Experimental and Modeling Approach of Irradiation Defects Recovery in Zirconium Alloys

Experimental and Modeling Approach of Irradiation Defects Recovery in Zirconium Alloys PDF Author: Joël Ribis
Publisher:
ISBN:
Category : Annealing
Languages : en
Pages : 22

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Book Description
During neutron irradiation, both interstitial and vacancy loops are formed in high concentration in zirconium alloys. Due to this high density of loops, the material is considerably hardened, but the recovery of the radiation damage during a heat treatment leads to a progressive softening of the irradiated material. The recovery of the radiation induced hardening has been investigated using microhardness tests. Transmission electron microscopy (TEM) observations performed on irradiated foils have also shown that the loop density falls while the loop size increases during the thermal annealing. Furthermore, the TEM analysis has revealed that only vacancy loops are present in the material after long term annealing, the interstitial loops having entirely disappeared. A numerical cluster dynamic modeling has also been used in order to reproduce the material recovery for various annealing conditions. The microstructural evolution during mechanical testing with various loading conditions has also been studied. It has been shown that during a creep test with low applied stress (130 MPa) and high temperature (450°C), the microstructure evolution can essentially be explained by the thermal recovery of the loops leading to glide of dislocations as found for an non-irradiated material. At intermediate temperature (400°C), it is shown that for low stress level (130 MPa) the microstructure evolution can also be explained by the thermal recovery of loops, whereas for higher stress (250 MPa), sweeping of loops by gliding dislocations can also occur. In addition, for an applied stress of 130 MPa and a temperature of 400°C, dislocation density is higher in the irradiated material than in the non-irradiated material deformed in the same conditions. It is also shown that secondary slip systems are more activated in the irradiated material than in the non-irradiated material. From this detailed analysis, the mechanical behavior during creep is interpreted in terms of microscopic deformation mechanisms.

Experimental and Modeling Approach of Irradiation Defects Recovery in Zirconium Alloys

Experimental and Modeling Approach of Irradiation Defects Recovery in Zirconium Alloys PDF Author: Joël Ribis
Publisher:
ISBN:
Category : Annealing
Languages : en
Pages : 22

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Book Description
During neutron irradiation, both interstitial and vacancy loops are formed in high concentration in zirconium alloys. Due to this high density of loops, the material is considerably hardened, but the recovery of the radiation damage during a heat treatment leads to a progressive softening of the irradiated material. The recovery of the radiation induced hardening has been investigated using microhardness tests. Transmission electron microscopy (TEM) observations performed on irradiated foils have also shown that the loop density falls while the loop size increases during the thermal annealing. Furthermore, the TEM analysis has revealed that only vacancy loops are present in the material after long term annealing, the interstitial loops having entirely disappeared. A numerical cluster dynamic modeling has also been used in order to reproduce the material recovery for various annealing conditions. The microstructural evolution during mechanical testing with various loading conditions has also been studied. It has been shown that during a creep test with low applied stress (130 MPa) and high temperature (450°C), the microstructure evolution can essentially be explained by the thermal recovery of the loops leading to glide of dislocations as found for an non-irradiated material. At intermediate temperature (400°C), it is shown that for low stress level (130 MPa) the microstructure evolution can also be explained by the thermal recovery of loops, whereas for higher stress (250 MPa), sweeping of loops by gliding dislocations can also occur. In addition, for an applied stress of 130 MPa and a temperature of 400°C, dislocation density is higher in the irradiated material than in the non-irradiated material deformed in the same conditions. It is also shown that secondary slip systems are more activated in the irradiated material than in the non-irradiated material. From this detailed analysis, the mechanical behavior during creep is interpreted in terms of microscopic deformation mechanisms.

Materials Ageing and Degradation in Light Water Reactors

Materials Ageing and Degradation in Light Water Reactors PDF Author: K L Murty
Publisher: Elsevier
ISBN: 0857097458
Category : Technology & Engineering
Languages : en
Pages : 441

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Book Description
Light water reactors (LWRs) are the predominant class of nuclear power reactors in operation today; however, ageing and degradation can influence both their performance and lifetime. Knowledge of these factors is therefore critical to safe, continuous operation. Materials ageing and degradation in light water reactors provides a comprehensive guide to prevalent deterioration mechanisms, and the approaches used to handle their effects.Part one introduces fundamental ageing issues and degradation mechanisms. Beginning with an overview of ageing and degradation issues in LWRs, the book goes on to discuss corrosion in pressurized water reactors and creep deformation of materials in LWRs. Part two then considers materials’ ageing and degradation in specific LWR components. Applications of zirconium alloys in LWRs are discussed, along with the ageing of electric cables. Materials management strategies for LWRs are then the focus of part three. Materials management strategies for pressurized water reactors and VVER reactors are considered before the book concludes with a discussion of materials-related problems faced by LWR operators and corresponding research needs.With its distinguished editor and international team of expert contributors, Materials ageing and degradation in light water reactors is an authoritative review for anyone requiring an understanding of the performance and durability of this type of nuclear power plant, including plant operators and managers, nuclear metallurgists, governmental and regulatory safety bodies, and researchers, scientists and academics working in this area. Introduces the fundamental ageing issues and degradation mechanisms associated with this class of nuclear power reactors Considers materials ageing and degradation in specific light water reactor components, including properties, performance and inspection Chapters also focus on material management strategies

Irradiation Damage Recovery in Some Zirconium Alloys

Irradiation Damage Recovery in Some Zirconium Alloys PDF Author: GJC Carpenter
Publisher:
ISBN:
Category : Electron microscopy
Languages : en
Pages : 16

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Book Description
The recovery of irradiation damage in a number of zirconium alloys has been studied by means of hardness measurements. The experiments were designed to examine the effect of different solutes (copper, aluminum, titanium, niobium, molybdenum) and metallurgical condition on the stability of irradiation-induced defect clusters.

Comprehensive Nuclear Materials

Comprehensive Nuclear Materials PDF Author:
Publisher: Elsevier
ISBN: 0081028660
Category : Science
Languages : en
Pages : 4871

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Book Description
Materials in a nuclear environment are exposed to extreme conditions of radiation, temperature and/or corrosion, and in many cases the combination of these makes the material behavior very different from conventional materials. This is evident for the four major technological challenges the nuclear technology domain is facing currently: (i) long-term operation of existing Generation II nuclear power plants, (ii) the design of the next generation reactors (Generation IV), (iii) the construction of the ITER fusion reactor in Cadarache (France), (iv) and the intermediate and final disposal of nuclear waste. In order to address these challenges, engineers and designers need to know the properties of a wide variety of materials under these conditions and to understand the underlying processes affecting changes in their behavior, in order to assess their performance and to determine the limits of operation. Comprehensive Nuclear Materials, Second Edition, Seven Volume Set provides broad ranging, validated summaries of all the major topics in the field of nuclear material research for fission as well as fusion reactor systems. Attention is given to the fundamental scientific aspects of nuclear materials: fuel and structural materials for fission reactors, waste materials, and materials for fusion reactors. The articles are written at a level that allows undergraduate students to understand the material, while providing active researchers with a ready reference resource of information. Most of the chapters from the first Edition have been revised and updated and a significant number of new topics are covered in completely new material. During the ten years between the two editions, the challenge for applications of nuclear materials has been significantly impacted by world events, public awareness, and technological innovation. Materials play a key role as enablers of new technologies, and we trust that this new edition of Comprehensive Nuclear Materials has captured the key recent developments. Critically reviews the major classes and functions of materials, supporting the selection, assessment, validation and engineering of materials in extreme nuclear environments Comprehensive resource for up-to-date and authoritative information which is not always available elsewhere, even in journals Provides an in-depth treatment of materials modeling and simulation, with a specific focus on nuclear issues Serves as an excellent entry point for students and researchers new to the field

Diffusion and Defect Studies in Zirconium and some of its Alloys

Diffusion and Defect Studies in Zirconium and some of its Alloys PDF Author: R.P. Agarwala
Publisher: Trans Tech Publications Ltd
ISBN: 303570628X
Category : Technology & Engineering
Languages : en
Pages : 90

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Book Description
This book is divided into two parts: the first part describes diffusion processes, and the second part describes radiation damage to - and cold-working of - zirconium and some of its important alloys.

Quantifying Irradiation Defects in Zirconium Alloys

Quantifying Irradiation Defects in Zirconium Alloys PDF Author: Levente Balogh
Publisher:
ISBN:
Category : Irradiation
Languages : en
Pages : 34

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Book Description
Irradiation-induced dislocations significantly affect the mechanical properties of zirconium alloys, altering slip and influencing creep and growth. Thus, the quantitative characterization of irradiation defects as a function of fluence, cold work, and/or thermal treatments is important for models that attempt to predict their impact on properties. Whole-pattern diffraction line-profile analysis (DLPA) is a well-established modern tool for microstructure characterization based on first-principle physical models for dislocation density measurements in plastically deformed materials. However, applying these DLPA methods directly to irradiated materials yields higher than expected dislocation density values compared with historical transmission electron microscopy (TEM) measurements and past line-broadening analysis studies calibrated to TEM observations. In an effort to understand these differences, a new microstructural model was developed for DLPA to specifically address dislocation structures consisting of elliptical a- and c-component loops. To compare the refined DLPA method with TEM measurements, high-resolution neutron diffraction patterns on nonirradiated and irradiated Zr-2.5Nb samples were collected with the Neutron Powder Diffractometer instrument at the Los Alamos Neutron Science Center and were evaluated. High-resolution TEM measurements were performed at the Reactor Materials Testing Laboratory, Queen's University, for comparison with the DLPA results. The capabilities and inherent uncertainties of both the refined DLPA and TEM methods are compared and discussed in detail. We show that the differences between the density values provided by DLPA and TEM are inherent to the methods and can be reconciled with the interpretation of the data.

Nuclear Science Abstracts

Nuclear Science Abstracts PDF Author:
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 1216

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Book Description


Understanding of Corrosion Mechanisms of Zirconium Alloys After Irradiation

Understanding of Corrosion Mechanisms of Zirconium Alloys After Irradiation PDF Author: Marc Tupin
Publisher:
ISBN:
Category : Corrosion
Languages : en
Pages : 41

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Book Description
The irradiation damage in the fuel cladding material is mainly caused by the neutron flux resulting from the fission reactions occurring in the fuel. From an experimental point of view, the neutrons have the disadvantage to activate materials by neutron capture rendering them difficult to handle. To avoid these constraints inherent in the handling of radioactive material, the radiation effects on the corrosion resistance of zirconium alloys can be studied by irradiating the materials with ions. A new experimental approach using ion irradiation was performed in the Microscopy and Irradiation Damage Studies Laboratory of the CEA in Saclay, with the aim to study more specifically the influence of the irradiation damages in the oxide on the corrosion rate of the zirconium alloys. This study was, moreover, focused on a particular distribution of defects in the oxide layer, basically, localised close to the metal/oxide interface. From the results of the irradiation of the metal/oxide interface, it was clearly shown that, whatever the incident ion, the irradiation of the internal interface results in a significant increase of the oxygen diffusion flux ratios between the most irradiated Zircaloy-4 and the unirradiated one, whereas that of the oxide formed on M5TM induces a big decrease of the oxygen diffusion flux in the film. These effects are less marked with helium ions compared to protons (M5TM is a trademark of AREVA NP registered in the United States and in other countries). Finally, the oxide irradiation impact on the oxygen diffusion through the layer could explain the corrosion acceleration factor observed on Zy4 during the first cycles of irradiation, but cannot alone explain observed corrosion accelerations under high burn-up conditions. The discussion on the oxide irradiation effects puts forward the probable role of the residual charge left by ion implantation.

Damage production and recovery in zirconium alloys irradiated with fusion neutrons

Damage production and recovery in zirconium alloys irradiated with fusion neutrons PDF Author: R. H. Zee
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
This report presents the experimental procedures, test data and general observations taken in a program to examine the effects on heater temperatures, when cold water is injected into a horizontal, heated test section. the experiments were conducted with a 19-rod, five metre long electrically heated array at various powers, preheat temperatures and injection water temperatures, and with various outlet feeder restrictions.

Fundamentals of Radiation Materials Science

Fundamentals of Radiation Materials Science PDF Author: GARY S. WAS
Publisher: Springer
ISBN: 1493934384
Category : Technology & Engineering
Languages : en
Pages : 1014

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Book Description
The revised second edition of this established text offers readers a significantly expanded introduction to the effects of radiation on metals and alloys. It describes the various processes that occur when energetic particles strike a solid, inducing changes to the physical and mechanical properties of the material. Specifically it covers particle interaction with the metals and alloys used in nuclear reactor cores and hence subject to intense radiation fields. It describes the basics of particle-atom interaction for a range of particle types, the amount and spatial extent of the resulting radiation damage, the physical effects of irradiation and the changes in mechanical behavior of irradiated metals and alloys. Updated throughout, some major enhancements for the new edition include improved treatment of low- and intermediate-energy elastic collisions and stopping power, expanded sections on molecular dynamics and kinetic Monte Carlo methodologies describing collision cascade evolution, new treatment of the multi-frequency model of diffusion, numerous examples of RIS in austenitic and ferritic-martensitic alloys, expanded treatment of in-cascade defect clustering, cluster evolution, and cluster mobility, new discussion of void behavior near grain boundaries, a new section on ion beam assisted deposition, and reorganization of hardening, creep and fracture of irradiated materials (Chaps 12-14) to provide a smoother and more integrated transition between the topics. The book also contains two new chapters. Chapter 15 focuses on the fundamentals of corrosion and stress corrosion cracking, covering forms of corrosion, corrosion thermodynamics, corrosion kinetics, polarization theory, passivity, crevice corrosion, and stress corrosion cracking. Chapter 16 extends this treatment and considers the effects of irradiation on corrosion and environmentally assisted corrosion, including the effects of irradiation on water chemistry and the mechanisms of irradiation-induced stress corrosion cracking. The book maintains the previous style, concepts are developed systematically and quantitatively, supported by worked examples, references for further reading and end-of-chapter problem sets. Aimed primarily at students of materials sciences and nuclear engineering, the book will also provide a valuable resource for academic and industrial research professionals. Reviews of the first edition: "...nomenclature, problems and separate bibliography at the end of each chapter allow to the reader to reach a straightforward understanding of the subject, part by part. ... this book is very pleasant to read, well documented and can be seen as a very good introduction to the effects of irradiation on matter, or as a good references compilation for experimented readers." - Pauly Nicolas, Physicalia Magazine, Vol. 30 (1), 2008 “The text provides enough fundamental material to explain the science and theory behind radiation effects in solids, but is also written at a high enough level to be useful for professional scientists. Its organization suits a graduate level materials or nuclear science course... the text was written by a noted expert and active researcher in the field of radiation effects in metals, the selection and organization of the material is excellent... may well become a necessary reference for graduate students and researchers in radiation materials science.” - L.M. Dougherty, 07/11/2008, JOM, the Member Journal of The Minerals, Metals and Materials Society.