Download or read book Fracture Toughness Shifts and Bounds for Irradiated Reactor Pressure Vessel Materials written by William L. Server and published by . This book was released on 1990 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transition temperature shift effects arising from neutron radiation embrittlement in ferritic nuclear pressure vessel materials are currently being evaluated using changes in the Charpy V-notch energy curve; typically, the temperature shift at the 41-J (30 ft-lb) energy level is used. Estimates of the 41 J (30 ft-lb) transition temperature are also projected based upon Nuclear Regulatory Commission Regulatory Guide 1.99, Revision 2. The estimated or measured Charpy shift is then applied to a lower-bound reference toughness KIR curve by moving the curve by the Charpy shift amount. Similarly, the flaw evaluation procedures in nonmandatory Appendix A of Section XI of the ASME Boiler and Pressure Vessel Code utilize the shifts in the equivalent of the KIR curve (termed the KIa curve for crack arrest) and a lower-bound static crack initiation toughness KIc curve. This study reviewed and tested this Code's approach, as well as the statistically based reference toughness method developed by W. Oldfield for estimating global tolerance bounds. Comparisons of actual, but limited, fracture toughness data and the predicted bounding curves indicate that the shifted KIR/KIc curves are generally very conservative. The Oldfield reference toughness approach for 95%-95% tolerance bounds is not as conservative, but may provide a better method. In terms of mean toughness shift behavior, the shifts predicted by Charpy V-notch results are not always a true indicator of the mean fracture toughness shift; however, the other margins included in Regulatory Guide 1.99, Revision 2 and those in the original unirradiated KIR/KIc curves appear to compensate for any nonconservatism in using the Charpy V-notch shift approach.

Download or read book An Approach for Predicting Reference Fracture Toughness in Irradiated Vessel Materials written by W. L. Server and published by . This book was released on 1988 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reference Fracture Toughness Procedures Applied to Pressure Vessel Materials written by American Society of Mechanical Engineers. Winter Annual Meeting and published by . This book was released on 1984 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Irradiated Dynamic and Arrest Fracture Toughness Compared to Lower Bound Predictions written by TR. Mager and published by . This book was released on 1992 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pressure-temperature operating curves for nuclear reactor pressure vessels are based upon a lower-bound fracture toughness curve which bounds rapid load dynamic initiation and crack arrest fracture toughness data. The ASME Boiler and Pressure Vessel Code defines the reference toughness (KIR) curve as this lower bound, and this KIR curve was developed solely from unirradiated dynamic and arrest fracture toughness data from one heat of SA533B-1 steel (HSST Plate 02) and two heats of SA508-2 steel. The effects of radiation embrittlement on the shape and shift of the KIR curve to account for the increase in reference temperature is thought to be conservative, but this conservatism has not been fully verified. This study reviews available data from past dynamic and arrest toughness tests on irradiated vessel steels from test reactor irradiations and compares the data to the shifted KIR curve using the transition temperature shift approach detailed in Regulatory Guide 1.99, Revision 2. Dynamic initiation and crack arrest fracture toughness data are available from only a few irradiated large specimen tests (that is, test specimens with thicknesses greater than about 51 mm [2 in.]); small specimen tests (including precracked Charpy) are used for the other comparisons. The limited results indicate that the Regulatory approach for shifting the KIR curve is very conservative even when the Regulatory Guide 1.99, Revision 2 "margin term" is not used and a correction for fluence rate is ignored. No change in shape for the dynamic toughness and arrest data (in particular for low upper shelf materials) was observed.

Download or read book Comparison of Irradiation induced Shifts of Kjc and Charpy Impact Toughness for Reactor Pressure Vessel Steels written by M. A. Sokolov and published by . This book was released on 2000 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reactor Pressure Vessel Structural Integrity Research written by and published by . This book was released on 1995 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Development continues on the technology used to assess the safety of irradiation-embrittled nuclear reactor pressure vessels (RPVs) containing flaws. Fracture mechanics tests on RPV steel, coupled with detailed elastic-plastic finite-element analyses of the crack-tip stress fields, have shown that (1) constraint relaxation at the crack tip of shallows surface flaws results in increased data scatter but no increase in the lower-bound fracture toughness, (2) the nil ductility temperature (NDT) performs better than the reference temperature for nil ductility transition (RT{sub NDT}) as a normalizing parameter for shallow-flaw fracture toughness data, (3) biaxial loading can reduce the shallow-flaw fracture toughness, (4) stress-based dual-parameter fracture toughness correlations cannot predict the effect of biaxial loading on a shallow-flaw fracture toughness because in-plane stresses at the crack tip are not influenced by biaxial loading, and (5) an implicit strain-based dual-parameter fracture toughness correlation can predict the effect of biaxial loading on shallow-flaw fracture toughness. Experimental irradiation investigations have shown that (1) the irradiation-induced shift in Charpy V-notch vs temperature behavior may not be adequate to conservatively assess fracture toughness shifts due to embrittlement, and (2) the wide global variations of initial chemistry and fracture properties of a nominally uniform material within a pressure vessel may confound accurate integrity assessments that require baseline properties.

Download or read book Fracture Toughness of Pressure Vessel Materials for Light Water Reactors written by F. J. Loss and published by . This book was released on 1976 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes progress in a cooperative research program between the Electric Power Research Institute (EPRI) and NRL on the fracture toughness of steels for nuclear reactor pressure vessels. For its contribution EPRI furnished a major protion of the materials and test specimens for the study by NRL. The program is also being conducted in collaboration with the Nuclear Regulatory Commission (NRC), Office of Nuclear Regulatory Research, and the Office of Naval Research. Related NRC sponsored work of broader scope is underway at NRL. A portion of the NRC work pertaining to the fracture toughness of nuclear pressure boundary materials is also reported here because of its relevance to the subject effort. The principal objectives of this program are: (1) to characterize the dynamic fracture initiation toughness K sub Id of three heats of LWR pressure vessel steel, (2) to develop experimental and analytical techniques for the interpretation and analysis of notched, three-point bend specimen behavior under impact loading, and (3) to assess the validity of plane strain K sub Id values as projected from the elastic plastic (J integral) analysis of smaller specimens. The present report describes progress in the dynamic toughness assessment of program materials by means of 1-in. (25mm) bend and precracked Charpy-V specimens. Also described is a one-dimensional, theoretical characterization of the forces and bending moments developed during impact of a notched beam. (Author).

Download or read book Resolution of the Reactor Vessel Materials Toughness Safety Issue written by Richard Johnson and published by . This book was released on 1981 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fracture Toughness of Light water Reactor Pressure Vessel Materials written by F. J. Loss and published by . This book was released on 1975 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Determination of Fracture Toughness Transition Temperature T for Nuclear Reactor Pressure Vessel Steels in Both the Unirradiated and Irradiated Conditions written by James F. Williams and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Determination of the fracture toughness of irradiated reactor pressure tubes using curved compact specimens written by C. K. Chow and published by . This book was released on 1988 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of a Crack Arrest Toughness Data Bank for Irradiated Reactor Pressure Vessel Materials written by and published by . This book was released on 1984 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comparison of Fracture Toughness of Irradiated Reactor Vessel Welds Predicted by ASTM E 900 and Measured written by KK. Yoon and published by . This book was released on 2000 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, a new predictive model has been developed by the NRC and is being implemented in ASTM Standard E 900, that addresses radiation-induced embrittlement of ferritic steels. The model is based on extensive Charpy impact energy data of irradiated reactor vessel steels obtained from surveillance programs. The final application of this new method is to predict fracture toughness of irradiated materials to determine pressure-temperature curves for nuclear power plant operation and RTPTS values in compliance with the current regulatory rules for the nuclear-utility industry.

Download or read book Application of Small Specimens to Fracture Mechanics Characterization of Irradiated Pressure Vessel Steels written by DE. McCabe and published by . This book was released on 1997 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, precracked Charpy V-notch (PCVN) specimens were used to characterize the fracture toughness of unirradiated and irradiated reactor pressure vessel steels in the transition region by means of three-point static bending. Fracture toughness at cleavage instability was calculated in terms of elastic-plastic KJc values. A statistical size correction based upon weakest-link theory was performed. The concept of a master curve was applied to analyze fracture toughness properties. Initially, size-corrected PCVN data from A 533 grade B steel, designated HSST Plate 02, were used to position the master curve and a 5% tolerance bound for KJc data. By converting PCVN data to 1T compact specimen equivalent KJc data, the same master curve and 5% tolerance bound curve were plotted against the Electric Power Research Institute valid linear-elastic KIc database and the ASME lower bound KIc curve. Comparison shows that the master curve positioned by testing several PCVN specimens describes very well the massive fracture toughness database of large specimens. These results give strong support to the validity of KJc. with respect to KIc in general and to the applicability of PCVN specimens to measure fracture toughness of reactor vessel steels in particular. Finally, irradiated PCVN specimens of other materials were tested, and the results are compared to compact specimen data. The current results show that PCVNs demonstrate very good capacity for fracture toughness characterization of reactor pressure vessel steels. It provides an opportunity for direct measurement of fracture toughness of irradiated materials by means of precracking and testing Charpy specimens from surveillance capsules. However, size limits based on constraint theory restrict the operational test temperature range for KJc data from PCVN specimens.

Download or read book Fracture Toughness and Tensile Properties of Irradiated Reactor Pressure Vessel Cladding Material written by MG. Horsten and published by . This book was released on 2001 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive testing programme was undertaken to evaluate the effects of irradiation, thermal ageing, specimen orientation, and test temperature on the fracture oughness and tensile behaviour of a Type 309L/308L stainless steel strip clad deposit. Specimens were irradiated in the high flux reactor (HFR) Petten to nominal neutron doses of 0.05 dpa and 0.1 dpa at 295°C. Testing was performed at room temperature, 100, 200 and 295°C. The fracture resistance properties of the clad material were unaffected by irradiation to 0.1 dpa, which is approximately twice the predicted end-of-life dose. The same neutron dose resulted in an increase in 0.2% yield stress (15-20 MPa) and a small loss of ductility (3%). Thermal ageing to the simulated pressurised water reactor (PWR) end-of-life thermal condition (1000 hrs at 400°C) had no significant effect on the fracture resistance behaviour or tensile properties of clad material in either irradiated or unirradiated condition. Clad fracture resistance properties were unaffected by orientation in the plane of the clad layer and were only dependent on test temperature.

Download or read book Development of a Crack Arrest Toughness Data Bank for Irradiated Reactor Pressure Vessel Materials written by 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 Determination of the Fracture Toughness of Irradiated Reactor Pressure Tubes Using Curved Compact Specimens written by CK. (Peter) Chow and published by . This book was released on 1988 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes a case in which nonstandard test configurations had to be used to assess fracture toughness, and an experimental, analytical program to support the validity of the results.