Fuel Porosity and Crack Effects on Transient Overpower Analysis

Abstract

Void volume within an FBR fuel pin is shown to have a substantial effect on predictions of cladding strain and lifetime for transient overpower accident analysis. This void volume is made up of the central cavity, radial and axial plane cracks, and manufactured porosity. Analytic models are described for predicting void distribution, crack closure and porosity collapse under fuel stress fields imposed by cladding. These models are incorporated in a computer code called DSTRESS. Results demonstrate the importance of void modeling in transient overpower accident analysis.