Preliminary result of validation study in SAS-SFR (SAS4A) code in simulated top and undercooled overpower conditions

Kawada, Kenichi   ; Takahashi, Katsuhiko*; Tobita, Yoshiharu

SAS-SFR (SAS4A) is the most advanced computer code for simulating the primary phase of the Core Disruptive Accident (CDA) of MOX-fueled Sodium-cooled Fast Reactors (SFR). A PIRT (Phenomena Identification and Ranking Table) for CDA of MOX-fueled SFR has been developed under an international collaboration framework between JAEA and European organizations (CEA and KIT). Based on this PIRT, the first systematic and comprehensive validation work for SAS-SFR(SAS4A) was conducted focusing on the fuel failure position under Transient Overpower (TOP) and transient undercooled overpower conditions. In the calculations of the selected CABRI experiments, the fuel failure positions under TOP and transient undercooled overpower were reproduced, using the failure prediction model of SAS-SFR(SAS4A). The mechanistic behavior of these results agrees with the experimental interpretation on the failure location in these experiments.