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Okajima, Satoshi; Wakai, Takashi
Nihon Kikai Gakkai 2017-Nendo Nenji Taikai Koen Rombunshu (DVD-ROM), 5 Pages, 2017/09
It was reported that the long distance travel of temperature distribution causes a new type of thermal ratcheting, even in the absence of primary stress. In this paper, based on the results of inelastic finite element analyses, we investigated saturation behavior of thermal ratcheting strain due to long range travel of temperature distribution. As a result, we revealed that the long distance travel of temperature distribution generates plastic strain distribution made maximum at the central part. Because of the shape of the generated strain distribution, the residual stress accumulates even at the central part of the region passed through the temperature distribution. In the case with excessive long traveling of temperature distribution, the region with plastic deformation extended to the surrounding region. Otherwise, sufficient magnitude of residual stress to cause shakedown behavior accumulated on entire region, and the accumulation of the plastic strain saturated.
Tanaka, Masaaki; Miyake, Yasuhiro*
Nihon Kikai Gakkai M&M 2015 Zairyo Rikigaku Kanfarensu Koen Rombunshu (Internet), 3 Pages, 2015/11
A prototype coupling method consisting of the fluid-structure thermal interaction simulation code MUGTHES and the structural thermal stress analysis code FINAS with interface program MUFIN has been developed in order to estimate the thermal fatigue in the SFRs. As a fundamental validation of the coupled method, it was applied to the water experiment for thermal mixing phenomena in a T-junction piping system. In the experiment, thermal interaction between the fluid and the structure made of aluminum installed to the branch pipe side wall was considered. Through the numerical simulations, applicability of the coupled method was confirmed.
Tanaka, Masaaki; Miyake, Yasuhiro*; Karakida, Yasuhisa*
Proceedings of 2nd International Conference on Maintenance Science and Technology (ICMST-Kobe 2014), p.79 - 80, 2014/11
A coupled method of fluid-structure thermal interaction simulation and thermal stress analysis has been developed through the interface program to carry out direct numerical estimation of the thermal fatigue. The prototype method was applied to the thermal mixing phenomena in T-junction Piping System.
Kuramochi, Masaya*; Yamamoto, Kazami; Kinsho, Michikazu
JAERI-Tech 2003-055, 148 Pages, 2003/07
JAERI-Tech-2003-055.pdf:24.48MB
The injection beam dump of the 3 GeV rapid cycling synchrotron (3 GeV-RCS) is to be installed to absorb the H
and H
beams that can not be changed into H
beam with a graphite foil. We estimate the maximum temperature and thermal stress of the injection beam dump. As a result, the temperature at the center region made of iron reached up to 370 K after several operation cycles (one cycle is three-week operation including one-week interval) under the 1kW-beam injection. Then, the temperature at the boundary between the iron region of the beam dump and the concrete wall of the tunnel was rather low temperature of about 320 K. And the maximum Mises stresses of 96 MPa and about 0.2 MPa were generated in the iron region and the concrete wall respectively. These values were much lower than the allowable temperature and stresses.
Matsui, Shingo*; Muto, Yasushi*; Shiina, Yasuaki
Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(2), p.175 - 186, 2003/06
no abstracts in English
Oba, Masaki; Maruyama, Yoichiro
JAERI-Research 2001-040, 24 Pages, 2001/08
JAERI-Research-2001-040.pdf:2.35MB
no abstracts in English
Minakawa, Nobuaki; Moriai, Atsushi; Otomo, Akitoshi; Rifai*
Nihon Zairyo Gakkai Dai-36-Kai X Sen Zairyo Kyodo Ni Kansuru Shimpojiumu Koen Rombunshu, p.272 - 275, 2000/09
no abstracts in English
*; *; Kawasaki, Hirotsugu; Aoto, Kazumi
JNC TY9400 2000-010, 138 Pages, 2000/03
JNC-TY9400-2000-010.pdf:5.15MB
None
Ishikura, Shuichi*; Kogawa, Hiroyuki; Teshigawara, Makoto; Kikuchi, Kenji; Futakawa, Masatoshi; Kaminaga, Masanori; Hino, Ryutaro
JAERI-Tech 2000-008, p.80 - 0, 2000/02
JAERI-Tech-2000-008.pdf:3.19MB
no abstracts in English
Ishiyama, Shintaro; Akiba, Masato; Eto, Motokuni
Journal of Nuclear Science and Technology, 37(1), p.90 - 101, 2000/01
no abstracts in English
Hada, Kazuhiko
Nihon Kikai Gakkai Rombunshu, A, 65(636), p.108 - 115, 1999/08
no abstracts in English
Kasahara, Naoto; Yacumpai, A.*; Takasho, Hideki*
JNC TN9400 99-019, 34 Pages, 1999/02
At incomplete mixing area of high temperature and low temperature fluids near the surface of structures, temperature fluctuation of fluid gives thermal fatigue damage to wall structures. This thermohydraulic and thermomechanical coupled phenomenon is called thermal striping, which has so complex mechanism and sometimes causes crack initiation on the structural surfaces that rational evaluation methods are required for screening rules in design codes. In this study, frequency response characteristics of structures and its mechanism were investigated by both numerical and theoretical methods. Based on above investigation, a structural response diagram was derived, which can predict stress amplitude of structures from temperature amplitude and frequency of fluids. Furthermore, this diagram was generalized to be the Non-dimensional structural response diagram by introducing non-dimensional parameters such as Biot number, non-dimensional frequency, and non-dimensional stress. The use of the Non-dimensional structural response diagram appears to evaluate thermal stress caused by thermal striping, rapidly without structural analysis, and rationally with considering attenuation by non-stationary heat transfer and thermal unloading. This diagram can also give such useful information as sensitive frequency range to adjust coupled thermohydraulic and thermomechanical analysis models taking account of four kinds of attenuation factors: turbulent mixing, molecular diffusion, non-stationaly heat transfer, and thermal unloading.
; Hirakawa, Yasushi; Kano, Shigeki; Yoshida, Eiichi
PNC TN9410 98-048, 56 Pages, 1998/03
Planar specimens of functionally gradient material (FGM) for thermal stress relaxation in fast reactor environment were formed and evaluated. FGMs of Al
O
-SUS316L system and YO-SUS316L system were deposited on SUS316L substrates by low pressure plasma spraying. The deposited coatings with 6 layers in which the ratio of ceramics/SUS316FR changes from 0 to 100% by 20% were successfully formed. Cross-sectional observation of the coatings showed no cracks and the hardness in the coating increased continuously from the substrate to the surface. From the results of X-ray diffraction, there were no changes in the structure of SUS316L and YO between the powder and the coating. On the contrary, in the case of AlO, 
- AlO phase was detected in the coating formed from 
_
_
$ powder. The specimens were exposed in liquid sodium at 823K or 923K for 3.6Ms(1000h). The coatings were damaged with many cracks in liquid sodium. It was revealed that the bonding strength between the sprayed particles were not sufficient. To improve the stability in liquid sodium, another specimens were formed with changing the chamber pressure during deposition. From the microstructural inspections of the specimens, the coating formed at higher chamber pressure showed less porosity.
Watanabe, Ryuzo*
PNC TJ9601 98-005, 85 Pages, 1998/03
To fabricate a long life fuel cladding tubes for the fast breeder reactor, the concept of functionally graded material was applied for the material combination of molybdenum/stainless steel/ titanium, in which titanium is placed at the inner side to withstand against fission products and neutron irradiation, and molybdenum at the outer side to withstand corrosion by liquid sodium coolant. Slurry dipping method was employed for the processing because of its capability of shape forming and microstructural control. The graded layers of titanium and molybdenum were formed on both sides of stainless steel substrate according to an optimum composition profile for the thermal stress reduction. Such graded layers were successfully formed by slurry dipping. Dispersion, sedimentation, viscosity, rheology, as well as yield value, of the slurries were investigated in detail inconnection with properties of dispersion medium, dispersion reagent, binder and raw powders. Low- and high-viscosity slurries were investigated to enlarge a possibility of film thickness control. For the low-viscosity slurry it is necessary to suppress the sedimentation of dispersion particles, while for the high-viscosity slurry it turned out to be important to clarify the flow characteristics of the slurry for the determination of the yield value, which is needed for the precise control of the dip-coated layer thickness. The forming conditions were determined for the low-viscosity slurry in taking sedimentation rate and sedimentation height as measures of slurry stability and dispersion, respectively. It was confirmed that slow sedimentation and low sedimentation height gave reproducible film forming. The high-viscosity slurry was free from sedimentation, and the control of the film thickness with viscosity and yield value was rather easier. The consolidation Process of the dip-coated layer, including drying and debinding, followed conventional powder metallurgical techniques, with particular ...
Chijimatsu, Masakazu*; Matsumoto, Kazuhiro*; Kanno, Takeshi; Ishiguro, Katsuhiko; Sugita, Yutaka; Moro, Yoshiji*; Ishikawa, Hirohisa
PNC TN8410 97-025, 57 Pages, 1997/01
None
Ishiyama, Shintaro; Akiba, Masato; Eto, Motokuni
Journal of Nuclear Materials, 228, p.275 - 283, 1996/00
Times Cited Count：4 Percentile：39.42(Materials Science, Multidisciplinary)no abstracts in English
kasahara, Naoto;
PNC TN9410 95-211, 32 Pages, 1995/08
In order to optimize elevated temperature structural systems in fast reactor plants, where main loading is thermal stress induced by transient operation of circuit, authors proposed new design frame by applying design by analysis concept to both structural design and system design. A key technology in this design frame is an integrated analysis method for both thermo-mechanical behaviors of structures and plant thermo-hydraulic dynamics, developing of a prototype code of which, named PARTS (Program for Arbitrary Real Time Simulation), was started this year. For the purpose to achieve flexible coupling of several codes, authors designed three categories of calculation parts (objects): (1)thermo-hydraulics of coolant, (2)thermo-mechanical behavior of structures, and (3)material strength. These calculation parts can be handled and connected easily on the PARTS-Workbench. Real time simulation is planed to be accomplished by parallel processing of individual parts calculation, and by prediction of neural-network which learned past calculation results. Object oriented languages, Smalltalk and C++, were adopted for implementation of calculation parts. The PARTS-Workbench was programed by visual Basic and Visual Smalltalk for considering user customization. In the next phase of study, parallel processing function and neural network parts will be incorporated in the PARTS code. Prototype of this code is going to be completed until F.Y.1996. and be applied to study of thermal mitigation structures.
