Degradation Mechanism Analysis on Spent Fuel Zircaloy Cladding in Interim Storage

• Main Authors: Chin-kun Chen, 陳錦坤
• Other Authors: Ching-Kong Chao
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/3ut72p

碩士 === 國立臺灣科技大學 === 機械工程系 === 94 === The Zircaloy cladding creep rupture is one of the degradation mechanisms for spent fuel in interim dry storage. According to the latest version of ISG-11, the author used the C*-Integral energy method applied in the analysis of creep effect for spent fuel cladding in interim dry storage, and discussed the different effects of hydride orientations, initial crack lengths and storage temperature on cladding failure in this paper. Finally, the result will estimate which kind of environment and storage conditions are most likely to cause degradation leading to cladding failure in the interim dry storage. In summary, it was found that the initial crack length and the temperature curve effects played an important role in the interim dry storage, but the hydrogen content and the hydride orientation are irrelevant. The results showed that the cladding with double cracks will cause the fastest penetration through any given thickness of cladding. If the storage temperature is kept at 400℃, the cladding can be preserved safely except when the initial length of the double cracks is longer than the maximum length. When the storage temperature rises slowly or remains at a constant temperature of 400℃, it will be safe for the cladding which stores in the interim dry storage. This study has established the relationship between the temperature and the crack growth in the interim dry storage. This paper also contains a reliable cladding integrity evaluation for spent fuel in the interim dry storage.