4.08.5.1 Application and Technical Issues

Generation IV advanced nuclear power systems are proposed; the temperature and dose regimes for their operation are shown in Figure 23.42 Among them, the supercritical water-cooled reactor (SCWR) and the lead fast reactor (LFR) require a higher neutron dose

at an operating temperature of 600 °C. It is known that 9Cr-ODS steels have superior compatibility with sodium, but their corrosion resistance is not adequate for SCPW and LBE at a temperature >600 °C. Thus, the most critical issue for the application of 9Cr-ODS steels to SCWR and LFR is to improve their resistance to corrosion.

It has been reported that the addition of chromium (>13 wt%) and aluminum (4 wt%) to ODS steels quite effectively suppresses corrosion in an SCPW and LBE environment. In general, however, an increase in the Cr content often results in increased susceptibility to ther­mal aging embrittlement. Furthermore, the addition of Al significantly reduces steel strength at high tempera­tures. Recent progress in R&D of high Cr-Al-added ODS ferritic steels is summarized in the proceedings of the International Conference of Advanced Power Plants (ICAPP) 2009. The oxidation and corrosion performance of Al-added 16Cr-ODS steels in SCPW and LBE environments is described in Section 4.08.7.