Abstract
This paper summarizes the results of supercritical water corrosion
studies of two ferritic oxide dispersion strengthen (ODS) steels MA956
and PM2000 at the temperature of the upper limit of potential peak
cladding temperature under normal operation, according to the conceptual
design being developed in the EU. As the high temperature and pressure
above the thermodynamic critical point of water result in higher
oxidation rate for conventional austenitic alloys than observed in
sub-critical light water reactor (LWR) conditions, ensuring adequate
corrosion resistance is critical for thin-wall components like fuel
cladding. This study concentrated on the investigation of two effects,
surface finish and orientation of the cuts. Two different surface
treated coupons were prepared in order to study the effect of cold work
in sample surface on corrosion resistance. Samples were exposed in
supercritical water at 650 °C and 25 MPa, for up to 1800 h. The
corrosion rate was evaluated by measuring the weight change of the
samples and by cross-section examinations. The microstructure of the
oxide layers was analyzed using a scanning electron microscope (SEM) in
conjunction with energy dispersive spectroscopy (EDS) and X-ray
diffraction analysis (XRD). Weight gain results of both ODS steels
proved a good resistance to general corrosion. Nevertheless the
cross-sectional SEM study showed signs of nodular corrosion, observed
mostly on the ground specimens after long exposure times.
Original language | English |
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Pages (from-to) | 147-156 |
Journal | Journal of Supercritical Fluids |
Volume | 81 |
DOIs | |
Publication status | Published - 2013 |
MoE publication type | A1 Journal article-refereed |
Keywords
- EDS
- general corrosion
- ODS steel
- SEM
- supercritical water
- surface finish