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Takahashi, Rieko*; Taniguchi, Naoki
Zairyo To Kankyo, 73(6), p.153 - 163, 2024/06
Carbon steel is one of the candidate materials for overpacks in geological disposal of high-level radioactive waste, and is known to susceptible to stress corrosion cracking(SCC) depending on the condition in carbonate environment. In order to understand the influence of temperature on the SCC susceptibility of carbon steel, slow strain rate test (SSRT) of rolled steel were performed in NaHCO aqueous solution with varying temperature in the range of 303-393K for conditions of 0.1-0.5 mol/dm, which is assumed to be the upper limit of carbonate concentration in groundwater in a geological disposal environment. As the results, no obvious influence of temperature on mechanical properties such as fracture strain ratio and reduction area ratio were observed, but SCC susceptibility based on SCC fracture ratio increased at relatively low temperatures of 303K and 323K. It was suggested that the reason for the higher SCC sensitivity at lower temperatures was due to slower repassivation at lower temperatures. Regarding the type of SCC, intergranular SCC was dominant at low temperatures and tended to transition to intergranular SCC at higher temperatures. Transgranular SCC tended to be observed at lower potentials than those at which intergranular SCC was observed.
Nakano, Hiroko; Uehara, Toshiaki; Takeuchi, Tomoaki; Shibata, Hiroshi; Nakamura, Jinichi; Matsui, Yoshinori; Tsuchiya, Kunihiko
JAEA-Technology 2015-049, 61 Pages, 2016/03
In Japan Atomic Energy Agency, we started a research and development so as to monitor the Nuclear Plant Facilities situations during a severe accident, such as a radiation-resistant monitoring camera under a severe accident, a radiation resistant in-water transmission system for conveying the information in-core and a heat-resistant signal cable. As part of advance in a heat-resistant signal cable, we maintained to ex-core high-temperature and pressure water loop test equipment which can be simulated conditions of BWRs and PWRs for evaluation reliability and property of construction sheath materials. This equipment consists of Autoclave, water conditioning tank, water pump, high-pressure metering pump, preheater, heat exchanger and pure water purification equipment. This report describes the basic design and the results of performance tests of construction machinery and tools of ex-core high-temperature and pressure water loop test equipment.
Nakano, Junichi; Miwa, Yukio; Koya, Toshio; Tsukada, Takashi
Journal of Nuclear Materials, 329-333(Part1), p.643 - 647, 2004/08
Times Cited Count:9 Percentile:52.01(Materials Science, Multidisciplinary)To study effects of minor elements on the irradiation assisted stress corrosion cracking (IASCC), high purity Type 304 and 316 stainless steels (SSs) were fabricated and added minor elements, Si or C. After neutron irradiation to 3.510n/m (E1MeV), the slow strain rate tests (SSRT) for the irradiated specimens was conducted in oxygeneted high purity water at 561 K. Fracture surface of the specimens was examined using the scanning electron microscope (SEM) after the SSRT. Fraction of intergranular stress corrosion cracking (IGSCC) on the fracture surface after the SSRT increased with netron fluence. Suppression of irradiation hardening and increase of peiod to SCC fracture as benefitical effects of the additional elements, Si or Mo, were not observed obviously. In high purity SS added C, fraction of IGSCC was the smallest in the all SSs, although irraidiation hardening level was the largest in the all SSs. Addition of C suppressed the susceptibility to IGSCC.
Nakano, Junichi; Tsukada, Takashi; Tsuji, Hirokazu; Terakado, Shogo; Koya, Toshio; Endo, Shinya
JAERI-Tech 2003-092, 54 Pages, 2004/01
Irradiation assisted stress corrosion cracking (IASCC) is a degradation phenomenon caused by synergy of neutron radiation, aqueous environment and stress on in-core materials, and it is an important issue in accordance with increase of aged light water reactors. Isolating crack initiation stage from crack growth stage is very useful for the evaluation of the IASCC behavior. Hence facility for in-situ observation during slow strain rate test (SSRT) for irradiated material was developed. As performance demonstrations of the facility, tensile test with in-situ observation and SSRT without observation were carried out using unirradiated type 304 stainless steel in 561 K water at 9 MPa. The following were confirmed from the results. (1) Handling, observation and recording of specimen can be operated using manipulators in the hot cell. (2) In-situ observation can be performed in pressurized high temperature water and flat sheet type specimen is suitable for the in-situ observation. (3) Test condition can be kept constantly and data can be obtained automatically for long test period.
Kaji, Yoshiyuki; Tsukada, Takashi
Proceedings of 11th German-Japanese Workshop on Chemical Information, p.101 - 103, 2003/06
The JAERI Material Performance Database (JMPD) was developed with a view to utilizing material performance data efficiently. Data from more than 11,600 test pieces are prepared for data evaluation in the JMPD. Some kinds of data analyses for mechanical properties have been performed by utilizing the JMPD. Irradiation Assisted Stress Corrosion Cracking (IASCC) of austenitic stainless steels in high temperature water is considered to be one of the key issues for life assessment of the core internals of nuclear power plants. This paper describes the present status of the JMPD and additional function of JMPD for analysis of IASCC data.
Department of Hot Laboratories
JAERI-Review 2002-039, 106 Pages, 2003/01
no abstracts in English
Nakano, Junichi; Miwa, Yukio; Tsukada, Takashi; Kikuchi, Masahiko; Kita, Satoshi; Nemoto, Yoshiyuki; Tsuji, Hirokazu; Jitsukawa, Shiro
Journal of Nuclear Materials, 307-311(Part2), p.1568 - 1572, 2002/12
Times Cited Count:13 Percentile:62.70(Materials Science, Multidisciplinary)Type 316LN stainless steel of the international thermonuclear experimental reactor (ITER) Grade (316LN-IG SS) is being considered for the first wall/ blanket component. Hot isostatic pressing (HIP) technique is expected for the fabrication of module. To evaluate the integrity and susceptibility to stress corrosion cracking (SCC) of HIPed 316LN-IG SS, tensile tests in vacuum and slow strain rate tests (SSRT) in high temperature water were performed. Specimen with the HIPed joint shows no deterioration of the tensile strength and susceptibility to SCC in oxygenated water. Thermally sensitized specimen with the HIPed joint was low susceptible to SCC in creviced environment. It is concluded that the strength at joint location is as high as that at the base alloy and the joint interface appears integrity.
Saito, Junichi; Ishii, Toshimitsu; Omi, Masao; Fujiki, Kazuo; Ito, Haruhiko; Takahashi, Hidetake
KAERI/GP-192/2002, p.3 - 11, 2002/00
no abstracts in English
; ; Kiuchi, Kiyoshi
JAERI-Research 96-019, 20 Pages, 1996/03
no abstracts in English
Tsukada, Takashi; Jitsukawa, Shiro; Shiba, Kiyoyuki; Sato, Yoshinori*; Shibahara, Itaru*; Nakajima, Hajime
Journal of Nuclear Materials, 207, p.159 - 168, 1993/00
Times Cited Count:7 Percentile:60.17(Materials Science, Multidisciplinary)no abstracts in English
Tsukada, Takashi; Shiba, Kiyoyuki; G.E.C.Bell*; Nakajima, Hajime; Kizaki, Minoru; Omi, Masao; Sudo, Kenji; Goto, Ichiro
JAERI-M 92-081, 27 Pages, 1992/06
no abstracts in English
Tsukada, Takashi
Bisho Shikenhen Zairyo Hyoka Gijyutsu No Shimpo, p.34 - 36, 1992/03
no abstracts in English
Tsukada, Takashi; Shiba, Kiyoyuki; Nakajima, Hajime; Sato, Yoshinori*; Shibahara, Itaru*
PNC-TN9410 92-295, 67 Pages, 1992/00
no abstracts in English
; Kiuchi, Kiyoshi; ;
Proc. of the Int. Symp. on Material Chemistry in Nuclear Environment, p.427 - 435, 1992/00
no abstracts in English
; Tsukada, Takashi; Nakajima, Hajime
JAERI-M 90-237, 103 Pages, 1991/01
no abstracts in English
Tsukada, Takashi; Shiba, Kiyoyuki; Omi, Masao; Kizaki, Minoru; ; Nakajima, Hajime
Proc. of the 3rd Asian Symp. on Research Reactor, 8 Pages, 1991/00
no abstracts in English