Nickel Cladded Structural Components for Advanced Reactors

Abstract

The aggressive corrosive environment along with higher operating temperature in molten salt reactors present significant challenges to existing structural materials that have been qualified in the ASME Section III, Division 5 Code for high temperature cyclic service. Corrosion resistant claddings offer an attractive near-term solution to mitigate corrosion concerns and enable the use of ASME Code qualified materials for advanced reactor structural components. Nickel provides good corrosion resistance to molten salts as well as good thermal and mechanical compatibility with existing ASME Code qualified materials, and therefore can be used as a cladding material for structural components in molten salt reactors. However, there are currently no ASME design rules for cladded components to guard against creep-fatigue failure and ratcheting strain accumulation under high temperature cyclic service. Recently, we have developed new design rules for components cladded with creep-compliant materials (e.g. nickel clad on 316H base metal) for high temperature cyclic service. These design rules require design parameters that can be established through relatively short-term testing for the clad material. This work shows how the design parameters for nickel are developed using fatigue and creep-fatigue test data. Finally, the paper walks through a sample problem detailing the application of the design rules to 316H components cladded with nickel.