Advanced technology fuel cladding materials and their oxidation at high temperature steam

Pham, V. H.   ; Yamashita, Shinichiro   ; Nemoto, Yoshiyuki  ; Ueno, Fumiyoshi  ; Okada, Yuji*; Sato, Daiki*; Ishibashi, Ryo*; Sasaki, Masana*

Since the disasters in 2011 at Fukushima Daiichi Nuclear Power Station, the need of developing advanced technology fuel cladding tubes which have better performance during normal operation, as well as severe accident conditions than the conventional Zry cladding has become obvious. Among various candidates for advanced technology fuel cladding materials, Cr-coated Zry and SiC cladding have become the most interested ones. In this study, oxidation tests of Cr-coated Zry and SiC materials at high-temperature steam are being studied and discussed to investigate their performance under severe accident conditions. The results of this investigations indicated that both Cr-coated Zry and SiC cladding materials showed beneficial aspects over the conventional Zry cladding. For example, Cr-coated Zry sample exhibited a lower oxidation reaction rate and produced less hydrogen gas at 1200C than that of Zry sample. In the meantime, SiC demonstrated excellent performance in steam at temperature below 1700C. However, formation of bubbles on SiC sample surface obversed at 1800C might lead to a higher oxiadtion reaction rate. Dispite the fact that oxidation of SiC may significantly increase at temperatures above 1800C, SiC is still the most potential candidate for ATF fuel cladding in terms of structural integrity and oxidation resistance in steam at present.