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Onizawa, Takashi; Nagae, Yuji; Kato, Shoichi; Wakai, Takashi
Zairyo, 66(2), p.122 - 129, 2017/02
The applicability of Modified 9Cr-1Mo steel (ASME Grade 91 steel) as the main structural material in advanced loop-type sodium cooled fast reactor has been explored to enhance the safety, the credibility and the economic competitiveness of fast reactor plants. It is well-known that the steel exhibits cyclic softening behavior. Decrease of tensile and creep strength in softened materials has been already reported by other researchers. This paper discusses the relationship between cyclic softening conditions and high temperature material properties. Grade 91 steel was softened by repeat of plastic strain. The softening behavior could be evaluated by the index of the softening rate. Decrease of tensile and creep strength in softened materials can be evaluated by the softening rate and it depends on the cyclic softening conditions.
Ando, Masami; Wakai, Eiichi; Sawai, Tomotsugu; Matsukawa, Shingo; Naito, Akira*; Jitsukawa, Shiro; Oka, Keiichiro*; Tanaka, Teruyuki*; Onuki, Somei*
JAERI-Review 2004-025, TIARA Annual Report 2003, p.159 - 161, 2004/11
The objectives of this study are to evaluate radiation hardening on ion-irradiated F82H up to 100 dpa and to examine the extra component of radiation hardening due to implanted helium atoms (up to 
3000 appmHe) in F82H under ratio of 0, 10, 100 appmHe/dpa.The ion-beam irradiation experiment was carried out at the TIARA facility of JAERI. Specimens were irradiated at 633 K by 10.5 MeV Fe ions with/without 1.05 MeV He ions. Micro-indentation tests were performed at loads to penetrate about 0.40 mm in the irradiated specimens using an UMIS-2000. The results are summarized as follows:1) As a result of the single irradiated F82H, the micro-hardness tended to increase about 30 dpa. 2) The extra radiation hardening was obviously caused by co-implanted helium atoms more than 1000 appm in F82H irradiated at 633 K. 3) In the dual-beam (100 appmHe/dpa) irradiated microstructure, nano-voids and fine defects were observed. It is suggested that the formation of nano-voids causes the extra radiation hardening by helium co-implantation.
Ando, Masami; Wakai, Eiichi; Sawai, Tomotsugu; Tanigawa, Hiroyasu; Furuya, Kazuyuki; Jitsukawa, Shiro; Takeuchi, Hiroshi; Oka, Keiichiro*; Onuki, Somei*; Koyama, Akira*
Journal of Nuclear Materials, 329-333(2), p.1137 - 1141, 2004/08
Times Cited Count：50 Percentile：93.84(Materials Science, Multidisciplinary)One of the most crucial issues on R&D of reduced activation ferritic/martensitic steels is the effect of helium on the degradation of fracture toughness. The synergistic effects of displacement damage and helium on F82H steel can be partially simulated by martensitic steels doped with 
B or 
Ni in a mixed spectrum fission reactor. However, the control of helium production rate is difficult and the chemical effects of B or Ni doping on mechanical property are not small. Therefore, multi-ion irradiation method is the most convenient and accurate method to simulate various irradiation conditions. Moreover, the effects of helium on irradiation hardening behavior can be examined by combining ion-irradiation with ultra micro-indentation technique. The purpose of this study is to examine the extra component of radiation hardening due to implanted helium in F82H. The extra component of irradiation hardening due to helium was hardly detected in the dual-beam irradiation. Therefore, the effect on irradiation hardening below 630K of helium (
500 appm) was very small.
The Working Team for Examination Operation of Samples from Primary Loop Recirculation Piping at Onag
JAERI-Tech 2004-003, 74 Pages, 2004/02
JAERI-Tech-2004-003.pdf:30.08MB
The present examination has been performed with the objective to provide technical basis for identifying causes of cracking through the examination of the samples, which was conducted at the post irradiation examinations facilities of JAERI, taken from the cracked region of the recirculation pipe at the Onagawa Nuclear Power Station Unit-1. The following findings were obtained from this examination result. (1) Cracks were observed near the weld region of inner surface of the pipe and depth of the crack was about 5 to 7mm. (2) Intergranular crackings were observed in the almost whole fracture surface. Partially transgranular cracking was observed at the surface layer with the depth of about 100
m. Microstructure formed by cold work and increase of hardness were observed in these surface layers. Cracks initiated near the region where hardness value was the highest. Based on the examination results described above concerning presence of tensile residual stress by welding and relatively high dissolved oxygen contents in core coolant and so on, it is concluded that these cracks were initiated in the cold work layer of inner surface by stress corrosion cracking (SCC) and propagated along the grain boundaries.
Furuya, Kazuyuki; Wakai, Eiichi; Ando, Masami; Sawai, Tomotsugu; Nakamura, Kazuyuki; Takeuchi, Hiroshi; Iwabuchi, Akira*
Journal of Nuclear Materials, 307-311(Part1), p.289 - 292, 2002/12
Times Cited Count：7 Percentile：44.35(Materials Science, Multidisciplinary)no abstracts in English
Ando, Masami; Tanigawa, Hiroyasu; Jitsukawa, Shiro; Sawai, Tomotsugu; Kato, Yudai*; Koyama, Akira*; Nakamura, Kazuyuki; Takeuchi, Hiroshi
Journal of Nuclear Materials, 307-311(Part1), p.260 - 265, 2002/12
Times Cited Count：39 Percentile：90.08(Materials Science, Multidisciplinary)no abstracts in English
Tanigawa, Hiroyasu; Jitsukawa, Shiro; Hishinuma, Akimichi; Ando, Masami*; Kato, Yudai*; Koyama, Akira*; Iwai, Takeo*
Journal of Nuclear Materials, 283-287(Part.1), p.470 - 473, 2000/12
Times Cited Count：21 Percentile：77.56(Materials Science, Multidisciplinary)no abstracts in English
*; *; Kawasaki, Hirotsugu; Aoto, Kazumi
JNC TY9400 2000-010, 138 Pages, 2000/03
JNC-TY9400-2000-010.pdf:5.15MB
None
; Ara, Katsuyuki
MAG-96-265, 0, p.11 - 24, 1996/12
no abstracts in English
Ara, Katsuyuki; ;
J. Pressure Vessel Technol., 118(4), p.447 - 453, 1996/11
Times Cited Count：14 Percentile：63.23(Engineering, Mechanical)no abstracts in English
Aoto, Kazumi; ; ; ; ; Hirakawa, Yasushi
PNC TN9410 97-076, 29 Pages, 1996/06
This report describes the check of the thermocouple well at the inlet of the intermediate heat exchanger (IHX) of C-loop of the secondary heat tansfer system of the prototype fast breeder reactor Monju, regarding the sodium leak accident of the thermocouple well at the outlet of the IHX of the same loop of the secondary heat transfer system of the same plant Monju. Various tests and inspections were performed to check damages at the part with rapid diameter change of the thermocouple well where stress concentration may occur, and to get the information about the integrity of the welded part between the thermocouple well and the attachment. The thermocouple well, the rapid diameter change part, larger and smaller part, respectively, of the thermocouple well, and welded part between the thermocouple well and the attachments were examined as written below. (1)Accurate measurement of the dimension. (2)Vibration test by tapping the thermocouple well. (3)Non destructive testing at some points. (4)Chemical composition analysis. (5)Microscopic observation of metalogical structure. (6)Detailed observation around the rapid diameter change part. (7)Hardness test. (8)Research on corrosion at the clearance. (9)Structure strength test of the thermocouple well. (10)Bending test of the thermocouple's sheath at high temperature.
Ara, Katsuyuki; ; ; Sakasai, Kaoru
Proceedings of 8th International Conference on Pressure Vessel Technology (ICPVT-8), 1, p.183 - 189, 1996/00
no abstracts in English
Suzuki, Masahide;
JAERI-Research 94-038, 23 Pages, 1994/11
JAERI-Research-94-038.pdf:0.87MB
no abstracts in English
Nagai, Shuichiro; ; Tobita, Noriyuki; Seki, Masayuki; *; *
PNC TN8410 91-099, 56 Pages, 1991/05
None
Seki, Masahiro; Ogawa, Masuro; Minato, Akio; ; Tone, Tatsuzo;
Nucl.Eng.Des./Fusion, 5, p.205 - 213, 1987/00
no abstracts in English
Ogawa, Masuro; Seki, Masahiro; Minato, Akio; ; Tone, Tatsuzo
Nihon Genshiryoku Gakkai-Shi, 28(11), p.1038 - 1044, 1986/11
Times Cited Count：0 Percentile：0.02(Nuclear Science & Technology)no abstracts in English
Shiraishi, K.;
Journal of Nuclear Materials, 117, p.134 - 142, 1983/00
Times Cited Count：12 Percentile：77.09(Materials Science, Multidisciplinary)no abstracts in English
; Shiraishi, K.
Nihon Genshiryoku Gakkai-Shi, 25(4), p.52 - 54, 1983/00
no abstracts in English
; ; Kuriyama, Isamu
Denki Gakkai Rombunshi, A, 101(5), p.279 - 284, 1981/00
no abstracts in English
