Water corrosion resistance of ODS ferritic-martensitic steel tubes

A water corrosion test was conducted on oxide dispersion strengthened (ODS) steels in consideration of the spent fuel-pool cooling condition. The two types of ODS steel tubes tested were 9Cr-ODS and 12Cr-ODS. A test temperature of 333K was selected for the test by considering the environment of spent fuel-pool cooling system. The water corrosion test was performed for 1000h under a degassed and Cl-controlled water environment at pH values of 8.4, 10 and 12. The result demonstrated that at a pH value of 12, the weight losses of 9Cr- and 12Cr-ODS are larger than those of PNC-FMS and PNC316. The test specimens lose their metallic gloss and a slightly blackish surface is observed. It is considered that 9Cr-ODS and 12Cr-ODS claddings keep their strength and are comparable to that of conventional austenitic stainless steel and ferritic-martensitic stainless steel claddings in consideration of the spent-fuel-pool cooling condition.