Kinetic study on eutectic reaction between boron carbide and stainless steel in sodium-cooled fast reactor

In a postulated severe accidental condition of sodium-cooled fast reactor (SFR), eutectic reaction between boron carbide (B₄C) and stainless steel (SS) may probably occur. Elucidation on the behavior of cited eutectic reaction is very important in terms of evaluation of core disruptive accidents in SFRs. For the first step to clarify the kinetic feature of B₄C-SS eutectic reaction, the preliminary thermogravimetry-differential thermal analysis (TG-DTA) measurements using individual reagent were performed to obtain the fundamental information and to confirm the applicability of sample crucibles. It was found that alumina crucible was applicable in terms of eutectic behavior. When accomplishing the TG-DTA measurement at a high temperature, a temperature correction using standard materials is indispensable to minimize the significant measurement uncertainty. Nickel (m.p.:1728 K) as a standard material was used for maximum temperature limit of the temperature correction. After its temperature correction, the TG-DTA measurement of B₄C-SS eutectic reaction were carried out. Based on the DTA curves at different heating rates, the kinetic parameters were roughly estimated by using Kissinger method. (author)