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Marium, M.*; Aoki, Kentaro*; He, Y.*; Yamamoto, Katsuhiro*; Suwansoontorn, A.*; Ikuta, Seiya*; Hara, Mitsuo*; Nagano, Shusaku*; Nagao, Yuki*; Nishikawa, Kei*; et al.
ACS Applied Energy Materials (Internet), 8(22), p.16589 - 16600, 2025/11
Times Cited Count：0 Percentile：0.00(Chemistry, Physical)Kada, Wataru*; Miura, Kenta*; Kato, Hijiri*; Saruya, Ryota*; Kubota, Atsushi*; Sato, Takahiro; Koka, Masashi; Ishii, Yasuyuki; Kamiya, Tomihiro; Nishikawa, Hiroyuki*; et al.
Nuclear Instruments and Methods in Physics Research B, 348, p.218 - 222, 2015/04
Times Cited Count：9 Percentile：53.79(Instruments & Instrumentation)Katsuyama, Jinya; Nishikawa, Hiroyuki*; Udagawa, Makoto; Nakamura, Mitsuyuki*; Onizawa, Kunio
Journal of Pressure Vessel Technology, 135(5), p.051402_1 - 051402_9, 2013/10
Times Cited Count：30 Percentile：71.66(Engineering, Mechanical)The residual stresses generated within the weld-overlay cladding and base material of reactor pressure vessel (RPV) steel was evaluated for as-welded and post-welded heat-treated conditions using thermo-elastic plastic creep analyses considering phase transformation. By comparing the analytical results with the experimentally determined values, we found a good agreement for the residual stress distribution within the cladding and the base material. It was shown that considering phase transformation during welding was important for improving the accuracy of residual stress analysis. Using the calculated residual stress distribution, we performed fracture mechanics analyses for an RPV during pressurized thermal shock events. We evaluated the effect of the weld residual stress on the structural integrity of an RPV. The results indicated that consideration of residual stress produced by weld-overlay cladding and PWHT is important for assessing the structural integrity of RPV.
Nishikawa, Hiroyuki*; Masaki, Koichi*; Katsuyama, Jinya; Onizawa, Kunio
Nihon Genshiryoku Gakkai Wabun Rombunshi, 12(3), p.211 - 221, 2013/09
Probabilistic fracture mechanics analysis code PASCAL3 has been developed at JAEA to support the validation of the codes and standards which provide the structural integrity assessment method of reactor pressure vessels (RPVs) during pressurized thermal shock. Previous version of PASCAL2 has many functions including the evaluation method for an embedded crack, PTS transient database, non-destructive inspection models. This code has been improved mainly focusing on cladding on the inner surface of RPV. Using the PASCAL3 code, effects of the initiation and growth model for a surface flaw have been analyzed to determine the standard condition of PASCAL3. Deterministic and probabilistic evaluation using PASCAL3 for current structural integrity assessment method for RPV has also been conducted. The results show that the consideration of warm pre-stress effect decreases the conditional probability
Osakabe, Kazuya*; Nishikawa, Hiroyuki*; Masaki, Koichi*; Katsuyama, Jinya; Onizawa, Kunio
Proceedings of the ASME 2013 Pressure Vessels and Piping Conference (PVP 2013) (DVD-ROM), 7 Pages, 2013/07
To assess the structural integrity of reactor pressure vessels (RPV) during pressurized thermal shock (PTS) events, a deterministic fracture mechanics approach has been widely used. According to Japan Electric Association Code (JEAC), the stress intensity factors (SIF) at the crack tip and the fracture toughness are calculated. The structural integrity is judged to be maintained unless the SIF during PTS events is less than fracture toughness. On the other hand, the application of a probabilistic fracture mechanics (PFM) analysis method has become attractive recently because uncertainties related to input parameters can be incorporated rationally. Probabilities of crack initiation and through-wall cracking can be obtained from PFM analyses. In this paper, in order to verify the applicability of a PFM method to JEAC, deterministic and probabilistic analyses have been performed and the effects of initial crack size on probability of crack initiation has been analyzed.
Tanabe, Yusuke*; Iwamoto, Takashi*; Takahashi, Junichi*; Nishikawa, Hiroyuki*; Sato, Takahiro; Ishii, Yasuyuki; Kamiya, Tomihiro
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 129, 2013/01
Omichi, Masaaki*; Takano, Katsuyoshi*; Sato, Takahiro; Kamiya, Tomihiro; Ishii, Yasuyuki; Okubo, Takeru; Koka, Masashi; Kada, Wataru; Sugimoto, Masaki; Nishikawa, Hiroyuki*; et al.
Journal of Nanoscience and Nanotechnology, 12, p.7401 - 7404, 2012/09
Times Cited Count：3 Percentile：14.92(Chemistry, Multidisciplinary)Takano, Katsuyoshi*; Asano, Atsushi*; Maeyoshi, Yuta*; Marui, Hiromi*; Omichi, Masaaki*; Saeki, Akinori*; Seki, Shu*; Sato, Takahiro; Ishii, Yasuyuki; Kamiya, Tomihiro; et al.
Journal of Photopolymer Science and Technology, 25(1), p.43 - 46, 2012/07
Times Cited Count：3 Percentile：8.77(Polymer Science)Onizawa, Kunio; Masaki, Koichi; Osakabe, Kazuya*; Nishikawa, Hiroyuki*; Katsuyama, Jinya; Nishiyama, Yutaka
Nihon Hozen Gakkai Dai-9-Kai Gakujutsu Koenkai Yoshishu, p.374 - 379, 2012/07
To assure the structural integrity of a reactor pressure vessel (RPV) is known as one of the critical issues to maintain the safe long-term operation of a nuclear power plant. In Japan, the assessment methods for RPV integrity, stipulated in the codes and standards, have been endorsed by the regulatory body. Authors have initiated extensive research on the improvement of structural integrity assessment methods of RPVs. In this paper, we describe some research results obtained from the first-year activity. These include the study on revisiting the technical background of the methods, such as loading conditions, postulated crack definition, the other evaluation methods. In addition, studies on probabilistic methods for the applicability to the current rules and the standardization of the probabilistic analysis methods have been presented.
Takano, Katsuyoshi*; Sugimoto, Masaki; Asano, Atsushi*; Maeyoshi, Yuta*; Marui, Hiromi*; Omichi, Masaaki*; Saeki, Akinori*; Seki, Shu*; Sato, Takahiro; Ishii, Yasuyuki; et al.
Transactions of the Materials Research Society of Japan, 37(2), p.237 - 240, 2012/06
Maeyoshi, Yuta*; Takano, Katsuyoshi*; Asano, Atsushi*; Marui, Hiromi*; Omichi, Masaaki*; Sato, Takahiro; Kamiya, Tomihiro; Ishii, Yasuyuki; Okubo, Takeru; Koka, Masashi; et al.
Japanese Journal of Applied Physics, 51(4R), p.045201_1 - 045201_4, 2012/04
Times Cited Count：1 Percentile：4.04(Physics, Applied)Nishikawa, Hiroyuki*; Osakabe, Kazuya*; Goto, Nobuhisa*; Suzuki, Hirokazu*; Katsuyama, Jinya; Onizawa, Kunio
Mizuho Joho Soken Giho (Internet), 4(1), 5 Pages, 2012/03
Stainless steel with 5 mm thickness is weld-overlay cladded on the inner surface reactor pressure vessels for protecting the vessel walls against the corrosion. Residual stress which corresponds to yield stress is generated near the cladding layer due to the weld-overlay cladding. However, there is no specific provision in the codes related to the cladding. Therefore, in order to confirm how the residual stress affects on the structural integrity of RPVs during pressurize thermal shock events, we evaluate the residual stress caused by the weld-overlay cladding and effects of the stress on the structural integrity. In this paper, the analysis method of welding residual stress of RPVs using finite element method and that of fracture mechanics considering postulated crack are introduced.
Matsuura, Hideaki*; Kochi, Shohei*; Nakaya, Hiroyuki*; Yasumoto, Takashi*; Nakao, Yasuyuki*; Shimakawa, Satoshi; Goto, Minoru; Nakagawa, Shigeaki; Nishikawa, Masabumi*
Nuclear Engineering and Design, 243, p.95 - 101, 2012/02
Times Cited Count：24 Percentile：81.99(Nuclear Science & Technology)The performance of a high-temperature gas-cooled reactor as a tritium production device was examined. A gas turbine high-temperature reactor of 300 MWe nominal capacity (GTHTR300) was assumed as the calculation target of a typical gas-cooled reactor, and using the continuous-energy Monte Carlo transport code MVP-BURN, burn-up simulations for the 3-dimensional entire-core region of GTHTR300 were carried out considering its unique double heterogeneity structure. It was shown that gas-cooled reactors with thermal output power of 3 GW in all can produce 6-10 kg of tritium in a year.
Tanabe, Yusuke*; Nishikawa, Hiroyuki*; Sato, Takahiro; Ishii, Yasuyuki; Kamiya, Tomihiro
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 163, 2012/01
Takano, Katsuyoshi*; Sato, Takahiro; Kamiya, Tomihiro; Ishii, Yasuyuki; Okubo, Takeru; Koka, Masashi; Kada, Wataru; Sugimoto, Masaki; Seki, Shuhei*; Nishikawa, Hiroyuki*
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 162, 2012/01
m band using focused proton beamMiura, Kenta*; Machida, Yuki*; Uehara, Masato*; Kiryu, Hiromu*; Ozawa, Yusuke*; Sasaki, Tomoyuki*; Hanaizumi, Osamu*; Sato, Takahiro; Ishii, Yasuyuki; Koka, Masashi; et al.
Key Engineering Materials, 497, p.147 - 150, 2012/00
Times Cited Count：7 Percentile：93.85(Engineering, Electrical & Electronic)m band using focused proton beamMiura, Kenta*; Machida, Yuki*; Uehara, Masato*; Kiryu, Hiromu*; Ozawa, Yusuke*; Sasaki, Tomoyuki*; Hanaizumi, Osamu*; Sato, Takahiro; Ishii, Yasuyuki; Koka, Masashi; et al.
Key Engineering Materials, 497, p.147 - 150, 2011/12
Times Cited Count：6 Percentile：2.48Sasaki, Akira; Nishihara, Katsunobu*; Sunahara, Atsushi*; Furukawa, Hiroyuki*; Nishikawa, Takeshi*; Koike, Fumihiro*
Plasma and Fusion Research (Internet), 6(Sp.1), p.2401145_1 - 2401145_4, 2011/12
Atomic processes and radiation from multiple charged ions in plasmas are of the interest in the investigation of plasma wall interaction and transport of impurity ions in the fusion devices. The emission from multiple charged ions is also investigated for the development of extreme ultra violet light (EUVL) sources at 
. Efficient emission through the 4d-4f + 4p-4d transition array is obtained from tin ions. An optimization of pumping conditions of laser produced plasma sources is carried out theoretically and experimentally. We also investigate an extension of the plasma light sources to short wavelength to 
using Gd and Tb plasmas. We discuss requirements to the atomic structure, rate coefficient and collisional radiative codes to determine ion abundance and level population as a function of plasma temperature and density, to calculate the radiation intensity as well as emission spectrum.
Kamiya, Tomihiro; Takano, Katsuyoshi; Sato, Takahiro; Ishii, Yasuyuki; Nishikawa, Hiroyuki*; Seki, Shu*; Sugimoto, Masaki; Okumura, Susumu; Fukuda, Mitsuhiro*
Nuclear Instruments and Methods in Physics Research B, 269(20), p.2184 - 2188, 2011/10
Times Cited Count：21 Percentile：79.93(Instruments & Instrumentation)Takano, Katsuyoshi; Sato, Takahiro; Ishii, Yasuyuki; Koka, Masashi; Kamiya, Tomihiro; Okubo, Takeru; Sugimoto, Masaki; Nishikawa, Hiroyuki*; Seki, Shu*
Transactions of the Materials Research Society of Japan, 36(3), p.305 - 308, 2011/09
