Development of elemental technologies for application of SiC fuel cladding to BWR

Ishibashi, Ryo*; Sasaki, Masana*; Shibata, Masatoshi*; Yasuda, Kenichi*; Nemoto, Yoshiyuki  ; Hinoki, Tatsuya*

Silicon carbide-based (SiC-based) materials are considered to provide outstanding passive safety features in beyond-design-basis severe accident (SA) scenarios. SiC-fiber-reinforced SiC-matrix ceramic composites have been developed for fuel structure applications such as cladding tubes. We have focused on development of fabrication and evaluation technologies such as corrosion resistant coating and end-plug joining to resolve technical issues for application to boiling water reactors (BWRs). The corrosion resistant coating aimed to prevent dissolution of silica from SiC to coolant water during normal operations of BWR. Metallic coatings on SiC were examined in terms of corrosion resistance in simulated BWR environment. Ti-coating performed good corrosion resistance. The end-plug joint aimed to provide sufficient strength against SA conditions. The joining technology that consists of a mechanical fastening and brazing are under development. Its joint strength and deformation mechanism were examined around the temperature at which the joint portion was estimated to reach during SA.