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Hoshiya, Taiji*; Takaya, Shigeru*; Ueno, Fumiyoshi; Nemoto, Yoshiyuki; Nagae, Yuji*; Miwa, Yukio; Abe, Yasuhiro*; Omi, Masao; Tsukada, Takashi; Aoto, Kazumi*
Transactions of the Materials Research Society of Japan, 29(4), p.1687 - 1690, 2004/06
JAERI and JNC have begun the cooperative research of evaluation techniques of structural material degradation in FBR and LWR, which based on magnetic and corrosion properties along grain boundaries. Magnetic method has been proposed as the one of the non-destructive detection techniques on the early stage of creep-damage before crack initiation for aged structural materials of FBRs. The effects of applied stress on natural magnetization were investigated on paramagnetic stainless steels having creep-damages. On the other hand, corrosion properties and magneto-optical characteristics of ion-irradiated stainless steels in the vicinity of grain boundaries were estimated by AFM and Kerr effect microscope, respectively. These degradations were induced by changes in characteristics in the vicinity of grain boundaries. It is found that the initial level of progressing process of damage can detect changes in magnetic and corrosion properties along grain boundaries of aged and degraded nuclear plants structural materials.
Shibata, Taiju; Kikuchi, Takayuki; Miyamoto, Satoshi*; Ogura, Kazutomo*
Nuclear Engineering and Design, 223(2), p.133 - 143, 2003/08
Times Cited Count：1 Percentile：10.88(Nuclear Science & Technology)The High Temperature Engineering Test Reactor (HTTR) can provide very large spaces at high temperatures for irradiation tests. The I-I type irradiation equipment was developed as the first irradiation rig. It will be served for an in-pile creep test on a stainless steel with large standard size specimens. It uses the ambient high temperature of the core for the irradiation temperature control. The target irradiation temperatures are 550 and 600
C with the target temperature deviation of 
3C. In this study, the irradiation temperature changes at transient conditions were analyzed by an FEM code and the temperature controllability of the equipment was examined by a mockup test. The controllability was evaluated with the measured temperature transient data at the core graphite components in the Rise-to-Power tests of the HTTR. The result indicates that the temperature control method of the equipment is effective to keep the irradiation temperature stable in the irradiation test.
Shibata, Taiju; Kikuchi, Takayuki; Shimakawa, Satoshi
Reactor Dosimetry in the 21st Century, p.211 - 218, 2003/00
The High Temperature Engineering Test Reactor (HTTR) is the first HTGR in Japan with a maximum power of 30 MW. The construction of it was completed successfully in March 2002. The HTTR aims to perform irradiation studies at its very wide irradiation spaces at high temperatures. Although the creep behavior of materials is measured by the large standard size specimens at out-of-pile, small size ones are generally used for in-pile creep tests because of the irradiation capability of reactors. The I-I type irradiation equipment, the first rig for the HTTR, is to be used for the in-pile creep test on a stainless steel with the standard specimens. The rig can give big tensile loads of about 9.8 kN on them. The temperatures of 550 and 600C and the fast neutron fluence of 1.2
10
n/m
are the targets of the test. Prior to the in-pile creep test, the in-core irradiation properties at the irradiation region are to be obtained by the rig as the first irradiation test. This paper describes the dosimetry plan at the first irradiation test and the subsequent data assessment procedure.
Shibata, Taiju; Kikuchi, Takayuki; Miyamoto, Satoshi*; Ogura, Kazutomo*
JAERI-Tech 2002-097, 19 Pages, 2002/12
The HTTR aims to establish and upgrade the technological basis for the HTGRs and to perform the innovative basic research on high temperature engineering. The HTTR is planned to be used to perform various tests such as, the safety demonstration test, high temperature test operation and irradiation test with large irradiation fields at high temperatures. This paper describes the design of the I-I type irradiation equipment, developed as the first rig for the HTTR, and does the planned dosimetry method at the first irradiation test. It was developed to perform in-pile creep test on a stainless steel with large standard size specimens. It can give great loads on the specimens stably and can control the irradiation temperature precisely. The in-core data are measured by differential transformers, thermocouples, SPNDs and neutron fluence monitors. The obtained data at the first test can be contributed to upgrade the technological basis for the HTGRs, since it is the first direct measurement of the in-core irradiation environments.
Isozaki, Futoshi*; Kikuchi, Taiji; Ioka, Ikuo; Ishikawa, Kazuyoshi; Hirata, Yuji*
JAERI-Tech 2002-074, 22 Pages, 2002/09
JAERI-Tech-2002-074.pdf:4.98MB
The pressurized tube specimens which enclosed high pressure inert gas were produced for the irradiation creep test. The pressurized tube specimen with 7mm outer diameter and 0.5mm wall thickness must be sealed by the welding, after the helium gas was impressed in the inside of tube. In this process, there was a technical problem of welding under high pressure, and it is difficult to seal the pressurized tube specimen in the present facility of our group. The production process was examined by taking shortening in production period and reduction in the cost into consideration. The sealing technology to enclose the helium gas up to 5.5MPa was established by new technique using the present facility and the mock-up test. And, it is necessary to measure the outer diameter of the pressurized tube specimen with high accuracy in order to predict irradiation creep deformation arising from neutron radiation and internal pressure. Therefore, the method for measuring at the 0.01mm measurement accuracy was established, which combined laser measuring instrument with the lathe.
Ioka, Ikuo; Miwa, Yukio; Tsuji, Hirokazu; Yonekawa, Minoru; Takada, Fumiki; Hoshiya, Taiji
JSME International Journal, Series A, 45(1), p.51 - 56, 2002/01
The low cycle creep-fatigue test with tensile strain hold of the austenitic stainless steel irradiated to 2dpa was carried out at 823K in vacuum. The applicability of creep-fatigue life prediction methods to the irradiated specimen was examined. The fatigue life on the irradiated specimen without tensile strain hold time was reduced by a factor of 2-5 in comparison with the unirradiated specimen. The fraction of intergranular fracture increased with increasing strain hold time. The decline in fatigue life of the irradiated specimen with tensile strain hold was almost equal to that of the unirradiated specimen. For the irradiated specimen, the time fraction damage rule trends to yield unsafe estimated lives and the ductility exhaustion damage rule trends to yield generous results. However, all of data were predicted within a factor of three on life by the linear damage rule.
Tsuji, Hirokazu; Fujii, Hidetoshi*
Proceedings of 10th German-Japanese Workshop on Chemical Information, p.127 - 130, 2002/00
A neural network model within a Bayesian framework was adopted based on the material database constructed by JAERI for prediction of creep rupture properties of irradiated type 304 stainless steel. Stress level was modeled as a function of 18 variables, including rupture life, creep test temperature, chemical compositions; 10 elements, heat treatment temperature, heat treatment duration, neutron irradiation temperature, fast neutron fluence, thermal neutron fluence, irradiation time, based on JAERI material database in which 347 creep rupture data sets of type 304 stainless steels were stored. The Bayesian method puts error bars on the predicted values of the rupture strength and allows the significance of each individual factor to be estimated.
Shibata, Taiju; Kikuchi, Takayuki; Miyamoto, Satoshi*; Ogura, Kazutomo*; Ishigaki, Yoshinobu*
Proceedings of OECD/NEA 2nd Information Exchange Meeting on Basic Studies in the Field of High-temperature Engineering, p.145 - 152, 2001/00
no abstracts in English
Kurata, Yuji; Itabashi, Yukio; Mimura, Hideaki*; Kikuchi, Taiji; Amezawa, Hiroo; Shimakawa, Satoshi; Tsuji, Hirokazu; Shindo, Masami
Journal of Nuclear Materials, 283-287(Part.1), p.386 - 390, 2000/12
Times Cited Count：6 Percentile：37.66(Materials Science, Multidisciplinary)no abstracts in English
Iyoku, Tatsuo; Ishihara, Masahiro; *
Journal of Nuclear Science and Technology, 28(10), p.921 - 931, 1991/10
no abstracts in English
Ogawa, Yutaka; Kondo, Tatsuo; ;
Proc.of 2nd Japan-US HTGR Safety Technology Seminar,Material Properties and Design Method Session, 9 Pages, 1978/00
no abstracts in English
JAERI-M 7349, 28 Pages, 1977/10
no abstracts in English
