Channelling Investigation of the Behaviour of Urania Under Low-energy Ion Irradiation

Channelling Investigation of the Behaviour of Urania Under Low-energy Ion Irradiation PDF Author: Tien Hien Nguyen
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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This thesis is dedicated to the investigation of the structural destabilisation of UO2 single crystal. Irradiations with 470-keV Xe, 500-keV Ce and 500-keV La ions (with corresponding ion range of Rp 85 nm and range straggling of Delta Rp _ 40 nm according to SRIM calculation) have been performed to investigate the destabilisation of UO2 single crystals induce by (i) the radiation damage effects due to the nuclear stopping process of a fission fragment at the end of their trajectories (ballistic contribution) and by (ii) the incorporation of a fission product at high concentration (chemical contribution). The energies and masses of bombarding ions were deliberately chosen so that they would have very similar projected range in UO2 in order to compare the effects induced by solubles (La and Ce) versus non soluble Xe species in UO2. Rutherford Backscattering Spectrometry in channelling geometry (RBS/C) was applied to study the defects induced. Channelling data were analysed afterwards by Monte-Carlo simulation with McChasy code assuming a two-class model of defects comprising (i) the randomly displaced atoms (RDA) and the bent channels (BC) defects. The accumulation of RDA with increasing ion fluence leads to a steep increase (build-up of defects) observed from 4 to 7 dpa regardless of nature of ions and a dramatic increase observed from 300 dpa (corresponding to _ 5 at. % of implanted ions) only for Xe irradiated crystal. The difference due to the soluble versus insoluble species was clearly observed. Such a difference was observed via the dramatic increase of RDA when the crystal is implanted at very high concentration only for crystal implanted with insoluble species. Moreover, the difference is also observed via the higher fraction of RDA created in the crystal irradiated with insoluble element. This phenomenon is mostly due to the size of implanted species in the matrix. Insoluble Xe atoms have the atomic radius which is larger than twice the atomic radius of U sub-lattice while soluble La and Ce atoms have the atomic radii of similar size as compared to U atom. Xe creates a much stronger stress field in UO2 crystal in comparison to La or Ce; a higher fraction of RDA is thus created. Conversely, the accumulation of BC with increasing ion fluence leads to very similar evolution versus ion fluence in all crystals implanted with the three elements .

Channelling Investigation of the Behaviour of Urania Under Low-energy Ion Irradiation

Channelling Investigation of the Behaviour of Urania Under Low-energy Ion Irradiation PDF Author: Tien Hien Nguyen
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
This thesis is dedicated to the investigation of the structural destabilisation of UO2 single crystal. Irradiations with 470-keV Xe, 500-keV Ce and 500-keV La ions (with corresponding ion range of Rp 85 nm and range straggling of Delta Rp _ 40 nm according to SRIM calculation) have been performed to investigate the destabilisation of UO2 single crystals induce by (i) the radiation damage effects due to the nuclear stopping process of a fission fragment at the end of their trajectories (ballistic contribution) and by (ii) the incorporation of a fission product at high concentration (chemical contribution). The energies and masses of bombarding ions were deliberately chosen so that they would have very similar projected range in UO2 in order to compare the effects induced by solubles (La and Ce) versus non soluble Xe species in UO2. Rutherford Backscattering Spectrometry in channelling geometry (RBS/C) was applied to study the defects induced. Channelling data were analysed afterwards by Monte-Carlo simulation with McChasy code assuming a two-class model of defects comprising (i) the randomly displaced atoms (RDA) and the bent channels (BC) defects. The accumulation of RDA with increasing ion fluence leads to a steep increase (build-up of defects) observed from 4 to 7 dpa regardless of nature of ions and a dramatic increase observed from 300 dpa (corresponding to _ 5 at. % of implanted ions) only for Xe irradiated crystal. The difference due to the soluble versus insoluble species was clearly observed. Such a difference was observed via the dramatic increase of RDA when the crystal is implanted at very high concentration only for crystal implanted with insoluble species. Moreover, the difference is also observed via the higher fraction of RDA created in the crystal irradiated with insoluble element. This phenomenon is mostly due to the size of implanted species in the matrix. Insoluble Xe atoms have the atomic radius which is larger than twice the atomic radius of U sub-lattice while soluble La and Ce atoms have the atomic radii of similar size as compared to U atom. Xe creates a much stronger stress field in UO2 crystal in comparison to La or Ce; a higher fraction of RDA is thus created. Conversely, the accumulation of BC with increasing ion fluence leads to very similar evolution versus ion fluence in all crystals implanted with the three elements .

Nuclear Science Abstracts

Nuclear Science Abstracts PDF Author:
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 600

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INIS Atomindex

INIS Atomindex PDF Author:
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 870

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Review of Fuel Failures in Water Cooled Reactors (2006-2015): IAEA Nuclear Energy Series No. Nf-T-2.5

Review of Fuel Failures in Water Cooled Reactors (2006-2015): IAEA Nuclear Energy Series No. Nf-T-2.5 PDF Author: International Atomic Energy Agency
Publisher:
ISBN: 9789201043191
Category : Business & Economics
Languages : en
Pages : 65

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Book Description
This updated version of Nuclear Energy Series NF-T-2.1 provides information on all aspects of fuel failures in current nuclear power plant operations.

The Foundations of Ethology

The Foundations of Ethology PDF Author: K. Lorenz
Publisher: Springer Science & Business Media
ISBN: 3709136717
Category : Psychology
Languages : en
Pages : 507

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Book Description
This book is a contribution to the history of ethology-not a definitive history, but the personal view of a major figure in that story. It is all the more welcome because such a grand theme as ethology calls for a range of perspectives. One reason is the overarching scope of the subject. Two great questions about life that constitute much of biology are "How does it work (structure and function)?" and "How did it get that way (evolu tion and ontogeny)?" Ethology addresses the antecedent of "it. " Of what are we trying to explain the mechanism and development? Surely behav ior, in all its wealth of detail, variation, causation, and control, is the main achievement of animal evolution, the essential consequence of animal structure and function, the raison d' etre of all the rest. Ethology thus spans between and overlaps with the ever-widening circles of ecol ogy over the eons and the ever-narrowing focus of physiology of the neurons. Another reason why the history of ethology needs perspectives is the recency of its acceptance. For such an obviously major aspect of animal biology, it is curious how short a time-less than three decades-has seen the excitement of an active field and a substantial fraternity of work ers, the addition of professors and courses to departments and curricula in biology (still far from universal}, and the normal complement of spe cial journals, symposia, and sessions at congresses.

Mars

Mars PDF Author: Viorel Badescu
Publisher: Springer Science & Business Media
ISBN: 3642036295
Category : Technology & Engineering
Languages : en
Pages : 716

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Book Description
th th Mars, the Red Planet, fourth planet from the Sun, forever linked with 19 and 20 Century fantasy of a bellicose, intelligent Martian civilization. The romance and excitement of that fiction remains today, even as technologically sophisticated - botic orbiters, landers, and rovers seek to unveil Mars’ secrets; but so far, they have yet to find evidence of life. The aura of excitement, though, is justified for another reason: Mars is a very special place. It is the only planetary surface in the Solar System where humans, once free from the bounds of Earth, might hope to establish habitable, self-sufficient colonies. Endowed with an insatiable drive, focused motivation, and a keen sense of - ploration and adventure, humans will undergo the extremes of physical hardship and danger to push the envelope, to do what has not yet been done. Because of their very nature, there is little doubt that humans will in fact conquer Mars. But even earth-bound extremes, such those experienced by the early polar explorers, may seem like a walk in the park compared to future experiences on Mars.

Thermal and Rheological Measurement Techniques for Nanomaterials Characterization

Thermal and Rheological Measurement Techniques for Nanomaterials Characterization PDF Author: Sabu Thomas
Publisher: Elsevier
ISBN: 032346145X
Category : Technology & Engineering
Languages : en
Pages : 294

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Book Description
Thermal and Rheological Measurement Techniques for Nanomaterials Characterization, Second Edition covers thermal and rheological measurement techniques, including their principle working methods, sample preparation and interpretation of results. This important reference is an ideal source for materials scientists and industrial engineers who are working with nanomaterials and need to know how to determine their properties and behaviors. Outlines key characterization techniques to determine the thermal and rheological behavior of different nanomaterials Explains how the thermal and rheological behavior of nanomaterials affect their usage Provides a method-orientated approach that explains how to successfully use each technique

Viability of Inert Matrix Fuel in Reducing Plutonium Amounts in Reactors

Viability of Inert Matrix Fuel in Reducing Plutonium Amounts in Reactors PDF Author: International Atomic Energy Agency
Publisher: IAEA
ISBN:
Category : Business & Economics
Languages : en
Pages : 100

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Book Description
The reactors around the world have produced more than 2000 tonnes of plutonium, contained in spent fuel or as separated forms through reprocessing. Disposition of fissile materials has become a primary concern of nuclear non-proliferation efforts worldwide. There is a significant interest in IAEA Member States to develop proliferation resistant nuclear fuel cycles for incineration of plutonium such as inert matrix fuels (IMFs). This publication reviews the status of potential IMF candidates and describes several identified candidate materials for both fast and thermal reactors: MgO, ZrO2, SiC, Zr alloy, SiAl, ZrN; some of these have undergone test irradiations and post irradiation examination. Also discussed are modelling of IMF fuel performance and safety analysis. System studies have identified strategies for both implementation of IMF fuel as homogeneous or heterogeneous phases, as assemblies or core loadings and in existing reactors in the shorter term, as well as in new reactors in the longer term.

The Fairy Tale of Nuclear Fusion

The Fairy Tale of Nuclear Fusion PDF Author: L. J. Reinders
Publisher: Springer Nature
ISBN: 3030643441
Category : Science
Languages : en
Pages : 628

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Book Description
This carefully researched book presents facts and arguments showing, beyond a doubt, that nuclear fusion power will not be technically feasible in time to satisfy the world's urgent need for climate-neutral energy. The author describes the 70-year history of nuclear fusion; the vain attempts to construct an energy-generating nuclear fusion power reactor, and shows that even in the most optimistic scenario nuclear fusion, in spite of the claims of its proponents, will not be able to make a sizable contribution to the energy mix in this century, whatever the outcome of ITER. This implies that fusion power will not be a factor in combating climate change, and that the race to save the climate with carbon-free energy will have been won or lost long before the first nuclear fusion power station comes on line. Aimed at the general public as well as those whose decisions directly affect energy policy, this book will be a valuable resource for informing future debates.

Physics Briefs

Physics Briefs PDF Author:
Publisher:
ISBN:
Category : Physics
Languages : en
Pages : 816

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