present a molecular dynamics study of Xe and Kr diffusion due to irradiation. Thermal spikes and cascades have been used to study the electronic stopping and ballistic phases of damage, respectively. Our results predict that O and Kr exhibit the greatest diffusivity and U the least, while Xe lies in between. It is concluded that the ballistic phase does not sufficiently account for the experimentally observed diffusion. Preliminary thermal spike calculations indicate that the electronic stopping phase generates greater fission gas displacement than the ballistic phase, although further calculation must be carried out to confirm this. A good description of the system by the empirical potentials is important over the very wide temperatures induced during thermal spike and damage cascade simulations. This has motivated the development of a parameter set for gas-actinide and gas-oxygen interactions that is complementary for use with a recent many-body potential set. A comprehensive set of density functional theory (DFT) calculations were used to study Xe and Kr incorporation at a number of sites in CeO 2 , ThO 2 , UO 2 and PuO 2 . These structures were used to fit a potential, which was used to generate molecular dynamics (MD) configurations incorporating Xe and Kr at 300 K, 1500 K, 3000 K and 5000 K. Subsequent matching to the forces predicted by DFT for these MD configurations was used to refine the potential set. This fitting approach ensured weighted fitting to configurations that are thermodynamically significant over a broad temperature range, while avoiding computationally expensive DFT-MD calculations. The resultant gas potentials were validated against DFT binding energies and are suitable for simulating combinations of Xe and Kr in solid solutions of CeO 2 , ThO 2 , UO 2 and PuO 2 , providing a powerful tool for the atomistic simulation of conventional nuclear reactor fuel UO 2 as well as advanced MOX fuels.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Radiochronometry in the CMX-4 Exercise-Draft
In a recent international exercise, 10 international nuclear forensics laboratories successfully performed radiochronometry on 3 low-enriched uranium oxide samples, providing 12 analytical results using 3 different parent-daughter pairs serving as independent chronometers. The vast majority of the results were consistent with one another and consistent with the known processing history of the materials. In general, for these particular samples, mass spectrometry gave more accurate and more precise analytical results than decay counting measurements. In addition, the concordance of the 235 U- 231 Pa and 234 U- 230 Th chronometers confirmed the validity of the age dating assumption, increasing our confidence in the resulting conclusions.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Towards resolving the Rare Earth Crisis: Acquiring thermodynamic data required for modelling of the formation of Th-bearing monazites
This report describes the Rare Earth Crisis and the effect of rare earth elements.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Measuring Uranium Decay Rates for Advancement of Nuclear Forensics and Geochronology
Radioisotopic dating techniques are highly valuable tools for understanding the history of physical and chemical processes in materials related to planetary sciences and nuclear forensics, and rely on accurate knowledge of decay constants and their uncertainties. The decay constants of U-238 and U-235 are particularly important to Earth science, and often the measured values with lowest reported uncertainties are applied, although they have not been independently verified with similar precision. New direct measurements of the decay constants of U-238, Th-234, U-235, and U-234 were completed, using a range of analytical approaches. An overarching goal of the project was to ensure the quality of results, including metrological traceability to facilitate implementation across diverse disciplines. This report presents preliminary results of these experiments, as a few final measurements and calculations are still in progress.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Activities to Establish Technical Confidence for HTGR Fuel Processing
The Savannah River National Laboratory (SRNL) and Jülicher Entsorgungsgesellschaft für Nuklearanlagen mbH (JEN) are partnering in the demonstration of a digestion technology for the processing of graphitebased nuclear fuels. The purpose of this partnership is to identify, demonstrate, and mature a technology for processing high temperature gas-cooled reactor (HTGR) fuel currently stored at the Jülich and Ahaus facilities in Germany. To enable a decision on receipt of the fuel by the U.S. Department of Energy (DOE), the technology for dispositioning the fuel must achieve an acceptable level of technical maturity, what is referred to as “technical confidence.”
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Alternative Energy: Production of H{sub 2} by Radiolysis of Water in the Rocky Cores of Icy Bodies
We applied a model of radiolysis in earthly rock–water mixtures to several known or suspected ocean worlds: Enceladus, Ceres, Europa, Titania, Oberon, Pluto, and Charon. In this model, radiation emitted by the long-lived radionuclides ({sup 40}K, {sup 232}Th, {sup 235}U, and {sup 238}U) contained in the ordinary chondrite-like rocks is partly absorbed by the water permeating the material of each body’s core. The physical and chemical processes that follow release molecular hydrogen (H{sub 2}), which is a molecule of astrobiological interest. We compared the calculated production of H{sub 2} by radiolysis in each body’s core to published estimates of production by serpentinization. This study presents production calculations over 4.5 Gyr for several values of rock porosity. We found that radiolysis can produce H{sub 2} quantities equivalent to a few percent of what is estimated from serpentinization. Higher porosity, which is unlikely at the scale of a body’s entire core but possible just under the seafloor, can increase radiolytic production by almost an order of magnitude. The products of water radiolysis also include several oxidants, allowing for production of life-sustaining sulfates. Though previously unrecognized in this capacity, radiolysis in an ocean world’s outer core could be a fundamental agent in generating the chemical energy that could support life.
79 ASTRONOMY AND ASTROPHYSICS↗
MATERIALS PROBLEMS RELATED TO THE ELECTRIC ARC JETS
Materials problems related to electric arc jets
THORIUM↗
Development of a dispersion strengthened nickel base alloy using the high intensity arc process Summary report
Dispersion strengthened nickel base alloy using high intensity arc process
NICKEL ALLOY↗
Recognition of > or = 3850 Ma water-lain sediments in West Greenland and their significance for the early Archaean Earth
A layered body of amphibolite, banded iron formation (BIF), and ultramafic rocks from the island of Akilia, southern West Greenland, is cut by a quartz-dioritic sheet from which SHRIMP zircon 206Pb/207Pb weighted mean ages of 3865 +/- 11 Ma and 3840 +/- 8 Ma (2 sigma) can be calculated by different approaches. Three other methods of assessing the zircon data yield ages of >3830 Ma. The BIFs are interpreted as water-lain sediments, which with a minimum age of approximately 3850 Ma, are the oldest sediments yet documented. These rocks provide proof that by approximately 3850 Ma (1) there was a hydrosphere, supporting the chemical sedimentation of BIF, and that not all water was stored in hydrous minerals, and (2) that conditions satisfying the stability of liquid water imply surface temperatures were similar to present. Carbon isotope data of graphitic microdomains in apatite from the Akilia island BIF are consistent with a bio-organic origin (Mojzsis et al. 1996), extending the record of life on Earth to >3850 Ma. Life and surface water by approximately 3850 Ma provide constraints on either the energetics or termination of the late meteoritic bombardment event (suggested from the lunar cratering record) on Earth.
NASA Discipline Exobiology↗
Forecast of Standard Atomic Weights for the Mononuclidic Elements – 2011
In this short report, I will provide an early warning about potential changes to the standard atomic weight values for the twenty mononuclidic and the so-called pseudo-mononuclidic ({sup 232}Th and {sup 231}Pa) chemical elements due to the estimated changes in the mass values to be published in the next Atomic Mass Tables within the next two years. There have been many new measurements of atomic masses, since the last published Atomic Mass Table. The Atomic Mass Data Center has released an unpublished version of the present status of the atomic mass values as a private communication. We can not update the Standard Atomic Weight Table at this time based on these unpublished values but we can anticipate how many changes are probably going to be expected in the next few years on the basis of the forthcoming publication of the Atomic Mass Table. I will briefly discuss the procedures that the Atomic Weights Commission used in deriving the recommended Standard Atomic Weight values and their uncertainties from the atomic mass values. I will also discuss some concern raised about a proposed change in the definition of the mole. The definition of the mole is now connected directly to the mass of a {sup 12}C isotope (which is defined as 12 exactly) and to the kilogram. A change in the definition of the mole will probably impact the mass of {sup 12}C.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
ALPHA SPECTROMETRIC EVALUATION OF SRM-995 AS A POTENTIAL URANIUM/THORIUM DOUBLE TRACER SYSTEM FOR AGE-DATING URANIUM MATERIALS
Uranium-233 (t{sub 1/2} {approx} 1.59E5 years) is an artificial, fissile isotope of uranium that has significant importance in nuclear forensics. The isotope provides a unique signature in determining the origin and provenance of uranium-bearing materials and is valuable as a mass spectrometric tracer. Alpha spectrometry was employed in the critical evaluation of a {sup 233}U standard reference material (SRM-995) as a dual tracer system based on the in-growth of {sup 229}Th (t{sub 1/2} {approx} 7.34E3 years) for {approx}35 years following radiochemical purification. Preliminary investigations focused on the isotopic analysis of standards and unmodified fractions of SRM-995; all samples were separated and purified using a multi-column anion-exchange scheme. The {sup 229}Th/{sup 233}U atom ratio for SRM-995 was found to be 1.598E-4 ({+-} 4.50%) using recovery-corrected radiochemical methods. Using the Bateman equations and relevant half-lives, this ratio reflects a material that was purified {approx} 36.8 years prior to this analysis. The calculated age is discussed in contrast with both the date of certification and the recorded date of last purification.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Bismuth 213 Cancer Treatment
See how INL scientists are increasing supplies of radioactive medical isotopes to treat cancer. For more information about INL research, visit http://www.facebook.com/idahonationallaboratory.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
A New Approach for Modeling and Analysis of Molten Salt Reactors Using SCALE
Explore the source record for details and available documents.
DOE↗
"Ask Argonne" - Dave Grabaskas, Nuclear Engineer, Part 2
Part 1 (http://www.youtube.com/watch?v=Vs_0wXoSL8M) of Dr. Dave Grabaskas' "Ask Argonne" video set drew many questions from the public. In Part 2, Grabaskas answers three of those questions.
22 GENERAL STUDIES OF NUCLEAR REACTORS↗