High-Fluence Irradiation Growth of Cold-Worked Zr-2.5Nb


Book Description

Irradiation growth specimens manufactured from cold-worked Zr-2.5Nb pressure tube material have been irradiated in Osiris at a fast flux of ~1.8 x 1018 n . m-2 . s-1E > 1 MeV, at nominal temperatures of 553 and 583 K, to growth strains of 1%. The pressure tubes have a pronounced crystallographic texture, with ~95% of the basal plane normals in the radial/transverse plane, predominantly in the transverse direction. Both longitudinal specimens, which generally exhibit positive growth strains, and transverse specimens, which generally exhibit negative strains with approximately 50% of the magnitude of the axial strains, show nonlinear growth, the rate increasing gradually with fluence up to 1.3 x 1026 n . m-2, E > 1 MeV (580 K) and 1.7 x 1026 n . m-2, E > 1 MeV (550 K).




The Effect of Temperature on the Irradiation Growth of Cold-Worked Zr-2.5 Nb


Book Description

Specimens of cold-worked Zr-2.5% Nb pressure tube material fabricated by several different routes have been irradiated unstressed in the Dido reactor at Atomic Energy Research Establishment (AERE) Harwell to fluences up to 7.5 x 1025 n/m2, E & 1 MeV (about 18 dpa). Their irradiation growth behavior has been investigated as a function of temperature in the range 553 to 623 K.







High-Fluence Irradiation Growth of Zirconium Alloys at 644 to 725 K


Book Description

Irradiation growth behavior of zirconium, Zircaloy-2 and Zircaloy-4,Zr-2.5Nb, and Zr-3.5Sn-0.8Mo-0.8Nb (EXCEL) was studied on specimens irradiated in the Experimental Breeder Reactor II (EBR-II) to fluences of 1.2 to 16.9 x 1025 neutrons (n).m-2 (E > 1 MeV) in the temperature range 644 to 725 K. In Zircaloy, growth and growth rate were observed to increase continuously with fluence up to 16.9 x 1025 n.m-2 with no indication of saturation in either recrystallized or cold-worked materials. Positive growth strains of 1.5% and negative strains of approximately 2% to 2.5% were observed in both recrystallized and cold-worked Zircaloy. The formation of both a-type loops and c component dislocations is recrystallized Zircaloy under irradiation appears to be the basis in this material for growth strains similar in magnitude to those in cold-worked Zircaloy. Alloy additions to zirconium can increase growth by as much as an order of magnitude for a given texture at the higher irradiation temperatures and fluences. A sharp change to increasing growth rate with temperature occurs in Zircaloy at ~670 K, with a similar trend indicated for the other alloys. Although growth in all these alloys is a strong function of crystallographic texture, an exact (1-3f) type of dependence is not always apparent. In Zr-2.5Nb the dependence of growth on texture appears to be masked by the precipitation of betaniobium, with a transition to a well-defined texture dependence being a function of fluence and temperature. Significant differences in growth behavior were observed in nominally similar Zircaloys, apparently due to minor microstructural or chemical differences.




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




Pressurized Heavy Water Reactors


Book Description

Pressurized Heavy Water Reactors: CANDU, the seventh volume in the JSME Series on Thermal and Nuclear Power Generation series, provides a comprehensive and complete review of a single type of reactor in a very accessible and practical way. The book presents the full lifecycle, from design and manufacturing to operation and maintenance, also covering fitness-for-service and long-term operation. It does not relate to any specific vendor-based technology, but rather provides a broad overview of the latest technologies from a variety of active locations which will be of great value to countries invested in developing their own nuclear programs. Including contemporary capabilities and challenges of nuclear technology, the book offers practical solutions to common problems faced, along with the safe and approved processes to reach suitable solutions. Professionals involved in nuclear power plant lifecycle assessment and researchers interested in the development and improvement of nuclear energy technologies will gain a deep understanding of PHWR nuclear reactor physics, chemistry and thermal-hydraulic properties. Provides a complete reference dedicated to the latest research on Pressurized Heavy Water Reactors and their economic and environmental benefits Goes beyond CANDU reactors to analyze the popular German and Indian designs, as well as plant design in Korea, Romania, China and Argentina Spans all phases of the nuclear power plant lifecycle, from design, manufacturing, operation, maintenance and long-term operation




High-Temperature Irradiation Growth in Zircaloy


Book Description

Irradiation growth behavior of Zircaloy-2 and -4 was studied on specimens irradiated in the Experimental Breeder Reactor II to fluences of 1.4 to 6.3 x 1025 neutrons (n).m-2 (E > 1 MeV) in the temperature range 644 to 723 K. Measurements in the three principal directions on annealed and cold-worked/stress-relieved Zircaloy-2 slab materials provided evidence that growth is a constant-volume process up to about 680 K. The growth strains were shown to be determined by the crystallographic texture, that is, proportional to (1-3(1-3fdc)), where), where fdc is the fraction of basal poles, is the fraction of basal poles, fc, in the direction d. The growth strains for annealed and cold-worked Zircaloy were large relative to previously reported data, were similar in magnitude, were strongly dependent on irradiation temperature, and varied linearly with fluence over the range investigated. Transmission electron microscopy on annealed Zircaloy-4 specimens revealed a few small voids and larger cavities, a grain boundary second phase, and dislocation loops, tangles, and arrays. The high growth strains in annealed Zircaloy appear to be governed by dislocation arrays formed during irradiation. This implies a change in growth mechanism from that pertaining at lower temperatures in annealed material. The data suggest a transition from saturating steady-state growth at lower temperatures to increasing and eventually high steady-state rates under the conditions of these tests.







Irradiation Growth of Zirconium Alloys


Book Description

Experimental investigation of irradiation growth on annealed Zircaloy-4 and 20% to 50% cold-worked Zr-2.5wt%Nb specimens with stress relief has been carried out. The specimens are irradiated in a heavy water reactor at 610 K to 4.2 x 1024 n/m2 (E > 1.0 MeV). The growth strains increase linearly with fluence. The saturation of growth is not observed for all specimens. The difference of growth behavior between two kinds of Zircaloy-4 tube may be associated with the content of minor alloying elements and impurities that influence the microstructure evolution under irradiation.