In order to investigate the neutron economy and safety of Accelerator Driven System, IAEA launched the Co-ordinated Researched Program (CRP), and issued an ADS benchmark. This ADS bench-mark was divided into several stages, and the 1
st stage devoted to analyzing the neutron performances of ADS and validating the nuclear databases and the codes. The burnup code system ANISN-DOT4.2-ORIGEN2 is developed. Initial enrichments of
233U which correspond to all given initial (BOL)
keff values are calculated. and then, the spatial distributions of power density (BOL), the void reactiv-ity effects, the spallation source effectiveness
φ*, and the evolution curves of
keff and source as function of time are also calculated for every given
keff (BOL). The numerical results are in a good agreement with those of various countries.