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Yamashita, Shinichiro; Ioka, Ikuo; Nemoto, Yoshiyuki; Kawanishi, Tomohiro; Kurata, Masaki; Kaji, Yoshiyuki; Fukahori, Tokio; Nozawa, Takashi*; Sato, Daiki*; Murakami, Nozomu*; et al.
Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.206 - 216, 2019/09
After the nuclear accident at Fukushima Daiichi Power Plant, research and development (R&D) program for establishing technical basis of accident-tolerant fuel (ATF) started from 2015 in Japan. Since then, both experimental and analytical studies necessary for designing a new light water reactor (LWR) core with ATF candidate materials are being conducted within the Japanese ATF R&D Consortium for implementing ATF to the existing LWRs, accompanying with various technological developments required. Until now, we have accumulated experimental data of the candidate materials by out-of-pile tests, developed fuel evaluation codes to apply to the ATF candidate materials, and evaluated fuel behavior simulating operational and accidental conditions by the developed codes. In this paper, the R&D progresses of the ATF candidate materials considered in Japan are reviewed based on the information available such as proceedings of international conference and academic papers, providing an overview of ATF program in Japan.
Katayama, Yoshinori; Hattori, Takanori; Fukui, Hiroshi*; Nozawa, Akifumi*; Funakoshi, Kenichi*
no journal, ,
Liquid water shows anomalous properties and these properties are attributed to a network structure formed by hydogen-bonded water molecules. Such an open strucutre due to the four-fold coordination is easily transformed to a denser structure by an increase of pressure. To study the structure of water under high pressure, we have carried out in-situ high-pressure high-temperature X-ray diffraction experiments in SPring-8, a large syncrotron radiation facility. In the previous study, we carried out X-ray diffraction measurements using a cubic-type multianvil press installed on BL14B1 and found that the structure of water changes to a simple structure which can be described by a hard shpare model. In this study, we used a Kawai-type double-stage press installed on BL04B1 and extended the maximum pressure to about 17 GPa. By using relatively large sample, 1.5 mm in diameter, high quality data with low background noise were obtained. The stcuture factor, 
, at ambient pressure has two maxima at 2A
and 3A. With increasing pressure, these maxima merged and formed a sharp peak which is resembles that for a simple liquid. Futher compression shifted the peak to high-Q direction. The increase of density is attributed to an increase of coordination number up to a few GPa and then it is attributed to a decrease of inter-molecular distance at higher pressures.
Katayama, Yoshinori; Hattori, Takanori; Fukui, Hiroshi*; Nozawa, Akifumi*; Funakoshi, Kenichi*
no journal, ,
Liquid water shows anomalous properties and these properties are attributed to a network structure formed by hydogen-bonded water molecules. To study the structure of water under high pressure, we have carried out in-situ high-pressure high-temperature X-ray diffraction experiments in SPring-8. In addition to the previous X-ray diffraction measurements using a cubic-type multianvil press installed on BL14B1, measurements up to about 17 GPa were successfully carried out using a Kawai-type double-stage press installed on BL04B1. The stcuture factor, , at ambient pressure has two maxima at 2A and 3A. With increasing pressure, these maxima merged and formed a sharp peak which is resembles that for a simple liquid. Futher compression shifted the peak to larger-Q direction. The increase of density is attributed to an increase of coordination number up to a few GPa and then it is attributed to a decrease of inter-molecular distance at higher pressures.
Yamashita, Shinichiro; Ioka, Ikuo; Nemoto, Yoshiyuki; Shirasu, Noriko; Kurata, Masaki; Kaji, Yoshiyuki; Fukahori, Tokio; Watanabe, Seiichi*; Kirimura, Kazuki*; Kakiuchi, Kazuo*; et al.
no journal, ,
Since the accident at Fukushima Daiichi Nuclear Power Station, enhancing the accident tolerance of Light Water Reactors (LWRs) became a topic of serious discussion, and the research and development (R&D) for improving the safety LWRs has been activated in many countries. In Japan, the R&D project on accident tolerant fuel and other components (ATFs) of LWRs, which is sponsored and organized by the Ministry of Economy, Trade and Industry (METI), has been initiated in 2015 for establishing technical basis of ATFs. The Japan Atomic Energy Agency (JAEA) has coordinated and carried out this ATF R&D project in cooperation with power plant providers, fuel venders and universities for making the best use of the experiences, knowledges in commercial uses of zirconium-base alloys in LWRs.
Yamashita, Shinichiro; Ioka, Ikuo; Nemoto, Yoshiyuki; Shirasu, Noriko; Kurata, Masaki; Kaji, Yoshiyuki; Fukahori, Tokio; Watanabe, Seiichi*; Murakami, Nozomu*; Sato, Hisaki*; et al.
no journal, ,
Since the accident at Fukushima Daiichi Nuclear Power Station, enhancing the accident tolerance of Light Water Reactors (LWRs) became a topic of serious discussion, and the research and development for improving the safety LWRs has been activated in many countries. This project is one of the projects that entrusted from the Ministry of Economy, Trade and Industry Agency for Natural Resources and Energy. Using a domestic human source, an analysis tool, know-how and experience, the basic technique to apply an accident tolerant fuel material to an existing LWRs is developed in the project. It is started from October, 2015 and is carrying out this project continuously.
Yamashita, Shinichiro; Ioka, Ikuo; Nemoto, Yoshiyuki; Kawanishi, Tomohiro; Kaji, Yoshiyuki; Fukahori, Tokio; Nozawa, Takashi*; Watanabe, Seiichi*; Murakami, Nozomu*; Sato, Hisaki*; et al.
no journal, ,
Yamashita, Shinichiro; Ioka, Ikuo; Nemoto, Yoshiyuki; Kawanishi, Tomohiro; Kaji, Yoshiyuki; Fukahori, Tokio; Nozawa, Takashi*; Watanabe, Seiichi*; Murakami, Nozomu*; Sato, Hisaki*; et al.
no journal, ,
Yamashita, Shinichiro; Ioka, Ikuo; Nemoto, Yoshiyuki; Kawanishi, Tomohiro; Kurata, Masaki; Kaji, Yoshiyuki; Fukahori, Tokio; Nozawa, Takashi*; Sato, Daiki*; Murakami, Nozomu*; et al.
no journal, ,
Research and development (R&D) program for establishing technical basis of ATFs for light water reactor (LWR) started in 2015. Since then the R&D is being conducted in cooperation with power plant providers, fuel venders, research institutes and universities for making the most use of the experiences in R&D, practical design, and evaluations of fuels and cores of commercial LWRs. Among currently explored ATF candidate materials in the program, silicon carbide composite reinforced by SiC fiber (SiC/SiC) and FeCrAl steel strengthened by dispersion of fine oxide particles (FeCrAl-ODS) offer several attractive features including the remarkable high temperature capabilities and the slow kinetics of steam oxidation reactions. This presentation will give an overview of the progress in ATF development and review the current status of data availability and integrity for the properties and behaviors of ATF candidate materials, followed by discussion on the primary differences from zirconium alloy in the behaviors in the severe accident scenarios. Finally, subjects to be solved for practical use of ATF will be summarized.
Yamashita, Shinichiro; Ioka, Ikuo; Nemoto, Yoshiyuki; Kurata, Masaki; Kawanishi, Tomohiro; Kaji, Yoshiyuki; Fukahori, Tokio; Watanabe, Seiichi*; Murakami, Nozomu*; Sato, Hisaki*; et al.
no journal, ,
In Japan, research and development (R&D) program for establishing technical basis of ATF started in 2015 and is being conducted in cooperation with power plant providers, fuel venders and universities for making the most use of the experiences in R&D, practical design, and evaluations of fuels and cores of commercial LWRs. The present paper reviews the progress of the development and summarizes subjects to be solved for ATF cladding, based on the attribute guide which was originally drawn up in the Japanese ATF R&D program as it should be an indicator of proper ATF development guidance.