Download or read book Microstructural Evolution in Fast neutron irradiated Austenitic Stainless Steels written by Roger E. Stoller and published by . This book was released on 1987 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Composite Model of Microstructural Evolution in Austenitic Stainless Steel Under Fast Neutron Irradiation written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A rate-theory-based model has been developed which includes the simultaneous evolution of the dislocation and cavity components of the microstructure of irradiated austenitic stainless steels. Previous work has generally focused on developing models for void swelling while neglecting the time dependence of the dislocation structure. These models have broadened our understanding of the physical processes that give rise to swelling, e.g., the role of helium and void formation from critically-sized bubbles. That work has also demonstrated some predictive capability by successful calibration to fit the results of fast reactor swelling data. However, considerable uncertainty about the values of key parameters in these models limits their usefulness as predictive tools. Hence the use of such models to extrapolate fission reactor swelling data to fusion reactor conditions is compromised.
Download or read book A Composite Model of Microstructural Evolution in Austenitic Stainless Steel Under Fast Neutron Irradiation written by GR. Odette and published by . This book was released on 1987 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: A rate-theory-based model has been developed which includes the simultaneous evolution of the dislocation and cavity components of the microstructure of irradiated austenitic stainless steels. Previous work has generally focused on developing models for void swelling while neglecting the time dependence of the dislocation structure. These models have broadened our understanding of the physical processes that give rise to swelling, for example, the role of helium and void formation from critically-sized bubbles. That work has also demonstrated some predictive capability by successful calibration to fit the results of fast reactor swelling data. However, considerable uncertainty about the values of key parameters in these models limits their usefulness as predictive tools. Hence, the use of such models to extrapolate fission reactor swelling data to fusion reactor conditions is compromised.
Download or read book Microstructural Evolution in Fast neutron irradiated Austenitic Stainless Steels written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The present work has focused on the specific problem of fast-neutron-induced radiation damage to austenitic stainless steels. These steels are used as structural materials in current fast fission reactors and are proposed for use in future fusion reactors. Two primary components of the radiation damage are atomic displacements (in units of displacements per atom, or dpa) and the generation of helium by nuclear transmutation reactions. The radiation environment can be characterized by the ratio of helium to displacement production, the so-called He/dpa ratio. Radiation damage is evidenced microscopically by a complex microstructural evolution and macroscopically by density changes and altered mechanical properties. The purpose of this work was to provide additional understanding about mechanisms that determine microstructural evolution in current fast reactor environments and to identify the sensitivity of this evolution to changes in the He/dpa ratio. This latter sensitivity is of interest because the He/dpa ratio in a fusion reactor first wall will be about 30 times that in fast reactor fuel cladding. The approach followed in the present work was to use a combination of theoretical and experimental analysis. The experimental component of the work primarily involved the examination by transmission electron microscopy of specimens of a model austenitic alloy that had been irradiated in the Oak Ridge Research Reactor. A major aspect of the theoretical work was the development of a comprehensive model of microstructural evolution. This included explicit models for the evolution of the major extended defects observed in neutron irradiated steels: cavities, Frank faulted loops and the dislocation network. 340 refs., 95 figs., 18 tabs.
Download or read book Microstructural Evolution of Austenitic Stainless Steels Irradiated in a Fast Reactor written by OV. Borodin and published by . This book was released on 1996 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analysis of the microstructure of the stainless steels 16Cr15Ni3MoNb and 18Cr10NiTi, irradiated at temperatures where changes in phase stability occur due to radiation-induced segregation, shows that the stability of second-phase particles depends on the structure of particle-matrix interface.
Download or read book Microstructure Evolution in Proton irradiated Austenitic Fe Cr Ni Alloys Under LWR Core Conditions written by Jian Gan and published by . This book was released on 1999 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microstructural Evolution of Martensitic Steels During Fast Neutron Iradiation written by and published by . This book was released on 1989 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Irradiation of martensitic/ferritic steels with fast neutrons (E> 0.1 MeV) to displacement damage levels of 30--50 dpa at temperatures of 300--500°C produces significant changes in the as-tempered microstructure. Dislocation loops and networks can be produced, irradiation-induced precipitates can form, the lath/subgrain boundary structure and the thermal precipitates produced during tempering can become unstable, and if helium is present, bubbles and voids can form. These microstructural changes caused by irradiation can have important effects on the properties of this class of steels for both fast breeder reactor (FBR) and magnetic fusion reactor (MFR) applications. The purpose of this paper is to compare reactor-irradiated and long-term thermally aged 9Cr--1MoVNb specimens, in order to distinguish effects due to displacement damage from those caused by elevated-temperature exposure alone. 7 refs., 1 fig.
Download or read book Microstructural Development of Titanium Modified Austenitic Stainless Steel Under Neutron Irradiation in HFIR Up to 57 Dpa written by S. Hamada and published by . This book was released on 1990 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Japanese prime candidate alloy (JPCA). a titanium-modified austenitic stainless steel, has shown good performance after irradiation in the high flux isotope reactor (HFIR) up to 34 dpa at 300 to 600°C, but considerable void swelling develops in solution annealed (SA) JPCA after irradiation to 57 dpa at 500°C. However, cold worked (CW) or cold worked and aged (CW + A) JPCA still demonstrates good performance after similar irradiation. Swelling resistance appears to depend strongly on the behavior of fine titanium-rich MC precipitates. This paper describes the microstructural evolution process observed in the JPCA steel during HFIR irradiation. The onset of rapid void swelling was related to MC precipitate dissolution, and the instability of the MC was interpreted in terms of a model involving the build and subsequent effects of a solute segregation zone in the matrix surrounding the precipitate particle.
Download or read book Official Communiqu of the 4821st closed Meeting of the Security Council Held in Private at Headquarters New York on Tuesday 9 September 2003 written by and published by . This book was released on 2003 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Observation and Interpretation of Microstructural Evolution and Swelling in Austenitic Steels Under Irradiation written by N. Sekimura and published by . This book was released on 1994 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Irradiation behavior of model austenitic steels is investigated to establish mechanistic modeling of swelling and other property changes under irradiation. Neutron irradiation experiments were performed using Material Open Test Assembly (MOTA) at 693, 793 and 873 K to 35 to 40 dpa in the Fast Flux Test Facility (FFTF) cycles 10 and 11. Cavity formation and dislocation development were quantitatively estimated to evaluate the effect of temperature history on the microstructural evolution under irradiation in fission reactors. Fine dislocation loops observed in the matrix of the alloys irradiated in cycle 10 were considered to come from the low-temperature irradiation during the reactor shut-down at the end of the cycle. Very few small loops were detected in identical specimens irradiated in FFTF cycle 11 where the reactor power and temperature were simultaneously decreased a short time during the shut-down.
Download or read book Radiation induced Changes in Microstructure written by F. A. Garner and published by ASTM International. This book was released on 1987 with total page 919 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microstructural Evolution of NF709 20Cr 25Ni 1 5MoNbTiN Under Neutron Irradiation written by and published by . This book was released on 2015 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, because of its superior creep and corrosion resistance as compared with general austenitic stainless steels, NF709 has emerged as a candidate structural material for advanced nuclear reactors. To obtain fundamental information about the radiation resistance of this material, this study examined the microstructural evolution of NF709 subjected to neutron irradiation to 3 displacements per atom at 500 °C. Transmission electron microscopy, scanning electron microscopy, and high-energy x-ray diffraction were employed to characterize radiation-induced segregation, Frank loops, voids, as well as the formation and reduction of precipitates. Radiation hardening of ~76% was estimated by nanoindentation, approximately consistent with the calculation according to the dispersed barrier-hardening model, suggesting Frank loops as the primary hardening source.
Download or read book Void Precipitate Association During Neutron Irradiation of Austenitic Stainless Steel written by PJ. Maziasz and published by . This book was released on 1987 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microstructural data have recently become available on a single heat of 316 stainless steel irradiated in EBR-II and HFIR, over a wide range of irradiation temperatures (55 to 750°C), doses (7 to 75 dpa), and several helium generation rates (0.5 to 55 atomic ppm He/dpa). Results on just one heat of steel minimize effects that may be related to compositional differences. In this work we present these data in order to offer a characterization of precipitate-void association within the context of the overall microstructural evolution. Observations on a second heat of steel are also presented here to allow us to assess which microstructural correlations are general. The analysis of experimental results leads us, first, to conclude that precipitate-void association is not only dependent upon local conditions at the precipitate interface but is also strongly related to the overall microstructural evolution. Second, we suggest a precipitation mechanism that helps to understand precipitate-void codevelopment.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1989 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book MICROSTRUCTURAL EVOLUTION OF MARTENSITIC STEELS DURING FAST NEUTRON IRASIATION written by P.J. MAZIASZ. and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Ti and C on the Microstructural Evolution of Rapidly Solidified Austenitic Stainless Steels Under Dual Ion Irradiation written by Chiang-Hsiung Tong and published by . This book was released on 1983 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Influence of Minor Alloying Elements and Stress on Microstructural Evolution and Void Swelling of Austenitic Steels Under Neutron Irradiation written by R. Hübner and published by . This book was released on 2000 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: A pressurized tube experiment was carried out in the British Prototype Fast Reactor (PFR) at Dounreay, U.K. in order to determine swelling and stress-induced swelling of four heats of the commercial German austenitic steel DIN 1.4970, with different contents of the minor alloying elements Si, Ti and Ti/C ratio. The maximum doses achieved are 106 dpaNRT at 420°C, 81 dpaNRT at 500°C and 61 dpaNRT at 600°C. The hoop stresses of the pressurized tubes were 0, 60 and 120 MPa at all irradiation temperatures. TEM-examinations have been carried out to determine the influence of the minor alloying elements and the stress on the void swelling and the microstructural evolution. All alloys exhibited the highest swelling values at 420°C and no swelling at 600°C. The measurements show the large effect of the minor alloying elements upon swelling and in-pile creep. The maximum swelling suppression is achieved by a high Si-content and an understoichiometric Ti/C ratio (understabilization). The analysis of the microstructural evolution shows that the swelling resistance is correlated to the formation and stability of very fine ?'-precipitates. For the alloy with the highest swelling resistance these precipitates can be found up to 106 dpaNRT at 420°C, whereas they dissolve in the course of irradiation for the alloys with lower swelling resistance.
