Influence of the Test Temperature on the Creep Rate of 0.12C18Cr10NiTi Structural Steel Irradiated in the BN-350 Reactor

Abstract

This article discusses the influence of irradiation in the BN-350 fast neutron reactor on the mechanical properties and the thermal creep of 0.12C18Cr10NiTi austenite steel for the purpose of estimating the lifetime of structure materials with regard to long-term storage of spent nuclear fuel. Mechanical tests have been performed at 350 and 450°C. It is established that at 450°C the strength properties increase and the relative elongation decrease up to destruction, which is attributed to inverse α' → γ transformation intensely running in the irradiated steel at 450°C. With the temperature increase from 350 to 450°C, the rate of established creep of the irradiated steel increases by ~3.7 times. The amount and sizes of carbide inclusions generated upon long-term exposure at 450°C decrease, which can shorten the time of dry storage of spent reactor fuel assemblies.