Selection of Materials for a Supercritical CO₂ Cooled

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Report Date: August 2002
Appendices: No

Abstract

An initial survey was made of published literature on candidate materials for service as structure, cladding, and fuel in a supercritical CO2 gas-cooled fast reactor. A principal emphasis was placed on corrosion resistance relying heavily on British AGR experience. The evidence strongly suggests that available steels will prove suitable for use in the core, reactor pressure vessel, and gas turbine power cycle. There is, however, a lack of corrosion data at the high CO2 pressures of current interest, 20 MPa, or in CO2 subjected to the intense fast neutron fluxes in a GCFR.

UC and US fuels are neutronically superior to UO2, which has proven to be otherwise suitable. However, both US and UC are oxidized by CO2, which probably limits them to use as cermets.

Zirconium and its alloys appear to be neutronically superior to steels, but convincing evidence that its corrosion resistance in CO2 is acceptable has not been found. Thus, the use of zirconium may be limited to fuel concepts where a protective clad layer is employed or where operating temperature is reduced below the current reference conditions of 550oC coolant outlet, 700 oC clad hot spot.
Program:     GFR: Gas-cooled Fast Reactors

Type:     TR 

RPT. No.: 1