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Book Embrittlement Recovery Due to Annealing of Reactor Pressure Vessel Steels

Download or read book Embrittlement Recovery Due to Annealing of Reactor Pressure Vessel Steels written by and published by . This book was released on 1996 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Embrittlement of reactor pressure vessels (RPVs) can be reduced by thermal annealing at temperatures higher than the normal operating conditions. Although such an annealing process has not been applied to any commercial plants in the United States, one US Army reactor, the BR3 plant in Belgium, and several plants in eastern Europe have been successfully annealed. All available Charpy annealing data were collected and analyzed in this project to develop quantitative models for estimating the recovery in 30 ft-lb (41 J) Charpy transition temperature and Charpy upper shelf energy over a range of potential annealing conditions. Pattern recognition, transformation analysis, residual studies, and the current understanding of the mechanisms involved in the annealing process were used to guide the selection of the most sensitive variables and correlating parameters and to determine the optimal functional forms for fitting the data. The resulting models were fitted by nonlinear least squares. The use of advanced tools, the larger data base now available, and insight from surrogate hardness data produced improved models for quantitative evaluation of the effects of annealing. The quality of models fitted in this project was evaluated by considering both the Charpy annealing data used for fitting and the surrogate hardness data base. The standard errors of the resulting recovery models relative to calibration data are comparable to the uncertainty in unirradiated Charpy data. This work also demonstrates that microhardness recovery is a good surrogate for transition temperature shift recovery and that there is a high level of consistency between the observed annealing trends and fundamental models of embrittlement and recovery processes.

Book Radiation Embrittlement of Nuclear Reactor Pressure Vessel Steels

Download or read book Radiation Embrittlement of Nuclear Reactor Pressure Vessel Steels written by Lendell E. Steele and published by ASTM International. This book was released on 1993 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Semiempirical Model for Annealing and Reirradiation Embrittlement in Pressure Vessel Steels

Download or read book Semiempirical Model for Annealing and Reirradiation Embrittlement in Pressure Vessel Steels written by RG. Lott and published by . This book was released on 1989 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: A model of recovery and reembrittlement in an annealed nuclear reactor pressure vessel steel is described. Modeling is an integral part of the overall approach to annealing because it provides a bridge between the experimental studies and the application of the results to actual pressure vessels. This model is based on a series of annealing and reirradiation studies performed using microhardness specimens. Most of these materials were originally irradiated in nuclear pressure vessel surveillance programs. The model is based on the concept of a benefit factor, which compares the annealed and unirradiated specimens to material that has been irradiated without an intermediate anneal. It is noted that the data can most reasonably be explained by assuming that the mechanism of annealing is a combination of reversible and nonreversible processes. This model can be used to predict transition temperature shifts in annealed materials.

Book Role of the Active Defect Complex in the Neutron Embrittlement and Thermal Recovery of High Copper Reactor Pressure Vessel Steels

Download or read book Role of the Active Defect Complex in the Neutron Embrittlement and Thermal Recovery of High Copper Reactor Pressure Vessel Steels written by JP. Highton and published by . This book was released on 1983 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annealing studies of irradiated and unirradiated pressure vessel steel have led to the conclusion that an active defect complex (ADC) is responsible for the enhanced embrittlement associated with steels containing significant levels of copper (>0.1%). These complexes, which already exist in the unirradiated steel, accumulate vacancies, produced either thermally or by neutron bombardment, and grow to such a size that the dislocation mobility is impaired and the yield stress increased. The number density of the sites appears to be a function of the copper level in the steel. Thus in low-copper steels the site spacing is too great to affect the yield stress.

Book Radiation Embrittlement and Annealing Recovery of CrNiMoV Pressure Vessel Steels with Different Copper and Phosphorus Content

Download or read book Radiation Embrittlement and Annealing Recovery of CrNiMoV Pressure Vessel Steels with Different Copper and Phosphorus Content written by R. Havel and published by . This book was released on 1993 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The influence of copper and phosphorus content on Charpy-V-notch impact energy, on dynamic fracture toughness, and on radiation hardening recovery of tensile and hardness properties by postirradiation annealing at different temperatures was explored for one commercial heat and six laboratory melts of CrNiMoV pressure vessel steels irradiated to 0.9 to 1.3 x 1023 n/m2 (E > 1 MeV) at 280°C.

Book Radiation Embrittlement of Nuclear Reactor Pressure Vessel Steels

Download or read book Radiation Embrittlement of Nuclear Reactor Pressure Vessel Steels written by Lendell E. Steele and published by ASTM International. This book was released on 1986 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Irradiation Annealing and Reirradiation Effects on American and Russian Reactor Pressure Vessel Steels

Download or read book Irradiation Annealing and Reirradiation Effects on American and Russian Reactor Pressure Vessel Steels written by MA. Sokolov and published by . This book was released on 2000 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVs) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. Even though a postirradiation anneal may be deemed successful, a critical aspect of continued RPV operation is the rate of embrittlement upon reirradiation. There are insufficient data available to allow for verification of available models of reirradiation embrittlement or for the development of a reliable predictive methodology. This is especially true in the case of fracture toughness data. Under the U.S.-Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS), Working Group 3 on Radiation Embrittlement, Structural Integrity, and Life Extension of Reactor Vessels and Supports agreed to conduct a comparative study of annealing and reirradiation effects on RPV steels. The Working Group agreed that each side would irradiate, anneal, reirradiate (if feasible), and test two materials of the other. Charpy V-notch (CVN) and tensile specimens were included. Oak Ridge National Laboratory (ORNL) conducted such a program (irradiation and annealing, including static fracture toughness) with two weld metals representative of VVER-440 and VVER-1000 RPVs, while the Russian Research Center-Kurchatov Institute (RRC-KI) conducted a program (irradiation, annealing, reirradiation, and reannealing) with Heavy-Section Steel Technology (HSST) Program Plate 02 and Heavy-Section Steel Irradiation (HSSI) Program Weld 73W. The results for each material from each laboratory are compared with those from the other laboratory. The ORNL experiments with the VVER welds included irradiation to about 1 x 1019 n/cm2 (>1 MeV), while the RRC-KI experiments with the U.S. materials included irradiations from about 2 to 18 x 1019 n/cm2 (>1 MeV). In both cases, irradiations were conducted at ~290 °C and annealing treatments were conducted at ~454 °C. The ORNL and RRC-KI experiments have shown generally good agreement for both the Russian and U.S. steels. While recoveries of the Charpy 41-J transition temperatures were substantial in all cases, significantly less recovery of the lateral expansion and shear fracture in some cases (no recovery in one case) deserves further attention. The RRC-KI results for the U.S. steels showed reirradiation embrittlement rates which are conservative relative to the lateral shift prediction based on Charpy impact energy.

Book Proceedings of the PRIMAVERA International Workshop on Re embrittlement After Annealing of Reactor Pressure Vessel Steels

Download or read book Proceedings of the PRIMAVERA International Workshop on Re embrittlement After Annealing of Reactor Pressure Vessel Steels written by A. Ballesteros and published by . This book was released on 2011 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: The International PRIMAVERA Workshop on "Re-embrittlement after Annealing of Reactor Pressure Vessel Steels" took place at JRC-IE Petten, Netherlands, in March 2011, and was organized together by the POS and MATTINO Actions of the SPNR and SFNR Units of JRC-IE. The main purpose of the workshop was to present the results of the PRIMAVERA project, which is currently in its final phase, to identify and discuss open issues in the topics covered by the project (annealing and re-embrittlement after annealing), and to propose additional investigations to address the identified open questions. A second objective of the workshop was to explore the possibilities of cooperation among the IAEA, JRC and the rest of the PRIMAVERA partners on research in advance materials and their behaviour under neutron irradiation, as materials from future reactors (e.g., Gen IV reactors) will be exposed to high neutron fluence and high temperature.

Book New Information on Neutron Embrittlement and Embrittlement Relief of Reactor Pressure Vessel Steels

Download or read book New Information on Neutron Embrittlement and Embrittlement Relief of Reactor Pressure Vessel Steels written by and published by . This book was released on 1964 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron embrittlement of the carbon and low-alloy steels investigated has been defined in terms of increases in the nil ductility transition (NDT) temperature. Increases in the NDT of pressure vessel steels as great as 545F have been observed. The extent of embrittlement has been shown to depend upon the neutron exposure, the type of steel, and the irradiation temperature. Embrittlement relief through annealing heat treatment at temperatures above the pressure vessel operating temperature has been demonstrated. Significant embrittlement relief was observed even with multiple irradiation-annealing cycles, the extent of relief being primarily dependent upon the irradiation temperature and the subsequent annealing temperature. Experimental data are reviewed with consideration for application to operating nuclear pressure vessel conditions. Preliminary results of power reactor surveillance and of the evaluation of one pressure vessel after nuclear service are related to experimental results. The value of extending the evaluation of surveillance speciments and of pressure vessels after removal from nuclear service are reviewed with reference to current uncertainties as to possible nuclear environmental and stress effects. (Author).

Book Radiation Embrittlement of Nuclear Reactor Pressure Vessel Steels

Download or read book Radiation Embrittlement of Nuclear Reactor Pressure Vessel Steels written by Lendell E. Steele and published by ASTM International. This book was released on 1989 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: