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Takamizawa, Hisashi; Hata, Kuniki; Nishiyama, Yutaka; Toyama, Takeshi*; Nagai, Yasuyoshi*
Journal of Nuclear Materials, 556, p.153203_1 - 153203_10, 2021/12
Times Cited Count:3 Percentile:43.41(Materials Science, Multidisciplinary)Solute clusters (SCs) formed in pressurized water reactor surveillance test specimens neutron-irradiated to a fluence of 1 10 n/cm were analyzed via atom probe tomography to understand the effect of silicon on solute clustering and irradiation embrittlement of reactor pressure vessel steels. In high-Cu bearing materials, Cu atoms were aggregated at the center of cluster surrounded by the Ni, Mn, and Si atoms like a core-shell structure. In low-Cu bearing materials, Ni, Mn, and Si atoms formed cluster and these solutes were not comprised core-shell structure in SCs. While the number of Cu atoms in clusters was decreased with decreasing nominal Cu content, the number of Si atoms had clearly increased. The cluster radius () and number density () decreased and increased, respectively, with increasing nominal Si content. The shift in the reference temperature for nil-ductility transition (RT) showed a good correlation with the square root of volume fraction () multiplied by r (). This suggested that the dislocation cutting through the particles mechanism dominates the precipitation hardening responsible for irradiation embrittlement. The negative relation between the nominal Si content and RT indicated that increasing of nominal Si content reduces the degree of embrittlement.
Ooka, Norikazu*; Ishii, Toshimitsu
Hihakai Kensa, 52(5), p.235 - 239, 2003/05
no abstracts in English
Onizawa, Kunio; Van Walle, E.*; Pavirich, W.*; Nanstad, R.*
NUREG/CR-6777, 81 Pages, 2002/08
no abstracts in English
Onizawa, Kunio; Suzuki, Masahide
Effects of Radiation on Materials: 20th International Symposium (ASTM STP 1405), p.79 - 96, 2001/07
no abstracts in English
Onizawa, Kunio; Tobita, Toru; Suzuki, Masahide
Effects of Radiation on Materials (ASTM STP 1366), p.204 - 219, 2000/00
no abstracts in English
Onizawa, Kunio; Tobita, Toru; Suzuki, Masahide
Proceedings of 15th International Conference on Structural Mechanics in Reactor Technology (SMiRT-15), 4, p.137 - 144, 1999/00
no abstracts in English
Nishiyama, Yutaka; Fukaya, Kiyoshi; Onizawa, Kunio; Suzuki, Masahide; ; ; ;
JAERI-Tech 98-041, 30 Pages, 1998/10
no abstracts in English
Onizawa, Kunio; Tobita, Toru; Suzuki, Masahide
Proc. of 2nd Int. Workshop on the Integrity of Nuclear Components, p.273 - 289, 1998/00
no abstracts in English
Onizawa, Kunio; Fukaya, Kiyoshi; Nishiyama, Yutaka; Suzuki, Masahide; ; Nakamura, Terumi*
Int. J. Press. Vessels Piping, 70(3), p.201 - 207, 1997/00
Times Cited Count:13 Percentile:71.86(Engineering, Multidisciplinary)no abstracts in English
Nakamura, Terumi*; ; Yoshida, Kazuo*; Sato, Akira*; Onizawa, Kunio; Nishiyama, Yutaka; Fukaya, Kiyoshi; Suzuki, Masahide
Ishikawajima Harima Giho, 36(2), p.91 - 97, 1996/03
no abstracts in English
Nishiyama, Yutaka; Fukaya, Kiyoshi; Onizawa, Kunio; Suzuki, Masahide; Shibata, Katsuyuki; ; Nakamura, Terumi*; Sato, Akira*; Yoshida, Kazuo*
JAERI-Tech 96-003, 30 Pages, 1996/02
no abstracts in English
Nakamura, Terumi*; Nishiyama, Yutaka
Genshiryoku Kogyo, 42(9), p.26 - 29, 1996/00
no abstracts in English
Onizawa, Kunio; Fukaya, Kiyoshi; Nishiyama, Yutaka; Suzuki, Masahide; Shibata, Katsuyuki; Kosaka, Atsuo; Kaihara, Shoichiro*; Nakamura, Terumi*; Sato, Akira*; Yoshida, Kazuo*; et al.
JAERI-Tech 94-017, 58 Pages, 1994/09
Regulatory codes require the surveillance test to evaluate the irradiation embrittlement of reactor pressure vessel during operation. However , it is anticipated that the number of those specimens is insufficient in case plant life is extended. Reconstitution techniques by electron beam weld, laser weld, arc stud weld as well as surface-activated joining (SAJ) have been investigated for the re-use of un-deformed parts from tested Charpy impact specimen. The important items for the reconstitution technique are to reduce the width of heat affected zone to maximize the material available, and to lower the maximum temperature of specimen during joining process to preclude the recovery of radiation damage. SAJ can be achieved from a removal pf surface contamination by rotating one-side specimen in vacuum with applying modest friction force. Therefore, SAJ method is expected to be suitable for specimen reconstitution in view of material heating and melting. This paper describes preliminary study to develop Charpy specimen reconstitution technique using reactor pressure vessel steel, A533B-1, by SAJ method. Test results showed that the SAJ method had a capability of joining affected zone less than 1.5mm in half width, and over-temperature region less than 3 mm in half width above reactor operating temperature during joining. It was also found that transition temperature from reconstituted Charpy specimen could be evaluated.
Onizawa, Kunio; Suzuki, Masahide; Ueda, Shuzo
JAERI-M 93-201, 73 Pages, 1993/10
no abstracts in English
; ; ; ; ; Shibahara, Itaru
PNC TN9410 92-321, 30 Pages, 1992/10
Integrity evaluations have been performed for the 2nd Fugen pressure tube test (8 years irradiation, 5.6 10n/cm (E1Mev)). Test items mainly consist of tensile test, bending test, corrosion test and hydrogen analysis. It has become clear using these data that the pressure tube material has maintained its integrity during the irradiation by the integrity assessment on both tensile and fracture toughness properties. Besides, both thickness loss by corrosion and absorbed hydrogen content were lower than those of design values.
;
JAERI-M 5868, 29 Pages, 1974/10
no abstracts in English
Nihon Genshiryoku Gakkai-Shi, 10(6), p.337 - 342, 1968/00
no abstracts in English