Irradiation Creep and Growth in Zirconium During Proton Bombardment


Book Description

The irradiation creep and growth behavior of zirconium alloys has been studied during irradiation with 3.5-MeV protons. Irradiations were carried out at temperatures in the range 423 to 623 K and strain measurements were recorded up to displacement levels of 0.03 displacements per atom (dpa). In annealed materials, a significant portion of the measured strain could be attributed to the presence of dislocation loops. The measured growth strain was found to be dependent on texture, grain dimensions, network dislocation structure (cold work), and temperature. Experiments to separate the irradiation creep and growth components of the total strain revealed that irradiation growth was by far the most significant component in cold-worked zirconium-niobium alloys but that the two components were approximately equal in annealed crystal bar zirconium specimens. An investigation of transient effects revealed that no strain transient was observed when the irradiation flux was removed. The strain rate was found to be proportional to the applied stress (at low stresses) and to the damage rate.










Irradiation Creep and Growth During Proton and Neutron Bombardment of Zircaloy-2 Plate


Book Description

Proton irradiation creep and in-pile creep and growth tests have been conducted on specimens cut from the same rolled and annealed Zircaloy-2 plate. The proton irradiation creep tests were carried out over the following ranges: stress, 0 to 267 MPa; damage rate, 0.15 to 7.0 x 10-7 dpa/s; temperature, 513 to 613 K; and dose, up to 1.44 dpa.




Effect of Stress on Radiation Damage in Neutron Irradiated Zirconium Alloys


Book Description

Structures developed in zirconium alloys during irradiation creep have been characterized by transmission electron microscopy (TEM). Alloys investigated were annealed Zircaloy-2, cold-worked Zircaloy-2 and cold-worked Zr-2.5Nb pressure tube material. Thin films were taken from material deformed in the NRU, NRX and Pickering-3 reactors at temperatures of 530 to 600 K under stresses of 117 to 552 MPa giving strains in the range 0.14 to 8.8 percent. Stress-induced orientation of dislocation loops makes a negligible contribution to irradiation creep at all stresses. At the lower stresses (and hence strains), the size and distribution of the damage is unaffected by stress, being the same in the head and gage sections of creep specimens. At higher stresses (strains), there is much clearing of the damage by plastic deformation. The deformation however is very uneven, producing structures in different grains of the same specimen that can show no deformation, swaths cleared of irradiation damage, or dislocation tangles or cell formation. The relevance of these TEM observations to irradiation creep mechanisms is discussed.










Zirconium in the Nuclear Industry


Book Description




Comprehensive Nuclear Materials


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