Improvement of plant reliability based on combining of prediction and inspection of crack growth due to intergranular stress corrosion cracking

Uchida, Shunsuke; Chimi, Yasuhiro; Kasahara, Shigeki; Hanawa, Satoshi; Okada, Hidetoshi*; Naito, Masanori*; Kojima, Masayoshi*; Kikura, Hiroshige*; Lister, D. H.*

Nuclear Engineering and Design, 341, p.112 - 123, 2019/01

https://doi.org/10.1016/j.nucengdes.2018.10.021

Improvement of plant reliability based on reliability-centered-maintenance (RCM) is going to be undertaken in NPPs. RCM is supported by risk-based maintenance (RBM). The combination of prediction and inspection is one of the key issues to promote RBM. Early prediction of IGSCC occurrence and its propagation should be confirmed throughout the entire plant systems which should be accomplished by inspections at the target locations followed by timely application of suitable countermeasures. From the inspections, accumulated data will be applied to confirm the accuracy of the code, to tune some uncertainties of the key data for prediction, and then, to increase their accuracy. The synergetic effects of prediction and inspection on application of effective and suitable countermeasures are expected. In the paper, the procedures for the combination of prediction and inspection are introduced.

Research on engineering technology in the full-scale demonstration of EBS and operation technology for HLW disposal; Research report in 2012 (Joint research)

Nakatsuka, Noboru; Sato, Haruo; Tanai, Kenji; Nakayama, Masashi; Sawada, Sumiyuki*; Asano, Hidekazu*; Saito, Masahiko*; Yoshino, Osamu*; Tsukahara, Shigeki*; Hishioka, Sosuke*; et al.

JAEA-Research 2013-034, 70 Pages, 2014/01

JAEA-Research-2013-034.pdf:9.11MB

Japan Atomic Energy Agency (JAEA) and Radioactive Waste Management Funding and Research Center (RWMC) concluded the letter of cooperation agreement on the research and development of radioactive waste disposal in April, 2005, and have been carrying out the collaboration work based on the agreement. JAEA have been carrying out the Horonobe Underground Research Laboratory (URL) Project which is intended for a sedimentary rock in the Horonobe town, Hokkaido, since 2001. In the project, geoscientific research and research and development on geological disposal technology are being promoted. Meanwhile, the government (the Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry) has been promoting construction of equipments for the full-scale demonstration of engineered barrier system and operation technology for high-level radioactive waste (HLW) disposal since 2008, to enhance public's understanding to the geological disposal of HLW, e.g. using underground facility. RWMC received an order of the project in fiscal year 2012 (2011/2012) continuing since fiscal year 2008 (2008/2009). Since topics in this project are included in the Horonobe URL Project, JAEA carried out this project as collaboration work continuing in fiscal year 2008. This report summarizes the results of engineering technology carried out in this collaboration work in fiscal year 2012. In fiscal year 2012, part of the equipments for emplacement of buffer material was produced and visualization test for water penetration in buffer material were carried out.

Probing carbon edge exposure of iron phthalocyanine-based oxygen reduction catalysts by soft X-ray absorption spectroscopy

Niwa, Hideharu*; Saito, Makoto*; Kobayashi, Masaki*; Harada, Yoshihisa*; Oshima, Masaharu*; Moriya, Shogo*; Matsubayashi, Katsuyuki*; Nabae, Yuta*; Kuroki, Shigeki*; Ikeda, Takashi; et al.

Journal of Power Sources, 223, p.30 - 35, 2013/02

https://doi.org/10.1016/j.jpowsour.2012.09.031

To design non-platinum, inexpensive, but high performance carbon-based cathode catalysts for polymer electrolyte fuel cells, it is important to elucidate the active site for oxygen reduction reaction (ORR). However, it is difficult to directly identify the active site by applying conventional structural or electronic probes to such complex systems. Here, we used C 1 X-ray absorption spectroscopy (XAS) to observe electronic structure of carbon in iron phthalocyanine-based catalysts, and found a signature of edge exposure below the edge, whose intensity is well correlated with the ORR activity. These results demonstrate that C 1 XAS can be used to characterize the ORR activity of carbon-based cathode catalysts in terms of the edge exposure.

Enhancement of local electrical conductivities in SiC by femtosecond laser modification

Deki, Manato; Ito, Takuto*; Yamamoto, Minoru*; Tomita, Takuro*; Matsuo, Shigeki*; Hashimoto, Shuichi*; Kitada, Takahiro*; Isu, Toshiro*; Onoda, Shinobu; Oshima, Takeshi

Applied Physics Letters, 98(13), p.133104_1 - 133104_3, 2011/03

https://doi.org/10.1063/1.3573786

Recent progress in the energy recovery linac project in Japan

Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05

http://accelconf.web.cern.ch/AccelConf/IPAC10/papers/tupe091.pdf

Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.

Improvement of the marine radionuclides prediction code in the off Shimokita Region

Kobayashi, Takuya; Togawa, Orihiko; Ito, Toshimichi; Otosaka, Shigeyoshi; Kawamura, Hideyuki; Hayashi, Keisuke*; Shima, Shigeki*; Nakayama, Tomoharu*; In, Teiji*

JAEA-Research 2009-040, 63 Pages, 2009/12

JAEA-Research-2009-040.pdf:12.19MB

A spent nuclear fuel reprocessing plant has the possibility of routine releases of liquid radioactive wastes from a discharge pipe to the off Shimokita region during its operations. Thus, for environmental safety, it is important to assess the migration processes of released radionuclides from the plant. Therefore, an ocean circulation prediction code and an oceanic radionuclides migration prediction code, which were developed by Japan Atomic Energy Agency, has been improved to describe the migration behavior of radionuclides in the off Shimokita region. Parameters on characteristics and dynamics of particulate materials in seawater have also been obtained in the study area for the adjustment and verification of the oceanic radionuclides migration prediction code. This report summarizes the primary results of the study which was carried out at the off Shimokita region from FY2003 to 2008.

MeV- and sub-MeV-photon sources based on Compton backscattering at SPring-8 and KPSI-JAEA

Kawase, Keigo; Kando, Masaki; Hayakawa, Takehito; Daito, Izuru; Kondo, Shuji; Homma, Takayuki; Kameshima, Takashi; Kotaki, Hideyuki; Chen, L.*; Fukuda, Yuji; et al.

Nuclear Physics Review, 26(Suppl.), p.94 - 99, 2009/07

We constructed MeV- and sub-MeV-photon sources by means of Compton backscattering with a laser light and an electron beam at SPring-8 and KPSI-JAEA. MeV-photon source consists of a continuous-wave optically-pumped far infrared laser and an 8-GeV stored electron beam. Sub-MeV-photon source consists of a Nd:YAG pulse-laser and an 150-MeV electron beam accelerated by a microtron. Both source have been succeeded backscattered photon generation. In this talk, I will present characteristics and future prospects of these photon sources.

ZnO as fast scintillators evaluated with Ni-like Ag laser

Furukawa, Yusuke*; Tanaka, Momoko; Murakami, Hidetoshi*; Saito, Shigeki*; Sarukura, Nobuhiko*; Nishikino, Masaharu; Yamatani, Hiroshi; Nishimura, Hiroaki*; Mima, Kunioki*; Kagamitani, Yuji*; et al.

Reza Kenkyu, 36(APLS), p.1028 - 1030, 2008/12

https://doi.org/10.2184/lsj.36.1028

Optical technologies in extreme ultraviolet (EUV) region have been receiving strong interests for the next generation lithography. Here we report properties of ZnO as scintillators in the EUV region, and to demonstrate the feasibility of using a Ni-like Ag EUV laser operated at 13.9-nm to evaluate these properties. The ZnO sample was irradiated with EUV laser pulses and the fluorescence was measured using a streak camera fitted with a spectrograph. A clear, excitonic, fluorescence peak was observed at around 380 nm with a decay lifetime of 3 ns. The prominent peak fluorescence is ideal for EUV detection and further applications including imaging.

Progress in R&D efforts on the energy recovery linac in Japan

Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.

Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06

Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.

Evaluation of fast EUV scintillator using 13.9 nm X-ray laser

Tanaka, Momoko; Furukawa, Hiroyuki*; Murakami, Hidetoshi*; Saito, Shigeki*; Sarukura, Nobuhiko*; Nishikino, Masaharu; Yamatani, Hiroshi; Nagashima, Keisuke; Kagamitani, Yuji*; Ehrentraut, D.*; et al.

Journal of Physics; Conference Series, 112(4), p.042058_1 - 042058_4, 2008/00

https://doi.org/10.1088/1742-6596/112/4/042058

Optical technologies in the extreme ultraviolet (EUV) region have been receiving strong interest for the next generation lithography. Efficient and fast scintillators are one of the key devices functioning in the EUV region. In this paper, we report excellent properties of ZnO and GaN as scintillators in the EUV region, and to demonstrate the feasibility of using a Ni-like Ag EUV laser operated at 13.9-nm to evaluate these properties. The sample was irradiated with EUV laser pulses, and the fluorescence spectrum and the fluorescence lifetime were measured using a streak camera fitted with a spectrograph. In the case of ZnO, a clear, excitonic, fluorescence peak was observed at around 380 nm with a decay lifetime of 3 ns. For GaN, a fluorescence peak at 370 nm having slower 5-ns decay time was observed. In this respect, the EUV scintillation properties of ZnO is said to be more favorable than GaN.