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Wakai, Eiichi; Kim, B. J.; Nozawa, Takashi; Kikuchi, Takayuki; Hirano, Michiko*; Kimura, Akihiko*; Kasada, Ryuta*; Yokomine, Takehiko*; Yoshida, Takahide*; Nogami, Shuhei*; et al.
Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 6 Pages, 2013/03
Wakai, Eiichi; Kikuchi, Takayuki; Kogawara, Takafumi; Kimura, Haruyuki; Yokomine, Takehiko*; Kimura, Akihiko*; Nogami, Shuhei*; Kurishita, Hiroaki*; Saito, Masahiro*; Nishimura, Arata*; et al.
Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 6 Pages, 2011/03
Japanese activities of test facilities in IFMIF-EVEDA (International Fusion Materials Irradiation Facility-Engineering Validation and Engineering Design Activities) project have three subjects of engineering design of post irradiation examination (PIE) facilities, small specimen test technique (SSTT), and engineering design of high flux test module (HFTM), and this paper is summarized about present status. Functional analysis and design of 2-D and 3-D models of PIE facility were performed. In HFTM, as materials of heater, W-3Re alloy and/or SiC/SiC composite were selected in the points of high temperature materials, fabrication technology and some suitable properties such as resistance of thermal shock, high temperature re-crystallization, ductility, resistance of irradiation degradation, and low-activation. In SSTT, a test machine of fracture toughness was designed and developed for small specimens with 10 mm square, and it had high accuracy controllability for stress and displacement.
Teshigawara, Makoto; Harada, Masahide; Saito, Shigeru; Oikawa, Kenichi; Maekawa, Fujio; Futakawa, Masatoshi; Kikuchi, Kenji; Kato, Takashi; Ikeda, Yujiro; Naoe, Takashi*; et al.
Journal of Nuclear Materials, 356(1-3), p.300 - 307, 2006/09
Times Cited Count：9 Percentile：52.88(Materials Science, Multidisciplinary)We adopted silver-indium-cadmium (Ag-In-Cd) alloy as a material of decoupler for decoupled moderator in JSNS. However, from the heat removal and corrosion protection points of view, the Ag-In-Cd alloy is needed to clad between Al alloys (Al5083). We attempted to obtain good bonding conditions for between Al5083 and ternary Ag-In-Cd alloys by HIPing tests. The good HIP condition was found for small test piece (
20mm). Though a hardened layer due to the formation of AlAg
was found in the bonding layer, the rupture strength of the bonding layer was more than 20 MPa, which was the calculated design stress. Bonding tests of a large size piece (200
20030 mm
), which simulated the real scale, were also performed according to the results of small size tests. The result also gave good bonding and enough required-mechanical-strength, however the rupture strength of the large size test was smaller than that of small one.
Teshigawara, Makoto; Harada, Masahide; Saito, Shigeru; Kikuchi, Kenji; Kogawa, Hiroyuki; Ikeda, Yujiro; Kawai, Masayoshi*; Kurishita, Hiroaki*; Konashi, Kenji*
Journal of Nuclear Materials, 343(1-3), p.154 - 162, 2005/08
Times Cited Count：10 Percentile：56.15(Materials Science, Multidisciplinary)For decoupled and poisoned moderator, a thermal neutron absorber, i.e., decoupler, is located around the moderator to give neutron beam with a short decay time. A B4C decoupler is already utilized, however, it is difficult to use in a MW class source because of He void swelling and local heating by (n,a) reaction. Therefore, a Ag-In-Cd (AIC) alloy which gives energy-dependence of macroscopic neutron cross section like that of B
C was chosen. However, from heat removal and corrosion protection points of view, AIC is needed to bond between an Al alloy (A6061-T6), which is the structural material of a moderator. An AIC plate is divided into a Ag-In (15wt%) and Ag-Cd (35wt%) plate to extend the life time, shorten by burn up of Cd. We performed bonding tests by HIP (Hot Isostatic Pressing). We found out that a better HIP condition was holding at 803 K, 100 MPa for 1 h for small test pieces (f20mm). Though a hardened layer is found in the bonding layer, the rupture strength of the bonding layer is more than 20 MPa, which is less than that of the design stress.
Kurishita, Hiroaki*; Yamamoto, Takuya*; Narui, Minoru*; Yoshitake, Tsunemitsu; Akasaka, Naoaki
JNC TY9400 2004-006, 48 Pages, 2004/04
JNC-TY9400-2004-006.pdf:1.95MB
Radiation embrittlement in high-strength ferritic/martensitic steels of 2WFK and 63WFS and oxide dispersion strengthened (ODS) martensitic steel of H-35 that were irradiated in the experimental fast reactor JOYO is evaluated by instrumented Charpy impact tests for miniaturized (1.5 x 1.5 x 20 mm) and half-sized Charpy V-notch (CVN) specimens. Effects of thermal aging and microstructural evolution during irradiation on radiation embrittlement are described. Next, in order to clarify the specimen size effects on the ductile-to-brittle transition temperature (DBTT) in Charpy impact testing, a method to evaluate the plastic constraint loss for differently sized CVN specimens that may be responsible for the size effects is proposed and applied to 2 WFK. In the method, the constraint factor, a, that is an index of the plastic constraint is defined as a = s*/sy*. Here, s* is the critical cleavage fracture stress which is a material constant and sy* is the uniaxial yield stress at the DBTT at the strain rate generated in the Charpy impact test. The procedures for evaluating each of s* and sy* are described and the result of s* and sy*, thus the value of a, is presented for various types of miniaturized and full-sized CVN specimens of 2 WFK. It is shown that there is the following relationship between a and the specimen size factor, (A*/b2). a=a0-k(A*/b2)0.4 Here, A* is the critical area for cleavage fracture and b is the ligament size. a0 and k are constants depending on a /W (a is the notch depth and W is the specimen width). a increases with increasing a /W.
Li, J.-F.*; Kawai, Masayoshi*; Kikuchi, Kenji; Igarashi, Tadashi*; Kurishita, Hiroaki*; Watanabe, Ryuzo*; Kawasaki, Akira*
Journal of Nuclear Materials, 321(2-3), p.129 - 134, 2003/09
Times Cited Count：15 Percentile：68.58(Materials Science, Multidisciplinary)For the development of tantalum-clad tungsten targets for spallation neutron sources, the bonding strength of tantalum-tungsten interface was investigated by means of an easy-to-use and miniaturized small punch (SP) test, in which a punching load is vertically applied to the center of a jointed disk. Cracks initiated and propagated in the tungsten side for all the samples hot-isostatically pressed (HIPed) at temperatures from 1673 to 2073 K, whereas nocrack and debonding were observed in the interface, indicating that the jointed interface is strongly bonded. The re-crystallization of tungsten occurs and results in its strength reduction, consequently the crack-initiating load decreases with HIPing temperature. The finite element analysis of the measured SP testing results shows that the maximum bonding strength can exceed 1000 MPa. The present study shows that SP test is suitable for the strength evaluation of jointed tantalum-tungsten interfaces.
Kawai, Masayoshi*; Furusaka, Michihiro; Li, J.-F.*; Kawasaki, Akira*; Yamamura, Tsutomu*; Mehmood, M.*; Kurishita, Hiroaki*; Kikuchi, Kenji; Takenaka, Nobuyuki*; Kiyanagi, Yoshiaki*; et al.
Proceedings of ICANS-XVI, Volume 3, p.1087 - 1096, 2003/07
In order to establish the technique fabricating a thin target slab with a real size, thin tantalum-clad tungsten slab with a hole for a thermocouple was fabricated with the high-precision machinery techniques and the HIP'ing method. The ultrasonic diagnostic showed that tantalum and tungsten bond was perfect. The HIP optimum condition was certified by means of the small punch test as already reported. The electrolytic coating technique in a molten salt was developed to make a thinner tantalum cladding on a tungsten target with a complicated shape, in order to reduce radioactivity from tantalum in an irradiated target.
Kawai, Masayoshi*; Furusaka, Michihiro*; Kikuchi, Kenji; Kurishita, Hiroaki*; Watanabe, Ryuzo*; Li, J.*; Sugimoto, Katsuhisa*; Yamamura, Tsutomu*; Hiraoka, Yutaka*; Abe, Katsunori*; et al.
Journal of Nuclear Materials, 318, p.35 - 55, 2003/05
R&D works for MW class solid target composed of tungsten to produce pulsed intense neutron source has been made in order to construct a future scattering facility. Three methods were investigated to prevent corrosion of tungsten from water; those are hipping, brazing and electric coating in molten salt bath. Hipping condition was optimized to be 1500 degree C in the previous work: here small punch test shows highest load for crack initiation of hipped materials at the boundary of W/Ta. The basic techniques for the other two methods were developed. Erosion test showed that uncovered W is susceptible of flowing water velocity. At high velocity w is easy to be eroded. For solid target design slab type and rod type targets were studied. As long as the optimized neutron performance is concerned, 1MW solid target is better than mercury target.
Kawai, Masayoshi*; Li, J.*; Watanabe, Ryuzo*; Kurishita, Hiroaki*; Kikuchi, Kenji; Igarashi, Tadashi*; Kato, Masahiro*
Dai-23-Kai Nihon Netsu Bussei Shimpojiumu Koen Rombunshu, p.313 - 315, 2002/11
The objective of the present study is to develop the stainless-steel-bonded tungsten alloys by powder metallurgy processes. Commercially available tungsten powders and stainless steel (SUS304L) powder were used as the raw materials and mixed by ball milling at the ratios of 97mass% W -3% SUS and 93mass% W -7mass% SUS. Powder compacts were formed by die pressing and cold isostatic pressing (CIP), then sintered mainly in vacuum at the temperatures above the melting point of the stainless steel phase. Some samples were fabricated by glass-encapsulated hot isostatic pressing (HIPing) at lower temperatures. The microstructural observation was made by scanning electron microscopy (SEM). The thermal properties of the produced alloy and various tungsten materials supplied from Allied Material Corp. was measured with the laser-frash method. It was found that stable liquid-phase-sintered microstructures were not easily formed in the tungsten-stainless steel system. The electron probe microanalysis (EPMA) revealed that tungsten was considerably dissolved in the stainless steel phase during sintering. Therefore, thermal conductivity of the W/7 mass% SUS alloy was 22.8-53.5 W/m/K that was very lower than theoretical value calculated from those of pure tungsten and stainless steel. Its temperature dependence is resembled to that of stainless steel, i.e., thermal conductivity increased with the specimen temperature as like stainless steel. The diffusivity of pure tungsten is compared with those of tungsten alloys.
Kawai, Masayoshi*; Kikuchi, Kenji; Kurishita, Hiroaki*; Li, J.*; Furusaka, Michihiro*
Journal of Nuclear Materials, 296(1-3), p.312 - 320, 2001/07
Times Cited Count：47 Percentile：93.66(Materials Science, Multidisciplinary)no abstracts in English
Kuwabara, K.*; Kurishita, Hiroaki*; Ukai, Shigeharu; Narui, Makoto*; Mizuta, Shunji; Yamazaki, M.*; Kayano, H.*
Journal of Nuclear Materials, 258-263(Part 2), p.1236 - 1241, 1998/10
Times Cited Count：29 Percentile：88.40(Materials Science, Multidisciplinary)None
Kurishita, Hiroaki*
PNC TJ9601 98-003, 38 Pages, 1998/03
None
Tanno, Takashi; Yano, Yasuhide; Oka, Hiroshi*; Kurishita, Hiroaki*
no journal, ,
Miniature 3 point bend test was applied to evaluate fracture toughness of ferritic/martensitic steel (PNC-FMS) for fast reactor subassembly wrapper tube. In this work, it was clarified that pre-crack length and open angle of side groove are important to obtain the certain and conservative fracture toughness with miniatured specimen. Finally, the fracture toughness value J
of PNC-FMS could be obtained with miniaturized specimen which can be applied to wrapper tube thickness.
Tanno, Takashi; Fujita, Koji; Yano, Yasuhide; Kurishita, Hiroaki*
no journal, ,
Miniature 3 point bend test was applied to evaluate fracture toughness of ferritic/martensitic steel (PNC-FMS) for fast reactor subassembly wrapper tube. In this work, the anisotropy in toughness of rolled PNC-FMS was successfully confirmed with the specimen which was modified in the geometry. In addition, it was confirmed that data can be obtained with good reproducibility for specimens having plural geometries.
Wakai, Eiichi; Kondo, Hiroo; Kanemura, Takuji; Hirakawa, Yasushi; Furukawa, Tomohiro; Kikuchi, Takayuki; Ito, Yuzuru*; Hoashi, Eiji*; Yoshihashi, Sachiko*; Horiike, Hiroshi*; et al.
no journal, ,
no abstracts in English
Tanno, Takashi; Oka, Hiroshi; Yano, Yasuhide; Kurishita, Hiroaki*
no journal, ,
Fracture toughness is an important property when ferritic martensitic steel (FMS) is irradiated and thermally aged. The goal of this study is to develop reasonably miniaturized fracture toughness test technique which can be applied for irradiated or sampled from welded small specimen. In this phase, the capability of miniature 3-point bend (3PB) test technique for evaluating toughness, and the side groove effect on miniatured specimen were confirmed. A miniature 3PB type J test conforming to ASTM 1820 was applied to the PNC-FMS developed for the fast reactor. The effect of the root radius of the side groove that controls the crack propagation was verified for the specimen miniaturized to 5 mm thickness, 3 mm width and 22.5 mm length according to the thickness of the wrapper tube. The crack winded and/or branched with root radius of 0.5 mm, the standard size of ASTM1820. But by making it 0.05 mm, it was possible to control the crack propagation along the side groove. As a result, J
= 300 kJ/m
was obtained, and a prospect of this technique was obtained for the fracture toughness evaluation of the wrapper tube by improving the side groove.
Tokunaga, Kazutoshi*; Fujiwara, Tadashi*; Ezato, Koichiro; Suzuki, Satoshi; Akiba, Masato; Kurishita, Hiroaki*; Yoshida, Naoaki*
no journal, ,
no abstracts in English
Osone, Ryuji; Bucheeri, A.; Kurishita, Hiroaki*; Kato, Masahiro*; Yamasaki, Kazuhiko*; Maekawa, Katsuhiro*; Naoe, Takashi; Futakawa, Masatoshi
no journal, ,
Liquid mercury target system for high power spallation neutron sources is being developed. When high intensity proton beams are injected into the target, pressure waves are generated by the thermal shock in mercury and pitting damage will be imposed on the target vessel. Bubble injection into mercury is effective to mitigate the pressure waves. In this work, we propose a method of fabricating meso-nozzle for bubble injection. The method is based on powder metallurgy by inserting thin glass fibers into a metal powder matrix to create a green compact, followed by sintering at a temperature between the melting points of the powder and the fiber. SUS316L and molybdenum powders were used as the nozzle matrix materials. In order to investigate optimum sintering condition, experiments were performed at different combination of pressing load and sintering temperature. We found that in molybdenum high relative density and straight hole with circlar cross section were obtained.
Bucheeri, A.; Kurishita, Hiroaki*; Kato, Masahiro*; Naoe, Takashi; Kogawa, Hiroyuki; Futakawa, Masatoshi; Maekawa, Katsuhiro*
no journal, ,
Mercury target system for high power spallation neutron sources is being developed. Proton beam will be injected into the target. Pressure waves will be generated and cavitation damage will be imposed on the target vessel. Injection of microbubbles may be effective to act as a cushion against pressure waves. Numerical simulations were carried out to investigate the optimum generation of microbubbles taking into account; wettability, bubbler size, gas flow rate, and liquid flowing velocity. It was found that orientation with respect to flowing liquid and bubbler geometry are essential parameters. The fabrication method uses Mo and 316L SS powders and glass fibers of 100 
m in diameter. Sintering at a temperature between melting point causes glass to evaporate leaving a hole and densify the powder. Green compacts were prepared at various compressive loads and then subjected to sintering. The hole exhibited straightness and a circular cross-section, and was free from powder and glass.
Teshigawara, Makoto; Harada, Masahide; Saito, Shigeru; Oikawa, Kenichi; Maekawa, Fujio; Kikuchi, Kenji; Kato, Takashi; Ikeda, Yujiro; Naoe, Takashi; Oi, Toshiyuki; et al.
no journal, ,
no abstracts in English
