Preliminary estimation of activation product inventory for reactor pressure vessel of Kori

DORT and ORIGEN2 code were used for calculation of neutron flux and inventory in reactor pressure vessel(RPV) of Kori Unit-1. To calculate neutron flux using DORT code, the reactor was divided into 94 mesh from the center of core to RPV and from 0 to 45 degree along the azimuth. The cross-sections of main nuclides were recalculated using neutron flux in the RPV region. The results showed that 95 % of the total activity in RPV came from the nuclides of 55Fe, 60Co, 59Ni and 63Ni. And the total activity with cooling of more than 50 years after decommissioning was no more than 0.2 % of at the time of shutdown. Considering the weight of RPV is 210 tons, the initial total activity of RPV reached to 5.25 X106 GBq. To verify results of ORIGEN2 calculation, comparison between calculated and measured value at RPV of Kori-1 was performed. The comparison results showed a good agreement