Synchrotron Diffraction Study of the Isothermal Oxidation of Uranium Dioxide at 250°C

2003 ◽  
Vol 802 ◽  
Author(s):  
Gurvan Rousseau ◽  
Lionel Desgranges ◽  
Jean-Claude Nièpce ◽  
Jean-François Bérar ◽  
Gianguido Baldinozzi
Keyword(s):  
Spent Nuclear Fuel ◽  
Structural Evolution ◽  
Isothermal Oxidation ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Long Term Storage ◽  
Instrumental Resolution ◽  
Term Storage

ABSTRACTThe structural evolution of UO2 during its oxidation to U3O8 at 250°C in air was studied by in-situ synchrotron X-ray diffraction on the D2AM-CRG beamline at ESRF. The aim of this study is to determine the phases that are likely to appear during the long-term storage of spent nuclear fuel. Our results are in disagreement with the literature in which the existence of an intermediate cubic phase is not reported. Instead, an α-U3O7 tetragonal phase (c/a < 1) was mentioned but not definitively observed. These previous interpretations may have been the result of poor instrumental resolution.

scholarly journals Effects of Long-Term Storage on the Detection of Proteins, DNA, and mRNA in Tissue Microarray Slides

2011 ◽  
Vol 59 (12) ◽  
pp. 1113-1121 ◽  
Author(s):  
Christina Karlsson ◽  
Mats G. Karlsson
Keyword(s):  
Gene Copy Number ◽  
Tissue Microarrays ◽  
Storage Conditions ◽  
Gene Copy ◽  
Histological Techniques ◽  
Long Term Storage ◽  
Term Storage ◽  
Formalin Fixed

Storage of tissue slides has been claimed to induce dramatically reduced antigen detection particularly for immunohistochemistry (IHC). With tissue microarrays, the necessity to serially cut blocks in order to obtain as much material as possible is obvious. The presumed adverse effect of storage might hamper such an approach. The authors designed an experimental setting consisting of four different storage conditions with storage time of tissue slides of up to 1 year. Detection of proteins, DNA, and mRNA was performed using IHC and in situ hybridization techniques. Slight but significant changes in IHC occurred over time. The most important factor is the primary antibody used: four showed no significant changes, whereas limited decreases in 8 antibodies could be detected by image analysis. Whether the antigen was nuclear or cytoplasmic/membranous did not matter. No major differences between different storage conditions could be shown, but storage at 4C was overall the best procedure. Furthermore, gene copy number aberrations, chromosomal translocations, and the presence of mRNA could be detected on slides stored up to 1 year. In conclusion, in tissues optimally formalin fixed and using modern histological techniques, only minute changes in tissue antigenicity are induced by long-term storage.

scholarly journals Decay heat power of spent nuclear fuel of power reactors with high burnup at long-term storage

2017 ◽  
Vol 153 ◽  
pp. 07035 ◽  
Author(s):  
Mikhail Ternovykh ◽  
Georgy Tikhomirov ◽  
Ivan Saldikov ◽  
Alexander Gerasimov
Keyword(s):  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Heat Power ◽  
Decay Heat ◽  
Long Term Storage ◽  
High Burnup ◽  
Term Storage

scholarly journals Modeling of decay heat removal from CONSTOR RBMK-1500 casks during long-term storage of spent nuclear fuel

Energy ◽  
2019 ◽  
Vol 170 ◽  
pp. 978-985 ◽  
Author(s):  
R. Poškas ◽  
V. Šimonis ◽  
H. Jouhara ◽  
P. Poškas
Keyword(s):  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Heat Removal ◽  
Decay Heat ◽  
Long Term Storage ◽  
Term Storage

Self-Irradiation of Monazite Ceramics: Contrasting Behavior of PuPO4 and (La,Pu)PO4 Doped with Pu-238

2004 ◽  
Vol 824 ◽  
Author(s):  
Boris E. Burakov ◽  
Maria A. Yagovkina ◽  
Vladimir M. Garbuzov ◽  
Alexander A. Kitsay ◽  
Vladimir A. Zirlin
Keyword(s):  
Radiation Damage ◽  
Crack Formation ◽  
Alpha Decay ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Deep Blue ◽  
Long Term Storage ◽  
First Time ◽  
Term Storage

AbstractTo investigate the behavior of monazite during accelerated radiation damage, which simulates effects of long term storage, 238Pu-doped polycrystalline samples of (La,Pu)PO4 and PuPO4 were synthesized for the first time ever and studied using powder X-ray diffraction (XRD) analysis and optical microscopy. The starting precursor materials were obtained by precipitation of La and (or) Pu from their aqueous nitrate solutions followed by calcination in air at 700°C for 1 hour, cold pressing, and sintering in air at 1200-1250°C for 2 hours. The 238Pu contents in ceramic samples measured using gamma spectrometry were (in wt.% el.): 8.1 for (La,Pu)PO4 and 7.2 for PuPO4. The (La,Pu)PO4 monazite remained crystalline at ambient temperature up to a cumulative dose of 1.19 × 1025 alpha decays/m3. In contrast, the PuPO4 monazite became nearly completely amorphous at a relatively low dose of 4.2 × 1024 alpha decays/m3. Swelling and crack formation due to the alpha decay damage was observed in the PuPO4 ceramic. Also, under self-irradiation this sample completely changed color from initial deep blue to black. The (La,Pu)PO4 monazite was characterized by a similar change in color from initial light blue to gray, however, no swelling or crack formation have so far been observed. The results of this study allow us to conclude that the radiation damage behavior of monazite strictly depends on the chemical composition. The justification of monazite-based ceramics as actinide waste forms requires additional investigation.

Population genetics and conservation of the critically endangered Clematis acerifolia (Ranunculaceae)

2005 ◽  
Vol 83 (10) ◽  
pp. 1248-1256 ◽  
Author(s):  
J. López-Pujol ◽  
F.-M. Zhang ◽  
S. Ge
Keyword(s):  
Genetic Diversity ◽  
Population Genetic ◽  
Critically Endangered ◽  
Ex Situ ◽  
Genetic Structuring ◽  
Long Term Storage ◽  
Hardy Weinberg Equilibrium ◽  
Term Storage

Allozyme electrophoresis was used to evaluate the levels of genetic diversity and population genetic structure of the critically endangered Clematis acerifolia Maximowicz (Ranunculaceae), a narrow endemic species in China. On the basis of variation at 19 putative loci in nine populations covering the entire distribution of this species, low values of genetic diversity were detected (P = 20.5%, A = 1.27, and He = 0.072). A significant deficiency of heterozygotes was found in all populations. Most loci showed deviations from the Hardy–Weinberg equilibrium, probably as a result of population genetic structuring. The high genetic divergence among populations (FST = 0.273) can be interpreted as an effect of the extinction of local populations and genetic drift within extant populations, and has probably been enhanced by habitat fragmentation in recent decades. Threats to this species are mainly anthropogenic (road works, construction of holiday resorts, and extraction activities), although stochastic risks cannot be ignored. Therefore, to preserve extant genetic variation of C. acerifolia, in situ strategies, such as the preservation of its habitat or at least the most diverse populations, and ex situ measures, such as the collection and long-term storage of seeds, should be adopted.

Elastic strains in polycrystalline UO2 samples implanted with He: micro Laue diffraction measurements and elastic modeling

2013 ◽  
Vol 1514 ◽  
pp. 125-130
Author(s):  
Axel Richard ◽  
Etienne Castelier ◽  
Herve Palancher ◽  
Jean-Sebastien Micha ◽  
Philippe Goudeau
Keyword(s):  
Spent Nuclear Fuel ◽  
Simple Expression ◽  
X Ray Diffraction ◽  
Laue Diffraction ◽  
X Ray ◽  
Elastic Stresses ◽  
Long Term Storage ◽  
Macro Scale ◽  
Grain Orientations

Abstract:In the framework of the study of long-term storage of the spent nuclear fuel, polycrystalline UO2 samples have been implanted with He ions. The thin implanted layer, close to the free surface is subjected to elastic stresses which are studied by x-ray diffraction (micro Laue diffraction) and a mechanical modeling. A simple expression of the displacement gradient tensor has been evidenced; it concerns only three terms (ε3, ε4 and ε5) which strongly evolve with considered grain orientations. Finally, we show that results obtained with micro diffraction are in very good agreement with conventional x-ray diffraction measurements done in laboratory at macro scale.

Long-term storage of spent nuclear fuel

2015 ◽  
Vol 14 (3) ◽  
pp. 252-257 ◽  
Author(s):  
Rodney C. Ewing
Keyword(s):  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Long Term Storage ◽  
Term Storage
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