Validation of sarax code system using joyo MK-I experiments

A new code SARAX for the fast reactor design and neutronics analysis has been developed and validated on a series of critical experimental facilities. In this paper, the works on the JOYO MK-I experiments are presented. JOYO reactor was a sodium cooled experimental fast reactor constructed at the Oarai Engineering Center (OEC), which loaded the MOX fuel. To validate the SARAX code, chosen experiments consisting of criticality experiments, control rod worth experiments, sodium void reactivity experiments and fuel replacement reactivity experiments are modeled and calculated. The processing methods for few-group cross section generation and core calculation are introduced. Numerical results agree well with reference results. The differences of keff between SARAX and experimental data are less than 300pcm. In addition, the results of reactivity effects also have acceptable accuracy. Most reactivity errors are smaller than 7%.