Overview of Oxidation Test Results of Austenitic Alloys Coated by CRN and Nicraly in High Temperature Steam Environments

Abstract

The current development of accident-tolerant fuel (ATF) claddings is aiming at the improvement of the high temperature integrity of new solutions over the existing zirconium claddings. The characterization of the new proposed cladding materials is essential in order to assess their feasibility in commercial use. The cladding material should tolerate loss of active cooling for a significant period without failing. This paper describes the experimental work done at VTT on a candidate cladding solution by using a high temperature steam furnace capable of working at temperatures up to 1600°C. Experiments were performed on Alloy 800H, NiCrAlY coated Alloy 800H tubes, and CrN coated AISI316L coupon specimens at the temperature of 1200°C in flowing steam conditions. Post-test analyses are reported in terms of weight change measurements and microstructure observations by using state of the art electron microscopes.