High Cr ODS steels performance under supercritical water environment

tThis paper summarizes the results of supercritical water corrosion studies of two ferritic oxide disper-sion strengthen (ODS) steels MA956 and PM2000 at the temperature of the upper limit of potential peakcladding temperature under normal operation, according to the conceptual design being developed inthe EU. As the high temperature and pressure above the thermodynamic critical point of water resultin higher oxidation rate for conventional austenitic alloys than observed in sub-critical light water reac-tor (LWR) conditions, ensuring adequate corrosion resistance is critical for thin-wall components likefuel cladding. This study concentrated on the investigation of two effects, surface finish and orientationof the cuts. Two different surface treated coupons were prepared in order to study the effect of coldwork in sample surface on corrosion resistance. Samples were exposed in supercritical water at 650◦Cand 25 MPa, for up to 1800 h. The corrosion rate was evaluated by measuring the weight change of thesamples and by cross-section examinations. The microstructure of the oxide layers was analyzed using ascanning electron microscope (SEM) in conjunction with energy dispersive spectroscopy (EDS) and X-raydiffraction analysis (XRD). Weight gain results of both ODS steels proved a good resistance to general cor-rosion. Nevertheless the cross-sectional SEM study showed signs of nodular corrosion, observed mostlyon the ground specimens after long exposure times.

NOVOTNY Radek;  JANIK Premysl;  PENTTILÄ Sami;  HAEHNER Peter;  MACAK Jan;  SIEGL J;  HAUSILD P; 

2013-08-16

ELSEVIER SCIENCE BV

JRC77477

0896-8446,   

http://www.sciencedirect.com/science/article/pii/S0896844613001642,    https://publications.jrc.ec.europa.eu/repository/handle/JRC77477,   

10.1016/j.supflu.2013.04.014,