Download or read book Effect of irradiation on the fracture toughness of hydrided zr 2 5 nb interim report on control tests on unirradiated material written by J. M. Smeltzer and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fracture toughness of hydrided zr 2 5nb pressure tube material irradiated in the NRU test reactor written by P. H. Davies and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was completed on hydrided specimens of zr-2.5 nb pressure tube material irradiated in the nru test reactor to fluences up to 5 x 10 sup(24) n.m. sup(-2). material with three different mixed hydride morphologies (m1, m2 and m3 with hydrogen concentrations in the range of 42 to 61 wt ppm, 62 to 75 wt ppm and 183 to 216 wt ppm, respectively, and hydride continuity coefficients (hccs) in the range 0.1 to 0.3) was supplied by ontario hydro technologies for irradiation. the morphologies consisted of mixed hydrides of different orientations (m1/m2) as well as predominantly circumferential hydrides (m3). the joint effect of irradiation and zirconium hydride significantly reduces the toughness of the material at all test temperatures up to the operating temperature range, 240 degrees c, and results in an increased incidence of discontinuous crack growth (crack jumping) and unstable fracture. after irradiation the transition temperature for upper shelf fracture behaviour is above 240 degrees c for all three hydride morphologies. the reduction in the maximum load toughness, k sub(ml), at 240 degrees c is about 30 mpa square root of m due to irradiation and up to a further 18 mpa square root of m (m2) and 22 mpa square root of m (m3) due to the zirconium hydride. fractographic evidence is presented which shows that the increased incidence of discontinuous crack growth and unstable fracture after irradiation is due not only to an increase in the number of hydride sites activated close to the radial-axial plane but also to changes in the ability of the remaining material to arrest the crack. in particular, material containing a high concentration of microsegregated species (zr-cl-c complex) promotes unstable fracture due to the reduced area and width of dimpled rupture zones (between fissures) available for crack arrest.

Download or read book Effect of Irradiation on the Fracture Properties of Zr 2 5Nb Pressure Tubes at the End of Design Life written by S. St Lawrence and published by . This book was released on 2005 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: To determine the fracture properties of Zr-2.5Nb pressure tubes irradiated until the end of design life, cantilever beam, curved compact toughness, and transverse tensile samples were prepared from a typical pressure tube and irradiated in the high flux reactor OSIRIS at CEA, Saclay, France. Experiments were conducted on two batches of samples mounted in two irradiation inserts. Each insert held sixteen samples of each type of specimen. The first insert was irradiated to a fluence corresponding to approximately half of the design life in a CANDU3 reactor. The experimental results were reported in [1]. Samples in the second insert were irradiated for 10.5 years in OSIRIS and received a maximum neutron fluence of 2.61 x 1026 n/m2 (E > 1 MeV), being equivalent to 2.98 x 1026 n/m2 (E > 1 MeV) in a CANDU reactor, i.e., corresponding to ~30 years operation in CANDU reactors at 80 % capacity factor. The present report describes the results of tensile, fracture toughness, and Delayed Hydride Cracking (DHC) tests and XRD microstructure analysis from the second batch of specimens. A continuous and gradual evolution in tensile, fracture, DHC properties, and dislocation densities is demonstrated without any evidence of a sudden change following the initial transitient at very low fluence. In the whole high fluence range, there is a very slow rate of increase in c-component dislocation density, strength, and DHC velocity and a slow reduction in elongation and Nb concentration in the ?-phase. The a-type dislocation density and fracture toughness remain approximately constant. The results from the second insert of specimens confirm that, following the initial transient at very low fluence, there is little further change in the fracture properties of Zr-2.5Nb pressure tube material. Therefore, material properties behave in a stable and predicable manner to the end of a 30 years design life for CANDU reactor pressure tubes.

Download or read book Effect of Long Term Irradiation on the Fracture Properties of Zr 2 5Nb Pressure Tubes written by S. Sagat and published by . This book was released on 2000 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results from fracture toughness and tensile and delayed hydride cracking (DHC) tests on Zr-2.5Nb pressure tubes removed from CANDU power reactors in the 1970s and 80s for surveillance showed considerable scatter. At that time, the cause of the scatter was unknown and prediction of fracture toughness to the end of the design life of a CANDU reactor using the surveillance data was difficult. To eliminate the heat-to-heat variability and to determine end-of-life mechanical properties, a program was undertaken to irradiate, in a high-flux reactor, fracture toughness, DHC, and transverse tensile specimens from a single "typical" pressure tube. Two inserts were placed in the OSIRIS reactor at CEA, Saclay, in 1988. Each insert held 16 of each type of specimen. The first insert, ERABLE 1, was designed so that half the specimens could be replaced at intervals and the properties could be measured as a function of fluence. All the specimens would be removed after a total fluence of 15 x 1025 n . m-2, E > 1 MeV. The second insert, ERABLE 2, was designed to run without interruption to a fluence of 30 x 1025 n . m-2, the fluence corresponding to 30 years' operation of a CANDU reactor at 90% capacity factor. The irradiation temperature was chosen to be 250°C, the inlet temperature of early CANDU reactors. The irradiation of ERABLE 1 has been completed and sets of specimens have been removed and tested with maximum fluences of approximately 0.7, 1.7, 2.8, 12, and 17 x 1025 n . m-2, E > 1 MeV. X-ray and TEM examinations have been performed on the material from fractured specimens to characterize the irradiation damage. Results showed that there is, initially, a large change in the mechanical properties before a fluence of 0.6 x 1025 n . m-2, E > 1 MeV (corresponding to an initial rapid increase in a-type dislocation density), followed by a gradual change. As expected, the fracture toughness decreased with fluence, whereas the yield strength, UTS, and DHC crack velocities all increased. Z-ray analysis showed that, although the a-type dislocation density remained constant after the initial increase, the number of c-component dislocations showed a steady increase, agreeing with the behavior seen in the mechanical specimens. Because the flux in OSIRIS is different from that in a CANDU reactor, specimens were also irradiated in NRU, a heavy water moderated test reactor with approximately the same flux as a CANDU reactor, to fluences of 0.3, 0.6, and 1.0 x 1025 n.m-2, E > 1 MeV for comparison. These initial results show that, once past the initial transient, one can have confidence that there will be little further degradation with fluence, with the results from the NRU specimens being similar to those from OSIRIS.

Download or read book Effect of Irradiation and Irridiation Temperature on the Fracture Toughness of Cold worked Zr 2 5 Wt Percent Nb written by Atomic Energy of Canada Limited and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components written by Manfred P. Puls and published by Springer Science & Business Media. This book was released on 2012-08-04 with total page 475 pages. Available in PDF, EPUB and Kindle. Book excerpt: By drawing together the current theoretical and experimental understanding of the phenomena of delayed hydride cracking (DHC) in zirconium alloys, The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Components: Delayed Hydride Cracking provides a detailed explanation focusing on the properties of hydrogen and hydrides in these alloys. Whilst the emphasis lies on zirconium alloys, the combination of both the empirical and mechanistic approaches creates a solid understanding that can also be applied to other hydride forming metals. This up-to-date reference focuses on documented research surrounding DHC, including current methodologies for design and assessment of the results of periodic in-service inspections of pressure tubes in nuclear reactors. Emphasis is placed on showing how our understanding of DHC is supported by progress in general understanding of such broad fields as the study of hysteresis associated with first order phase transformations, phase relationships in coherent crystalline metallic solids, the physics of point and line defects, diffusion of substitutional and interstitial atoms in crystalline solids, and continuum fracture and solid mechanics. Furthermore, an account of current methodologies is given illustrating how such understanding of hydrogen, hydrides and DHC in zirconium alloys underpins these methodologies for assessments of real life cases in the Canadian nuclear industry. The all-encompassing approach makes The Effect of Hydrogen and Hydrides on the Integrity of Zirconium Alloy Component: Delayed Hydride Cracking an ideal reference source for students, researchers and industry professionals alike.

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1973 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Zirconium in the Nuclear Industry written by Gerry D. Moan and published by ASTM International. This book was released on 2002 with total page 891 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation The 41 papers of this proceedings volume were first presented at the 13th symposium on Zirconium in the Nuclear Industry held in Annecy, France in June of 2001. Many of the papers are devoted to material related issues, corrosion and hydriding behavior, in-reactor studies, and the behavior and properties of Zr alloys used in storing spent fuel. Some papers report on studies of second phase particles, irradiation creep and growth, and material performance during loss of coolant and reactivity initiated accidents. Annotation copyrighted by Book News, Inc., Portland, OR.

Download or read book Correlation Between Irradiated and Unirradiated Fracture Toughness of Zr 2 5Nb Pressure Tubes written by CK. Chow and published by . This book was released on 1994 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three coordinated research programs were undertaken on the fracture toughness of Zr-2.5Nb pressure tubes to determine relationships between irradiated and unirradiated values, the effect of long-term irradiation, and the causes of the variation in toughness. The present paper describes results from these programs and their implications.

Download or read book Size geometry and material effects in fracture toughness testing of irradiated zr 2 5nb pressure tube material written by P. H. Davies and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Correlation between irradiated and unirradiated fracture toughness of zr 2 5nb pressure tubes written by P. H. Davies and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fast temperature ramp tests on zircaloy-4 fuel sheathing were conducted at heating rates of 300 degrees c - 500 degrees c/s on uniaxially and biaxially stressed specimens in argon atmosphere. the specimens were heated to an isothermal temperature either in the alpha phase region t less than or equal to 800 degrees c or in the beta phase region 1000 degrees c less than or equal to t less than or equal to 1200 degrees c and held at temperature for 300s. for the biaxially stressed specimens, pressures ranged from 0.08 mpa to 1.58 mpa while the uniaxial stress range was 1.6 mpa to 18 mpa. up to 1100 degrees c, the strains obtained were within the expected 2 percent - 5 percent range. but above 1100 degrees c, the final strains were about 1.4 - 8 times the expected value. no significant difference in final strain values were observed between specimens ramped at approximately 300 degrees c/s and 500 degrees c/s. the creep rates obtained after 300s were in good agreement with the creep rate predictions for slower ramped (100 degrees c/s) specimens.

Download or read book The effect of irradiation and irradiation temperature on the fracture toughness of cold worked zr 2 5 wt percent nb written by L. A. Simpson and published by . This book was released on 1984 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Hydride Morphology on Zr 2 5Nb Fracture Toughness written by AC. Wallace and published by . This book was released on 1989 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of hydride morphology on the axial fracture toughness of cold-worked Zr-2.5Nb pressure tube material have been determined between room temperature and 240°C. Tests were performed on small compact tension specimens machined from samples of material prepared with different morphologies and hydrogen concentrations. The morphologies were characterized by a parameter referrred to as the hydride continuity coefficient (HCC), which provides a measure of the extent to which hydrides are oriented in the axial-radial plane of the pressure tube. Hydrides in this orientation are known to be detrimental to the fracture properties of the tube. Fracture toughness was characterized by a J-R curve technique, from which it is possible to estimate the maximum stable size of a through-wall axial crack for typical reactor operating conditions. Material with HCC values greater than 0.5 exhibited low toughness from room temperature to 240°C, at which temperature there was an abrupt transition to an upper shelf toughness value. As HCC decreases, the transition to upper shelf toughness occurs more gradually and is complete at a lower temperature.

Download or read book Effect of Irradiation and Irradiation Temperature on the Fracture Toughness of Cold Worked Zr 2 5 Wt Nb written by Atomic Energy of Canada Limited and published by . This book was released on 1983 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Summary of fracture toughness properties of zr2 5nb pre irradiated rolled joint materials written by D. D. Himbeault and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Use of Subsized Specimens for Evaluating the Fracture Toughness of Irradiated Materials written by FH. Huang and published by . This book was released on 1986 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of specimen size, temperature, and irradiation on fracture toughness were studied in unirradiated compact tension specimens of Alloy A286 and HT-9 and irradiated specimens of 20% cold-worked Type 316 stainless steel. Techniques for specimen preparation and test procedures were developed using unirradiated specimens of A286 with the specimen size identical to that of irradiated specimens of 20% cold-worked Type 316 stainless steel. Fracture toughness tests on these precracked specimens were conducted at various temperatures, and test results were analyzed using the multiple specimen R-curve method. Owing to irradiation hardening and post-irradiation toughness degradation, sufficient constraint existed in thin irradiated specimens to permit the application of the J-integral approach. Analysis showed the absence of a significant size effect among the specimens tested and that the size requirements for an ASTM valid JIc test were satisfied, indicating that small specimens may be used for post-irradiation fracture toughness testing. The results are discussed in terms of size criteria for valid JIc determination and conditions for J-controlled crack growth.

Download or read book Correlation between irradiated and unirradiated fracture toughness of zr 2 5nb pressure tube material written by P. H. Davies and published by . This book was released on 1993 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: