scholarly journals Tc and Re Behavior in Borosilicate Waste Glass Vapor Hydration Tests

2006 ◽  
Vol 985 ◽  
Author(s):  
David A. McKeown ◽  
Andrew C. Buechele ◽  
Wayne W. Lukens ◽  
David K. Shuh ◽  
Ian L. Pegg
Keyword(s):  
High Mobility ◽  
Sample Surface ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Long Term Storage ◽  
Before And After ◽  
X Ray Absorption ◽  
Term Storage ◽  
Scanning Electron

AbstractTechnetium (Tc), found in some nuclear wastes, is of particular concern with regard to long-term storage, because of its long-lived radioactivity and high mobility in the environment. Tc and rhenium (Re), commonly used as a non-radioactive surrogate for Tc, were studied to assess their behavior in borosilicate glass under hydrothermal conditions in the Vapor Hydration Test (VHT). X-ray absorption spectroscopy (XAS) and scanning electron microscopy (SEM) measurements were made on the original Tc- and Re-containing glasses and their corresponding VHT samples, and show different behavior for Tc and Re under VHT conditions. XAS indicates that, despite starting with different Tc(IV) and Tc(VII) distributions in each glass, the VHT samples have 100% Tc(IV)O6 environments. SEM shows complete alteration of the original glass, Tc enrichment near the sample surface, and Tc depletion in the center. Perrhenate (Re(VII)O4−) is dominant in both Re-containing samples before and after the VHT, where Re is depleted near the VHT sample surface and more concentrated toward the center.

Dissolution Characteristics and Morphology of Large-sized Scorodite Particles Synthesized from Fe(II) and As(V) in Aqueous Solution

2012 ◽  
Vol 31 (4-5) ◽  
pp. 451-458 ◽  
Author(s):  
S. Fujieda ◽  
K. Shinoda ◽  
T. Inanaga ◽  
M. Abumiya ◽  
S. Suzuki
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Surface Defects ◽  
Atmospheric Temperature ◽  
Orthorhombic Structure ◽  
X Ray ◽  
Long Term Storage ◽  
Transmission Electron ◽  
Term Storage

AbstractA novel process for preparing scorodite particles with a diameter of approximately 20 µm from Fe(II) and As(V) in aqueous solution has been developed by DOWA Metals and Mining. In the present study, the dissolution characteristics of iron and arsenic from the scorodite particles synthesized by this process have been investigated under different conditions. The results show that the concentration of arsenic dissolved from the particles in aqueous solution is very low, but it has a complicated dependence on the temperature and pH of the solution. Transmission electron microscopy (TEM) with an energy dispersive X-ray spectrometer (EDS) was used to analyze the morphology, structure, and composition of the scorodite particles. The results indicate that the scorodite particles exhibit a nearly octahedral shape with planes composed of almost (111) planes in the orthorhombic structure. The concentration of iron at the surface of the particles is higher than that of iron inside of the particles. This characteristic morphology, along with the minimal surface defects of the scorodite particles, is considered to be responsible for the low dissolution of arsenic from the particles in aqueous solution. Atmospheric temperature and solution conditions were also found to be important for the safe, long-term storage of arsenic using scorodite particles.

scholarly journals EFFECT OF FREEZING ON THE MILK QUALITY OF COWS

2020 ◽  
pp. 54-57
Author(s):  
Lyubov Valentinovna Efimova ◽  
Tatyana Vyacheslavovna Zaznobina ◽  
Elena Vladimirovna Gatilova ◽  
Olga Valeryevna Ivanova
Keyword(s):  
Quality Indicators ◽  
Age Groups ◽  
Milk Quality ◽  
Long Term Storage ◽  
Before And After ◽  
Frozen State ◽  
Term Storage ◽  
Two Age Groups

Due to the fact that milk has a short shelf life, the issue of its freezing and long-term storage in the frozen state is relevant. A study was conducted on the effect of freezing on the milk quality after its defrosting of cows-mothers and cows-daughters of Red-Motley breed. As a result, it was established how milk quality indicators to change after five months of storage in a frozen state in cows of two age groups. A high correlation was established between quality indicators before and after freezing. The influence of the “freezing” factor on milk quality indicators was recognized statistically significant, the “generation” factor – not significant.

scholarly journals Does long-term storage of clay samples influence their mechanical characteristics?

2020 ◽  
Vol 57 (2) ◽  
pp. 304-309 ◽  
Author(s):  
Mustapha Abdellaziz ◽  
Mahmoud N. Hussien ◽  
Mohamed Chekired ◽  
Mourad Karray
Keyword(s):  
Mechanical Characteristics ◽  
Long Term Storage ◽  
Temperature And Humidity ◽  
Before And After ◽  
Prime Objective ◽  
Term Storage ◽  
Physical And Mechanical Characteristics

The prime objective of this study is to assess the influence of long-term storage on the physical and mechanical characteristics of clay samples. Samples from two different clays were sealed and stored in a temperature- and humidity-controlled room at the geotechnical laboratory of the Université de Sherbrooke for up to 27 years. The stored clay samples were tested before and after long-term storage and the results compared in this note. The comparison showed that even with long-term storage, the majority of the physical and mechanical characteristics of the samples were preserved.

scholarly journals XPS Investigation of ceramic matrixes for disposal of long-living radioactive waste products

2004 ◽  
Vol 19 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Yury Teterin ◽  
Serguei Stefanovskij ◽  
Serguei Yudintsev ◽  
George Bek-Uzarov ◽  
Anton Teterin ◽  
...  
Keyword(s):  
Electron Spectroscopy ◽  
Spectral Structure ◽  
Waste Products ◽  
X Ray ◽  
Air Atmosphere ◽  
Highly Active ◽  
Long Term Storage ◽  
Term Storage

The synthesis of ceramic matrixes for the long-term storage of highly active radionuclide wastes and determination of physical and chemical forms of radionuclides in them is one of the important problems in radioecology. It enables to create purpose fully materials for the long-term storage of radionuclides. In the present work the samples of ceramics [CaCe0.9Ti2O6.8(I) and CaCeTi2O7(II}] formed under various conditions were investigated with the X-ray photo electron spectroscopy. It is necessary for synthesis of ceramic matrixes, for the disposal of the plutonium and others tetravalent actinides. A technique was developed for the determination of cerium oxidation state (Ce3+ and Ce4+) on the basis of the X-ray photo electron spectroscopy spectral structure characteristics. It was established that the sample (I) formed at 300 MPa and T = 1400 ?C in the air atmosphere contained on the surface two types of cerium ions in the ratio ? 63 atomic % of Ce3+ and 37 atomic % of Ce4+, and the sample (II) formed at 300 MPa and T= 1300 ?C in the oxygen atmosphere contained on its surface two types of cerium ions also, but in the ratio ? 36 atomic % of Ce3+ and 64 atomic % of Ce4+. It was established that on the surface of the studied ceramics carbonates of calcium and/or cerium could be formed under influence of the environment that leads to the destruction of ceramics.

scholarly journals Features of formation of durability of corn hybrids seeds for their cultivation, postharvest processing and storage

Agrology ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 137-142
Author(s):  
M. Ya. Kyrpa ◽  
N. S. Filipkova
Keyword(s):  
Seed Production ◽  
Necessary Condition ◽  
Prolonged Storage ◽  
Hydrothermal Conditions ◽  
Corn Hybrids ◽  
Long Term Storage ◽  
Processing And Storage ◽  
And Storage ◽  
Term Storage

The organization of the sowing material stocks is a necessary condition for stable seed production of any crop. Insurance, reserve, breeding and transi-tional funds are such stocks in corn seed production. Their creation and maintenance largely depend on the economic longev-ity of seeds, which can be formed at the stages of cultivation, harvesting, post-harvest processing and storage of seed. However, the data on the peculiarities of the formation of seed longevity of corn hybrids and their ability to long-term storage are lim-ited. That is why research in this area is considered relevant and important. The results of study of regularities of formation and factors of longevity of corn hybrids seeds of domestic selection are summarized in the executed work. Ecological, technical-technological and varietal factors are formed dur-ing corn cultivation, har-vesting and processing. The greatest dependence is noted on the hydrothermal conditions, start-ing from the stage of cultivation, and then – in the stages after harvesting - the modes of drying and separation of seed. High economic durability is provided under the following conditions: hydro-term coefficient at the level of 0,5–0,7 – for vegetation and 0,3–0,4 – for maturing, dry-ing temperature within 36–400С at humidity of seeds of 20–30%, fractional separation, removal from the seeds mass of the unstable frac-tion containing 18–20% of the total. Some of the factors included a sign of seed size, which is clearly manifested at the stage of long-term storage of seed. Sowing fractions differ significantly in terms of size, including the weight of 1000 seeds and their linear size. The greatest economic durability is inherent in the first and second of all factions. It is recommended to obtain them by calibrating the seeds on separating sieves with round holes with a diameter of 8–10 mm, depending on the hybrids. Prolonged storage is proposed on the basis of a combination of two factors – low humidity and airtight packaging of seeds. This significantly reduces resource costs and extends the economic longevity of corn hybrid seeds to 4–5 years.

Ceramic Immobilisation Options for Technetium

2012 ◽  
Vol 1518 ◽  
pp. 111-116 ◽  
Author(s):  
Martin C. Stennett ◽  
Daniel J. Backhouse ◽  
Colin L. Freeman ◽  
Neil C. Hyatt
Keyword(s):  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
High Mobility ◽  
X Ray Diffraction ◽  
Host Matrix ◽  
X Ray ◽  
Separate Fraction ◽  
X Ray Absorption ◽  
Snf Reprocessing

ABSTRACTTechnetium-99 (99Tc) is a fission product produced during the burning of nuclear fuel and is particularly hazardous due to its long half life (210000 years), relatively high content in nuclear fuel (approx. 1 kg per ton of SNF), low sorption, and high mobility in aerobic environments. During spent nuclear fuel (SNF) reprocessing Tc is released either as a separate fraction or in complexes with actinides and zirconium. Although Tc has historically been discharged into the marine environment more stringent regulations mean that the preferred long term option is to immobilise Tc in a highly stable and durable matrix. This study investigated the feasibility of incorporating of Mo (as a Tc analogue) in a crystalline host matrix, synthesis by solid state synthesis under different atmospheres. Samples have been characterised with X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray absorption spectroscopy (XAS).

A simple hermetic sample holder for X-ray diffraction analysis of uranium hydride

2007 ◽  
Vol 40 (4) ◽  
pp. 796-798 ◽  
Author(s):  
Bingyun Ao ◽  
Xiaolin Wang ◽  
Yongjun Wei ◽  
Yanzhi Zhang
Keyword(s):  
Diffraction Analysis ◽  
Sample Holder ◽  
X Ray Diffraction ◽  
Aging Effects ◽  
X Ray ◽  
Long Term Storage ◽  
Toxic Materials ◽  
First Results ◽  
Term Storage

In order to help resolve unknowns regarding aging effects of uranium during long-term storage of tritium, a number of experiments have been carried out by several researchers. However, almost no literature is available on the structural change of uranium tritide, mainly because its high toxicity and air-sensitivity render appropriate experiments very difficult. In this paper, a simple hermetic sample holder that fits the Philips X'Pert Pro X-ray diffractometer is described. It may be used to study the aging effects of uranium tritide during storage. The sample holder mainly consists of an aluminium container for sample storage and a Mylar window for X-ray measurements. This sample holder can also be used with other air-sensitive, radioactive and toxic materials. In this paper, the first results obtained from X-ray diffraction analysis of uranium hydride are presented.

scholarly journals On the Suitability of Lanthanides as Actinide Analogs

2008 ◽  
Vol 1104 ◽  
Author(s):  
Kenneth Raymond ◽  
Geza Szigethy
Keyword(s):  
Chemical Separation ◽  
Careful Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Term Storage ◽  
Chemical Models ◽  
Bonding Properties ◽  
Materials Used ◽  
Term Storage

AbstractWith the current level of actinide materials used in civilian power generation and the need for safe and efficient methods for the chemical separation of these species from their daughter products and for long-term storage requirements, a detailed understanding of actinide chemistry is of great importance. Due to the unique bonding properties of the f-elements, the lanthanides are commonly used as structural and chemical models for the actinides, but differences in the bonding between these 4f and 5f elements has become a question of immediate applicability to separations technology. This brief overview of actinide coordination chemistry in the Raymond group at UC Berkeley/LBNL examines the validity of using lanthanide analogs as structural models for the actinides, with particular attention paid to single crystal X-ray diffraction structures. Although lanthanides are commonly accepted as reasonable analogs for the actinides, these comparisons suggest the careful study of actinide materials independent of their lanthanide analogs to be of utmost importance to present and future efforts in nuclear industries.

Behavior of 238Pu-Doped Cubic Zirconia under Self-Irradiation

2003 ◽  
Vol 807 ◽  
Author(s):  
Boris E. Burakov ◽  
Maria A. Yagovkina ◽  
Maria V. Zamoryanskaya ◽  
Alexander A. Kitsay ◽  
Vladimir M. Garbuzov ◽  
...  
Keyword(s):  
Alpha Decay ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Zirconia ◽  
Long Term Storage ◽  
Fluorite Type ◽  
Image Position ◽  
Actinide Transmutation ◽  
Term Storage

ABSTRACTTo investigate the resistance of cubic zirconia to accelerated radiation damage, which simulates effects of long term storage, 238Pu-doped polycrystalline samples of cubic zirconia, (Zr,Gd,Pu)O2, were obtained and studied using X-ray diffraction analysis (XRD), electron probe microanalysis (EPMA), optical and scanning electron microscopy (SEM), and modified MCC-1 static leach test. The ceramic material was characterized by the following chemical composition (from EPMA in wt.% element): Zr = 50.2, Gd = 15.4, Pu = 12.2. This corresponds to the estimated formula, Zr0.79Gd0.14Pu0.07O1.99. The content of 238Pu estimated was approximately 9.9 wt.%. The XRD measurements were carried out after the following cumulative doses (in alpha decay/m3 × 1023): 3, 27, 62, 110, 134, 188, 234, and 277. Even after extremely high self-irradiation, cubic zirconia retained its crystalline structure. All XRD analyses showed no phases other than a cubic fluorite-type structure. The following results of normalized Pu mass loss (NL, in g/m2, without correction for ceramic porosity) were obtained from static leach tests (in deionized water at 90°C for 28 days) for 4 cumulative doses (in alpha decay/m3 × 1023):The results obtained confirm the high resistance of cubic zirconia to self-irradiation. This allows us to consider zirconia-based ceramic as the universal material that is suitable for actinide transmutation and geological disposal.

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