Three-dimensional finite element analysis of pilgering process of hybrid-layer cladding for advanced small modular fast reactor application

Abstract

Small Modular Reactors (SMRs) are being rapidly developed based on extensive naval experience in order to provide much higher safety and flexibility in tailoring capacity. Liquid-metal cooled fast-neutron SMRs need improved structural materials with better corrosion resistance. An innovative cladding material called a functionally graded composite has been developed at MIT for service with liquid-metal coolants. In this study, using materials data for Fe-12Cr-2Si and F91 alloys, 3-dimensional computational analyses of the elastic-plastic pilgering process of a functionally graded composite tube have been made using a finite element modeling technique to describe the hybrid-layer plate. In plate rolling, our results show that, because of flow stress differences between the two alloys, the curvature of the rolled plate and thickness reduction rate of the two alloys can be modified by controlling the speed of each roll die, and the friction coefficient. With an upper/lower roll speed ratio of 1.36, or upper/lower friction coefficient ratio of 2.0, the bending of the rolled plate and its strain distribution are minimized. These results from the analysis will be utilized to design a process for the optimization of pilgering for functionally graded composites to produce fuel cladding and coolant pipes with yield and cost efficiency.