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Shimodaira, Masaki; Ha, Yoosung; Takamizawa, Hisashi; Katsuyama, Jinya; Onizawa, Kunio
Proceedings of ASME 2023 Pressure Vessels and Piping Conference (PVP 2023) (Internet), 11 Pages, 2023/07
In the current structural integrity assessment of the reactor pressure vessel, the accurate reference temperature (T
) based on the Master Curve method is necessary. The T can be estimated by using the Mini-C(T) fracture toughness specimen in accordance with ASTM E1921 and JEAC4216, which prescribe the pre-crack straightness criteria. A requirement in ASTM E1921 has been revised in a decade to increase the accuracy and reasonability, and the applicable crack curvature has been varied by applied codes. The pre-crack curvature of the Mini-C(T) specimen might have an impact on the T because of the variation of the plastic constraint. In this work, the effect of the crack curvature on the fracture toughness (K
) evaluation using the Mini-C(T) specimen was quantitatively evaluated by using the finite element analysis (FEA) including the Weibull stress analysis, to discuss the difference in a requirement of the crack straightness in ASTM E1921 and JEAC4216. FEAs showed a possibility that the upper limit curvature would decrease the plastic constraint, and consequently obtain higher K in the Mini-C(T) specimen. Furthermore, if the upper limit curvature according to the ASTM E1921-21 was allowed, the T would be estimated as non-conservative based on the Weibull stress analysis. In contrast, the difference in (T) between the crack with upper limit curvature according to JEAC4216 and the ideal straight crack was not significant.
Zarazovski, M.*; Pistra, V.*; Lauerova, D.*; Obermeier, F.*; Mora, D.*; Dubyk, Y.*; Bolinder, T.*; Cueto-Felgueroso, C.*; Szavai, S.*; Dudra, J.*; et al.
Proceedings of ASME 2022 Pressure Vessels and Piping Conference (PVP 2022) (Internet), 11 Pages, 2022/07
Shimodaira, Masaki; Tobita, Toru; Takamizawa, Hisashi; Katsuyama, Jinya; Hanawa, Satoshi
Journal of Pressure Vessel Technology, 144(1), p.011304_1 - 011304_7, 2022/02
Times Cited Count：0 Percentile：0(Engineering, Mechanical)In the structural integrity assessment of a reactor pressure vessel (RPV), the fracture toughness (K) should be higher than the stress intensity factor at the crack tip of an under-clad crack (UCC), which is prescribed in JEAC4206-2016. However, differences in crack depth and existence of cladding between the postulated crack and fracture toughness test specimens would be affected to the plastic constraint state and K evaluation. In this study, we performed fracture toughness tests and finite element analyses (FEAs) to investigate the effect of cladding on K evaluation. FEA showed that the cladding decreased the plastic constraint in the UCC rather than the surface crack. Moreover, it was also found that the apparent K for the UCC was higher than that for the surface crack from tests and the local approach.
Shimodaira, Masaki; Tobita, Toru; Nagoshi, Yasuto*; Lu, K.; Katsuyama, Jinya
Proceedings of ASME 2021 Pressure Vessels and Piping Conference (PVP 2021) (Internet), 8 Pages, 2021/07
In the structural integrity assessment of a reactor pressure vessel (RPV), the fracture toughness (K) should be higher than the stress intensity factor at the crack tip of a semi-elliptical shaped under-clad crack (UCC), which is prescribed in JEAC4206-2016. However, differences in crack depth and existence of cladding between the postulated crack and fracture toughness test specimens would be affected to the plastic constraint state and K evaluation. In this study, we performed fracture toughness tests and finite element analyses to investigate the effect of plastic constraint and cladding on the semi-elliptical shaped crack in K evaluation. The apparent K value evaluated at the deepest point of the crack exceeded 5% fracture probability based on the Master Curve method estimated from C(T) specimens, and the conservativeness of the current integrity assessment method was confirmed. Few initiation sites were observed along the tip of semi-elliptical shaped crack other than the deepest point. The plastic constraint state was also analyzed along the crack tip, and it was found that the plastic constraint at the crack tip near the surface was lower than that for the deepest point. Moreover, it was quantitatively showed that the UCC decreased the plastic constraint. The local approach suggested higher K value for the UCC than that for the surface crack, reflecting the low constraint effect for the UCC.
Department of Hot Laboratories
JAERI-Review 2005-003, 105 Pages, 2005/02
JAERI-Review-2005-003.pdf:21.21MB
no abstracts in English
Tanigawa, Hiroyasu; Sakasegawa, Hideo*; Hashimoto, Naoyuki*; Zinkle, S. J.*; Klueh, R. L.*; Koyama, Akira*
Fusion Materials Semiannual Progress Report for the Period Ending (DOE/ER-0313/35), p.33 - 36, 2004/04
Extraction replica samples were prepared from F82H-IEA, F82H HT2, JLF-1 and ORNL9Cr to analyze the precipitate distribution. The samples were examined to obtain precipitate size distribution with TEM and to analyze chemical composition distribution with SEM. Back-scattered electron imaging was found to be the effective way to separate Ta-rich precipitate from other precipitates. Results showed that most of the precipitates were M23C6, and the shape is a round ellipsoid in F82H-IEA and HT2, but was a long ellipsoid in JFL-1 and ORNL9Cr. It was also found that MX precipitates were few and large and contain Ti in F82H-IEA and HT2, but a lot of fine MX precipitates without Ti were observed in JLF-1 and ORNL9Cr.
Tanigawa, Hiroyasu; Sakasegawa, Hideo*; Payzant, E. A.*; Zinkle, S. J.*; Klueh, R. L.*; Koyama, Akira*
Fusion Materials Semiannual Progress Report for the Period Ending (DOE/ER-0313/35), p.37 - 40, 2004/04
XRD analyses were performed on the extraction residue of HFIR 11J-irradiated RAFs to investigate the overall precipitate character. Un-irradiated and aged specimens were examined as well. Results suggested that the distinctive peaks of M23C6 (M; Cr, Fe, W) were observed on all specimens. Peaks possibly related to MX (M;Ta,Ti,V : X ; C, N) were observed on the specimens extracted from un-irradiated JLF-1 and ORNL9Cr, but those peaks were not observed on irradiated specimens.
Tanigawa, Hiroyasu; Hashimoto, Naoyuki*; Sokolov, M. A.*; Klueh, R. L.*; Ando, Masami
Fusion Materials Semiannual Progress Report for the Period Ending (DOE/ER-0313/35), p.58 - 60, 2004/04
1TCT fracture toughness specimens of F82H-IEA steel were fatigue precracked and sliced in specimen thickness wise for microstructure analysis around the precrack. The microstructure around the precrack was observed by optical microscopy (OM), scanning electron microscopy (SEM), orientation imaging microscopy (OIM), and transmission electron microscopy (TEM). TEM samples around the crack front were prepared by focused ion beam (FIB) processor. The fracture surfaces of tested 1TCT specimens were also observed. OM observation showed that the precrack penetration was straight in the beginning, and then tended to follow a prior austenite grain boundary and to branch into 2 to 3 directions at the terminal. SEM and OIM observations revealed that the both microstructures around the precracks and ahead of the precrack had turned into cell structure, which is the typical microstructure of fatigue-loaded F82H. TEM images and inverse pole figures obtained from the crack-front region confirmed this structure change.
Nishiyama, Yutaka; Suzuki, Masahide
Kinzoku, 73(8), p.48 - 52, 2003/08
no abstracts in English
*; ; ; *; *
PNC TN9410 91-132, 85 Pages, 1991/06
A series of high temperature fracture toughness tests of 9Cr type steels was put in practice on a three-years scheme in 1988. In this experimental study, Mod.9Cr-1Mo steel, 9Cr-2Mo steel and 9Cr-1Mo-Nb-V steel are tested, and these fructure toughness are investigated on the basis of J integral. In a first year, high temperature fracture toughness test method was established using R-curve method and unloading compliance method, and J
values of Mod. 9Cr-1Mo steel were measured at RT, 400
C, 500C, 550C and 600C. In a second year, fracture toughness tests of 9Cr-2Mo steel, 9Cr-1Mo-V-Nb steel and these aged materials were performed, and several factors which affected fracture toughness values of 9Cr type steels were clarified. In this report, the test results in a second year are summarized. In a last year, fracture toughness tests of weldment and thick plate of 9Cr type steel are going to be carried out. Furthermore, an effect of crack direction on J value will be studied.
*; *; Kano, Shigeki; *; *; *; *
PNC TN9410 89-096, 105 Pages, 1989/05
A series of high temperature fracture toughness tests of 9Cr type steel was put in practice on a three-year scheme in 1988, In this experimental study, Mod.9Cr-1Mo steel, 9Cr-2Mo steel and TEMPALOY SW-9(9Cr-1Mo-Nb-V) steel are tested, and fracture toughness (J
) of base metal (As-received, SR-treated, Aged) and weldment (weld metal, HAZ) of these three types of steel are investigated. In a first year, fracture toughness tests of base metal (As-received, SR-treated) of Mod.9Cr-1Mo steel were carried out at RT, 400C, 500C, 550C and 600C, respectively. In this report, the test results in the first year are shown. Fracture toughness tests were performed using R-curve method and unloading compliance method according to ASTM E813. The fracture toughness value was the lowest at 400C. Even at 400C, however, Mod.9Cr-1Mo steel showed enough high fracture toughness (J
350kJ/m
), In the fracture toughness test, tearing modurous T
was also measured.
;
JAERI-M 86-145, 28 Pages, 1986/10
no abstracts in English
; ;
Nihon Genshiryoku Gakkai-Shi, 28(10), p.966 - 971, 1986/10
Times Cited Count：3 Percentile：40.87(Nuclear Science & Technology)no abstracts in English
; *; Nakajima, Hajime; Kondo, Tatsuo
Nucl.Eng.Des., 93, p.95 - 106, 1986/00
Times Cited Count：6 Percentile：58.99(Nuclear Science & Technology)no abstracts in English
; Nakajima, Hajime; Kondo, Tatsuo
JAERI-M 84-208, 25 Pages, 1984/11
no abstracts in English
Kondo, Tatsuo; Nakajima, Hajime
Nihon Zairyo Kyodo Gakkai Koen Rombunshu, p.101 - 125, 1983/00
no abstracts in English
; ; ;
Tetsu To Hagane, 61(8), p.1032 - 1039, 1982/00
no abstracts in English
*;
JAERI-M 8808, 23 Pages, 1980/04
no abstracts in English
;
Atsuryoku Gijutsu, 14(3), p.127 - 134, 1976/03
no abstracts in English
