Study On The Corrosion Behavior Of T91and316L Steels In Liquid LBE

The Liquid Lead-Bismuth Eutectic (LBE) is considered as a potential candidatematerial of the spallation target and coolant for Accelerator Driven Sub-critical system(ADS), but the high temperature, high velocity and high-density LBE will have acorrosive effect on the structural materials, the technology of oxygen measurement andcontrol is the key of reactor. It is significant to carry out the corrosive experiments inoxygen controlled LBE.This test condition in this paper were based on the working condition of theself-designed CLEAR-I (China LEAd-based Reactor) of Nuclear Safety Institute of theChinese Academy. T91and316L steels are the typical candidate structural materials ofreactor, the high temperature corrosion tests of them are performed at480℃with theLBE velocity of0.3m/s. In order to estimate the cross section, corrosion products andthe thickness, the corrosion behavior of materials exposed in LBE with differentconcentration of oxygen were examined by scanning electron microscopy(SEM), energydispersion X-ray spectroscopy (EDS) and X-ray diffraction (XRD).The test results showed that i.e.(1) In non-oxygen controlled LBE, oxide film weregenerated on the surface of both specimens exposed in LBE after500h,1000h and1500h, the thickness of corrosion film are increasing with the increase of time.(2)When the oxygen concentration was10-6wt%, the thinner corrosion film were detctedon the surface of both steels exposed in LBE after600h and1500h compared with thesituation in non-oxygen controlled LBE after500h and1500h respectively.(3) Innon-oxygen controlled LBE and LBE with10-6wt%[O], neither dissolution nor LBEpenetrating into the matrix was detected. A thick corrosion film was detected on thesurface of T91specimen, the corrosion products was composed of two sub-layers i.e.the outer layer Fe3O4and the inner layer (Fe,Cr)3O4, while a single thinner corrosionlayer (Fe,Cr)3O4was observed on316L specimen surface.(4) When the oxygenconcentration was10-8wt%, both316L and T91steels exposed in LBE after600h weresubjected to dissolution of the alloying elements and LBE penetration corrosion, T91behaved a better dissolution corrosion resistance than316L steel.Tests results will be used for accumulating experience and data for engineeringverification for future reactor.