PNNL

Abstract

The evaluation of spent nuclear fuel casks under impact loading is an important safety topic that is reviewed as part of cask certification by the United States Nuclear Regulatory Commission. Explicit dynamic finite element models of full cask systems are increasingly common in industry for determining structural integrity during hypothetical drop accidents. Full cask model results are also used as the loading basis for single fuel pin impact models, which evaluate the response of fuel cladding under drop conditions. In this paper, a simplified cask system is evaluated to illustrate several important structural dynamic phenomena, including the effect of gaps between components, the difference in local response at various points on a cask during impact, and the effect of modeling various simplified representations of the basket and fuel assemblies contained within the cask. This paper focuses on the cask impact analysis, and how loading conditions for a subsequent fuel assembly or fuel cladding analysis can be extracted.