R&D program for Establishing Technical Basis of Accident Tolerant Fuel Materials in Japan

Yamashita, Shinichiro   ; Ioka, Ikuo  ; Nemoto, Yoshiyuki  ; Kawanishi, Tomohiro; Kaji, Yoshiyuki  ; Fukahori, Tokio  ; Nozawa, Takashi*; Watanabe, Seiichi*; Murakami, Nozomu*; Sato, Hisaki*; Kondo, Takao*; Sakamoto, Kan*; Kusagaya, Kazuyuki*; Ukai, Shigeharu*; Kimura, Akihiko*; Yamaji, Akifumi*

In order to increase accident tolerance of light water reactors (LWRs), fuel rod, channel box and control rod with new materials and concepts have been considered and developed in Japan. Since 2015, Japan Atomic Energy Agency has conducted and coordinated the Japanese R&D program of accident tolerant fuel (ATF) for establishing technical basis of ATF under a program sponsored and organized by the Ministry of Economy, Trade and Industry (METI). ATF candidate materials considered in this METI program are silicon carbide (SiC) composite and FeCrAl steel strengthened by dispersion of fine oxide particles (FeCrAl-ODS). SiC composite is a highly attractive material because of its lower hydrogen generation rate and lower reaction heat in comparison with conventional Zircaloy. Therefore, practical uses for a fuel cladding of pressurized water reactor (PWR) and for the fuel cladding, channel box of boiling water reactor (BWR) are expected. On the other hand, FeCrAl-ODS steel is a promising material and is considered to apply to the fuel cladding of BWR. Until now, we have been accumulated experimental data of the candidate materials by out-of-pile tests, developed fuel evaluation codes to apply to the candidate materials, evaluated fuel behavior simulating operational and accidental conditions by the developed code. In this paper, we will report the updates of out-of-pile data and evaluation results.