The survey and evaluation of oxidation for core material of the austenitic stainless steels in carbon dioxide gas-cooled reactor

Mizuta, Shunji ; not registered; not registered  

lt is necessary for feasibility study of fast reactor to evaluate the oxidation of the austenitic stainless steels in the case of using for core material in carbon dioxide gas-cooled reactor. The properties for oxidation of austenitic stainless steels in carbon dioxide were surveyed in literatures and the data were selected after evaluation of factors for oxidation in carbon dioxide. The equation of oxidation in carbon dioxide for PE16, 20Cr/25Ni/Nb, 18Cr-8Ni and JNC Cladding materials were proposed. The equation for oxidation of austenitic stainless steels were expressed as upper limit for the equation according to parabolic law. The equation for JNC cladding materials (PNC316, PNC1520, 14Cr-25Ni) was proposed based the oxidation behavior of 18Cr-8Ni which is same oxidation region for weight gain in three-component system of Fe-Cr-Ni, in addition to evaluate of effect for silicon content. The oxidation equation of 20Cr/25Ni/Nb was applied to the high Ni alloy of JNC cladding material. The obtained equation is as follows, X = 4.4W1000, W = , kp = exp(-Q/(RT)), X: oxide thickness[m], W : weight gain[gcm], kp : parabolic rate constant[gcm s], t :time[sec] : constant[gcmS], Q : activation energy[J・mol], R : gas constant[8.314J K mol], T : temperature[K] (1) PE16 : kp = 1.09010 exp(-192,500/(RD)), (2) 20Cr/25Ni/Nb : kp = 1.65110 exp(-201,300/(RT)) High Ni alloy (JNC), (3)18Cr-8Ni : kp = 1.50310 exp(-60,000/(RT)), (4) PNC316, PNC1520 : kp = 1.50310 exp(-60,000/(RT))0.62 14Cr-25Ni(JNC) The weight gain is (3)(4)(2)(1) in order.