Multi-hazard performance of reinforced concrete dry casks subjected to chloride attack and tip-over impact

Vertical concrete dry storage systems (or dry casks) are circular containers made of steel and/or reinforced concrete, specifically developed for storing spent nuclear fuel (SNF). In the United States, dry casks have an intended life of 40 years; however, in the absence of a permanent repository for storage of SNF, it is expected that dry casks will remain in service for a significantly longer period of time. Tipping-over is considered as one of the hypothetical accident conditions. The consequence of such an incident may be more severe if the structural integrity of the dry cask is compromised during the extended service life due to steel corrosion and related material degradation. In this study, structural performance of a 1/3-scale vertical concrete cask is evaluated under combined corrosion-induced damage and tip-over impact. The results are compared with those from a control cask, which is only subjected to impact but no corrosion-induced damage. The impact response of both casks in terms of acceleration, velocity, and strain was measured and compared. The damage after testing is investigated in terms of cracking and deformation to identify the failure modes for each cask and the effects of aging on the structural performance.