130 likes | 254 Views
Corrosion and Compatibility in Advanced Reactor Systems. Hugh Isaacs BNL isaacs@bnl.gov. ENVIRONMENT CANDIDATE MATERIALS liquid metals Na iron based alloys Pb-Bi iron based
E N D
Corrosion and Compatibility in Advanced Reactor Systems Hugh Isaacs BNL isaacs@bnl.gov ENVIRONMENT CANDIDATE MATERIALS liquid metals Na iron based alloys Pb-Bi iron based helium/graphite Ni based alloys supercritical water Fe,Ni,Ti,Zr, based alloys stress corrosion cracking molten salt
liquid metal compatibility • solubility in liquid metal • construction alloys • interstitials O, C, N, H • solid surfaces • extraction • insertion • products • mass transport gradients • in liquid • activity in solids reaction
Pb/PbO Na/Na2O Ellingham-Richardson-Diagram
Pb/Pb-Bi 600 C 6000 h CrMoV steel 300 h 2CrSiMoV steel 300–500 ppm Mg + 10-40 ppm Ti 300–500 ppm Mg corrosion inhibition of ferritic steels by 50-500 ppm Zr, Ti forms nitrides or nitrides+carbides on steel surfaces
oxygen concentration effects on steels flowing Pb 550C 3000 h
Pb/Pb-Bi Pb 15Cr–11Ni–3Si–MoNb low oxygen 550C 2000 h controlled oxygen Groynin (1998)
He 1000C 1000h reducing conditions oxidizing conditions Inconel 617 Hynes 230 Wright 2008
carburizing under oxide highly carburizing best region highly oxidizing strongly reducing He “thermodynamic” representation of alloy behavior Wright 2008 Quadakkers 1988
Supercritical water alloy systems under study Ferritic–martensitic Austenitic Ni-based weight gain largest weight gain < ferritic-m little weight gain than ferritic–martensitic complex parametrics except below the pseudo-critical Cr reduces rate good grain boundary eng. precipitate hardened pit lowest rates at 300 ppb O implant Y - major improvement Zirconium Titanium std alloys corrode optimized comps ~ austenitic optimized comp > austenitics Was et al. (2007)
Supercritical water Stress Corrosion Cracking austenitic IGSCC > ferritic-martensitic acidic additions increase cracking higher Cr increases susceptibility to HCl increased pressure increases SCC ferritic -m in pure systems resistant to 600 C
-2 -1 log pCO=0 +1 +2 Temperature 0-3000 K