Radiation-Induced Decomposition of U(VI) Phase to Nanocrystals of UO2

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Languages : en
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Radiation-Induced Decomposition of U(VI) Phase to Nanocrystals of UO2

Radiation-Induced Decomposition of U(VI) Phase to Nanocrystals of UO2 PDF Author:
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Languages : en
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Radiation-Induced Decomposition of U(VI) Alteration Phases of UO2

Radiation-Induced Decomposition of U(VI) Alteration Phases of UO2 PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 1

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U{sup 6+} phases are common alteration products of spent nuclear fuel under oxidizing conditions, and they may potentially incorporate actinides, such as long-lived 239Pu and 237Np, delaying their transport to the biosphere. In order to evaluate the ballistic effects of [alpha]-decay events on the stability of the U{sup 6+}-phases, they report, for the first time, the results of ion beam irradiations (1.0 MeV Kr{sup 2+}) for six different structures of U{sup 6+}-phases: uranophane, kasolite, boltwoodite, saleeite, carnotite, and liebigite. The target uranyl-minerals were characterized by powder X-ray diffraction and identification confirmed by SAED in TEM. The TEM observation revealed no initial contamination of uraninite in these U{sup 6+} phases. All of the samples were irradiated with in situ TEM observation using 1.0 MeV Kr{sup 2+} in the IVEM (intermediate-voltage electron microscope) at the IVEM-Tandem Facility of Argonne National Laboratory. The ion flux was 6.3 x 1011 ions/cm2/sec. The specimen temperatures during irradiation were 298 and 673 K, respectively. The Kr{sup 2+}-irradiation decomposed the U{sup 6+}-phases to nanocrystals of UO2 at doses as low as 0.006 dpa. The cumulative doses for the pure U{sup 6+}-phases, e.g., uranophane, at 0.1 and 1 m.y. are calculated to be 0.009 and 0.09 dpa using SRIM2003. However, with the incorporation of 1 wt.% 239Pu, the calculated doses reach 0.27 and ≈ 1.00 dpa in ten thousand and one hundred thousand years, respectively. Under oxidizing conditions, multiple cycles of radiation-induced decomposition to UO2 followed by alteration to U6-phases should be further investigated to determine the fate of trace elements that may have been incorporated in the U{sup 6+}-phases.

Radiation-Induced Decomposition of U(vi) Alteration Phases of UO2

Radiation-Induced Decomposition of U(vi) Alteration Phases of UO2 PDF Author: R. C. Ewing
Publisher:
ISBN:
Category :
Languages : en
Pages :

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U{sup 6+}-phases are common alteration products of spent nuclear fuel under oxidizing conditions, and they may potentially incorporate actinides, such as long-lived {sup 239}Pu and {sup 237}Np, delaying their transport to the biosphere. In order to evaluate the ballistic effects of {alpha}-decay events on the stability of the U{sup 6+}-phases, we report, for the first time, the results of ion beam irradiations (1.0 MeV Kr{sup 2+}) for six different structures of U{sup 6+}-phases: uranophane, kasolite, boltwoodite, saleeite, carnotite, and liebigite. The target uranyl-minerals were characterized by powder X-ray diffraction and identification confirmed by SAED (selected area electron diffraction) in TEM (transmission electron microscopy). The TEM observation revealed no initial contamination of uraninite in these U{sup 6+} phases. All of the samples were irradiated with in situ TEM observation using 1.0 MeV Kr{sup 2+} in the IVEM (intermediate-voltage electron microscope) at the IVEM-Tandem Facility of Argonne National Laboratory. The ion flux was 6.3 x 10{sup 11} ions/cm{sup 2}/sec. The specimen temperatures during irradiation were 298 and 673 K, respectively. The Kr{sup 2+}-irradiation decomposed the U{sup 6+}-phases to nanocrystals of UO{sub 2} at doses as low as 0.006 dpa. The cumulative doses for the pure U{sup 6+}-phases, e.g., uranophane, at 0.1 and 1 million years (m.y.) are calculated to be 0.009 and 0.09 dpa using SRIM2003. However, with the incorporation of 1 wt.% {sup 239}Pu, the calculated doses reach 0.27 and {approx}1.00 dpa in ten thousand and one hundred thousand years, respectively. Under oxidizing conditions, multiple cycles of radiation-induced decomposition to UO{sub 2} followed by alteration to U{sup 6+}-phases should be further investigated to determine the fate of trace elements that may have been incorporated in the U{sup 6+}-phases.

RADIATION-INDUCED DECOMPOSITION OF U(VI) ALTERATION PHASES OF UO2

RADIATION-INDUCED DECOMPOSITION OF U(VI) ALTERATION PHASES OF UO2 PDF Author:
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Languages : en
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Supramolecular Chemistry in the 3rd Millennium

Supramolecular Chemistry in the 3rd Millennium PDF Author: Catherine E. Housecroft
Publisher: MDPI
ISBN: 3036514635
Category : Science
Languages : en
Pages : 264

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Book Description
This Special Issue is one of the first for the new MDPI flagship journal Chemistry (ISSN 2624-8549) which has a broad remit for publishing original research in all areas of chemistry. The theme of this issue is Supramolecular Chemistry in the 3rd Millennium and I am sure that this topic will attract many exciting contributions. We chose this topic because it encompasses the unity of contemporary pluridisciplinary science, in which organic, inorganic, physical and theoretical chemists work together with molecular biologists and physicists to develop a systems-level understanding of molecular interactions. The description of supramolecular chemistry as 'chemistry beyond the molecule' (Jean-Marie Lehn, Nobel Lecture and Gautam R. Desiraju, Nature, 2001, 412, 397) addresses the wide variety of weak, non-covalent interactions that are the basis for the assembly of supramolecular architectures, molecular receptors and molecular recognition, programed molecular systems, dynamic combinatorial libraries, coordination networks and functional supramolecular materials. We welcome submissions from all disciplines involved in this exciting and evolving area of science.

Nuclear Power and the Environment

Nuclear Power and the Environment PDF Author: Royal Society of Chemistry (Great Britain)
Publisher: Royal Society of Chemistry
ISBN: 1849731942
Category : Business & Economics
Languages : en
Pages : 247

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Book Description
Reviews the political and social context for nuclear power generation, the nuclear fuel cycles and their implications for the environment.

Radioactive Waste Forms for the Future

Radioactive Waste Forms for the Future PDF Author: Werner Lutze
Publisher: North Holland
ISBN:
Category : Science
Languages : en
Pages : 802

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Book Description
This volume presents a compilation of important information on the full range of radioactive waste forms that have been developed, or at least suggested, for the incorporation of high-level nuclear waste. Many of the results were published in the ''gray literature'' of final reports of national laboratories or in various, generally less available, proceedings volumes. This is the first publication to draw information on nuclear waste forms for high-level wastes together into a single volume. Although borosilicate glass has become the standard waste form, additional research in this compound is still necessary. With improved technology (particularly processing technologies) and with a more detailed knowledge of repository conditions, glasses and second generation waste forms with improved performance properties can be developed. Sustained research programs on nuclear waste form development will yield results that can only add to public confidence and the final, safe disposal of nuclear waste. The aim of this volume is to provide a 'spring board' for these future research efforts. A detailed presentation is given on the properties and performance of non-crystalline waste forms (borosilicate glass, sintered glass, and lead-iron phosphate glass), and crystalline waste forms (Synroc, tailored ceramics, TiO 2 - ceramic matrix, glass-ceramics and FUETAP concrete). A chapter on Novel Waste Forms reviews a number of methods that warrant further development because of their potential superior performance and unique applications. The final chapter includes a tabulated comparison of important waste form properties and an extended discussion on the corrosion process and radiation damage effects for each waste form. Of particular interest is a performance assessment of nuclear waste borosilicate glass and the crystalline ceramic Synroc. This is the first detailed attempt to compare these two important waste forms on the basis of their materials properties. The discussion emphasizes the difficulties in making such a comparison and details the types of data that are required. Each chapter has been written by an expert and includes a current compilation of waste form properties with an extensive list of references. This volume will provide a stimulus for future research as well as useful reference material for scientists working in the field of nuclear waste disposal and materials science.

Bioinorganic Photochemistry

Bioinorganic Photochemistry PDF Author: Grazyna Stochel
Publisher: John Wiley & Sons
ISBN: 9781405193276
Category : Science
Languages : en
Pages : 398

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Book Description
Bioinorganic photochemistry is a rapidly evolving field integrating inorganic photochemistry with biological, medical and environmental sciences. The interactions of light with inorganic species in natural systems, and the applications in artificial systems of medical or environmental importance, form the basis of this challenging inter-disciplinary research area. Bioinorganic Photochemistry provides a comprehensive overview of the concepts and reactions fundamental to the field, illustrating important applications in biological, medical and environmental sciences. Topics covered include: Cosmic and environmental photochemistry Photochemistry of biologically relevant nanoassemblies Molecular aspects of photosynthesis Photoinduced electron transfer in biosystems Modern therapeutic strategies in photomedicine The book concludes with an outlook for the future of environmental protection, discussing emerging techniques in the field of pollution abatement, and the potential for bioinorganic photochemistry as a pathway to developing cheap, environmentally friendly sources of energy. Written as an authoritative guide for researchers involved in the development of bioinorganic photochemical processes, Bioinorganic Photochemistry is also accessible to scientists new to the field, and will be a key reference source for advanced courses in inorganic, and bioinorganic chemistry.

Structural Chemistry of Inorganic Actinide Compounds

Structural Chemistry of Inorganic Actinide Compounds PDF Author: Sergey Krivovichev
Publisher: Elsevier
ISBN: 0080467911
Category : Science
Languages : en
Pages : 505

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Book Description
Structural Chemistry of Inorganic Actinide Compounds is a collection of 13 reviews on structural and coordination chemistry of actinide compounds. Within the last decade, these compounds have attracted considerable attention because of their importance for radioactive waste management, catalysis, ion-exchange and absorption applications, etc. Synthetic and natural actinide compounds are also of great environmental concern as they form as a result of alteration of spent nuclear fuel and radioactive waste under Earth surface conditions, during burn-up of nuclear fuel in reactors, represent oxidation products of uranium miles and mine tailings, etc. The actinide compounds are also of considerable interest to material scientists due to the unique electronic properties of actinides that give rise to interesting physical properties controlled by the structural architecture of respective compounds. The book provides both general overview and review of recent developments in the field, including such emergent topics as nanomaterials and nanoparticles and their relevance to the transfer of actinides under environmental conditions.* Covers over 2,000 actinide compounds including materials, minerals and coordination polymers* Summarizes recent achievements in the field* Some chapters reveal (secret) advances made by the Soviet Union during the 'Cold war'

Biophysics

Biophysics PDF Author: William C. Parke
Publisher: Springer Nature
ISBN: 3030441466
Category : Science
Languages : en
Pages : 703

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Book Description
This comprehensive and extensively classroom-tested biophysics textbook is a complete introduction to the physical principles underlying biological processes and their applications to the life sciences and medicine. The foundations of natural processes are placed on a firm footing before showing how their consequences can be explored in a wide range of biosystems. The goal is to develop the readers’ intuition, understanding, and facility for creative analysis that are frequently required to grapple with problems involving complex living organisms. Topics cover all scales, encompassing the application of statics, fluid dynamics, acoustics, electromagnetism, light, radiation physics, thermodynamics, statistical physics, quantum biophysics, and theories of information, ordering, and evolutionary optimization to biological processes and bio-relevant technological implementations. Sound modeling principles are emphasized throughout, placing all the concepts within a rigorous framework. With numerous worked examples and exercises to test and enhance the reader’s understanding, this book can be used as a textbook for physics graduate students and as a supplementary text for a range of premedical, biomedical, and biophysics courses at the undergraduate and graduate levels. It will also be a useful reference for biologists, physicists, medical researchers, and medical device engineers who want to work from first principles.