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Ikushima, Kazuki*; Shibahara, Masakazu*; Nishikawa, Satoru*; Furukawa, Takashi*; Akita, Koichi; Suzuki, Hiroshi; Morooka, Satoshi
E-Journal of Advanced Maintenance (Internet), 9(3), p.NT87_1 - NT87_5, 2017/11
Akita, Koichi; Shibahara, Masakazu*; Ikushima, Kazuki*; Nishikawa, Satoru*; Furukawa, Takashi*; Suzuki, Hiroshi; Harjo, S.; Kawasaki, Takuro; Vladimir, L.*
Yosetsu Gakkai Rombunshu (Internet), 35(2), p.112s - 116s, 2017/06
Ikushima, Kazuki*; Kitani, Yuji*; Shibahara, Masakazu*; Nishikawa, Satoru*; Furukawa, Takashi*; Akita, Koichi; Suzuki, Hiroshi; Morooka, Satoshi
Yosetsu Gakkai Rombunshu (Internet), 35(2), p.75s - 79s, 2017/06
Ikushima, Kazuki*; Shibahara, Masakazu*; Akita, Koichi; Suzuki, Hiroshi; Morooka, Satoshi; Nishikawa, Satoru*; Furukawa, Takashi*
Welding in the World, 61(3), p.517 - 527, 2017/05
In this study, first, an analysis method to predict the behaviour of residual stress distribution on shot peening process was proposed. In the proposed method, the load distribution on the collision of shots was modelled, and it was integrated with the dynamic analysis method based on the idealized explicit FEM (IEFEM). The accuracy of the proposed analysis system was confirmed by comparing the stress distribution on the collision of a single shot with the results analyzed by ABAQUS. The thermal elastic plastic analysis method using IEFEM was applied to the analysis of residual stress distribution of multi-pass welded pipe joint. The calculated residual stress distribution was compared with the measured residual stress distribution using X-ray diffraction (XRD). As a result, it was shown that the both welding residual distribution agree well with each other. Considering the calculated welding residual stress distribution, the modification of stress distribution due to shot peening was predicted by the proposed analysis system. As a result, the similar stress distribution with measurement by XRD was obtained in case that a large number of collisions are considered.
Suzuki, Kenji*; Yamagishi, Aoi*; Nishikawa, Satoru*; Shobu, Takahisa
Hozengaku, 11(2), p.91 - 98, 2012/07
In this study, a residual stress distribution in a dissimilar plate butt-welded joint was simulated by a thermo-elastic finite element method. The base metal was the austenitic stainless steel SUS316L. The other base metal was nickel super-alloy NCF600, and the weld metal was the alloy 82 (YNiCr-3). The dimensions of the plate butt-welded joint were a width of 200 mm, a length of 250 mm and a thickness of 25 mm. The welding joint was fabricated by TIG welding with 22 passes. For comparison, the residual stress distribution for the similar butt-welded joint of SUS316L was simulated as well as the dissimilar welded joint. According to the simulated results, there was not the difference in the thermal field between the similar and the dissimilar welded joints. The residual stress distribution in the similar welded joint became symmetrical to the welding center after removal of the weld bead. For the dissimilar welded joint, the peak of the residual stresses moved to the NCF600 side a little. The residual stress level of the dissimilar welded joint was large compared with the similar welded joint. The residual stress of the welding direction was larger than that of the transverse direction.
Akita, Koichi; Suzuki, Hiroshi; Nishikawa, Satoru*; Okita, Shigeru*
Nihon Zairyo Gakkai Dai-61-Ki Tsujo Sokai, Gakujutsu Koenkai Rombunshu (USB Flash Drive), 2 Pages, 2012/05
Residual stresses on the surface and inside of ultrasonic shot peened dissimilar weld joint were measured using X-ray and neutron diffraction before and after thermal loading. Mechanism of residual stress relaxation due to thermal loading was discussed.
Hoshiya, Taiji; Shimakawa, Satoshi; ; *
Journal of Nuclear Materials, 191-194, p.1070 - 1074, 1992/00
Times Cited Count：10 Percentile：67.8(Materials Science, Multidisciplinary)no abstracts in English
Hoshiya, Taiji; Shimakawa, Satoshi; ; *; Watanabe, Kenji*
Journal of Nuclear Materials, 179-181, p.1119 - 1122, 1991/00
Times Cited Count：17 Percentile：84.12(Materials Science, Multidisciplinary)no abstracts in English
Yasumoto, Takashi*; Matsuura, Hideaki*; Shimakawa, Satoshi; Nakao, Yasuyuki*; Kochi, Shohei*; Nakaya, Hiroyuki*; Goto, Minoru; Nakagawa, Shigeaki; Nishikawa, Masabumi*
no journal, ,
no abstracts in English
Matsuura, Hideaki*; Yasumoto, Takashi*; Shimakawa, Satoshi; Kochi, Shohei*; Nakaya, Hiroyuki*; Nakao, Yasuyuki*; Goto, Minoru; Nakagawa, Shigeaki; Nishikawa, Masabumi*
no journal, ,
no abstracts in English
Matsuura, Hideaki*; Kochi, Shohei*; Nakaya, Hiroyuki*; Yasumoto, Takashi*; Nakao, Yasuyuki*; Shimakawa, Satoshi; Goto, Minoru; Nakagawa, Shigeaki; Nishikawa, Masabumi*
no journal, ,
The performance of a high-temperature gas-cooled reactor as a tritium production device for fusion reactors was examined by performing a core burn-up calculation with the continuous-energy Monte Carlo code MVP-BURN. It was shown that the high-temperature gas cooled reactor can contribute to the tritium production for fusion reactors.
Kochi, Shohei*; Matsuura, Hideaki*; Nakaya, Hiroyuki*; Nakao, Yasuyuki*; Shimakawa, Satoshi; Goto, Minoru; Nakagawa, Shigeaki; Nishikawa, Masabumi*
no journal, ,
Changes in a control rod value and a production amount of tritium with burnup were examined with a continuous energy Monte Carlo code MVP-BURN for a high temperature gas cooled reactor in which B
C control rods were replaced with Li control rods. It was shown that the amount of tritium production was increased about 20% from the previous study and the excess reactivity was properly controlled by installing the Li control rods into the outer region of the core.
Goto, Minoru; Nakagawa, Shigeaki; Shimakawa, Satoshi; Matsuura, Hideaki*; Nakao, Yasuyuki*; Nishikawa, Masabumi*; Nakaya, Hiroyuki*
no journal, ,
A High Temperature Gas-cooled Reactor (HTGR) with lithium particle, which can produce a large amount of tritium without the change of the original reactor design, is proposed as a tritium production device for an initial fusion reactor. However, the tritium production using High Temperature Engineering Test Reactor (HTGR) is not carried out so far and the investigation of the problem about its system is not carried out so far, too. Therefore we extracted a problem from an engineering viewpoint and investigated the feasibility. The problems are expected to be solved by using the HTTR technologies, which are manufacturing the coated fuel particle and handling of the fuel, and the system is feasible from an engineering viewpoint.
Nakaya, Hiroyuki*; Matsuura, Hideaki*; Nakao, Yasuyuki*; Nishikawa, Masabumi*; Goto, Minoru; Shimakawa, Satoshi; Nakagawa, Shigeaki
no journal, ,
111The performance of the tritium production by High Temperature Gas-cooled Reactor (HTGR) was evaluated in case of using GTHTR300 as a HTGR. In the evaluation, parametric study was performed for the fuel exchange period and the operation period for one batch. The amount of tritium production was calculated by whole core burnup calculation using the continuous-energy Monte Carlo transport code MVP-BURN. As a result, 23 kg of tritium, which is required for a fusion reactor as fuel, is produced for 1.7 year with the condition in which the fuel exchange period and the operation period are set to 30 days and 240 days, respectively.
Akita, Koichi; Suzuki, Hiroshi; Moriai, Atsushi; Harjo, S.; Nishikawa, Satoru*
no journal, ,
To clarify the relaxation process on dissimilar metal weld joints, 
stress measurements during thermal cycles from RT to 593 K were conducted using a neutron engineering diffractometer, TAKUMI in J-PARC. The effects of the difference in thermal expansion coefficient of the materials and the temperature dependence of the yield strength on the residual stress relaxation were discussed based on the experimental results.
Akita, Koichi; Suzuki, Hiroshi; Nishikawa, Satoru*; Moriai, Atsushi; Harjo, S.; Vladimir, L.*
no journal, ,
The materials used for the dissimilar weld joint were a SUS316L stainless steel and a NCF600 nickel alloy for the base plates, and an Alloy82 nickel alloy for the weld metal. The ultrasonic shot peening (USP) was applied to the sample surface after welding. The residual stress mappings of the as-peened and heat treated (593 K, 2 h) samples were measured at room temperature using KOWARI in ANSTO. In the results, the reduction of the tensile residual stress was observed near the interface of the weld metal and the nickel base plate. To clarify the relaxation process, the in-situ stress measurements during thermal cycles from RT to 593 K were conducted using TAKUMI in J-PARC. The effects of the difference in thermal expansion coefficient of the materials and the temperature dependence of the yield strength on the residual stress relaxation were disscussed based on the experimental results.
Akita, Koichi; Nishikawa, Satoru*; Suzuki, Hiroshi; Moriai, Atsushi; Harjo, S.
no journal, ,
Residual stress measurements inside a dissimilar metal welded joint were performed during thermal cycles using an engineering neutron diffractometer, TAKUMI in J-PARC/MLF. The materials used for the welded joint were SUS316L and NCF600 for base plates, and Alloy82 for the weld metal. Tensile residual stresses were observed at the depth of 4.2 mm of the welded joint at the room temperature. As the temperature increased, the tensile residual stresses in NCF600 and Alloy82 increased, whereas the tensile residual stress in SUS316L decreased. These phenomena in the temperature increasing process can be explained by the thermal expansion coefficient of each material.
Akita, Koichi; Nishikawa, Satoru*; Shibahara, Masakazu*; Ikushima, Kazuki*; Suzuki, Hiroshi; Moriai, Atsushi; Harjo, S.; Aizawa, Kazuya
no journal, ,
To clarify the residual stress relaxation process in a dissimilar weld joint, the in-situ neutron stress measurements during thermal cycles were conducted using TAKUMI in J-PARC. The materials used for the base plates were a Ni-alloy (NCF600) and a stainless steel (SUS316L). The temperature range was from RT to 593 K. From the experimental results, it was found that residual stress of the Ni-alloy increased, while the residual stress of the stainless steel decreased, in the heating process. And, the residual stress of the Ni-alloy reaches the yield strength of the material in the heating process. It results in the redistribution of the residual stress, and therefore the residual stress relaxation occurs.
Akita, Koichi; Moriai, Atsushi; Suzuki, Hiroshi; Harjo, S.; Nishikawa, Satoru*; Shibahara, Masakazu*; Ikushima, Kazuki*
no journal, ,
Internal residual stresses of a dissimilar weld joint under cyclic thermal aging were measured using neutron diffraction technique and the residual stress relaxation process was investigated.
Kitamura, Yoshisato*; Okada, Takashi*; Ikushima, Kazuki*; Shibahara, Masakazu*; Nishikawa, Satoru*; Akita, Koichi
no journal, ,
no abstracts in English
