[2I08-17] SiC

[2I13] The feasibility study on SiC composite fuel cladding for the Accident Tolerant Fuel to the existing PWR plants

(2)Study on fuel rod behavior during operation

*Kenichiro Furumoto¹, Hideyuki Teshima¹, Seiichi Watanabe¹, Teruhisa Yamamoto¹, Shinichiro Yamashita², Noriko Shirasu², Hiroaki Saito² (1. MNF, 2. JAEA)

Keywords:accident tolerant fuel, SiC composite, fuel cladding, PWR, fuel rod behavior

Analytical evaluations were performed to investigate in-pile behavior of the fuel rod with SiC composite fuel cladding as an accident tolerant fuel during normal and transient operational conditions. In SiC and conventional Zr-based alloys, not only basic material properties differ, but there are some specific behaviors in SiC such as dissolution due to corrosion, and secondary stress caused by the differential swelling across the cladding wall due to temperature dependence of the swelling. We developed the method to calculate such specific behavior of SiC by modification of fuel performance evaluation code and combination with finite-element approach. As the result of the analysis, fuel temperature with SiC composite cladding tended to become higher relative to conventional Zr rod. And large stresses would be applied to SiC composite cladding due to PCMI and secondary stress due to differential swelling. In order to reduce cladding stresses, effects of the changes of cladding wall thickness and annular pellet were discussed in this work.